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Sample records for high strength portland

  1. Rheological Properties of Very High-Strength Portland Cement Pastes: Influence of Very Effective Superplasticizers

    Directory of Open Access Journals (Sweden)

    Adriano Papo

    2010-01-01

    Full Text Available The influence of the addition of very effective superplasticizers, that are commercially available, employed for maximising the solid loading of very high-strength Portland cement pastes, has been investigated. Cement pastes were prepared from deionized water and a commercially manufactured Portland cement (Ultracem 52.5 R. Cement and water were mixed with a vane stirrer according to ASTM Standard C305. The 0.38 to 0.44 water/cement ratio range was investigated. Three commercial superplasticizing agents produced by Ruredil S.p.a. were used. They are based on a melamine resin (Fluiment 33 M, on a modified lignosulphonate (Concretan 200 L, and on a modified polyacrylate (Ergomix 1000. Rheological tests were performed at 25°C by using the rate controlled coaxial cylinder viscometer Rotovisko-Haake 20, system M5-osc., measuring device MV2P with serrated surfaces. The tests were carried out under continuous flow conditions. The results of this study were compared with those obtained in a previous article for an ordinary Portland cement paste.

  2. The maximum percentage of fly ash to replace part of original Portland cement (OPC) in producing high strength concrete

    Science.gov (United States)

    Mallisa, Harun; Turuallo, Gidion

    2017-11-01

    This research investigates the maximum percent of fly ash to replace part of Orginal Portland Cement (OPC) in producing high strength concrete. Many researchers have found that the incorporation of industrial by-products such as fly ash as in producing concrete can improve properties in both fresh and hardened state of concrete. The water-binder ratio was used 0.30. The used sand was medium sand with the maximum size of coarse aggregate was 20 mm. The cement was Type I, which was Bosowa Cement produced by PT Bosowa. The percentages of fly ash to the total of a binder, which were used in this research, were 0, 10, 15, 20, 25 and 30%; while the super platicizer used was typed Naptha 511P. The results showed that the replacement cement up to 25 % of the total weight of binder resulted compressive strength higher than the minimum strength at one day of high-strength concrete.

  3. Quantitative study on the effect of high-temperature curing at an early age on strength development of concrete. Experiment with mortar using moderate-heat portland cement

    International Nuclear Information System (INIS)

    Sugiyama, Hisashi; Chino, Shigeo

    1999-01-01

    The effect of high-temperature curing at an early age on the strength development of concrete using moderate-heat portland cement was quantitatively studied. High-temperature curing conditions were set so as to give systematic variations in the temperature-time factors. As a result, the integrated value of curing temperature during the period having a significant effect on the strength development was proposed as a parameter that expressed the degree of high-temperature curing. The effect of high-temperature curing on the strength development of concrete using moderate-heat portland cement could be exactly predicted with the integrated value of curing temperature during the period from 0 to 3 days. (author)

  4. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    International Nuclear Information System (INIS)

    Li, Zhengqi

    2017-01-01

    The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [es

  5. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

    Directory of Open Access Journals (Sweden)

    Zhengqi Li

    2017-03-01

    Full Text Available The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete.

  6. Evaluation of the strength and radiopacity of Portland cement with varying additions of bismuth oxide.

    Science.gov (United States)

    Saliba, E; Abbassi-Ghadi, S; Vowles, R; Camilleri, J; Hooper, S; Camilleri, J

    2009-04-01

    To study the effect of addition of various proportions of bismuth oxide on compressive strength and radiopacity of Portland cement. The compressive strength of white Portland cement and cement replaced with 10, 15, 20, 25 and 30% bismuth oxide was evaluated by testing cylinders 6 mm in diameter and 12 mm high. Twelve cylinders were tested for each material under study. The radiopacity of the cements tested was evaluated using an aluminium step-wedge and densitometer. The optical density was compared with the relevant thickness of aluminium (Al). Statistical analysis was performed using Analysis of Variance (ANOVA) with P = 0.05 and Tukey test to perform multiple comparison tests. Various additions of bismuth oxide had no significant effect on the strength of the material when compared with the unmodified Portland cement (P > 0.05). The radiopacity of the cements tested ranged from 2.02 mm Al for Portland cement to 9.79 mm Al for the highest bismuth replacement. Addition of bismuth oxide did not affect the compressive strength of Portland cement. All the bismuth oxide cement mixtures had radio-opacities higher than 3 mm thickness of aluminium.

  7. Push-out strength of modified Portland cements and resins.

    Science.gov (United States)

    Iacono, Francesco; Gandolfi, Maria Giovanna; Huffman, Bradford; Sword, Jeremy; Agee, Kelli; Siboni, Francesco; Tay, Franklin; Prati, Carlo; Pashley, David

    2010-02-01

    Modified calcium-silicate cements derived from white Portland cement (PC) were formulated to test their push-out strength from radicular dentin after immersion for 1 month. Slabs obtained from 42 single-rooted extracted teeth were prepared with 0.6 mm diameter holes, then enlarged with rotary instruments. After immersion in EDTA and NaOC1, the holes were filled with modified PCs or ProRoot MTA, Vitrebond and Clearfil SE. Different concentrations of phyllosilicate (montmorillonite-MMT) were added to experimental cements. ProRoot MTA was also included as reference material. Vitrebond and Clearfil SE were included as controls. Each group was tested after 1 month of immersion in water or PBS. A thin-slice push-out test on a universal testing machine served to test the push-out strength of materials. Results were statistically analyzed using the least squares means (LSM) method. The modified PCs had push-out strengths of 3-9.5 MPa after 1 month of immersion in water, while ProRoot MTA had 4.8 MPa. The push-out strength of PC fell after incubation in PBS for 1 month, while the push-out strength of ProRoot MTA increased. There were no significant changes in Clearfil SE Bond or Vitrebond after water or PBS storage.

  8. Prediction of potential compressive strength of Portland clinker from its mineralogy

    DEFF Research Database (Denmark)

    Svinning, K.; Høskuldsson, Agnar; Justnes, H.

    2010-01-01

    Based on a statistical model first applied for prediction of compressive strength up to 28 d from the microstructure of Portland cement, potential compressive strength of clinker has been predicted from its mineralogy. The prediction model was evaluated by partial least squares regression...

  9. Achievement of 900kgf/cm[sup 2] super workable high strength concrete with belite portland cement. (elevator building of cement silo in Chichibu cement). Part 1. ; Development of cement for super workable high strength concrete. Ko belite kei cement de 900kgf/cm[sup 2] wo tassei (Chichibu cement cement sairo no elevaor to). 1. ; Koryudo kokyodo concrete yo no cement no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, M.; Fukaya, Y.; Nawa, T. (Chichibu Cement Co. Ltd., Tokyo (Japan))

    1993-08-01

    This paper describes the features of high belite Portland cement which can make the super workable high strength concrete, and the properties of concrete using this. The super workable concrete is required an excellent segregation resistance property as well as high flow property. Since the high belite Portland cement contains a small amount of C[sub 3]S in the clinker, the amounts of C[sub 3]A and C[sub 4]AF can be reduced without hindering the calcination of clinker. Additionally, since it contains a large amount of C[sub 2]S with low heat of hydration, an increase in the temperature of members can be suppressed. 'Chichibu High Flow Cement' having characteristics of this high belite Portland cement was developed for the super workable high strength concrete. The concrete using the High Flow Cement exhibited the maximum flow value of 70cm. It also exhibited the strength of 1,075 kgf/cm[sup 2] at the age of 91 days, and 1,100 kgf/cm[sup 2] at the age of 14 days under insulating. 4 refs., 8 figs., 2 tabs.

  10. The Influence of Diatomite on the Strength and Microstructure of Portland Cement

    OpenAIRE

    Liu Jun; Shao Peng; Wang Shihao

    2016-01-01

    To study the influence of the types and mixing amount of diatomite on the Portland cement, we prepared the cement specimen doped with the calcined first-grade, first-grade and second-grade diatomite ,tested the 3d, 7d, 14d compressive strength, and studied and discussed phase, structure and morphology of diatomite in the binary system by the method of XRD, SEM . Experimental results show that with the addition of diatomite, the strength of cement paste increase; the optimal contents of calcin...

  11. The Influence of Diatomite on the Strength and Microstructure of Portland Cement

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2016-01-01

    Full Text Available To study the influence of the types and mixing amount of diatomite on the Portland cement, we prepared the cement specimen doped with the calcined first-grade, first-grade and second-grade diatomite ,tested the 3d, 7d, 14d compressive strength, and studied and discussed phase, structure and morphology of diatomite in the binary system by the method of XRD, SEM . Experimental results show that with the addition of diatomite, the strength of cement paste increase; the optimal contents of calcined first-grade ,first-grade and second-grade diatomite in Portland cement are 5%,Compared to the blank group, the strength of specimen can be increased by 54.6%, 15.4% and 10.2%, respectively; At the same time ,the 7d microscopic hydration of different diatomite particles were analyzed through the experiment , and the shell of calcined diatomite particles were better hydrated than that of first-grade and second-grade diatomite particles. The results indicate that the diatomite can improve the strength of cement paste, the hydration of different diatomite particles can influence the growth of cement paste strength.

  12. Increase in the strength characteristics of Portland cement due to introduction of the compound mineral supplements

    Science.gov (United States)

    Il'ina, Liliia; Gichko, Nikolai; Mukhina, Irina

    2016-01-01

    At the initial phase of hardening it is the limestone component that plays a major role in the hardening process, which acts as the substrate for the crystallization of hydrate tumors due to its chemical affinity with the products of Portland cement hydration. After 7 days, the diopside supplement influences the processes more significantly. Diopside has a high modulus of elasticity compared to the cement paste. As a result, stresses are redistributed within the cement paste and the whole composition is hardened. An increase in the quantity of diopside in the compound supplement to more than 66.7% does not provide a substantial increase in the strength of the cement paste. As the hardness of diopside is higher than the hardness of limestone, much more energy is required to grind it down to a usable component. Therefore, a further increase in the quantity of diopside in the compound supplement is not economically feasible. An evaluation of the optimum quantity of input compound mineral supplements can be made based on the ideas of close packing of spherical particles and the Pauling rules. The optimum content of the supplement is 8-8.5% provided that its dispersion and density are close to the dispersion and density of the binder. An increase in the dispersion of the supplement reduces its optimal quantity.

  13. Effect of water curing duration on strength behaviour of portland composite cement (PCC) mortar

    Science.gov (United States)

    Caronge, M. A.; Tjaronge, M. W.; Hamada, H.; Irmawaty, R.

    2017-11-01

    Cement manufacturing of Indonesia has been introduced Portland Composite Cement (PCC) to minimize the rising production cost of cement which contains 80% clinker and 20% mineral admixture. A proper curing is very important when the cement contains mineral admixture materials. This paper reports the results of an experimental study conducted to evaluate the effect of water curing duration on strength behaviour of PCC mortar. Mortar specimens with water to cement ratio of (W/C) 0.5 were casted. Compressive strength, flexural strength and concrete resistance were tested at 7, 28 and 91 days cured water. The results indicated that water curing duration is essential to continue the pozzolanic reaction in mortar which contributes to the development of strength of mortar made with PCC.

  14. EFFECT OF SEA WATER ON THE STRENGTH OF POROUS CONCRETE CONTAINING PORTLAND COMPOSITE CEMENT AND MICROFILAMENT POLYPROPYLENE FIBER

    OpenAIRE

    TJARONGE, M.W

    2011-01-01

    The aim of this research is to study the influence of sea water on the strength of porous concrete containing Portland Composite cement and micro monofilament polypropylene fibre. The specimens of porous concrete were immersed in the sea water up to 28 days. The compressive strength test and flexural strength test were carried out at 3, 7 and 28 days in order to investigate the strength development. The test result indicated that the strength of porous concrete can develop in t...

  15. Increasing the compressive strength of portland cement concrete using flat glass powder

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Junior, Edson Jansen Pedrosa de; Bezerra, Helton de Jesus Costa Leite; Politi, Flavio Salgado; Paiva, Antonio Ernandes Macedo, E-mail: edson.jansen@ifma.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia do Maranha (IFMA), Sao Luis, MA (Brazil). Dept. de Mecanica e Materiais

    2014-08-15

    This paper analyzes the compressive strength of Portland cement concrete in response to the incorporation of 5%, 10% and 20% of flat glass powder in place of sand, at w/c (water/cement) ratios of 0.50, 0.55 and 0.58. A statistical analysis of variance (ANOVA) was performed after 7, 14 and 28 days of curing. The compressive strength test results indicate that the concrete containing a w/c ratio of 0.50 can be used for structural applications, regardless of the waste glass content, as can that with a w/c ratio of 0.55 containing 20% of waste glass. We suggest that the use of flat glass powder in place of sand in the above mentioned percentages is feasible for the production of an environmentally appropriate and structurally applicable concrete. However, the concrete's fluidity and void content must be taken into account. (author)

  16. Pore size distribution, strength, and microstructure of portland cement paste containing metal hydroxide waste

    Energy Technology Data Exchange (ETDEWEB)

    Majid, Z.A.; Mahmud, H.; Shaaban, M.G.

    1996-12-31

    Stabilization/solidification of hazardous wastes is used to convert hazardous metal hydroxide waste sludge into a solid mass with better handling properties. This study investigated the pore size development of ordinary portland cement pastes containing metal hydroxide waste sludge and rice husk ash using mercury intrusion porosimetry. The effects of acre and the addition of rice husk ash on pore size development and strength were studied. It was found that the pore structures of mixes changed significantly with curing acre. The pore size shifted from 1,204 to 324 {angstrom} for 3-day old cement paste, and from 956 to 263 {angstrom} for a 7-day old sample. A reduction in pore size distribution for different curing ages was also observed in the other mixtures. From this limited study, no conclusion could be made as to any correlation between strength development and porosity. 10 refs., 6 figs., 3 tabs.

  17. Modeling of Hydration, Compressive Strength, and Carbonation of Portland-Limestone Cement (PLC Concrete

    Directory of Open Access Journals (Sweden)

    Xiao-Yong Wang

    2017-01-01

    Full Text Available Limestone is widely used in the construction industry to produce Portland limestone cement (PLC concrete. Systematic evaluations of hydration kinetics, compressive strength development, and carbonation resistance are crucial for the rational use of limestone. This study presents a hydration-based model for evaluating the influences of limestone on the strength and carbonation of concrete. First, the hydration model analyzes the dilution effect and the nucleation effect of limestone during the hydration of cement. The degree of cement hydration is calculated by considering concrete mixing proportions, binder properties, and curing conditions. Second, by using the gel–space ratio, the compressive strength of PLC concrete is evaluated. The interactions among water-to-binder ratio, limestone replacement ratio, and strength development are highlighted. Third, the carbonate material contents and porosity are calculated from the hydration model and are used as input parameters for the carbonation model. By considering concrete microstructures and environmental conditions, the carbon dioxide diffusivity and carbonation depth of PLC concrete are evaluated. The proposed model has been determined to be valid for concrete with various water-to-binder ratios, limestone contents, and curing periods.

  18. Influence of the waste glass in the axial compressive strength of Portland cement concrete

    International Nuclear Information System (INIS)

    Miranda Junior, E.J.P.; Paiva, A.E.M.

    2012-01-01

    In this work, was studied the influence of the incorporation of waste glass, coming from the stage of thinning and polishing of a company of thermal glass treatments, in the axial compressive strength of Portland cement concrete. The coarse and ground aggregates used was crushed stone and sand, respectively. For production of the concrete, percentages of glass residues of 5%, 10% and 20% had been used in substitution to the sand, and relations water/cement (a/c) 0,50, 0,55 and 0,58. The cure of the test bodies was carried through in 7, 14 and 28 days. The statistics analysis of the results was carried out through of the analysis of variance for each one of the cure times. From the results of the compressive strength of the concrete, it could be observed that the concrete has structural application for the relation a/c 0,5, independently of waste glass percentage used, and for the relation a/c 0,55 with 20% of waste glass. (author)

  19. Hydration rate and strength development of low-heat type portland cement mortar mixed with pozzolanic materials

    International Nuclear Information System (INIS)

    Matsui, Jun

    1998-01-01

    Recently, low-heat type Portland cement was specified in Japan Industrial Standards (JIS). Its hydration proceeds slowly. The results of the research so far obtained indicate that slow hydration of cement and mixing of pozzolanic materials with cement make micro-structure of harded cement paste dense and durable. In this study, a blended cement using low-heat type Portland cement and some of pozzolanic materials has been newly developed and its strength property and hydration ratio were checked. The followings are conclusion. (1) Hydration rate of cement paste varies with the replacement ratio of pozzolanic materials. (2) A good liner relationship between strength and total hydration rate of cement paste was observed. (3) A proper replacement ratio of both base-cement and pozzolanic material for manufacturing a blended cement is 50%. (author)

  20. The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

    OpenAIRE

    Solikin Mochamad; Setiawan Budi

    2017-01-01

    High volume fly ash concrete becomes one of alternatives to produce green concrete as it uses waste material and significantly reduces the utilization of Portland cement in concrete production. Although using less cement, its compressive strength is comparable to ordinary Portland cement (hereafter OPC) and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly ...

  1. A comparative evaluation of compressive strength of Portland cement with zinc oxide eugenol and Polymer-reinforced cement: an in vitro analysis.

    Science.gov (United States)

    Prakasam, S; Bharadwaj, Prakasam; Loganathan, S C; Prasanth, B Krishna

    2014-01-01

    The purpose of this study is to evaluate the ultimate compressive strength of 50% and 25% Portland cement mixed with Polymer-reinforced zinc oxide eugenol and zinc oxide eugenol cement after 1 hour, 24 hours, and 7 days. One hundred and eighty samples were selected. The samples were made cylindrical of size 6 × 8 mm and were divided into six groups as follows with each group consisting of 10 samples. Group 1: Polymer-reinforced zinc oxide eugenol with 50% Portland cement (PMZNPC 50%) Group 2: Polymer-reinforced zinc oxide eugenol with 25% Portland cement (PMZNPC 25%) Group 3: Polymer-reinforced zinc oxide eugenol with 0% Portland cement (PMZNPC 0%) Group 4: Zinc oxide eugenol with 50% Portland cement (ZNPC 50%) Group 5: Zinc oxide eugenol with 25% Portland cement (ZNPC 25%) Group 6: Zinc oxide eugenol with 0% Portland cement (ZNPC 0%) These samples were further subdivided based on time interval and were tested at 1 hour, 24 hours and at 7 th day. After each period of time all the specimens were tested by vertical CVR loaded frame with capacity of 5 tones/0473-10kan National Physical laboratory, New Delhi and the results were statistically analyzed using ANOVA and Scheffe test. Polymer-reinforced cement with 50% Portland cement, Zinc oxide with 50% Portland cement, Polymer-reinforced cement with 25% Portland cement and Zinc oxide with 25% Portland cement exhibited higher compressive strength when compared to Zinc oxide with 0% Portland cement and Polymer-reinforced cement with 0% Portland cement, at different periods of time. The difference between these two groups were statistically significant (P Portland cement in Zinc oxide eugenol and Polymer-modified zinc oxide cement can be used as core build up material and permanent filling material. It is concluded that 50% and 25% Portland cement in zinc oxide eugenol and polymer-modified zinc oxide eugenol results in higher compressive strength and hence can be used as permanent filling material and core built

  2. The biomineralization ability of mineral trioxide aggregate and Portland cement on dentin enhances the push-out strength.

    Science.gov (United States)

    Reyes-Carmona, Jessie F; Felippe, Mara S; Felippe, Wilson T

    2010-02-01

    Recently, it was shown that the interaction of each of mineral trioxide aggregate (MTA) and Portland cement with dentin in phosphate-buffered saline (PBS) promotes a biomineralization process that leads to the formation of an interfacial layer with tag-like structures at the cement-dentin interface. This study analyzes the influence of the biomineralization process on the push-out strength of ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), MTA Branco (Angelus Soluções Odontológicas, Londrina, PR, Brazil), MTA BIO (Angelus Soluções Odontológicas), or Portland cement with and without calcium chloride. Dentin discs with standardized cavities were filled with ProRoot MTA, MTA Branco, MTA BIO, white Portland cement + 20% bismuth oxide (PC1), or PC1 + 10% of calcium chloride (PC2). The specimens were randomly divided into two groups: cement in contact with a wet cotton pellet for 72 hours or immersed in PBS for 2 months. The bond strengths were measured with the Instron Testing machine (Model 4444; Instron Corp, Canton, MA), and the fractured surfaces on the root walls were observed by scanning electron microscopy. All samples immersed in PBS displayed a significantly greater resistance to displacement than that observed for the samples in contact with a wet cotton pellet for 72 hours (p Portland cements. It was concluded that the biomineralization process positively influenced the push-out bond strength of the cements, particularly the MTA groups. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Bracket bond strength and cariostatic potential of an experimental resin adhesive system containing Portland cement.

    Science.gov (United States)

    Iijima, Masahiro; Hashimoto, Masanori; Nakagaki, Susumu; Muguruma, Takeshi; Kohda, Naohisa; Endo, Kazuhiko; Mizoguchi, Itaru

    2012-09-01

    To determine if a new experimental resin-based material containing Portland cement (PC) can help prevent enamel caries while providing adequate shear bond strength (SBS). Brackets were bonded to human premolars with experimental resin-based adhesive pastes composed of three weight rations of resin and PC powder (PC 30, 7:3; PC 50, 5:5; PC 70, 3:7; n  =  7). Self-etching primer (SEP) adhesive (Transbond Plus) and resin-modified glass ionomer cement (RMGIC) adhesive (Fuji Ortho FC Automix) were used for comparison. All of the bonded teeth were subjected to alternating immersion in demineralizing (pH 4.55) and remineralizing (pH 6.8) solutions for 14 days. The SBS for each sample was examined, and the Adhesive Remnant Index (ARI) score was calculated. The hardness and elastic modulus of the enamel were determined by a nanoindenter at 20 equidistant depths from the external surface at 100 µm from the bracket edge. Data were compared by one-way analysis of variance and a chi-square test. PC 50 and PC 70 showed significantly greater SBS than Fuji Ortho FC Automix, although Transbond Plus showed significantly greater SBS than other bonding systems. No significant difference in the ARI category was observed among the five groups. For specimens bonded with PC 50 and PC 70, the hardness and elastic modulus values in most locations were equivalent to those of Fuji Ortho FC Automix. Experimental resin-based bonding material containing PC provides adequate SBS and a caries-preventive effect equivalent to that of the RMGIC adhesive system.

  4. Influence of the waste glass in the axial compressive strength of Portland cement concrete; Influencia dos residuos vitreos na resistencia a compressao axial do concreto de cimento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Junior, E.J.P.; Paiva, A.E.M., E-mail: edson.jansen@hotmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao (PPGEM/IFMA), Sao Luis, MA (Brazil). Programa de Pos-Graduacao em Engenharia de Materiais

    2012-07-01

    In this work, was studied the influence of the incorporation of waste glass, coming from the stage of thinning and polishing of a company of thermal glass treatments, in the axial compressive strength of Portland cement concrete. The coarse and ground aggregates used was crushed stone and sand, respectively. For production of the concrete, percentages of glass residues of 5%, 10% and 20% had been used in substitution to the sand, and relations water/cement (a/c) 0,50, 0,55 and 0,58. The cure of the test bodies was carried through in 7, 14 and 28 days. The statistics analysis of the results was carried out through of the analysis of variance for each one of the cure times. From the results of the compressive strength of the concrete, it could be observed that the concrete has structural application for the relation a/c 0,5, independently of waste glass percentage used, and for the relation a/c 0,55 with 20% of waste glass. (author)

  5. Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber; Predicción del comportamiento de retracción por secado de morteros de cemento Pórtland de alta resistencia bajo la influencia combinada de árido fino y micro fibra de acero.

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhengqi

    2017-07-01

    The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [Spanish] Se ha estudiado la trabajabilidad, resistencia a la compresión (28 días) y la retracción al secado de morteros de cemento Pórtland de muy alta resistencia (121-142 MPa) reforzados con micro fibra de acero, con la influencia combinada de contenido de árido fino y de micro fibra de acero. El aumento en el contenido de árido fino resultó en la disminución de la trabajabilidad, resistencia a la compresión y la retracción por secado de los morteros con un contenido de fibra específico. El aumento en el contenido de fibra dio lugar a la disminución de la trabajabilidad y la retracción por secado, y a un aumento en la resistencia a la compresión a 28 días en morteros con un contenido específico de á rido fino. El modelo modificado de Gardner predijo con más precisión la retracción por secado de mortero de alta resistencia, seguido por el modelo de Ross y el modelo ACI 209R-92. El modelo de Gardner dio la predicción menos exacta debido al hecho de que se desarrolló sobre bases de datos de hormigones de resistencia normal.

  6. Mechanical properties of high-strength concrete

    Science.gov (United States)

    Mokhtarzadeh, Alireza

    This report summarizes an experimental program conducted to investigate production techniques and mechanical properties of high strength concrete in general and to provide recommendations for using these concretes in manufacturing precast/prestressed bridge girders. Test variables included total amount and composition of cementitious material (portland cement, fly ash, and silica fume), type and brand of cement, type of silica fume (dry densified and slurry), type and brand of high-range water-reducing admixture, type of aggregate, aggregate gradation, maximum aggregate size, and curing. Tests were conducted to determine the effects of these variables on changes in compressive strength and modulus of elasticity over time, splitting tensile strength, modulus of rupture, creep, shrinkage, and absorption potential (as an indirect indicator of permeability). Also investigated were the effects of test parameters such as mold size, mold material, and end condition. Over 6,300 specimens were cast from approximately 140 mixes over a period of 3 years.

  7. High strength ferritic alloy

    International Nuclear Information System (INIS)

    1977-01-01

    A high strength ferritic steel is specified in which the major alloying elements are chromium and molybdenum, with smaller quantities of niobium, vanadium, silicon, manganese and carbon. The maximum swelling is specified for various irradiation conditions. Rupture strength is also specified. (U.K.)

  8. Effect of saliva and blood contamination on the bi-axial flexural strength and setting time of two calcium-silicate based cements: Portland cement and biodentine.

    Science.gov (United States)

    Alhodiry, W; Lyons, M F; Chadwick, R G

    2014-03-01

    This study evaluated the effect of contamination with saliva and blood on the bi-axial flexural strength and setting time of pure gray Portland cement and Biodentine (Septodont, Allington, UK). A one-way ANOVA showed that contamination caused no significant difference between the cements in bi-axial flexural strength (P> 0.05). However there was a significant difference in setting time (PPortland cement taking longer than Biodentine, regardless of the contaminant, and contamination with blood increased the setting time of both materials. Biodentine was similar in strength to Portland cement, but had a shorter setting time for both contaminated and non-contaminated samples.

  9. Prediction of compressive strength up to 28 days from microstructure of Portland cement

    DEFF Research Database (Denmark)

    Svinning, K.; Høskuldsson, Agnar; Justnes, H.

    2008-01-01

    represented by curves from X-ray diffraction analysis and differential thermogravimetric analysis, as well as particle size distributions. PLS gave maximum explained variance in compressive strength at 1, 2, 7 and 28 days of 93%, 90%, 79% and 67%, respectively. The high explained variance makes the prediction...

  10. High-volume natural volcanic pozzolan and limestone powder as partial replacements for portland cement in self-compacting and sustainable concrete

    KAUST Repository

    Celik, Kemal; Jackson, Marie D.; Mancio, Mauricio; Meral, Cagla; Emwas, Abdul-Hamid M.; Mehta, P. Kumar; Monteiro, Paulo José Meleragno

    2014-01-01

    A laboratory study demonstrates that high volume, 45% by mass replacement of portland cement (OPC) with 30% finely-ground basaltic ash from Saudi Arabia (NP) and 15% limestone powder (LS) produces concrete with good workability, high 28-day compressive strength (39 MPa), excellent one year strength (57 MPa), and very high resistance to chloride penetration. Conventional OPC is produced by intergrinding 95% portland clinker and 5% gypsum, and its clinker factor (CF) thus equals 0.95. With 30% NP and 15% LS portland clinker replacement, the CF of the blended ternary PC equals 0.52 so that 48% CO2 emissions could be avoided, while enhancing strength development and durability in the resulting self-compacting concrete (SCC). Petrographic and scanning electron microscopy (SEM) investigations of the crushed NP and finely-ground NP in the concretes provide new insights into the heterogeneous fine-scale cementitious hydration products associated with basaltic ash-portland cement reactions. © 2013 Published by Elsevier Ltd.

  11. Formula of Moulding Sand, Bentonite and Portland Cement toImprove The Quality of Al-Si Cast Alloy

    OpenAIRE

    Andoko Andoko; Poppy Puspitasari; Avita Ayu Permanasari; Didin Zakaria Lubis

    2017-01-01

    A binder is any material used to strengthen the bonding of moulding sand grains. The primary function of the binder is to hold the moulding sand and other materialstogether to produce high-quality casts. In this study, there were four binder compositions being tested, i.e. 5% bentonite + 5% Portland cement, 4% bentonite + 6% Portland cement, 6% bentonite + 4% Portland cement, and 7% bentonite + 3% Portland cement. Each specimen was measured for its compressive strength, shear strength, tensil...

  12. High strength alloys

    Science.gov (United States)

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  13. Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers the determination of the ability of glazed ceramic wall tile, ceramic mosaic tile, quarry tile, and pavers to be bonded to portland cement paste. This test method includes both face-mounted and back-mounted tile. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  14. Microstructural characterization of phases and interfaces of Portland cement mortar using high resolution microscopy

    International Nuclear Information System (INIS)

    Barreto, M.F.O.; Brandao, P.R.G.

    2014-01-01

    In Portland cement mortars it is of paramount importance to investigate the bond strength between mortar and masonry by means of the study of interfaces and surfaces that make up the system mortar/ceramic block. In this work the aim was to characterize the chemical compositions, microstructures, surfaces and interfaces of mortars applied on ceramic blocks. Therefore, two important characterization tools were used: field-effect gun (FEG) scanning electron microscope (SEM) - FEI Quanta 200 with energy-dispersive (X-ray) spectrometer (EDS) and SEM system with EGF Nanofabrication FIB - FEI Quanta 3D FEG also with an EDS coupled. To date the results obtained from the research show that the characterization of cementitious materials with high resolution SEM is an important tool in the detection and differentiation of hydrated calcium silicates (CSH), calcium hydroxide (Ca(OH)2), ettringite and calcium carbonate by means of morphological, topographical and chemical data, thus providing extremely reliable as well as qualitative data from the structure of cementitious materials. (author)

  15. Microstructural characterization of phases and interfaces of Portland cement mortar using high resolution microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, M.F.O.; Brandao, P.R.G., E-mail: matheusfob@yahoo.com.br, E-mail: pbrandao@demin.ufmg.br [Universidade Federal de Minas Gerais (UFMG), MG (Brazil)

    2014-07-01

    In Portland cement mortars it is of paramount importance to investigate the bond strength between mortar and masonry by means of the study of interfaces and surfaces that make up the system mortar/ceramic block. In this work the aim was to characterize the chemical compositions, microstructures, surfaces and interfaces of mortars applied on ceramic blocks. Therefore, two important characterization tools were used: field-effect gun (FEG) scanning electron microscope (SEM) - FEI Quanta 200 with energy-dispersive (X-ray) spectrometer (EDS) and SEM system with EGF Nanofabrication FIB - FEI Quanta 3D FEG also with an EDS coupled. To date the results obtained from the research show that the characterization of cementitious materials with high resolution SEM is an important tool in the detection and differentiation of hydrated calcium silicates (CSH), calcium hydroxide (Ca(OH)2), ettringite and calcium carbonate by means of morphological, topographical and chemical data, thus providing extremely reliable as well as qualitative data from the structure of cementitious materials. (author)

  16. Compressive Strength of Volcanic Ash/Ordinary Portland Cement Laterized Concrete

    Directory of Open Access Journals (Sweden)

    Olusola K. O.

    2010-01-01

    Full Text Available This study investigates the effect of partial replacement of cement with volcanic ash (VA on the compressive strength of laterized concrete. A total of 192 cubes of 150mm dimensions were cast and cured in water for 7, 14, 21, and 28 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively, while a control mix of 28-day target strength of 25 N/mm2 was adopted. The results show that the density and compressive strength of concrete decreased with increase in volcanic ash content. The 28-day, density dropped from 2390 kg/m3 to 2285 kg/m3 (i.e. 4.4% loss and the compressive strength from 25.08 N/mm2 to 17.98 N/mm2 (i.e. 28% loss for 0-30% variation of VA content with no laterite introduced. The compressive strength also decreased with increase in laterite content; the strength of the laterized concrete however increases as the curing age progresses.

  17. PHYSICAL AND STRENGTH PROPERTIES OF BRICKS PRODUCED FROM PORTLAND CEMENT AND SAW DUST OF DANIELIA OLIVERII WOOD

    Directory of Open Access Journals (Sweden)

    David Oriabure EKHUEMELO

    2016-12-01

    Full Text Available This study investigated the use of sawdust as partial replacement for sand in wood-concrete hollow blocks. Sharp sand, ordinary Portland cement (binder and sawdust were used as raw materials. Sawdust was treated by boiling then sieved after drying using British Standard sieve of 3.35mm to remove sticky wood capable of causing pores. The quantities of sawdust used were 0%, 5%, 10%, 15% and 20%. A mixing proportion of 1:8 cement sand ratio, moulding machine with single 6” (450mm x 225mm x 150mm mould and vibrated with 5.0KW power machine for adequate compaction were used. Wood-concrete block was cured for 28 days. The blocks produced were tested for compressive strength and water absorption. The results showed that mean compressive strength of 100% sand was 2.81N/mm2 followed by 95% sand and 5% sawdust replacement with 1.58N/mm2 ; 90% Sand and 10% sawdust replacement with 0.55N/mm2 ; 85% sand and 15% sawdust replacement with 0.43 N/mm2 and 80% sand 20% sawdust replacement with 0.24N/mm2 . The result further showed that as the percentage of sawdust increased, the compressive strength decreased. At 28 days, the compressive strength of blocks with 5% SD replacement satisfied meets Ghana Building Code for non- load bearing walls. The results also reveals that blocks with 80% sand 20% sawdust replacement level has the highest water absorption (23.72% followed by 85% Sand and 15% sawdust replacement (20.40%; 90% sand and 10% sawdust replacement (18.0%; 95% sand and 5% sawdust replacement (12.12% and 100% sand and 0% sawdust replacement (11.43%. It was concluded that 5% sawdust (8kg replacement and cured 28 days could be used for non-load bearing walls. It was recommended that further research should be carried out to evaluate sawdust replacement level within the range of 1-4% to ascertain results that could be used for various other purposes.

  18. Physical and Strength Properties of Bricks Produced from Portland Cement and Saw Dust of Danielia Oliverii Wood

    Directory of Open Access Journals (Sweden)

    David Oriabure EKHUEMELO

    2016-12-01

    Full Text Available This study investigated the use of sawdust as partial replacement for sand in wood-concrete hollow blocks. Sharp sand, ordinary Portland cement (binder and sawdust were used as raw materials. Sawdust was treated by boiling then sieved after drying using British Standard sieve of 3.35mm to remove sticky wood capable of causing pores. The quantities of sawdust used were 0%, 5%, 10%, 15% and 20%. A mixing proportion of 1:8 cement sand ratio, moulding machine with single 6” (450mm x 225mm x 150mm mould and vibrated with 5.0KW power machine for adequate compaction were used. Wood-concrete block was cured for 28 days. The blocks produced were tested for compressive strength and water absorption. The results showed that mean compressive strength of 100% sand was 2.81N/mm2 followed by 95% sand and 5% sawdust replacement with 1.58N/mm2 ; 90% Sand and 10% sawdust replacement with 0.55N/mm2 ; 85% sand and 15% sawdust replacement with 0.43 N/mm2 and 80% sand 20% sawdust replacement with 0.24N/mm2 . The result further showed that as the percentage of sawdust increased, the compressive strength decreased. At 28 days, the compressive strength of blocks with 5% SD replacement satisfied meets Ghana Building Code for non- load bearing walls. The results also reveals that blocks with 80% sand 20% sawdust replacement level has the highest water absorption (23.72% followed by 85% Sand and 15% sawdust replacement (20.40%; 90% sand and 10% sawdust replacement (18.0%; 95% sand and 5% sawdust replacement (12.12% and 100% sand and 0% sawdust replacement (11.43%. It was concluded that 5% sawdust (8kg replacement and cured 28 days could be used for non-load bearing walls. It was recommended that further research should be carried out to evaluate sawdust replacement level within the range of 1-4% to ascertain results that could be used for various other purposes.

  19. A comparative evaluation of compressive strength of Portland cement with zinc oxide eugenol and Polymer-reinforced cement: An in vitro analysis

    OpenAIRE

    S Prakasam; Prakasam Bharadwaj; S C Loganathan; B Krishna Prasanth

    2014-01-01

    Objective: The purpose of this study is to evaluate the ultimate compressive strength of 50% and 25% Portland cement mixed with Polymer-reinforced zinc oxide eugenol and zinc oxide eugenol cement after 1 hour, 24 hours, and 7 days. Materials and Methods: One hundred and eighty samples were selected. The samples were made cylindrical of size 6 × 8 mm and were divided into six groups as follows with each group consisting of 10 samples. Group 1: Polymer-reinforced zinc oxide eugenol with...

  20. High Early-Age Strength Concrete for Rapid Repair

    Science.gov (United States)

    Maler, Matthew O.

    The aim of this research was to identify High Early-Age Strength (HES) concrete batch designs, and evaluate their suitability for use in the rapid repair of highways and bridge decks. To this end, two criteria needed to be met; a minimum compressive strength of 20.68 MPa (3000 psi) in no later than 12 hours, and a drying shrinkage of less than 0.06 % at 28 days after curing. The evaluations included both air-entrained, and non-air-entrained concretes. The cement types chosen for this study included Type III and Type V Portland cement and "Rapid Set"--a Calcium Sulfoaluminate (CSA) cement. In addition, two blended concretes containing different ratios of Type V Portland cement and CSA cement were investigated. The evaluation of the studied concretes included mechanical properties and transport properties. Additionally, dimensional stability and durability were investigated. Evaluations were conducted based on cement type and common cement factor. Fresh property tests showed that in order to provide a comparable workability, and still remain within manufactures guideline for plasticizer, the water-to-cement ratio was adjusted for each type of cement utilized. This resulted in the need to increase the water-to-cement ratio as the Blaine Fineness of the cement type increased (0.275 for Type V Portland cement, 0.35 for Type III Portland cement, and 0.4 for Rapid Set cement). It was also observed that negligible changes in setting time occurred with increasing cement content, whereas changes in cement type produced notable differences. The addition of air-entrainment had beneficial effect on workability for the lower cement factors. Increasing trends for peak hydration heat were seen with increases in cement factor, cement Blaine Fineness, and accelerator dosage. Evaluation of hardened properties revealed opening times as low as 5 hours for Type V Portland cement with 2.0 % accelerator per cement weight and further reduction in opening time by an hour when accelerator

  1. The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

    Directory of Open Access Journals (Sweden)

    Solikin Mochamad

    2017-01-01

    Full Text Available High volume fly ash concrete becomes one of alternatives to produce green concrete as it uses waste material and significantly reduces the utilization of Portland cement in concrete production. Although using less cement, its compressive strength is comparable to ordinary Portland cement (hereafter OPC and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly Ash Concrete. The experiment and data analysis were prepared using minitab, a statistic software for design of experimental. The specimens were concrete cylinder with diameter of 15 cm and height of 30 cm, tested for its compressive strength at 56 days. The result of the research demonstrates that high volume fly ash concrete can produce comparable compressive strength which meets the strength of OPC design strength especially for high strength concrete. In addition, the best mix proportion to achieve the design strength is the combination of high strength concrete and 50% content of fly ash. Moreover, the use of spraying method for curing method of concrete on site is still recommended as it would not significantly reduce the compressive strength result.

  2. Achievement of 900kgf/cm[sup 2] super workable high strength concrete with belite Portland cement (elevator building of cement silo in Chichibu cement). 2. ; Application to the actual structure. Ko belite kei cement de 900kgf/cm[sup 2] wo tassei (Chichibu cement cement silo no elevator to). 2. ; Jitsukozobutsu eno tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Yoda, K.; Sakuramoto, F. (Kajima Corp., Tokyo (Japan))

    1993-08-01

    For the purpose of rationalization of concrete works, the super workable high strength concrete was applied to the underground part of elevator building of cement silo in the Kumagaya Works, Chichibu Cement, and was successfully put into practice. Quality control values of the super workable high strength concrete were 65[plus minus]5cm in the slump flow and 900kgf/cm[sup 2] in the compressive strength at the age of 28 days. Addition of the admixture was 1.25% of the unit cement amount. Based on the linear correlation between the slump flow and mixer load immediately before discharge, the slump flow was controlled by the mixer load. Property of the fresh concrete, fluidity, compacting property, material segregation resistance property, and strength property were examined by using a sidewall test model. For all tests, satisfactory properties were obtained. Subsequently, the actual structure was successfully constructed. As a result, laborsaving and improvement of productivity were confirmed for the super workable high strength concrete work. 3 refs., 8 figs., 4 tabs.

  3. Effect of mixes made of coal bottom ash and fly ash on the mechanical strength and porosity of Portland cement

    Directory of Open Access Journals (Sweden)

    Argiz, C.

    2013-03-01

    Full Text Available New additions to the cement are needed to achieve a more sustainable and durable construction material. Within this context, bottom ashes can be used as a main constituent of Portland cements when it is mixed in an optimized proportion with fly ashes. The mechanical characteristics of standarized mortars made of mixes of pulverized coal combustion bottom and fly ashes are studied. The mortars were made of ordinary Portland cement (CEM I 42.5 N and mixes of bottom ashes with fly ashes in similar proportions to those of CEM II/A-V, CEM II/B-V and CEM IV/A (V. Summing up, it can be said that the utilization of bottom ashes mixed with fly ashes in replacement levels from 0% to 100% do not affect significantively on the mechanical caracteristics of the mortars considered in the present study which had an addition maximum content of 35%.

    La utilización de nuevas adiciones en el cemento es necesaria con el fin de obtener un material más sostenible y durable. En este sentido, las cenizas de fondo o cenicero de las centrales termoeléctricas de carbón se podrían reciclar siendo empleadas como un componente principal de los cementos Portland. Se han estudiado las propiedades mecánicas de unos morteros normalizados elaborados con mezclas de cenizas volantes con cenizas de fondo fabricados con unos porcentajes similares a los correspondientes de los CEM II/A-V, CEM II/B-V y CEM IV/A (V. En conclusión, la utilización de mezclas de cenizas de fondo o cenicero con cenizas volantes sustituyendo a éstas últimas entre el 0% y el 100%, no influye significativamente en el comportamiento mecánico de los morteros estudiados en los que el contenido máximo de adición ha sido del 35%, si bien afecta a determinados aspectos microestructurales, como la cantidad y distribución de poros capilares.

  4. Experimental Analysis of Concrete Strength at High Temperatures and after Cooling

    Directory of Open Access Journals (Sweden)

    E. Klingsch

    2009-01-01

    Full Text Available In recent years, the cement industry has been criticized for emitting large amounts of carbon dioxide; hence it is developing environment-friendly cement, e.g., blended, supersulfated slag cement (SSC. This paper presents an experimental analysis of the compressive strength development of concrete made from blended cement in comparison to ordinary cement at high temperature. Three different types of cement were used during these tests, an ordinary portland cement (CEM I, a portland limestone cement (CEM II-A-LL and a new, supersulfated slag cement (SSC. The compressive strength development for a full thermal cycle, including cooling down phase, was investigated on concrete cylinders. It is shown that the SSC concrete specimens perform similar to ordinary cement specimens. 

  5. Compressive and flexural strength of high strength phase change mortar

    Science.gov (United States)

    Qiao, Qingyao; Fang, Changle

    2018-04-01

    High-strength cement produces a lot of hydration heat when hydrated, it will usually lead to thermal cracks. Phase change materials (PCM) are very potential thermal storage materials. Utilize PCM can help reduce the hydration heat. Research shows that apply suitable amount of PCM has a significant effect on improving the compressive strength of cement mortar, and can also improve the flexural strength to some extent.

  6. High-strength beryllium block

    International Nuclear Information System (INIS)

    Pinto, N.P.; Keith, G.H.

    1977-01-01

    Beryllium billets hot isopressed using fine powder of high purity have exceptionally attractive properties; average tensile ultimate, 0.2% offset yield strength and elongation are 590 MPa, 430 MPa and 4.0% respectively. Properties are attributed to the fine grain size (about 4.0 μm average diameter) and the relatively low levels of BeO present as fine, well-dispersed particles. Dynamic properties, e.g., fracture toughness, are similar to those of standard grade, high-purity beryllium. The modulus of beryllium is retained to very high stress levels, and the microyield stress or precision elastic limit is higher than for other grades, including instrument grades. Limited data for billets made from normal-purity fine powders show similar room temperature properties. (author)

  7. Experimental Investigation of the Fracture Behaviour of Reinforced Ultra High Strength Concrete

    DEFF Research Database (Denmark)

    Ulfkjær, J. P.; Henriksen, M. S.; Aarup, B.

    the structural behaviour of a very high strength cement based material with and without steel fibres is investigated. A simple structural geometry has been tested, namely a beam subjected to three point bending. The results shows that the increase of ductility of the material also gives a more ductile behaviour......In the last fifteen years new types of cement based materials have been developed in Denmark at the Aalborg Portland Cement Factory. These types of new materials are characterized by very high strength even when mixed at room temperature and using conventional mixing techniques. In this paper...

  8. STRENGTH OF NANOMODIFIED HIGH-STRENGTH LIGHTWEIGHT CONCRETES

    Directory of Open Access Journals (Sweden)

    NOZEMTСEV Alexandr Sergeevich

    2013-02-01

    Full Text Available The paper presents the results of research aimed at development of nanomodified high-strength lightweight concrete for construction. The developed concretes are of low average density and high ultimate compressive strength. It is shown that to produce this type of concrete one need to use hollow glass and aluminosilicate microspheres. To increase the durability of adhesion between cement stone and fine filler the authors offer to use complex nanodimensinal modifier based on iron hydroxide sol and silica sol as a surface nanomodifier for hollow microspheres. It is hypothesized that the proposed modifier has complex effect on the activity of the cement hydration and, at the same time increases bond strength between filler and cement-mineral matrix. The compositions for energy-efficient nanomodified high-strength lightweight concrete which density is 1300…1500 kg/m³ and compressive strength is 40…65 MPa have been developed. The approaches to the design of high-strength lightweight concrete with density of less than 2000 kg/m³ are formulated. It is noted that the proposed concretes possess dense homogeneous structure and moderate mobility. Thus, they allow processing by vibration during production. The economic and practical implications for realization of high-strength lightweight concrete in industrial production have been justified.

  9. Valorisation of sugarcane bagasse ash (SCBA with high quartz content as pozzolanic material in Portland cement mixtures

    Directory of Open Access Journals (Sweden)

    A. M. Pereira

    2018-04-01

    Full Text Available Portland cement (OPC production is one of the most contaminating greenhouse gas producing activities. In order to reduce OPC consumption, several alternatives are being assessed, and the use of pozzolanic material is one of them. This paper presents study on the reactivity of sugarcane bagasse ash (SCBA, a residue from sugarcane industry, as a pozzolanic material. In order to evaluate SCBA reactivity, it was mixed in pastes with hydrated lime and OPC, which were microstructurally characterised. These studies showed that SCBA presents some pozzolanic characteristics. Studies on mortars in which OPC was replaced by SCBA in the range 10–30% were also carried out. Replacement in the range 15–20% yielded the best behaviour in terms of compressive strength. Finally, it can be concluded this ash could be valorised despite its relative low pozzolanic reactivity.

  10. A study of photon interaction in some building materials: High-volume admixture of blast furnace slag into Portland cement

    International Nuclear Information System (INIS)

    Kurudirek, Murat; Tuerkmen, Ibrahim; Ozdemir, Yueksel

    2009-01-01

    Total mass attenuation coefficients, mean free paths (MFP), half-value (HVT) and tenth-value (TVT) thicknesses of Portland cement and three mixtures have been calculated in function of the energy from 1 keV to 100 GeV. Both in the low- and high-energy region there were significant variations in those parameters where photoelectric process and pair production partially dominates, respectively. In general, the attenuation parameters were found to vary with chemical composition, density of given material and photon energy.

  11. A study of photon interaction in some building materials: High-volume admixture of blast furnace slag into Portland cement

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)], E-mail: mkurudirek@gmail.com; Tuerkmen, Ibrahim [Faculty of Engineering, Department of Civil Engineering, Ataturk University, 25240 Erzurum (Turkey); Ozdemir, Yueksel [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2009-09-15

    Total mass attenuation coefficients, mean free paths (MFP), half-value (HVT) and tenth-value (TVT) thicknesses of Portland cement and three mixtures have been calculated in function of the energy from 1 keV to 100 GeV. Both in the low- and high-energy region there were significant variations in those parameters where photoelectric process and pair production partially dominates, respectively. In general, the attenuation parameters were found to vary with chemical composition, density of given material and photon energy.

  12. Assessment the potential of using Carbon nanotubes reinforcements for improving the tensile/flexural strength and fracture toughness of Portland cement paste for damage resistant concrete transportation infrastructures.

    Science.gov (United States)

    2010-09-01

    The focus of this study was on exploring the use of nanotechnology-based nano-filaments, such as carbon : nanotubes (CNTs) and nanofibers (CNFs), as reinforcement in improving the mechanical properties of Portland : cement paste as a construction mat...

  13. Properties of expansive cements, made with Portland cement, gypsum and high alumina cement

    Directory of Open Access Journals (Sweden)

    Monfore, G. E.

    1966-03-01

    Full Text Available Not availableLos cementos expansivos se han desarrollado durante las tres décadas pasadas, principalmente por las investigaciones llevadas a cabo en Francia, URSS y Estados Unidos. Los cementos expansivos que fueron utilizados en los estudios de los cuales se da cuenta en el presente trabajo se obtuvieron mediante la mezcla de cemento Portland, cemento aluminoso y yeso. En las investigaciones se utilizaron morteros con los cuales se pudo determinar los efectos de la composición, tiempo y temperatura de curado sobre las resistencias, dilatación libre, retracción y desarrollo de resistencias en probetas pretensadas. Se hace una revisión sobre los estudios hechos con cementos expansivos y desarrollados en la Universidad de California. Las propiedades de taIes hormigones son, en términos generales, comparables a aquellos obtenidos con mezclas de cementos portland, cemento aluminoso y yeso. Es necesaria más información sobre pérdidas de tensión en los aceros y durabilidad de los hormigones autopretensados.

  14. About the possibility of obtaining cementitious soil composites of high strength on the basis of belozems of carbonate composition

    Science.gov (United States)

    Karapetyan, K. A.; Hayroyan, S. G.; Manukyan, E. S.

    2018-04-01

    The problem of manufacturing high strength cementitious soils based on belozems of carbonate composition, which experience compression (no less than 10 MPa), without application of surface active substances is considered. The portland cement of type 400 was used as a binding agent to develop compositions of cementitious soil composites, and the ordinary pipe water was used to obtain solutions of cementitious soils. The chemical and mineralogical composition of the initial ingredients and the granulometric composition of belozems were determined. The measurements showed that the upper and lower plasticity limits, the optimum moisture content, and the maximal density of the skeleton of belozems, as well as the considered compositions of cementitious soils, are insignificant, while the plasticity index of cementitious soils is less than one for belozems. It is experimentally proved that an increase in the portland cement amount lead to an increase in the compressive strength of cementitious soils with a decreasing speed. But for the same amount of portland cement used in the cementitious soil compositions, the values of the strength ratio of the pieces tested at the age of 60 and 28 days remain the same and are approximately equal to 1.2. A comparison of experimental data showed that it seems to be real to manufacture a cementitious soil on the basis of belozems of carbonate composition, which contain 10% of cement of the weight of dry mixture and have strength more than 10 MPa, without adding any surfactants to the material composition.

  15. Microstructure and durability of Portland cement-carbon nanotube composites

    OpenAIRE

    MacLeod, Alastair James Neil

    2017-01-01

    The incorporation of carbon nanotubes (CNTs), fibres with diameters less than 100 nanometres that exhibit a tensile strength in excess of ten times greater than steel, into Portland cement (OPC) is a relatively novel, yet promising, development for next-generation construction materials exhibiting enhanced strength and ductility, even multifunctionality. When added to Portland cement, creating a Portland cement-CNT nanocomposite material (OPC-CNT), CNTs promote the nucleation of the princi...

  16. Solidification/Stabilization of High Nitrate and Biodenitrified Heavy Metal Sludges with a Portland Cement/Flyash System

    International Nuclear Information System (INIS)

    Canonico, J.S.

    1995-01-01

    Pond 207C at Rocky Flats Environmental Technology Site (RFETS) contains process wastewaters characterized by high levels of nitrates and other salts, heavy metal contamination, and low level alpha activity. The purpose of this research was to investigate the feasibility of treating a high-nitrate waste, contaminated with heavy metals, with a coupled dewateriug and S/S process, as well as to investigate the effects of biodenitrification pretreatment on the S/S process. Pond 207C residuals served as the target waste. A bench-scale treatability study was conducted to demonstrate an S/S process that would minimize final product volume without a significant decrease in contaminant stabilization or loss of desirable physical characteristics. The process formulation recommended as a result a previous S/S treatability study conducted on Pond 207C residuals was used as the baseline formulation for this research. Because the actual waste was unavailable due to difficulties associated with radioactive waste handling and storage, a surrogate waste, of known composition and representative of Pond 207C residuals, was used throughout this research. The contaminants of regulatory concern added to the surrogate were cadmium, chromium, nickel, and silver. Product volume reduction was achieved by dewatering the waste prior to S/S treatment. The surrogate was dewatered by evaporation at 60 to 80 C to total solids contents from 43% to 78% by weight, and treated with Portland cement and fly ash. Two cement to flyash ratios were tested, 2:1 and 1:2, by weight. Contaminant leachability testing was conducted with a 0.5 water to pozzolan (the cement/flyash mixture) ratio and both cement to flyash ratios. Each product was tested for unconfined compressive strength (UCS) and for contaminant leachability by the Toxicity Characteristics Leaching Procedure (TCLP). At the highest solids content achieved by dewatering, 78% solids by weight, the predicted final waste form volume f or Pond 207C

  17. On high temperature strength of carbon steels

    International Nuclear Information System (INIS)

    Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

    1977-01-01

    In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

  18. Basalt waste added to Portland cement

    Directory of Open Access Journals (Sweden)

    Thiago Melanda Mendes

    2016-08-01

    Full Text Available Portland cement is widely used as a building material and more than 4.3 billion tons were produced in 2014, with increasing environmental impacts by this industry, mainly through CO2 emissions and consumption of non-removable raw materials. Several by-products have been used as raw materials or fuels to reduce environmental impacts. Basaltic waste collected by filters was employed as a mineral mixture to Portland cement and two fractions were tested. The compression strength of mortars was measured after 7 days and Scanning Electron Microscopy (SEM and Electron Diffraction Scattering (EDS were carried out on Portland cement paste with the basaltic residue. Gains in compression strength were observed for mixtures containing 2.5 wt.% of basaltic residue. Hydration products observed on surface of basaltic particles show the nucleation effect of mineral mixtures. Clinker substitution by mineral mixtures reduces CO2 emission per ton of Portland cement.

  19. The Effect of TiO₂ Doped Photocatalytic Nano-Additives on the Hydration and Microstructure of Portland and High Alumina Cements.

    Science.gov (United States)

    Pérez-Nicolás, María; Navarro-Blasco, Íñigo; Fernández, José M; Alvarez, José Ignacio

    2017-10-14

    Mortars with two different binders (Portland cement (PC) and high alumina cement (HAC)) were modified upon the bulk incorporation of nano-structured photocatalytic additives (bare TiO₂, and TiO₂ doped with either iron (Fe-TiO₂) or vanadium (V-TiO₂)). Plastic and hardened state properties of these mortars were assessed in order to study the influence of these nano-additives. Water demand was increased, slightly by bare TiO₂ and Fe-TiO₂, and strongly by V-TiO₂, in agreement with the reduction of the particle size and the tendency to agglomerate. Isothermal calorimetry showed that hydration of the cementitious matrices was accelerated due to additional nucleation sites offered by the nano-additives. TiO₂ and doped TiO₂ did not show pozzolanic reactivity in the binding systems. Changes in the pore size distribution, mainly the filler effect of the nano-additives, accounted for the increase in compressive strengths measured for HAC mortars. A complex microstructure was seen in calcium aluminate cement mortars, strongly dependent on the curing conditions. Fe-TiO₂ was found to be homogeneously distributed whereas the tendency of V-TiO₂ to agglomerate was evidenced by elemental distribution maps. Water absorption capacity was not affected by the nano-additive incorporation in HAC mortars, which is a favourable feature for the application of these mortars.

  20. The Effect of TiO2 Doped Photocatalytic Nano-Additives on the Hydration and Microstructure of Portland and High Alumina Cements

    Directory of Open Access Journals (Sweden)

    María Pérez-Nicolás

    2017-10-01

    Full Text Available Mortars with two different binders (Portland cement (PC and high alumina cement (HAC were modified upon the bulk incorporation of nano-structured photocatalytic additives (bare TiO2, and TiO2 doped with either iron (Fe-TiO2 or vanadium (V-TiO2. Plastic and hardened state properties of these mortars were assessed in order to study the influence of these nano-additives. Water demand was increased, slightly by bare TiO2 and Fe-TiO2, and strongly by V-TiO2, in agreement with the reduction of the particle size and the tendency to agglomerate. Isothermal calorimetry showed that hydration of the cementitious matrices was accelerated due to additional nucleation sites offered by the nano-additives. TiO2 and doped TiO2 did not show pozzolanic reactivity in the binding systems. Changes in the pore size distribution, mainly the filler effect of the nano-additives, accounted for the increase in compressive strengths measured for HAC mortars. A complex microstructure was seen in calcium aluminate cement mortars, strongly dependent on the curing conditions. Fe-TiO2 was found to be homogeneously distributed whereas the tendency of V-TiO2 to agglomerate was evidenced by elemental distribution maps. Water absorption capacity was not affected by the nano-additive incorporation in HAC mortars, which is a favourable feature for the application of these mortars.

  1. Technical Note: Filler and superplasticizer usage on high strength concrete

    Directory of Open Access Journals (Sweden)

    Sümer, M.

    2007-08-01

    Full Text Available In this research, the effects of filler (rock-dust usage on high strength concrete have been investigated through lab experiments and some results have been obtained. The experiments involved three series of concrete with different cement proportions of 375 kg/m3, 400 kg/m3, and 425 kg/m3. For each series of concrete, three different groups of samples have been prepared, the first one being the reference concrete which contained 0% chemical admixture and 0% filler, the second one contained 1.5% chemical admixture and 0% filler and finally the last group contained 1.5% chemical admixture and 5% filler to the weight of cement used. The chemical admixture used was a type of Super plasticizer with a brand name of “DARACEM 190”, and the cement used was Ordinary Portland Cement of target compressive strength 42.5 N/mm2, obtained from Nuh Cement Plant. For each batch, Slump Tests and Unit Weight Tests were performed. For each stage and group, two 15 cm cubic samples have been tested for Compressive Strength after being cured in water at 20 ± 2 °C for ages of 3 days, 7 days, 28 and 60 days. The total number of samples was 72. As a result, filler usage was found to reduce the porosity of Concrete, increase the Unit Weight of Concrete, increase the need for water and improve the Compressive Strength Properties of Concrete.En el presente trabajo se estudia la influencia de la utilización de un “filler” (polvo mineral en el comportamiento del hormigón de altas prestaciones. Para ello, se realizan ensayos de laboratorio en los que se emplean tres series de hormigón, cada una con una dosificación de cemento distinta, de 375, 400 y 425 kg/m3. Se preparan tres grupos de probetas de cada serie, el primero o de referencia con 0% de aditivo químico y 0% de “filler”, el segundo con un 1,5% del aditivo químico y 0% de “filler” y el tercero con un 1,5% del aditivo químico y un 5% de “filler” en peso del cemento. Como aditivo se

  2. Advanced high strength steels for automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Galan, J.; Samek, L.; Verleysen, P.; Verbeken, K.; Houbert, Y.

    2012-11-01

    The car industry is facing pressure because of the growing demand for more fuel-efficient passenger cars. In order to limit energy consumption and air pollution the weight of the car body has to be reduced. At the same time, high levels of safety have to be guaranteed. In this situation, the choice of material becomes a key decision in car design. As a response to the requirements of the automotive sector, high strength steels and advanced high strength steels have been developed by the steel industry. These modern steel grades offer an excellent balance of low cost, light weight and mechanical properties. (Author) 48 refs.

  3. Resistência à compressão do solo-cimento com substituição parcial do cimento Portland por resíduo cerâmico moído Compressive strength of soil-cement with partial replacement of the Portland cement by crushed ceramic waste

    Directory of Open Access Journals (Sweden)

    Rivanildo Dallacort

    2002-12-01

    Full Text Available Neste trabalho, apresenta-se o estudo experimental da resistência à compressão do solo-cimento, com substituição parcial do cimento Portland por resíduo cerâmico moído. Para tanto, foram ensaiados 81 espécimenes cilíndricos desse material à compressão, em que parte do cimento foi substituída por material cerâmico moído. Realizou-se uma programação fatorial, na qual três variáveis foram selecionadas para estudo: o teor de material ligante (cimento + resíduo cerâmico, a umidade do solo e o teor de resíduo cerâmico adicionado. É apresentado um estudo estatístico através de análise de variância da massa específica do material e da resistência a compressão. Tal estudo permitiu concluir-se que substituições de 25 e 57% do teor de cimento por material cerâmico podem produzir blocos de solo-cimento com resistências superiores a 2 MPa, com teor de material ligante de 6 e 8%, respectivamente.In this paper, an experimental study of the compressive strength of soil-cement with partial replacement of the Portland cement by crushed ceramic waste is presented and discussed. For this, eighty-one cylindrical specimens of soil-cement were tested, where part of cement percentage was replaced by crushed ceramic waste. The experiment was conducted in factorial design and three variables were selected and studied: the binding material content (cement + ceramic waste, soil moisture content and the ratio of ceramic waste. A statistical study using variance analysis of the specific mass and compressive strength of the material is presented. This study concluded that replacement ratios of 25 and 57% of the Portland cement by crushed ceramic material can be used to fabricate soil-cement bricks with strength higher than 2 MPa, for a binding material content of 6 and 8% respectively.

  4. Numerical Model of High Strength Concrete

    Science.gov (United States)

    Wang, R. Z.; Wang, C. Y.; Lin, Y. L.

    2018-03-01

    The purpose of this paper is to present a three-dimensional constitutive model based on the concept of equivalent uniaxial strain. closed Menetrey-Willam (CMW) failure surfaces which combined with Menetrey-Willam meridian and the cap model are introduced in this paper. Saenz stress-strain model is applied and adjusted by the ultimate strength parameters from CMW failure surface to reflect the latest stress or strain condition. The high strength concrete (HSC) under tri-axial non-proportional loading is considered and the model in this paper performed a good prediction.

  5. Making High-Tensile-Strength Amalgam Components

    Science.gov (United States)

    Grugel, Richard

    2008-01-01

    Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

  6. High-strength mineralized collagen artificial bone

    Science.gov (United States)

    Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

    2014-03-01

    Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

  7. Use of red mud as addition for portland cement mortars

    International Nuclear Information System (INIS)

    Ribeiro, D.V.; Morelli, M.R.

    2011-01-01

    The aim of the present research work was to investigate the possibility of adding red mud, an alkaline leaching waste that is obtained from bauxite during the Bayer process for alumina production, in the raw meal of Portland cement mortars. The red mud is classified as dangerous, according to NBR 10004/2004, and world while generation reached over 117 million tons/year. This huge production requires high consuming products to be used as incorporation matrix and we studied the influence of red mud addition on the characteristics of cement mortars and concrete. In this paper the properties of Portland cement mortars incorporating high amounts of red mud was evaluated: pH variation, fresh (setting time, workability or normal consistency and water retention), and hardened state (mechanical strength, capillary water absorption, density and apparent porosity). Results seem promising for red mud additions up to 20 wt%. (author)

  8. Microcracking and durability of high strength concretes

    International Nuclear Information System (INIS)

    Yssorche, M.P.

    1995-07-01

    Durability of 28 days compressive strength concrete of 20 to 120 MPa has been studied. The ability of concrete to transport aggressive agents has been determined for four properties: the air permeability, the chloride diffusivity, the water absorption and the carbonation. A chloride migration test for high and very high strength concrete (HSC and VHSC) has been built. The relationship between transport properties and the compressive strength after one and 28 days of humid curing has always the same shape: transport decreases when strength increases. However, transport properties often vary in the ordinary concrete field. Beyond, the domain is much more limited. The relationship between transport properties and strength valid for ordinary concrete can not be simply extrapolated for HSC and VHSC. To determine the part of microcracking of HSC and VHSC, concrete behaviour stored in two mediums has been studied: the ones shaming the storing condition of concrete in auto-desiccation, the others reproducing the storing conditions of concrete in desiccation. Auto-desiccation (measuring relative humidity at balance) and desiccation (measuring mass losses) have been showed. Microcracks and shrinkage strains have been measured. It has been showed that auto-desiccation microcracks proving in HSC or VHSC don't question the durability. Microcracks, as for permeability, do not develop between 28 days and one year. On the contrary, desiccation microcracks observed in HSC and VHSC, increase with transport properties between 28 days and 1.5 year. Thus, a bulk concrete is always more durable than a cover concrete. At last, the good influence of increase of curing of 1 to 28 days on the transport of all concretes has been emphasized. (author)

  9. cimento portland

    Directory of Open Access Journals (Sweden)

    Fábio Akira Mori

    2007-01-01

    Full Text Available The characteristics of cement bonded particleboards can be jeopardized by chemical incompatibility between some lignocellulosic materials and cement, which can inhibit the glue of this cement; however, this effect can be minimized with chemicals treatments of the materials. The different species of Eucalyptus can be promising as raw material in the production of these panels, mainly residues produced in form of barks. The objective of the work was to evaluate chemical compatibility of wood and barks (without and with chemical treatment of Eucalyptus grandis with cement. The chemical treatment of barks was carried out with sodium hydroxide. Results showed that the Eucalyptus grandis wood presented a moderate aptitude with cement, the treated barks presented high aptitude and the untreated bark presented extremely low aptitude. It was verified positive influence of the chemical treatment in the barks, making possible, in the future, the incorporation of these elements in the manufacturing of cement-bonded particleboard.

  10. High-Tensile Strength Tape Versus High-Tensile Strength Suture: A Biomechanical Study.

    Science.gov (United States)

    Gnandt, Ryan J; Smith, Jennifer L; Nguyen-Ta, Kim; McDonald, Lucas; LeClere, Lance E

    2016-02-01

    To determine which suture design, high-tensile strength tape or high-tensile strength suture, performed better at securing human tissue across 4 selected suture techniques commonly used in tendinous repair, by comparing the total load at failure measured during a fixed-rate longitudinal single load to failure using a biomechanical testing machine. Matched sets of tendon specimens with bony attachments were dissected from 15 human cadaveric lower extremities in a manner allowing for direct comparison testing. With the use of selected techniques (simple Mason-Allen in the patellar tendon specimens, whip stitch in the quadriceps tendon specimens, and Krackow stitch in the Achilles tendon specimens), 1 sample of each set was sutured with a 2-mm braided, nonabsorbable, high-tensile strength tape and the other with a No. 2 braided, nonabsorbable, high-tensile strength suture. A total of 120 specimens were tested. Each model was loaded to failure at a fixed longitudinal traction rate of 100 mm/min. The maximum load and failure method were recorded. In the whip stitch and the Krackow-stitch models, the high-tensile strength tape had a significantly greater mean load at failure with a difference of 181 N (P = .001) and 94 N (P = .015) respectively. No significant difference was found in the Mason-Allen and simple stitch models. Pull-through remained the most common method of failure at an overall rate of 56.7% (suture = 55%; tape = 58.3%). In biomechanical testing during a single load to failure, high-tensile strength tape performs more favorably than high-tensile strength suture, with a greater mean load to failure, in both the whip- and Krackow-stitch models. Although suture pull-through remains the most common method of failure, high-tensile strength tape requires a significantly greater load to pull-through in a whip-stitch and Krakow-stitch model. The biomechanical data obtained in the current study indicates that high-tensile strength tape may provide better repair

  11. Puzzolanic cements of greater resistance at the attack of selenitic waters than the high sulfate resistance portland cements, and viceverse

    Directory of Open Access Journals (Sweden)

    Talero, Rafael

    1987-09-01

    Full Text Available This work confirms the certainty of the predictions of useful service given by Kaluosek and al. for the sulphate resistant portland cements (type V, USA, subject to severe selenitic attack. Two sulphate resistant portland cements, were tested by means of the Le Chatelier Anstett method. The tarts were destroyed at ages of three years, having detected in them the presence of thaumasite by XRD. Even so, the impossibility and possibility thaumasite formation was confirmed in pozzolanic cements tarts, which either had or did not have adequate amount of pozzolana (diatomite for such purpose.

    Este trabajo confirman las predicciones de vida útil dadas por Kalousek y colaboradores, para los cementos portland de elevada resistencia al ataque de los iones sulfato (tipo V, USA, sometidos a un severo ataque selenitoso. Se ensayaron dos cementos portland de elevada resistencia al ataque del yeso, mediante el ensayo de Le Chatelier-Anstett. Sus tortas correspondientes se destruyeron a la edad de tres años, habiéndose detectado en las mismas la presencia de thaumasita por DRX. Asimismo se confirmó la imposibilidad y posibilidad de formación de thaumasita en tortas de cementos puzolánicos, los cuales tenían, o no, respectivamente, una adecuada cantidad de puzolana (diatomita para tales fines.

  12. DOE hearing on the draft area recommendation report for the Crystalline Repository Project, Portland High School, Portland, Maine: Volume 1, March 25, 1986: Transcript of proceedings

    International Nuclear Information System (INIS)

    1986-01-01

    This document contains a transcript of the comments of 13 witnesses. These meetings were held to hear public comments regarding the selection of a site for a second high-level nuclear waste repository

  13. High-strength chromium--molybdenum rails

    International Nuclear Information System (INIS)

    Smith, Y.E.; Sawhill, J.M. Jr.; Cias, W.W.; Eldis, G.T.

    1976-01-01

    A laboratory study was conducted with the aim of developing an as-rolled rail of over 100 ksi (689 N/mm 2 ) yield strength. A series of compositions providing both pearlitic and bainitic microstructures was evaluated. A fine pearlitic structure was developed in a 0.73 percent C -- 0.83 percent Mn -- 0.16 percent Si -- 0.75 percent Cr -- 0.21 percent Mo steel by simulating the mill cooling rate of 132-lb/yd (65.5-kg/m) rail. Two 100-ton commercial heats were made of this approximate composition and processed into 132-lb/yd (65.5-kg/m) rail. Samples tested in the laboratory ranged from 109 to 125 ksi (750 to 860 N/mm 2 ) in yield strength. The chromium-molybdenum rails also exhibited excellent fracture toughness and fatigue properties. Sections of the rail were joined by both flash-butt welding and thermite welding. The hardness peaks produced in the flash-butt welds could be reduced by applying either a postweld current or an induction heating cycle. The high-strength chromium-molybdenum rails have been in service for over eight months in curved sections of an ore railway that carries over 55 million gross long tons per year. 7 tables, 18 figs

  14. 2015 City of Portland, Maine, Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 2015 City of Portland Maine Lidar Data Acquisition and Processing Woolpert Order No. 75564 Contractor: Woolpert, Inc. This task is for a high resolution data set of...

  15. Effect of rice husk ash and fly ash on the compressive strength of high performance concrete

    Science.gov (United States)

    Van Lam, Tang; Bulgakov, Boris; Aleksandrova, Olga; Larsen, Oksana; Anh, Pham Ngoc

    2018-03-01

    The usage of industrial and agricultural wastes for building materials production plays an important role to improve the environment and economy by preserving nature materials and land resources, reducing land, water and air pollution as well as organizing and storing waste costs. This study mainly focuses on mathematical modeling dependence of the compressive strength of high performance concrete (HPC) at the ages of 3, 7 and 28 days on the amount of rice husk ash (RHA) and fly ash (FA), which are added to the concrete mixtures by using the Central composite rotatable design. The result of this study provides the second-order regression equation of objective function, the images of the surface expression and the corresponding contours of the objective function of the regression equation, as the optimal points of HPC compressive strength. These objective functions, which are the compressive strength values of HPC at the ages of 3, 7 and 28 days, depend on two input variables as: x1 (amount of RHA) and x2 (amount of FA). The Maple 13 program, solving the second-order regression equation, determines the optimum composition of the concrete mixture for obtaining high performance concrete and calculates the maximum value of the HPC compressive strength at the ages of 28 days. The results containMaxR28HPC = 76.716 MPa when RHA = 0.1251 and FA = 0.3119 by mass of Portland cement.

  16. Energy costs and Portland water supply system

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, W.M.; Hawley, R.P.

    1981-10-01

    The changing role of electrical energy on the Portland, Oregon, municipal-water-supply system is presented. Portland's actions in energy conservation include improved operating procedures, pump modifications, and modifications to the water system to eliminate pumping. Portland is implementing a small hydroelectric project at existing water-supply dams to produce an additional source of power for the area. Special precautions in construction and operation are necessary to protect the high quality of the water supply. 2 references, 7 figures.

  17. Development of Self-Consolidating High Strength Concrete Incorporating Treated Palm Oil Fuel Ash

    Directory of Open Access Journals (Sweden)

    Belal Alsubari

    2015-04-01

    Full Text Available Palm oil fuel ash (POFA has previously been used as a partial cement replacement in concrete. However, limited research has been undertaken to utilize POFA in high volume in concrete. This paper presents a study on the treatment and utilization of POFA in high volume of up to 50% by weight of cement in self-consolidating high strength concrete (SCHSC. POFA was treated via heat treatment to reduce the content of unburned carbon. Ordinary Portland cement was substituted with 0%, 10%, 20%, 30%, and 50% treated POFA in SCHSC. Tests have been conducted on the fresh properties, such as filling ability, passing ability and segregation resistance, as well as compressive strength, drying shrinkage and acid attack resistance to check the effect of high volume treated POFA on SCHSC. The results revealed that compared to the control concrete mix, the fresh properties, compressive strength, drying shrinkage, and resistance against acid attack have been significantly improved. Conclusively, treated POFA can be used in high volume as a cement replacement to produce SCHSC with an improvement in its properties.

  18. Development of Self-Consolidating High Strength Concrete Incorporating Treated Palm Oil Fuel Ash

    Science.gov (United States)

    Alsubari, Belal; Shafigh, Payam; Jumaat, Mohd Zamin

    2015-01-01

    Palm oil fuel ash (POFA) has previously been used as a partial cement replacement in concrete. However, limited research has been undertaken to utilize POFA in high volume in concrete. This paper presents a study on the treatment and utilization of POFA in high volume of up to 50% by weight of cement in self-consolidating high strength concrete (SCHSC). POFA was treated via heat treatment to reduce the content of unburned carbon. Ordinary Portland cement was substituted with 0%, 10%, 20%, 30%, and 50% treated POFA in SCHSC. Tests have been conducted on the fresh properties, such as filling ability, passing ability and segregation resistance, as well as compressive strength, drying shrinkage and acid attack resistance to check the effect of high volume treated POFA on SCHSC. The results revealed that compared to the control concrete mix, the fresh properties, compressive strength, drying shrinkage, and resistance against acid attack have been significantly improved. Conclusively, treated POFA can be used in high volume as a cement replacement to produce SCHSC with an improvement in its properties.

  19. Protective claddings for high strength chromium alloys

    Science.gov (United States)

    Collins, J. F.

    1971-01-01

    The application of a Cr-Y-Hf-Th alloy as a protective cladding for a high strength chromium alloy was investigated for its effectiveness in inhibiting nitrogen embrittlement of a core alloy. Cladding was accomplished by a combination of hot gas pressure bonding and roll cladding techniques. Based on bend DBTT, the cladding alloy was effective in inhibiting nitrogen embrittlement of the chromium core alloy for up to 720 ks (200hours) in air at 1422 K (2100 F). A significant increase in the bend DBTT occurred with longer time exposures at 1422 K or short time exposures at 1589 K (2400 F).

  20. Comparison of Thermal Stability of Dry High-strength Concrete and Wet High-strength Concrete

    Science.gov (United States)

    Musorina, Tatiana; Katcay, Aleksandr; Selezneva, Anna; Kamskov, Victor

    2018-03-01

    High-strength concrete is a modern material, which occupies it`s own niche on the construction material market. It is applicable in a large-scale high-rise construction, particularly an underground construction is a frequently used solution for a space saving. Usually underground structure is related to a wet usage environment. Though not all properties of the high-strength concrete are investigated to the full extent. Under adverse climatic conditions of the Russian Federation one of the most important properties for constructional materials is a thermal capacity. Therefore, the main purpose of the paper is to compare a thermal capacity of the high-strength concrete in humid conditions and a thermal capacity of the high-strength concrete in dry operational condition. During the study dependency between thermal capacity and design wall thickness and ambient humidity has to be proven with two experiments. As a result the theoretical relation between thermal capacity characteristic - thermal inertia and wall thickness and ambient humidity was confirmed by the experimental data. The thermal capacity of a building is in direct ratio to the construction thickness. It follows from the experiments and calculations that wet high-strength concrete has less thermal stability.

  1. Advanced high strength steels for automotive industry

    Directory of Open Access Journals (Sweden)

    Galán, J.

    2012-04-01

    Full Text Available The car industry is facing pressure because of the growing demand for more fuel-efficient passenger cars. In order to limit energy consumption and air pollution the weight of the carbody has to be reduced. At the same time, high levels of safety have to be guaranteed. In this situation, the choice of material becomes a key decision in car design. As a response to the requirements of the automotive sector, high strength steels and advanced high strength steels have been developed by the steel industry. These modern steel grades offer an excellent balance of low cost, light weight and mechanical properties.

    La industria del automóvil se enfrenta a una creciente demanda de vehículos de pasajeros más eficientes. Con el fin de disminuir el consumo de energía y la contaminación ambiental, el peso del vehículo tiene que ser reducido, al mismo tiempo que se garantizan altos niveles de seguridad. Ante esta situación, la elección de material se convierte en una decisión crucial en el diseño del vehículo. Como respuesta a las necesidades del sector automovilístico, nuevos aceros avanzados y de alta resistencia, han sido desarrollados por la industria siderúrgica. Dichos tipos de acero ofrecen un excelente equilibrio de precio, peso y propiedades mecánicas.

  2. Weld Design, Testing, and Assessment Procedures for High Strength Pipelines

    Science.gov (United States)

    2011-12-20

    Long-distance high-strength pipelines are increasingly being constructed for the efficient transportation of energy products. While the high-strength linepipe steels and high productivity welding processes are being applied, the procedures employed f...

  3. Poet Portland Approval

    Science.gov (United States)

    This update August 9, 2016 letter from EPA approves the petition, with modifications, from Poet Biorefining-Portland, LLC, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel

  4. Effect of total cementitious content on shear strength of high-volume fly ash concrete beams

    International Nuclear Information System (INIS)

    Arezoumandi, Mahdi; Volz, Jeffery S.; Ortega, Carlos A.; Myers, John J.

    2013-01-01

    Highlights: ► Existing design standards conservatively predicted the capacity of the HVFAC beams. ► In general, the HVFAC beams exceeded the code predicted shear strengths. ► The cementitious content did not have effect on the shear behavior of the HVFAC beams. - Abstract: The production of portland cement – the key ingredient in concrete – generates a significant amount of carbon dioxide. However, due to its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. This paper compares two experimental studies that were conducted to investigate the shear strength of full-scale beams constructed with high-volume fly ash concrete (HVFAC) – concrete with at least 50% of the cement replaced with fly ash. The primary difference between the two studies involved the amount of cementitious material, with one mix having a relatively high total cementitious content (502 kg/m 3 ) and the other mix having a relatively low total cementitious content (337 kg/m 3 ). Both mixes utilized a 70% replacement of portland cement with a Class C fly ash. Each of these experimental programs consisted of eight beams (six without shear reinforcing and two with shear reinforcing in the form of stirrups) with three different longitudinal reinforcement ratios. The beams were tested under a simply supported four-point loading condition. The experimental shear strengths of the beams were compared with both the shear provisions of selected standards (US, Australia, Canada, Europe, and Japan) and a shear database of conventional concrete (CC) specimens. Furthermore, statistical data analyses (both parametric and nonparametric) were performed to evaluate whether or not there is any statistically significant difference between the shear strength of both mixes. Results of these

  5. High strength air-dried aerogels

    Science.gov (United States)

    Coronado, Paul R.; Satcher, Jr., Joe H.

    2012-11-06

    A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

  6. Low velocity impact behaviour of ultra high strength concrete panels

    Indian Academy of Sciences (India)

    Ultra high strength concrete; panel; drop weight test; impact analysis;. ABAQUS. 1. Introduction. Ultra high strength concrete ... Knight (2012) investigated the dynamic behaviour of steel fibre reinforced concrete plates under impact loading with ...

  7. High strength cast aluminum alloy development

    Science.gov (United States)

    Druschitz, Edward A.

    The goal of this research was to understand how chemistry and processing affect the resulting microstructure and mechanical properties of high strength cast aluminum alloys. Two alloy systems were investigated including the Al-Cu-Ag and the Al-Zn-Mg-Cu systems. Processing variables included solidification under pressure (SUP) and heat treatment. This research determined the range in properties that can be achieved in BAC 100(TM) (Al-Cu micro-alloyed with Ag, Mn, Zr, and V) and generated sufficient property data for design purposes. Tensile, stress corrosion cracking, and fatigue testing were performed. CuAl2 and Al-Cu-Fe-Mn intermetallics were identified as the ductility limiting flaws. A solution treatment of 75 hours or longer was needed to dissolve most of the intermetallic CuAl 2. The Al-Cu-Fe-Mn intermetallic was unaffected by heat treatment. These results indicate that faster cooling rates, a reduction in copper concentration and a reduction in iron concentration might increase the ductility of the alloy by decreasing the size and amount of the intermetallics that form during solidification. Six experimental Al-Zn-Mg-Cu series alloys were produced. Zinc concentrations of 8 and 12wt% and Zn/Mg ratios of 1.5 to 5.5 were tested. Copper was held constant at 0.9%. Heat treating of the alloys was optimized for maximum hardness. Al-Zn-Mg-Cu samples were solution treated at 441°C (826°F) for 4 hours before ramping to 460°C (860°F) for 75 hours and then aged at 120°C (248°F) for 75 hours. X-ray diffraction showed that the age hardening precipitates in most of these alloys was the T phase (Mg32Zn 31.9Al17.1). Tensile testing of the alloys showed that the best mechanical properties were obtained in the lowest alloy condition. Chilled Al-8.2Zn-1.4Mg-0.9Cu solidified under pressure resulted in an alloy with a yield strength of 468MPa (68ksi), tensile strength of 525MPa (76ksi) and an elongation of 9%.

  8. Effect of High-Temperature Curing Methods on the Compressive Strength Development of Concrete Containing High Volumes of Ground Granulated Blast-Furnace Slag

    Directory of Open Access Journals (Sweden)

    Wonsuk Jung

    2017-01-01

    Full Text Available This paper investigates the effect of the high-temperature curing methods on the compressive strength of concrete containing high volumes of ground granulated blast-furnace slag (GGBS. GGBS was used to replace Portland cement at a replacement ratio of 60% by binder mass. The high-temperature curing parameters used in this study were the delay period, temperature rise, peak temperature (PT, peak period, and temperature down. Test results demonstrate that the compressive strength of the samples with PTs of 65°C and 75°C was about 88% higher than that of the samples with a PT of 55°C after 1 day. According to this investigation, there might be optimum high-temperature curing conditions for preparing a concrete containing high volumes of GGBS, and incorporating GGBS into precast concrete mixes can be a very effective tool in increasing the applicability of this by-product.

  9. Influence of bagasse ash and recycled concrete aggregate on hardened properties of high-strength concrete

    Directory of Open Access Journals (Sweden)

    P. Rattanachu

    2018-04-01

    Full Text Available This research aimed to use of bagasse ash as a cement replacement in high-strength recycled aggregate concrete (HS-RAC. Crushed limestone was replaced with 100% recycled concrete aggregate (RCA and the ground bagasse ash (GBA was used to partially replace ordinary Portland cement (OPC at 20, 35 and 50%wt of binder to cast HS-RAC. The results indicated that the replacing of crushed limestone with RCA had a negative impact on the properties of the concrete. Increasing the amount of GBA in HS-RAC resulted in a decrease in density and an increase in the volume of permeable pore space. The concrete mixtures prepared with 20%wt GBA replacement of OPC promoted greater the compressive strength than the conventional concrete (CT concrete at 90 days or more. HS-RAC with GBA (up to 50% was more durable in terms of chloride ion penetration resistance, although it had lower compressive strength than the CT concrete.

  10. Comparison and Analysis of Steel Frame Based on High Strength Column and Normal Strength Column

    Science.gov (United States)

    Liu, Taiyu; An, Yuwei

    2018-01-01

    The anti-seismic performance of high strength steel has restricted its industrialization in civil buildings. In order to study the influence of high strength steel column on frame structure, three models are designed through MIDAS/GEN finite element software. By comparing the seismic performance and economic performance of the three models, the three different structures are comprehensively evaluated to provide some references for the development of high strength steel in steel structure.

  11. Microstructure of high-strength foam concrete

    International Nuclear Information System (INIS)

    Just, A.; Middendorf, B.

    2009-01-01

    Foam concretes are divided into two groups: on the one hand the physically foamed concrete is mixed in fast rotating pug mill mixers by using foaming agents. This concrete cures under atmospheric conditions. On the other hand the autoclaved aerated concrete is chemically foamed by adding aluminium powder. Afterwards it is cured in a saturated steam atmosphere. New alternatives for the application of foam concretes arise from the combination of chemical foaming and air curing in manufacturing processes. These foam concretes are new and innovative building materials with interesting properties: low mass density and high strength. Responsible for these properties are the macro-, meso- and microporosity. Macropores are created by adding aluminium powder in different volumes and with different particle size distributions. However, the microstructure of the cement matrix is affected by meso- and micropores. In addition, the matrix of the hardened cement paste can be optimized by the specific use of chemical additives for concrete. The influence of aluminium powder and chemical additives on the properties of the microstructure of the hardened cement matrices were investigated by using petrographic microscopy as well as scanning electron microscopy.

  12. Slippage of steel in high and normal strength concrete

    International Nuclear Information System (INIS)

    Ahmed, K.; Siddiqi, Z.A.; Yousaf, M.

    2007-01-01

    Composite action of any reinforced concrete member is only possible if sufficient bond strength exists between steel reinforcing bars and concrete, which can adequately transfer shear stress between them. Bond strength is a function of compressive strength of concrete and hence high strength concrete has higher bond strength (1-2). Therefore required development length can be reduced. In order to investigate the effect of development length on bond stress and slip relationships, experimental investigation was carried out. In this experimentation 24 pull-out samples of high strength concrete and normal strength concrete were casted and tested. The results of this investigation revealed that by increasing the development length from 5db to 10db bond strength increases for both high and normal strength concrete as shown in Figure 11, 12 and 13. However in case of normal strength concrete increase in bond strength is more compared to that in high strength concrete as it is clear from Figure 11 and Figure 13. The increase in bond strength is observed even at 10db development length but the extent is less for 19 mm than 16 mm bars as shown in Figure 12 and Figure 13. This is in agreement with the earlier findings of Chen et al (3) and Harajli et al (1). However in case of HSC the total slippage at 10db is 50% greater than at 5db. This may be due to the fact that more no of concrete keys participate in resisting the slippage. (author)

  13. Ultrafine portland cement performance

    Directory of Open Access Journals (Sweden)

    C. Argiz

    2018-04-01

    Full Text Available By mixing several binder materials and additions with different degrees of fineness, the packing density of the final product may be improved. In this work, ultrafine cement and silica fume mixes were studied to optimize the properties of cement-based materials. This research was performed in mortars made of two types of cement (ultrafine Portland cement and common Portland cement and two types of silica fume with different particle-size distributions. Two Portland cement replacement ratios of 4% and 10% of silica fume were selected and added by means of a mechanical blending method. The results revealed that the effect of the finer silica fume mixed with the coarse cement enhances the mechanical properties and pore structure refinement at a later age. This improvement is somewhat lower in the case of ultrafine cement with silica fume.

  14. Chemical constitution, physical properties, and biocompatibility of experimentally manufactured Portland cement.

    Science.gov (United States)

    Hwang, Yun-Chan; Kim, Do-Hee; Hwang, In-Nam; Song, Sun-Ju; Park, Yeong-Joon; Koh, Jeong-Tae; Son, Ho-Hyun; Oh, Won-Mann

    2011-01-01

    An experimental Portland cement was manufactured with pure raw materials under controlled laboratory conditions. The aim of this study was to compare the chemical constitution, physical properties, and biocompatibility of experimentally manufactured Portland cement with those of mineral trioxide aggregate (MTA) and Portland cement. The composition of the cements was determined by scanning electron microscopy (SEM) and energy-dispersive x-ray analysis (EDAX). The setting time and compressive strength were tested. The biocompatibility was evaluated by using SEM and XTT assay. SEM and EDAX revealed the experimental Portland cement to have a similar composition to Portland cement. The setting time of the experimental Portland cement was significantly shorter than that of MTA and Portland cement. The compressive strength of the experimental Portland cement was lower than that of MTA and Portland cement. The experimental Portland cement showed a similar biocompatibility to MTA. The experimental Portland cement might be considered as a possible substitute for MTA in clinical usage after further testing. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. Influence of silica fume on the strength of high strength concrete

    International Nuclear Information System (INIS)

    Akram, T.; Memon, S.A.; Khan, S.A.

    2007-01-01

    HSC (High Strength Concrete) does not become evident by a sudden change in the behavior of 'ordinary strength' concrete. There is a gradual effect that becomes more noticeable when the strength level exceeds about 40-45 MPa. There cannot be a precise level of strength which defines this change in effect. The effects are on strength and workability, requiring us to take into account in our mix proportioning, the ramifications of fineness of cement on workability and of type of aggregate and aggregate/cement ratio on strength. In fact, the selection of materials becomes more critical as the concrete strength increases and that if very high strength is required (100 MPa and higher), relatively few materials may be suitable. An experimental investigation is carried out to evaluate the feasibility of producing HSC using locally available materials and to study the influence of silica fume on the strength of HSC. The main variables in this research is amount of silica fume. The parameters that are kept constant are the amount of cement equal to 580 kg/m3, dosage of HRWRA (High Range Water Reducing Admictures) equal to 4 % by weight of cementitious materials and the ratio of fine aggregate to coarse aggregate (1:2.3). Test results revealed that it is feasible to produce HSC using locally available materials. The optimum percentage of silica fume was found to be 15 % by weight of cement. (author)

  16. Development of K-Basin High-Strength Homogeneous Sludge Simulants and Correlations Between Unconfined Compressive Strength and Shear Strength

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yasuo; Baer, Ellen BK; Chun, Jaehun; Yokuda, Satoru T.; Schmidt, Andrew J.; Sande, Susan; Buchmiller, William C.

    2011-02-20

    K-Basin sludge will be stored in the Sludge Transport and Storage Containers (STSCs) at an interim storage location on Central Plateau before being treated and packaged for disposal. During the storage period, sludge in the STSCs may consolidate/agglomerate, potentially resulting in high-shear-strength material. The Sludge Treatment Project (STP) plans to use water jets to retrieve K-Basin sludge after the interim storage. STP has identified shear strength to be a key parameter that should be bounded to verify the operability and performance of sludge retrieval systems. Determining the range of sludge shear strength is important to gain high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from the STSCs. The shear strength measurements will provide a basis for bounding sludge properties for mobilization and erosion. Thus, it is also important to develop potential simulants to investigate these phenomena. Long-term sludge storage tests conducted by Pacific Northwest National Laboratory (PNNL) show that high-uranium-content K-Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has 'paste' and 'chunks' with shear strengths of approximately 3-5 kPa and 380-770 kPa, respectively. High-uranium-content sludge samples subjected to hydrothermal testing (e.g., 185 C, 10 hours) have been observed to form agglomerates with a shear strength up to 170 kPa. These high values were estimated by measured unconfined compressive strength (UCS) obtained with a pocket penetrometer. Due to its ease of use, it is anticipated that a pocket penetrometer will be used to acquire additional shear strength data from archived K-Basin sludge samples stored at the PNNL Radiochemical Processing Laboratory (RPL) hot cells. It is uncertain whether the pocket penetrometer provides accurate shear strength measurements of the material. To assess the bounding material strength and

  17. Study on creep of fiber reinforced ultra-high strength concrete based on strength

    Science.gov (United States)

    Peng, Wenjun; Wang, Tao

    2018-04-01

    To complement the creep performance of ultra-high strength concrete, the long creep process of fiber reinforced concrete was studied in this paper. The long-term creep process and regularity of ultra-high strength concrete with 0.5% PVA fiber under the same axial compression were analyzed by using concrete strength (C80/C100/C120) as a variable. The results show that the creep coefficient of ultra-high strength concrete decreases with the increase of concrete strength. Compared with ACI209R (92), GL2000 models, it is found that the predicted value of ACI209R (92) are close to the experimental value, and the creep prediction model suitable for this experiment is proposed based on ACI209R (92).

  18. Fatigue strength of repaired cracks in welded connections made of very high strength steels

    NARCIS (Netherlands)

    Akyel, A.

    2017-01-01

    For cyclically loaded structures, fatigue design becomes one of the important design criteria. The state of art shows that with modification of the conventional structural design methodology, the use of very high strength steels may have a positive effect on fatigue strength of welded connections.

  19. Mechanical behavior of high strength ceramic fibers at high temperatures

    Science.gov (United States)

    Tressler, R. E.; Pysher, D. J.

    1991-01-01

    The mechanical behavior of commercially available and developmental ceramic fibers, both oxide and nonoxide, has been experimentally studied at expected use temperatures. In addition, these properties have been compared to results from the literature. Tensile strengths were measured for three SiC-based and three oxide ceramic fibers for temperatures from 25 C to 1400 C. The SiC-based fibers were stronger but less stiff than the oxide fibers at room temperature and retained more of both strength and stiffness to high temperatures. Extensive creep and creep-rupture experiments have been performed on those fibers from this group which had the best strengths above 1200 C in both single filament tests and tests of fiber bundles. The creep rates for the oxides are on the order of two orders of magnitude faster than the polymer derived nonoxide fibers. The most creep resistant filaments available are single crystal c-axis sapphire filaments. Large diameter CVD fabricated SiC fibers are the most creep and rupture resistant nonoxide polycrystalline fibers tested to date.

  20. Effect of microstructure on the high temperature strength of nitride

    Indian Academy of Sciences (India)

    Effect of microstructure on the high temperature strength of nitride bonded silicon carbide composite. J Rakshit P K Das. Composites Volume ... The effect of these parameters on room temperature and high temperature strength of the composite up to 1300°C in ambient condition were studied. The high temperature flexural ...

  1. Influence of Temperature on Workability and Compressive Strength of Ordinary Concrete with High Calcium Fly Ash

    Directory of Open Access Journals (Sweden)

    Gołaszewski Jacek

    2017-06-01

    Full Text Available The rheological properties of fresh ordinary concrete are closely affected by temperature and time. The paper presents the study of consistency of fresh concrete mixtures made with Portland cement and cement with calcareous fly ash. Two types of admixtures were used. It was proven that the temperature has a clear effect on workability and compressive strength concrete. Influence on workability can be reduced by selecting the appropriate superplasticizer and cement.

  2. The influence of loading on the corrosion of steel in cracked ordinary Portland cement and high performance concretes

    Science.gov (United States)

    Jaffer, Shahzma Jafferali

    Most studies that have examined chloride-induced corrosion of steel in concrete have focused on sound concrete. However, reinforced concrete is seldom uncracked and very few studies have investigated the influence of cracked concrete on rebar corrosion. Furthermore, the studies that have examined the relationship between cracks and corrosion have focused on unloaded or statically loaded cracks. However, in practice, reinforced concrete structures (e.g. bridges) are often dynamically loaded. Hence, the cracks in such structures open and close which could influence the corrosion of the reinforcing steel. Consequently, the objectives of this project were (i) to examine the effect of different types of loading on the corrosion of reinforcing steel, (ii) the influence of concrete mixture design on the corrosion behaviour and (iii) to provide data that can be used in service-life modelling of cracked reinforced concretes. In this project, cracked reinforced concrete beams made with ordinary Portland cement concrete (OPCC) and high performance concrete (HPC) were subjected to no load, static loading and dynamic loading. They were immersed in salt solution to just above the crack level at their mid-point for two weeks out of every four (wet cycle) and, for the remaining two weeks, were left in ambient laboratory conditions to dry (dry cycle). The wet cycle led to three conditions of exposure for each beam: (i) the non-submerged region, (ii) the sound, submerged region and (iii) the cracked mid-section, which was also immersed in the solution. Linear polarization resistance and galvanostatic pulse techniques were used to monitor the corrosion in the three regions. Potentiodynamic polarization, electrochemical current noise and concrete electrical resistance measurements were also performed. These measurements illustrated that (i) rebar corroded faster at cracks than in sound concrete, (ii) HPC was more protective towards the rebar than OPCC even at cracks and (iii) there

  3. Correlation between compressive strength and ultrasonic pulse velocity of high strength concrete incorporating chopped basalt fibre

    Science.gov (United States)

    Shafiq, Nasir; Fadhilnuruddin, Muhd; Elshekh, Ali Elheber Ahmed; Fathi, Ahmed

    2015-07-01

    Ultrasonic pulse velocity (UPV), is considered as the most important test for non-destructive techniques that are used to evaluate the mechanical characteristics of high strength concrete (HSC). The relationship between the compressive strength of HSC containing chopped basalt fibre stands (CBSF) and UPV was investigated. The concrete specimens were prepared using a different ratio of CBSF as internal strengthening materials. The compressive strength measurements were conducted at the sample ages of 3, 7, 28, 56 and 90 days; whilst, the ultrasonic pulse velocity was measured at 28 days. The result of HSC's compressive strength with the chopped basalt fibre did not show any improvement; instead, it was decreased. The UPV of the chopped basalt fibre reinforced concrete has been found to be less than that of the control mix for each addition ratio of the basalt fibre. A relationship plot is gained between the cube compressive strength for HSC and UPV with various amounts of chopped basalt fibres.

  4. The assessment of bond strength between heat damaged concrete and high strength fibre reinforced concrete

    Science.gov (United States)

    Zahid, M. Z. A. Mohd; Muhamad, K.

    2017-09-01

    The aim of this study is to assess the bond strength between heat damaged concrete and high strength fibre reinforced concrete (HPFRC). Firstly, this paper presents the various steps taken to prepare the HPFRC with self-compacting property. The minimum targeted slump flow is 600 mm and minimum targeted compressive strength is 80 MPa. The key mix variables considered are such as type of superplasticizer, water cement ratio and silica fume content. Then, the bond strength between the heat damaged concrete with HPFRC was examined. The experimental parameters are heating temperature, surface treatment technique and curing method and the results show that, all experimental parameters are significantly affected the bond strength between heat damaged concrete and HPFRC.

  5. Strength of precast concrete shear joints reinforced with high-strength wire ropes

    DEFF Research Database (Denmark)

    Joergensen, Henrik B.; Hoang, Linh Cao; Hagsten, Lars German

    2017-01-01

    This paper concerns the in-plane shear strength of connections between precast concrete wall elements reinforced with looped high-strength wire ropes. The looped wire ropes are pre-installed in so-called ‘wire boxes’ which function as shear keys. Although only a small amount of research...... on the shear strength of such connections can be found in the literature, this type of connection is increasingly being used because wire ropes are much more construction-friendly than traditional U-bars. A rigid plastic upper bound model for the shear strength of wall connections reinforced with looped wire...... ropes that are pre-installed in wire boxes is presented along with test results on the shear strength of connections with double-wire boxes. It is shown that the plastic solution agrees well with both the obtained test results and results from previously conducted tests....

  6. Strength Gain Properties up to five-year age of high-strength mass concrete

    International Nuclear Information System (INIS)

    Mitarai, Y.; Shigenobu, M.; Hiramine, T.; Inoue, K.; Nakane, S.; Ohike, T.

    1991-01-01

    Genkai No.3 plant of Kyushu Electric Power Co., Inc. presently under construction is a PWR type nuclear power plant with 1180 MW power output, and a prestressed concrete containment vessel (PCCV) was adopted for the reactor. The concrete used for the construction of the PCCV is the mass concrete with the wall thickness of 1.3 m in the general parts of the cylinder, and about 2 m at buttresses. It is the high strength concrete of the specified strength 420 kgf/cm 2 . As the preliminary study for the construction using such high strength mass concrete, the examination was carried out on the strength gain property of structural concrete using full scale simulated members. The various problems in the quality control were contemplated based on the results of the examination, and were reflected to actual construction, designating 13 weeks as the age for strength control, in order to build the concrete structures with high reliability. In this report, the outline of the study on the strength gain up to 5 year age carried out in the preliminary study is discussed. The experimental method, the method of evaluating structural strength, the mixing proportion of concrete and the results are reported. (K.I.)

  7. Evaluation of microsilica admixture for production of high strength concrete.

    Science.gov (United States)

    1990-08-01

    This study consisted of a laboratory evaluation of the effect of microsilica on the physical properties of both plastic and hardened portland cement concrete. Microsilica (silica fume) is a by-product of the industrial manufacture of ferro silicon an...

  8. Development of LTCC Materials with High Mechanical Strength

    International Nuclear Information System (INIS)

    Kawai, Shinya; Nishiura, Sousuke; Terashi, Yoshitake; Furuse, Tatsuji

    2011-01-01

    We have developed LTCC materials suitable for substrates of RF modules used in mobile phone. LTCC can provide excellent solutions to requirements of RF modules, such as down-sizing, embedded elements and high performance. It is also important that LTCC material has high mechanical strength to reduce risk of fracture by mechanical impact. We have established a method of material design for high mechanical strength. There are two successive steps in the concept to achieve high mechanical strength. The first step is to improve mechanical strength by increasing the Young's modulus, and the second step is either further improvement through the Young's modulus or enhancement of the fracture energy. The developed material, so called high-strength LTCC, thus possesses mechanical strength of 400MPa, which is twice as strong as conventional material whose mechanical strength is approximately 200MPa in typical. As a result, high-strength LTCC shows an excellent mechanical reliability, against the drop impact test for example. The paper presents material design and properties of LTCC materials.

  9. Blasted copper slag as fine aggregate in Portland cement concrete.

    Science.gov (United States)

    Dos Anjos, M A G; Sales, A T C; Andrade, N

    2017-07-01

    The present work focuses on assessing the viability of applying blasted copper slag, produced during abrasive blasting, as fine aggregate for Portland cement concrete manufacturing, resulting in an alternative and safe disposal method. Leaching assays showed no toxicity for this material. Concrete mixtures were produced, with high aggregate replacement ratios, varying from 0% to 100%. Axial compressive strength, diametrical compressive strength, elastic modulus, physical indexes and durability were evaluated. Assays showed a significant improvement in workability, with the increase in substitution of fine aggregate. With 80% of replacement, the concrete presented lower levels of water absorption capacity. Axial compressive strength and diametrical compressive strength decreased, with the increase of residue replacement content. The greatest reductions of compressive strength were found when the replacement was over 40%. For tensile strength by diametrical compression, the greatest reduction occurred for the concrete with 80% of replacement. After the accelerated aging, results of mechanic properties showed a small reduction of the concrete with blasted copper slag performance, when compared with the reference mixture. Results indicated that the blasted copper slag is a technically viable material for application as fine aggregate for concrete mixtures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Portland blended cements: demolition ceramic waste management

    International Nuclear Information System (INIS)

    Trezza, M.A.; Zito, S.; Tironi, A.; Irassar, E.F.; Rahhal, V.F.

    2017-01-01

    Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement. [es

  11. Increasing Lean Mass and Strength: A Comparison of High Frequency Strength Training to Lower Frequency Strength Training.

    Science.gov (United States)

    Thomas, Michael H; Burns, Steve P

    The purpose of this study was to determine the effect strength training frequency has on improvements in lean mass and strength. Participants were 7 women and 12 men, age ( χ̄ = 34.64 years ± 6.91 years), with strength training experience, training age ( χ̄ = 51.16 months ± 39.02 months). Participants were assigned to one of two groups to equal baseline group demographics. High frequency training group (HFT) trained each muscle group as the agonist, 3 times per week, exercising with 3 sets per muscle group per session (3 total body workouts). Low frequency training group (LFT) trained each muscle group as the agonist one time per week, completing all 9 sets during that one workout. LFT consisted of a routine split over three days: 1) pectoralis, deltoids, and triceps; 2) upper back and biceps; 3) quadriceps, hamstrings, calves, and abdominals. Following eight weeks of training, HFT increased lean mass by 1.06 kg ± 1.78 kg, (1.9%), and LFT increased lean mass by .99 kg ± 1.31 kg, (2.0%). HFT strength improvements on the chest press was 9.07 kg ± 6.33 kg, (11%), and hack squat 20.16 kg ± 11.59 kg, (21%). LFT strength improvements on chest press was 5.80kg ± 4.26 kg, (7.0%), and hack squat 21.83 kg ± 11.17 kg, (24 %). No mean differences between groups were significant. These results suggest that HFT and LFT of equal set totals result in similar improvements in lean mass and strength, following 8 weeks of strength training.

  12. Stabilization of marly soils with portland cement

    Science.gov (United States)

    Piskunov, Maksim; Karzin, Evgeny; Lukina, Valentina; Lukinov, Vitaly; Kholkin, Anatolii

    2017-10-01

    Stabilization of marlous soils with Portland cement will increase the service life of motor roads in areas where marl is used as a local road construction material. The result of the conducted research is the conclusion about the principal possibility of stabilization of marlous soils with Portland cement, and about the optimal percentage of the mineral part and the binding agent. When planning the experiment, a simplex-lattice plan was implemented, which makes it possible to obtain a mathematical model for changing the properties of a material in the form of polynomials of incomplete third order. Brands were determined for compressive strength according to GOST 23558-94 and variants of stabilized soils were proposed for road construction.

  13. Hospital waste ashes in Portland cement mortars

    International Nuclear Information System (INIS)

    Genazzini, C.; Zerbino, R.; Ronco, A.; Batic, O.; Giaccio, G.

    2003-01-01

    Nowadays, most concretes incorporate mineral additions such as pozzolans, fly ash, silica fume, blast furnace slag, and calcareous filler among others. Although the technological and economical benefits were the main reasons for the use of mineral additions, the prevention of environmental contamination by means of proper waste disposal becomes a priority. The chance of incorporating hospital waste ashes in Portland cement-based materials is presented here. Ash characterization was performed by chemical analysis, X-ray diffraction, radioactive material detection, and fineness and density tests. Conduction calorimetry and setting time tests were developed on pastes including ash contents from 0% to 100%. Mortars were prepared including ash contents up to 50% of cement. The results of setting time, temperature development, flexural and compressive strengths, water absorption, density, and leachability are analyzed. Results indicate that Portland cement systems could become an alternative for the disposal of this type of ashes

  14. [Compressive and bend strength of experimental admixed high copper alloys].

    Science.gov (United States)

    Sourai, P; Paximada, H; Lagouvardos, P; Douvitsas, G

    1988-01-01

    Mixed alloys for dental amalgams have been used mainly in the form of admixed alloys, where eutectic spheres are blend with conventional flakes. In the present study the compressive strength, bend strength and microstructure of two high-copper alloys (Tytin, Ana-2000) is compared with three experimental alloys prepared of the two high copper by mixing them in proportions of 3:1, 1:1 and 1:3 by weight. The results revealed that experimental alloys inherited high early and final strength values without any significant change in their microstructure.

  15. The possibility of using high strength reinforced concrete

    International Nuclear Information System (INIS)

    Miura, Nobuaki

    1991-01-01

    There is recently much research about and developments in reinforced concrete using high strength concrete and reinforcement. As a result, some high-rise buildings and nuclear buildings have been constructed with such concrete. Reinforced concrete will be stronger in the future, but there is a limit to its strength defined by the character of the materials and also by the character of the reinforced concrete members made of the concrete and reinforcement. This report describes the merits and demerits of using high strength reinforced concrete. (author)

  16. Engineering Performance of High Strength Concrete Containing Steel Fibre Reinforcement

    Directory of Open Access Journals (Sweden)

    Md Azree Othuman Mydin

    2013-09-01

    Full Text Available The development and utilization of the high strength concrete in the construction industry have been increasing rapidly. Fiber reinforced concrete is introduced to overcome the weakness of the conventional concrete because concrete normally can crack under a low tensile force and it is known to be brittle. Steel fibre is proved to be the popular and best combination in the high strength concrete to result the best in the mechanical and durability properties of high strength concrete with consideration of curing time, steel fibre geometry, concrete grade and else more. The incorporation of steel fibre in the mortar mixture is known as steel fibre reinforced concrete have the potential to produce improvement in the workability, strength, ductility and the deformation of high strength concrete. Besides that, steel fibre also increases the tensile strength of concrete and improves the mechanical properties of the steel fibre reinforced concrete. The range for any high strength concrete is between 60MPa-100MPa. Steel fibre reinforced concrete which contains straight fibres has poorer physical properties than that containing hooked end stainless steel fibre due to the length and the hooked steel fibre provide a better effective aspects ratio. Normally, steel fibre tensile strength is in the range of 1100MPa-1700MPa. Addition of less steel fibre volumes in the range of 0.5% to 1.0% can produce better increase in the flexural fatigue strength. The strength can be increased with addition of steel fibre up to certain percentage. This paper will review and present some basic properties of steel fibre reinforced concrete such as mechanical, workability and durability properties.

  17. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    Energy Technology Data Exchange (ETDEWEB)

    Han, K.; Embury, J.D.

    1998-10-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications.

  18. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    International Nuclear Information System (INIS)

    Han, K.; Embury, J.D.

    1998-01-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications

  19. Formability Characterization of a New Generation High Strength Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sriram Sadagopan; Dennis Urban; Chris Wong; Mai Huang; Benda Yan

    2003-05-16

    Advanced high strength steels (AHSS) are being progressively explored by the automotive industry all around the world for cost-effective solutions to accomplish vehicle lightweighting, improve fuel economy, and consequently reduce greenhouse emissions. Because of their inherent high strength, attractive crash energy management properties, and good formability, the effective use of AHSS such as Duel Phase and TRIP (Transformation Induced Plasticity) steels, will significantly contribute to vehicle lightweighting and fuel economy. To further the application of these steels in automotive body and structural parts, a good knowledge and experience base must be developed regarding the press formability of these materials. This project provides data on relevant intrinsic mechanical behavior, splitting limits, and springback behavior of several lots of mild steel, conventional high strength steel (HSS), advanced high strength steel (AHSS) and ultra-high strength steel (UHSS), supplied by the member companies of the Automotive Applications Committee (AAC) of the American Iron and Steel Institute (AISI). Two lots of TRIP600, which were supplied by ThyssenKrupp Stahl, were also included in the study. Since sheet metal forming encompasses a very diverse range of forming processes and deformation modes, a number of simulative tests were used to characterize the forming behavior of these steel grades. In general, it was found that formability, as determined by the different tests, decreased with increased tensile strength. Consistant with previous findings, the formability of TRIP600 was found to be exceptionally good for its tensile strength.

  20. Investigation of stress–strain models for confined high strength ...

    Indian Academy of Sciences (India)

    High strength concrete; confined concrete; stress–strain models; ... One of its advantages is the lessening column cross-sectional areas. It was ..... Ahmad S H, Shah S P 1982 Stress–strain curves of concrete confined by spiral reinforcement.

  1. A calculation method of cracking moment for the high strength ...

    Indian Academy of Sciences (India)

    mal stress and crack width for the tensional behaviour of concrete and has been proposed by ... stresses. To calculate concrete stress in a cross section of high strength concrete beams, failure strain is ..... American Concrete. Institute, Detroit.

  2. Translucency and Strength of High Translucency Monolithic Zirconium Oxide Materials

    Science.gov (United States)

    2016-05-17

    Zirconium -Oxide Materials presented at/published to the Journal of General Dentistry with MDWI 41-108, and has been assigned local file #16208. 2...Zirconia-Oxide Materials 6. TITLE OF MATERIAL TO BE PUBLISHED OR PRESENTED: Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide...OBSOLETE 48. DATE Page 3 of 3 Pages Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide Materials Abstract Dental materials

  3. Increased strength of concrete subject to high loading rates

    International Nuclear Information System (INIS)

    Curbach, M.

    1987-01-01

    Within the scope of this work various problems are discussed which occur in connection with concrete under high tensile loading rates (e.g. when a plane crashes on a nuclear power plant very high loads occur which act only for a very short time). Particularly the causes for the already frequently noticed increases in strength with increasing loading rates are investigated and also the question whether this increased strength can be taken into account when dimensioning a construction. (MM) [de

  4. Equipment and Protocols for Quasi-Static and Dynamic Tests of Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC)

    Science.gov (United States)

    2016-08-01

    Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) En gi ne er R es ea rc h an d D ev el op m en t Ce nt er Brett A...Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) Brett A. Williams, Robert D. Moser, William F. Heard, Carol F...equipment and protocols for tests of both very-high-strength concrete (VHSC) and high- strength high-ductility concrete (HSHDC) to predict blast

  5. Comparison of the physical and mechanical properties of MTA and portland cement.

    Science.gov (United States)

    Islam, Intekhab; Chng, Hui Kheng; Yap, Adrian U Jin

    2006-03-01

    This study evaluated and compared the pH, radiopacity, setting time, solubility, dimensional change, and compressive strength of ProRoot MTA (PMTA), ProRoot MTA (tooth colored formula) (WMTA), white Portland cement (WP), and ordinary Portland cement (OP). The results showed that PMTA and Portland cement have very similar physical properties. However, the radiopacity of Portland cement is much lower than that of PMTA. The compressive strength of PMTA was greater than Portland cement at 28 days. The major constituent of PMTA is Portland cement. Given the low cost of Portland cement and similar properties when compared to PMTA, it is reasonable to consider Portland cement as a possible substitute for PMTA in endodontic applications. However, industrially manufactured Portland cement is not approved currently for use in the United States and therefore no clinical recommendation can be made for its use in the human body. Further in vitro and in vivo tests, especially with regards its biocompatibility, should be conducted to ascertain if it meets the FDA requirements for use as a medical device.

  6. Development of Mix Design Method in Efforts to Increase Concrete Performance Using Portland Pozzolana Cement (PPC)

    Science.gov (United States)

    Krisnamurti; Soehardjono, A.; Zacoeb, A.; Wibowo, A.

    2018-01-01

    Earthquake disaster can cause infrastructure damage. Prevention of human casualties from disasters should do. Prevention efforts can do through improving the mechanical performance of building materials. To achieve high-performance concrete (HPC), usually used Ordinary Portland Cement (OPC). However, the most widely circulating cement types today are Portland Pozzolana Cement (PPC) or Portland Composite Cement (PCC). Therefore, the proportion of materials used in the HPC mix design needs to adjust to achieve the expected performance. This study aims to develop a concrete mix design method using PPC to fulfil the criteria of HPC. The study refers to the code/regulation of concrete mixtures that use OPC based on the results of laboratory testing. This research uses PPC material, gravel from Malang area, Lumajang sand, water, silica fume and superplasticizer of a polycarboxylate copolymer. The analyzed information includes the investigation results of aggregate properties, concrete mixed composition, water-binder ratio variation, specimen dimension, compressive strength and elasticity modulus of the specimen. The test results show that the concrete compressive strength achieves value between 25 MPa to 55 MPa. The mix design method that has developed can simplify the process of concrete mix design using PPC to achieve the certain desired performance of concrete.

  7. Influence of Eco-Friendly Mineral Additives on Early Age Compressive Strength and Temperature Development of High-Performance Concrete

    Science.gov (United States)

    Kaszynska, Maria; Skibicki, Szymon

    2017-12-01

    High-performance concrete (HPC) which contains increased amount of both higher grade cement and pozzolanic additives generates more hydration heat than the ordinary concrete. Prolonged periods of elevated temperature influence the rate of hydration process in result affecting the development of early-age strength and subsequent mechanical properties. The purpose of the presented research is to determine the relationship between the kinetics of the heat generation process and the compressive strength of early-age high performance concrete. All mixes were based on the Portland Cement CEM I 52.5 with between 7.5% to 15% of the cement mass replaced by the silica fume or metakaolin. Two characteristic for HPC water/binder ratios of w/b = 0.2 and w/b = 0.3 were chosen. A superplasticizer was used to maintain a 20-50 mm slump. Compressive strength was determined at 8h, 24h, 3, 7 and 28 days on 10x10x10 cm specimens that were cured in a calorimeter in a constant temperature of T = 20°C. The temperature inside the concrete was monitored continuously for 7 days. The study determined that the early-age strength (t<24h) of concrete with reactive mineral additives is lower than concrete without them. This is clearly visible for concretes with metakaolin which had the lowest compressive strength in early stages of hardening. The amount of the superplasticizer significantly influenced the early-age compressive strength of concrete. Concretes with additives reached the maximum temperature later than the concretes without them.

  8. Corrosion fatigue of high strength fastener materials in seawater

    Science.gov (United States)

    Tipton, D. G.

    1983-12-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  9. Microchip Electrophoresis at Elevated Temperatures and High Separation Field Strengths

    Science.gov (United States)

    Mitra, Indranil; Marczak, Steven P.; Jacobson, Stephen C.

    2014-01-01

    We report free-solution microchip electrophoresis performed at elevated temperatures and high separation field strengths. We used microfluidic devices with 11-cm long separation channels to conduct separations at temperatures between 22 (ambient) and 45 °C and field strengths from 100 to 1000 V/cm. To evaluate separation performance, N-glycans were used as a model system and labeled with 8-aminopyrene-1,3,6-trisulfonic acid to impart charge for electrophoresis and render them fluorescent. Typically, increased diffusivity at higher temperatures leads to increased axial dispersion and poor separation performance; however, we demonstrate that sufficiently high separation field strengths can be used to offset the impact of increased diffusivity in order to maintain separation efficiency. Efficiencies for these free-solution separations are the same at temperatures of 25, 35, and 45 °C with separation field strengths ≥500 V/cm. PMID:24114979

  10. Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

    Directory of Open Access Journals (Sweden)

    Keun-Hyeok Yang

    2015-01-01

    Full Text Available This study examined the relative strength-maturity relationship of high-strength concrete (HSC specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1 isothermal curing conditions of 5°C, 20°C, and 40°C and (2 terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

  11. Improving Strength-Ductility Balance of High Strength Dual-Phase Steels by Addition of Vanadium

    Science.gov (United States)

    Gong, Yu; Hua, M.; Uusitalo, J.; DeArdo, A. J.

    For galvanized or galvannealed steels to be commercially successful, they must exhibit several attributes: (i) easy and inexpensive processing in the hot mill, cold mill and on the coating line, (ii) high strength with good formability and spot weldability, and (iii) good corrosion resistance, especially after cold forming. For good corrosion resistance, the coating must have sufficient coverage, be of uniform thickness, and most importantly, the coating must survive the cold stamping or forming operation. The purpose of this paper is to present research aiming at improving the steel substrate, such that high strength can be obtained while maintaining good global formability (tensile ductility), local formability (sheared-edge ductility), and good spot weldability. It is well-known that the strength of DP steels is controlled by several factors, including the amount of martensite found in the final microstructure. Recent research has revealed that the amount of austenite formed during intercritical annealing can be strongly influenced by the annealing temperature and the pre-annealing conditions of the hot band (coiling temperature) and cold band (% cold reduction). Current experiments have explored the combination of pre-annealing conditions and four annealing practices to help define the best practice to optimize the strength-formability balance in these higher strength DP steels. The steels used in these experiments contained (i) low carbon content for good spot weldability, (ii) the hardenability additions Mo and Cr for strength, and (iii) V for grain refinement, precipitation hardening and temper resistance. When processed correctly, these steels exhibited UTS levels up to 1000MPa, total elongation to 25%, reduction in area to 45%, and Hole Expansion Ratios to 50%. The results of this program will be presented and discussed.

  12. Tensile strength/yield strength (TS/YS) ratios of high-strength steel (HSS) reinforcing bars

    Science.gov (United States)

    Tavio, Anggraini, Retno; Raka, I. Gede Putu; Agustiar

    2018-05-01

    The building codes such as American Concrete Institute (ACI) 318M-14 and Standard National Indonesia (SNI) 2847:2013 require that the ratio of tensile strength (TS) and yield strength (YS) should not less than 1.25. The requirement is based on the assumption that a capability of a structural member to develop inelastic rotation capacity is a function of the length of the yield region. This paper reports an investigation on various steel grades, namely Grades 420, 550, 650, and 700 MPa, to examine the impact of different TS/YS ratios if it is less or greater than the required value. Grades 550, 650, and 700 MPa were purposely selected with the intention to examine if these higher grades are still promising to be implemented in special structural systems since they are prohibited by the building codes for longitudinal reinforcement, whereas Grade 420 MPa bars are the maximum limit of yield strength of reinforcing bars that is allowable for longitudinal reinforcement of special structural systems. Tensile tests of these steel samples were conducted under displacement controlled mode to capture the complete stress-strain curves and particularly the post-yield response of the steel bars. From the study, it can be concluded that Grade 420 performed higher TS/YS ratios and they were able to reach up to more than 1.25. However, the High Strength Still (HSS) bars (Grades 550, 600, and 700 MPa) resulted in lower TS/YS ratios (less than 1.25) compared with those of Grade 420 MPa.

  13. Influence of irradiation on high-strength graphites

    International Nuclear Information System (INIS)

    Virgil'ev, Yu.S.; Grebennik, V.N.; Kalyagina, I.P.

    1989-01-01

    To ensure efficiency of the graphite elements of the construction of the masonry of reactors, the graphite must possess high radiation stability, strength, and heat resistance. In this connection, the physical properties of graphites based on uncalcined petroleum coke with a binder - high-temperature hard coal pitch - the amount of which reaches 40% are considered in this paper

  14. El strength function at high spin and excitation energy

    International Nuclear Information System (INIS)

    Barrette, J.

    1983-04-01

    Recently giant dipole resonance-like concentration of the dipole strength function in nuclei was observed at both high excitation energies and high spins. This observation raises the possibility of obtaining new information on the shape of rapidly rotating heated nuclei. Recent experimental results on this subject are reviewed

  15. Strength-toughness requirements for thick walled high pressure vessels

    International Nuclear Information System (INIS)

    Kapp, J.A.

    1990-01-01

    The strength and toughness requirements of materials for use in high pressure vessels has been the subject of some discussion in the meetings of the Materials Task Group of the Special Working Group High Pressure Vessels. A fracture mechanics analysis has been performed to theoretically establish the required toughness for a high pressure vessel. This paper reports that the analysis performed is based on the validity requirement for plane strain fracture of fracture toughness test specimens. This is that at the fracture event, the crack length, uncracked ligament, and vessel length must each be greater than fifty times the crack tip plastic zone size for brittle fracture to occur. For high pressure piping applications, the limiting physical dimension is the uncracked ligament, as it can be assumed that the other dimensions are always greater than fifty times the crack tip plastic zone. To perform the fracture mechanics analysis several parameters must be known: these include vessel dimensions, material strength, degree of autofrettage, and design pressure. Results of the analysis show, remarkably, that the effects of radius ratio, pressure and degree of autofrettage can be ignored when establishing strength and toughness requirements for code purposes. The only parameters that enter into the calculation are yield strength, toughness and vessel thickness. The final results can easily be represented as a graph of yield strength against toughness on which several curves, one for each vessel thickness, are plotted

  16. Optimal welding technology of high strength steel S690QL

    Directory of Open Access Journals (Sweden)

    Dusan Arsic

    2015-02-01

    Full Text Available In this paper is presented the detailed procedure for defining the optimal technology for welding the structures made of the high strength steel S690QL. That steel belongs into a group of steels with exceptional mechanical properties. The most prominent properties are the high tensile strength and impact toughness, at room and at elevated temperatures, as well. However, this steel has a negative characteristic - proneness to appearance of cold cracks.  That impedes welding and makes as an imperative to study different aspects of this steel's properties as well as those of eventual filler metal. Selection and defining of the optimal welding technology of this high strength steel is done for the purpose of preserving the favorable mechanical properties once the welded joint is realized; properties of the welded metal and the melting zone, as well as in the heat affected zone, which is the most critical zone of the welded joint.

  17. Additively manufactured hierarchical stainless steels with high strength and ductility

    Science.gov (United States)

    Wang, Y. Morris; Voisin, Thomas; McKeown, Joseph T.; Ye, Jianchao; Calta, Nicholas P.; Li, Zan; Zeng, Zhi; Zhang, Yin; Chen, Wen; Roehling, Tien Tran; Ott, Ryan T.; Santala, Melissa K.; Depond, Philip J.; Matthews, Manyalibo J.; Hamza, Alex V.; Zhu, Ting

    2018-01-01

    Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

  18. Review on fatigue behavior of high-strength concrete after high temperature

    Science.gov (United States)

    Zhao, Dongfu; Jia, Penghe; Gao, Haijing

    2017-06-01

    The fatigue of high-strength concrete after high temperature has begun to attract attention. But so far the researches work about the fatigue of high-strength concrete after high temperature have not been reported. This article based on a large number of literature. The research work about the fatigue of high-strength concrete after high temperature are reviewed, analysed and expected, which can provide some reference for the experimental study of fatigue damage analysis.

  19. Localized bending fatigue behavior of high-strength steel monostrands

    DEFF Research Database (Denmark)

    Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.

    2012-01-01

    In this paper, the localized bending fatigue behavior of pretensioned high strength steel monostrands is investigated. Furthermore, a new methodology using an optical photogrammetry system, which can quantify surface deformations on the strand is presented. The system allows measurement of the st......In this paper, the localized bending fatigue behavior of pretensioned high strength steel monostrands is investigated. Furthermore, a new methodology using an optical photogrammetry system, which can quantify surface deformations on the strand is presented. The system allows measurement...... displacement (opening/closing and sliding) of the helically wound wires. Moreover, the results are a step towards understanding the bending fatigue damage mechanisms of monostrand cables....

  20. Shock characterization of an ultra-high strength concrete

    International Nuclear Information System (INIS)

    Erzar, B.; Pontiroli, C.; Buzaud, E.

    2016-01-01

    Nowadays, the design of protective structures may imply ultra-high performance concretes. These materials present a compressive strength 5 times higher than standard concretes. However, few reliable data on the shock response of such materials are available in the literature. Thus, a characterization of an ultra-high strength concrete has been conducted by means of hydrostatic and triaxial tests in the quasi-static regime, and plate impact experiments for shock response. Data have been gathered up to 6 GPa and a simple modelling approach has been applied to get a reliable representation of the shock compression of this concrete. (authors)

  1. High strength tungsten heavy alloys with molybdenum additions

    International Nuclear Information System (INIS)

    Bose, A.; Sims, D.M.; German, R.M.

    1987-01-01

    Tungsten heavy alloys are candidates for numerous applications based on the unique combination of high density, high strength, and high ductility coupled with excellent machinability. Though there has been considerable research on heavy alloys, the primary focus has been on the ductility. These alloys are well suited for ballistic uses due to their high densities and it is expected that for superior ballistic performance, a high hardness, high strength and moderate ductility alloy would be ideal. The major goal of this investigation was to obtain heavy alloys with hardness greater than HRA 72. It is evident from the phase diagrams that molybdenum, which goes into solution in tungsten, nickel and iron, could act as a potential strengthening addition. With this in view, tungsten heavy alloys with molybdenum additions were fabricated from mixed elemental powders. A baseline composition of 90W-7Ni-3Fe was chosen to its good elongation and moderate strength. The molybdenum additions were made by replacing the tungsten. Compared to the baseline properties with no molybdenum addition, the strength and hardness showed a continuous increase with molybdenum addition. The ductility of the alloy continued to decrease with increasing molybdenum content, but even with 16% wt. % molybdenum of the elongation was still around 6%. An interesting facet of these alloying additions is the grain refinement that is brought about by adding to molybdenum to the system. The grain refinement is related to the lower solubility of tunbsten in the matrix due to partial displacement by molybdenum

  2. Behavior and strength of beams cast with ultra high strength concrete containing different types of fibers

    Directory of Open Access Journals (Sweden)

    M.M. Kamal

    2014-04-01

    Full Text Available Ultra-high performance concrete (UHPC is a special type of concrete with extraordinary potentials in terms of strength and durability performance. Its production and application implement the most up-to-date knowledge and technology of concrete manufacturing. Sophisticated structural designs in bridges and high-rise buildings, repair works and special structures like nuclear facilities are currently the main fields of applications of UHPC. This paper aimed to evaluate the behavior of ultra-high strength concrete beams. This paper also aimed to determine the effect of adding fibers and explore their effect upon the behavior and strength of the reinforced concrete beams. A total of twelve simple concrete beams with and without shear reinforcements were tested in flexure. The main variables taken into consideration in this research were the type of fibers and the percentage of longitudinal reinforcement as well as the existence or absence of the web reinforcement. Two types of fibers were used including steel and polypropylene fibers. The behavior of the tested beams was investigated with special attention to the deflection under different stages of loading, initial cracking, cracking pattern, and ultimate load. Increased number of cracks was observed at the end of loading due to the use of fibers, which led to the reduced width of cracks. This led to increased stiffness and higher values of maximum loads.

  3. Reduction of the Early Autogenous Shrinkage of High Strength Concrete

    Directory of Open Access Journals (Sweden)

    Drago Saje

    2015-01-01

    Full Text Available The results of a laboratory investigation on the early autogenous shrinkage of high strength concrete, and the possibilities of its reduction, are presented. Such concrete demonstrates significant autogenous shrinkage, which should, however, be limited in the early stages of its development in order to prevent the occurrence of cracks and/or drop in the load-carrying capacity of concrete structures. The following possibilities for reducing autogenous shrinkage were investigated: the use of low-heat cement, a shrinkage-reducing admixture, steel fibres, premoistened polypropylene fibres, and presoaked lightweight aggregate. In the case of the use of presoaked natural lightweight aggregate, with a fraction from 2 to 4 mm, the early autogenous shrinkage of one-day-old high strength concrete decreased by about 90%, with no change to the concrete's compressive strength in comparison with that of the reference concrete.

  4. Long-term high temperature strength of 316FR steel

    International Nuclear Information System (INIS)

    Takahashi, Yukio

    1995-01-01

    As low-carbon medium-nitrogen type 316 stainless steel (316FR) was selected as a primary candidate for main structural material of a next fast reactor plant in Japan, its long-term high-temperature strength gains much interest from many organizations involved in design activities of the plant. Central Research Institute of Electric Power Industry (CRIEPI), as a research organization for electric power industry in Japan, has been conducting a multi-year project under the sponsorship of Ministry of International Trade and Industry (MITI) for studying the long-term high temperature strength of this steel. Data obtained by various strength tests, including short-time tensile, fatigue, creep and creep-fatigue tests for this steel are given in this paper. The results of study on creep-fatigue life prediction methods are also presented. It was found that modified ductility exhaustion method previously proposed by the author has satisfactory accuracy in creep-fatigue life estimation

  5. Fatigue life of high strength steel for cold forming

    Directory of Open Access Journals (Sweden)

    R. Ulewicz

    2017-01-01

    Full Text Available The article presents the results of fatigue tests carried out on STRENX-type high-strength cold forming steel. For high-cycle fatigue tests carried out using low cycle loading frequencies of around 30 Hz, a ROTOFLEX machine was used. For ultra high-cycle tests, a KAUP-ZU testing machine was employed, which enables fatigue tests to be performed with symetric specimen loading (R = -1 and at a frequency of f ≈ 20 kHz. The relationships σa = f(N were determined experimentally in the high and ultra high-cycle region for STRENX high-strength steel. To determine the fatigue crack initiation mechanism, the fractographic analysis of fatigue fractures was made.

  6. Modelling porewater chemistry in hydrated Portland cement

    International Nuclear Information System (INIS)

    Berner, U.R.

    1987-01-01

    Extensive employment of concrete is foreseen in radioactive waste repositories. A prerequisite for modelling the interactions between concrete and formation waters is characterization of the concrete system. Available experimental data from high pressure squeezing of cement pore-water indicate that, besides the high pH due to alkali hydroxide dissolution, cement composition itself influences the solubility determining solid phases. A model which simulates the hydration of Portland cement assuming complete hydration of the main clinker minerals is presented. The model also includes parameters describing the reactions between the cement and blending agents. Comparison with measured pore-water data generally gives a consistent picture and, as expected, the model gives correct predictions for pure Portland cements. For blended cements, the required additional parameters can, to some extent, be derived from pore-water analysis. 14 references, 1 figure, 4 tables

  7. Strength Development of High-Strength Ductile Concrete Incorporating Metakaolin and PVA Fibers

    Directory of Open Access Journals (Sweden)

    Muhammad Fadhil Nuruddin

    2014-01-01

    Full Text Available The mechanical properties of high-strength ductile concrete (HSDC have been investigated using Metakaolin (MK as the cement replacing material and PVA fibers. Total twenty-seven (27 mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

  8. Strength development of high-strength ductile concrete incorporating Metakaolin and PVA fibers.

    Science.gov (United States)

    Nuruddin, Muhammad Fadhil; Khan, Sadaqat Ullah; Shafiq, Nasir; Ayub, Tehmina

    2014-01-01

    The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

  9. Modelling of tension stiffening for normal and high strength concrete

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1998-01-01

    form the model is extended to apply to biaxial stress fields as well. To determine the biaxial stress field, the theorem of minimum complementary elastic energy is used. The theory has been compared with tests on rods, disks, and beams of both normal and high strength concrete, and very good results...

  10. High-strength porous carbon and its multifunctional applications

    Science.gov (United States)

    Wojtowicz, Marek A; Rubenstein, Eric P; Serio, Michael A; Cosgrove, Joseph E

    2013-12-31

    High-strength porous carbon and a method of its manufacture are described for multifunctional applications, such as ballistic protection, structural components, ultracapacitor electrodes, gas storage, and radiation shielding. The carbon is produced from a polymer precursor via carbonization, and optionally by surface activation and post-treatment.

  11. Rheology of High-Melt-Strength Polypropylene for Additive Manufacturing

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Kamleitner, Florian; Jagenteufel, Ralf

    Acrylonitrile butadiene styrene (ABS) is a widely used material for additive manufacturing (AM) fused deposition modeling (FDM). The rheological properties of high-melt-strength polypropylene (HMS-PP) were compared to commercially available ABS 250 filament to study the possibility of using...

  12. Anaerobic dynamic membrane bioreactors for high strength wastewater treatment

    NARCIS (Netherlands)

    Ersahin, M.E.; Gimenez Garcia, J.B.; Ozgun, H.; Tao, Y.; Van Lier, J.B.

    2013-01-01

    A laboratory scale external anaerobic dynamic membrane bioreactor (AnDMBR) treating high strength wastewater was operated to assess the effect of gas sparging velocity and organic loading rate on removal efficiency and dynamic membrane (DM) filtration characteristics. An increase in gas sparging

  13. Performance assessment on high strength steel endplate connections after fire

    NARCIS (Netherlands)

    Qiang, X.; Wu, N.; Jiang, X.; Bijlaard, F.S.K.; Kolstein, M.H.

    2017-01-01

    Purpose – This study aims to reveal more information and understanding on performance and failure mechanisms of high strength steel endplate connections after fire. Design/methodology/approach – An experimental and numerical study on seven endplate connections after

  14. Influence of curing regimes on compressive strength of ultra high

    Indian Academy of Sciences (India)

    The present paper is aimed to identify an efficient curing regime for ultra high performance concrete (UHPC), to achieve a target compressive strength more than 150 MPa, using indigenous materials. The thermal regime plays a vital role due to the limited fineness of ingredients and low water/binder ratio. By activation of the ...

  15. Study on Fatigue Characteristics of High-Strength Steel Welds

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hong Suk; Yoo, Seung Won; Park, Jong Chan [Hyundai Motor Group, Seoul (Korea, Republic of)

    2015-03-15

    High-strength steel has replaced mild steel as the material of choice for truck decks or frames, owing to the growing demand for lightweight vehicles. Although studies on the weld fatigue characteristics of mild steel are available, studies on high-strength steels have been seldom conducted. In this study, firstly, we surveyed a chosen number of approaches and selected the Radaj method, which uses the notch factor approach, as the one suitable for evaluating the fatigue life of commercial vehicles. Secondly, we obtained the S-N curves of HARDOX and ATOS60 steel welds, and the F-N curves of the T-weld and overlapped-weld structures. Thirdly, we acquired a general S-N curve of welded structures made of high-strength steel from the F-N curve, using the notch factor approach. Fourthly, we extracted the weld fatigue characteristics of high-strength steel and incorporated the results in the database of a commercial fatigue program. Finally, we compared the results of the fatigue test and the CAE prediction of the example case, which demonstrated sufficiently good agreement.

  16. Oxidation Phenomena in Advanced High Strength Steels : Modelling and Experiment

    NARCIS (Netherlands)

    Mao, W.

    2018-01-01

    Galvanized advanced high strength steels (AHSS) will be the most competitive structural material for automotive applications in the next decade. Oxidation of AHSS during the recrystalization annealing process in a continuous galvanizing line to a large extent influences the quality of zinc coating

  17. Crack formation and fracture energy of normal and high strength ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. The crack path through composite materials such as concrete depends on the mechanical interaction of inclusions with the cement-based matrix. Fracture energy depends on the deviations of a real crack from an idealized crack plane. Fracture energy and strain softening of normal, high strength, and self- ...

  18. Improving the casting properties of high-strength aluminium alloys:

    OpenAIRE

    Ekrt, Ondřej; Šerák, Jan; Vojtěch, Dalibor

    2004-01-01

    Al-Zn-Mg-Cu alloys are examples of high-strength alloys. After age-hardening they often possess tensile strengths of more than 500 MPa. However, their casting properties are relatively poor as a result of solidification intervals that are too wide. Therefore, they often require an extrusion, rolling, or forging treatment, and the production of small series of special parts can, as a consequence, be very expensive. In this study, an improvement in the castability and a reduction of the hot-tea...

  19. Fracture Energy of High-Strength Concrete in Compression

    DEFF Research Database (Denmark)

    Dahl, Henrik; Brincker, Rune

    is essential for understanding the fracture mechanism of concrete in compression. In this paper a series of tests is reported, carried out for the purpose of studying the fracture mechanical properties of concrete in compression. Including the measurement and study of the descending branch, a new experimental...... method has been used to investigate the influence of boundary conditions, loading rate, size effects and the influence of the strength on the fracture energy of high-strength concrete over the range 70 MPa to 150 MPa, expressed in nominal values....

  20. Portland-pfa cement: a comparison between intergrinding and blending

    Energy Technology Data Exchange (ETDEWEB)

    Monk, M

    1983-09-01

    Portland-pfa cements containing 20-40% (by weight) pfa have been prepared in the laboratory both by intergrinding the ashes with clinker and by blending with cement. Cement properties have been assessed according to BS 4550 and scanning electron microscopy was used to examine the effects of grinding upon the pfa particles. The work has shown that intergrinding leads to an improvement in the water-reducing properties of coarse pfas and also in their pozzolanic activity as indicated by compressive strength development at later ages. Setting times have been found to be essentially the same for blended and interground cements, both being considerably longer than for typical ordinary Portland cements. Thus the results of this investigation indicate that, provided pfa's are chemically acceptable, they can be used for Portland-pfa cement manufacture by intergrinding irrespective of their coarseness.

  1. Theoretical design and advanced microstructure in super high strength steels

    International Nuclear Information System (INIS)

    Caballero, F.G.; Santofimia, M.J.; Garcia-Mateo, C.; Chao, J.; Garcia de Andres, C.

    2009-01-01

    A theoretical design procedure based on phase transformation theory alone has been successfully applied to design steels with a microstructure consisting of a mixture of bainitic ferrite and retained austenite. Using thermodynamics and kinetics models, a set of four carbide free bainitic steels with a 0.3 wt.% carbon content were designed and manufactured following a thermomechanical treatment consisting of hot rolling and two-step cooling. The designed steels present significant combinations of strength and ductility, with tensile strengths ranging from 1500 to 1800 MPa and total elongations over 15%. However, a carbon content of 0.3 wt.% is still high for in-use properties such as weldability. In this sense, a reduction in the average carbon content of advanced bainitic steels was proposed. Improved bainitic steels with a carbon content of 0.2 wt.% reached combinations of strength and ductility comparable to those in TRIP assisted steels.

  2. Recent trends in steel fibered high-strength concrete

    International Nuclear Information System (INIS)

    Shah, Abid A.; Ribakov, Y.

    2011-01-01

    Highlights: → Recent studies on steel fibred high strength concrete (SFHSC) are reviewed. → Different design provisions for SFHSC are compared. → Applications of SFHSC in new and existing structures and elements are discussed. → Using non-destructive techniques for quality control of SFHSC are reviewed. -- Abstract: Steel fibered high-strength concrete (SFHSC) became in the recent decades a very popular material in structural engineering. High strength attracts designers and architects as it allows improving the durability as well as the esthetics of a construction. As a result of increased application of SFHSC, many experimental studies are conducted to investigate its properties and to develop new rules for proper design. One of the trends in SFHSC structures is to provide their ductile behavior that is desired for proper structural response to dynamic loadings. An additional goal is to limit development and propagation of macro-cracks in the body of SFHSC elements. SFHSC is tough and demonstrates high residual strengths after appearance of the first crack. Experimental studies were carried out to select effective fiber contents as well as suitable fiber types, to study most efficient combination of fiber and regular steel bar reinforcement. Proper selection of other materials like silica fume, fly ash and super plasticizer has also high importance because of the influence on the fresh and hardened concrete properties. Combination of normal-strength concrete with SFHSC composite two-layer beams leads to effective and low cost solutions that may be used in new structures as well as well as for retrofitting existing ones. Using modern nondestructive testing techniques like acoustic emission and nonlinear ultrasound allows verification of most design parameters and control of SFHSC properties during casting and after hardening. This paper presents recent experimental results, obtained in the field SFHSC and non-destructive testing. It reviews the

  3. Application of high strength steel to nuclear reactor containment vessel

    International Nuclear Information System (INIS)

    Susukida, H.; Sato, M.; Takano, G.; Uebayashi, T.; Yoshida, K.

    1976-01-01

    Nuclear reactor containment vessels are becoming larger in size with the increase in the power generating capacity of nuclear power plants. For example, a containment vessel for a PWR power plant with an output of 1,000 MWe becomes an extremely large one if it is made of the conventional JIS SGV 49 (ASTM A 516 Gr. 70) steel plates less than 38 mm in thickness. In order to design the steel containment vessel within the conventional dimensional range, therefore, it is necessary to use a high strength steel having a higher tensile strength than SGV 49 steel, good weldability and a higher fracture toughness and moreover, possessing satisfactory properties without undergoing post-weld heat treatment. The authors conducted a series of verification tests on high strength steel developed by modifying the ASTM A 543 Grade B Class 1 steel with a view to adopting it as a material for the nuclear reactor containment vessels. As the result of evaluation of the test results from various angles, we confirmed that the high strength steel is quite suitable for the manufacture of nuclear reactor containment vessels. (auth.)

  4. Behaviour of high-strength concrete incorporating ground ...

    African Journals Online (AJOL)

    106. Behaviour of high-strength concrete incorporating ground granulated blast furnace slag at high-temperature. Comportement à haute température du béton à haute résistance à base de laitier granulé de haut fourneau. Imene Saadi*1 & Abdelaziz Benmarce2. 1Laboratoire Matériaux Géométraux et Environnement, ...

  5. Microcapillary Features in Silicon Alloyed High-Strength Cast Iron

    Directory of Open Access Journals (Sweden)

    R.K. Hasanli

    2017-04-01

    Full Text Available Present study explores features of silicon micro capillary in alloyed high-strength cast iron with nodular graphite (ductile iron produced in metal molds. It identified the nature and mechanism of micro liquation of silicon in a ductile iron alloyed with Nickel and copper, and demonstrated significant change of structural-quality characteristics. It was concluded that the matrix of alloyed ductile iron has a heterogeneous structure with cross reinforcement and high-silicon excrement areas.

  6. Bainitic high-strength cast iron with globular graphite

    Science.gov (United States)

    Silman, G. I.; Makarenko, K. V.; Kamynin, V. V.; Zentsova, E. A.

    2013-07-01

    Special features of formation of bainitic structures in grayed cast irons are considered. The influence of the graphite phase and of the special features of chemical composition of the iron on the intermediate transformation in high-carbon alloys is allowed for. The range of application of high-strength cast irons with bainitic structure is determined. The paper is the last and unfinished work of G. I. Silman completed by his disciples as a tribute to their teacher.

  7. Mechanical Properties of Heat Affected Zone of High Strength Steels

    Science.gov (United States)

    Sefcikova, K.; Brtnik, T.; Dolejs, J.; Keltamaki, K.; Topilla, R.

    2015-11-01

    High Strength Steels became more popular as a construction material during last decade because of their increased availability and affordability. On the other hand, even though general use of Advanced High Strength Steels (AHSS) is expanding, the wide utilization is limited because of insufficient information about their behaviour in structures. The most widely used technique for joining steels is fusion welding. The welding process has an influence not only on the welded connection but on the area near this connection, the so-called heat affected zone, as well. For that reason it is very important to be able to determine the properties in the heat affected zone (HAZ). This area of investigation is being continuously developed in dependence on significant progress in material production, especially regarding new types of steels available. There are currently several types of AHSS on the world market. Two most widely used processes for AHSS production are Thermo-Mechanically Controlled Processing (TMCP) and Quenching in connection with Tempering. In the presented study, TMCP and QC steels grade S960 were investigated. The study is focused on the changes of strength, ductility, hardness and impact strength in heat affected zone based on the used amount of heat input.

  8. NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert Radtke

    2006-01-31

    The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.

  9. Development of a high strength, hydrogen-resistant austenitic alloy

    International Nuclear Information System (INIS)

    Chang, K.M.; Klahn, D.H.; Morris, J.W. Jr.

    1980-08-01

    Research toward high-strength, high toughness nonmagnetic steels for use in the retaining rings of large electrical generators led to the development of a Ta-modified iron-based superalloy (Fe-36 Ni-3 Ti-3 Ta-0.5 Al-1.3 Mo-0.3 V-0.01 B) which combines high strength with good toughness after suitable aging. The alloy did, however, show some degradation in fatigue resistance in gaseous hydrogen. This sensitivity was associated with a deformation-induced martensitic transformation near the fracture surface. The addition of a small amount of chromium to the alloy suppressed the martensite transformation and led to a marked improvement in hydrogen resistance

  10. High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Mariano Velez

    2008-03-31

    Calcium-iron-phosphate glasses were developed whose chemical durabilities in alkaline solutions (pH 13) were comparable or superior to those of commercial alkaline-resistant (AR) silica-based glasses. However, the tensile strength of Ca-Fe-phosphate fibers, after being exposed to alkaline environments, including wet Portland cement pastes, is lower than that of current AR silicate fibers. Another series of Ca-Fe-phosphate glasses were developed with excellent chemical durability in strong acidic solutions (H2SO4, HF), indicating potential applications where silica-based fibers degrade very quickly, including E-glass. The new Ca-Fe-phosphate glasses can be melted and processed 300 to 500°C lower than silica-based glasses. This offers the possibility of manufacturing glass fibers with lower energy costs by 40-60% and the potential to reduce manufacturing waste and lower gas emissions. It was found that Ca-Fe-phosphate melts can be continuously pulled into fibers depending on the slope of the viscosity-temperature curve and with viscosity ~100 poise, using multi-hole Pt/Rh bushings.

  11. Oxidation resistant high creep strength austenitic stainless steel

    Science.gov (United States)

    Brady, Michael P.; Pint, Bruce A.; Liu, Chain-Tsuan; Maziasz, Philip J.; Yamamoto, Yukinori; Lu, Zhao P.

    2010-06-29

    An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800.degree. C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.

  12. Fatigue Life of High-Strength Steel Offshore Tubular Joints

    DEFF Research Database (Denmark)

    Petersen, Rasmus Ingomar; Agerskov, Henning; Lopez Martinez, Luis

    1996-01-01

    In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high-strength......In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high......-strength steel with a yield stress of 820-830 MPa and with high weldability and toughness properties. The test specimens of both series had the same geometry. The present report concentrates on the results obtained in the investigation on the high-strength steel tubular joints.The test specimens were fabricated...... from Ø 324-610 mm tubes, and the joints were loaded in in-plane bending. Both fatigue tests under constant amplitude loading and tests with a stochastic loading that is realistic in relation to offshore structures, are included in the investigation.A comparison between constant amplitude and variable...

  13. High-energy behavior of field-strength interactions

    International Nuclear Information System (INIS)

    Levin, D.N.

    1976-01-01

    It is known that spontaneously broken gauge theories are the only renormalizable theories of massive spin-one particles with mass dimension less than or equal to 4. This paper describes a search for renormalizable interactions with higher mass dimension. Specifically, we examine the high-energy behavior of a class of models which involve field-strength interactions. Power counting shows that the high-energy behavior of these models is no worse than the naively estimated high-energy behavior of a gauge theory in the U gauge. Therefore, there may be a ''soft'' symmetry-breaking mechanism (for instance, a soft divergence of an antisymmetric tensor current) which enforces renormalizable high-energy behavior in the same way that spontaneously broken gauge invariance guarantees the renormalizability of gauge theories. This hope is supported by the existence of ''gauge theories'' of strings, which describe analogous interactions of strings and field strengths. Unfortunately, this idea is tarnished by explicit calculations in which renormalizability is imposed in the form of unitarity bounds. These unitarity bounds imply that all possible field-strength couplings must be zero and that the remaining interactions describe a spontaneously broken gauge theory. Thus this result supports an earlier conjecture that gauge theories are the only renormalizable theories of massive vector bosons

  14. High-strength shape memory steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

    1996-01-01

    Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

  15. Creep and Shrinkage of High Strength Concretes: an Experimental Analysis

    Directory of Open Access Journals (Sweden)

    Berenice Martins Toralles carbonari

    2002-01-01

    Full Text Available The creep and shrinkage behaviour of high strength silica fume concretes is significantly different from that of conventional concretes. In order to represent the proper time-dependent response of the material in structural analysis and design, these aspects should be adequately quantified. This paper discusses an experimental setup that is able to determine the creep and shrinkage of concrete from the time of placing. It also compares different gages that can be used for measuring the strains. The method is applied to five different concretes in the laboratory under controlled environmental conditions. The phenomena that are quantified can be classified as basic shrinkage, drying shrinkage, basic creep and drying creep. The relative importance of these mechanisms in high strength concrete will also be presented.

  16. Fundamental corrosion characterization of high-strength titanium alloys

    International Nuclear Information System (INIS)

    Schutz, R.W.; Grauman, J.S.

    1984-01-01

    Many commercially available and several developmental high-strength titanium alloys were evaluated for application in chloride-containing environments with respect to general, crevice, and stress corrosion resistance. Studies in boiling reducing and oxidizing acid chloride media permitted identification of certain high-strength titanium alloys, containing ≥4 weight % molybdenum, which are significantly more resistant than unalloyed titanium with respect to general and crevice attack. Data regression analysis suggests that molybdenum and vanadium impart a significant positive effect on alloy corrosion resistance under reducing acid chloride conditions, whereas aluminum is detrimental. Little effect of metallurgical condition (that is, annealed versus aged) on corrosion behavior of the higher molybdenum-containing alloys was noted. No obvious susceptibility to chloride and sulfide stress corrosion cracking (SCC) was detected utilizing U-bend specimens at 177 0 C

  17. Normal and refractory concretes for LMFBR applications. Volume 1. Review of literature on high-temperature behavior of portland cement and refractory concretes. Final report

    International Nuclear Information System (INIS)

    Bazant, Z.P.; Chern, J.C.; Abrams, M.S.; Gillen, M.P.

    1982-06-01

    The extensive literature on the properties and behavior at elevated temperature of portland cement concrete and various refractory concretes was reviewed to collect in concise form the physical and chemical properties of castable refractory concretes and of conventional portland cement concretes at elevated temperature. This survey, together with an extensive bibliography of source documents, is presented in Volume 1. A comparison was made of these properties, the relative advantages of the various concretes was evaluated for possible liquid metal fast breeder reactor applications, and a selection was made of several materials of interest for such applications. Volume 2 concludes with a summary of additional knowledge needed to support such uses of these materials together with recommendations on research to provide that knowledge

  18. Research on Inhibition for Corrosion Fatigue of High Strength Alloys

    Science.gov (United States)

    1978-12-15

    4140 , $740 1225-1275 1600-1675 1525-1575 1100 1000.. 925 850 725 4340 1225-1275 1600-1650 1500-1550 1100 1045 921. 875 72531 0 0 85 7 0 (I43 7-.22...1 0 le -kI Io o CRACK GROWTH RATE PJamOC Figure 24. Factors that Affect the Crack Growth Rate of High- Strength AISI 4340 Steels in Aqueous

  19. Grinding damage assessment on four high-strength ceramics.

    Science.gov (United States)

    Canneto, Jean-Jacques; Cattani-Lorente, Maria; Durual, Stéphane; Wiskott, Anselm H W; Scherrer, Susanne S

    2016-02-01

    The purpose of this study was to assess surface and subsurface damage on 4 CAD-CAM high-strength ceramics after grinding with diamond disks of 75 μm, 54 μm and 18 μm and to estimate strength losses based on damage crack sizes. The materials tested were: 3Y-TZP (Lava), dense Al2O3 (In-Ceram AL), alumina glass-infiltrated (In-Ceram ALUMINA) and alumina-zirconia glass-infiltrated (In-Ceram ZIRCONIA). Rectangular specimens with 2 mirror polished orthogonal sides were bonded pairwise together prior to degrading the top polished surface with diamond disks of either 75 μm, 54 μm or 18 μm. The induced chip damage was evaluated on the bonded interface using SEM for chip depth measurements. Fracture mechanics were used to estimate fracture stresses based on average and maximum chip depths considering these as critical flaws subjected to tension and to calculate possible losses in strength compared to manufacturer's data. 3Y-TZP was hardly affected by grinding chip damage viewed on the bonded interface. Average chip depths were of 12.7±5.2 μm when grinding with 75 μm diamond inducing an estimated loss of 12% in strength compared to manufacturer's reported flexural strength values of 1100 MPa. Dense alumina showed elongated chip cracks and was suffering damage of an average chip depth of 48.2±16.3 μm after 75 μm grinding, representing an estimated loss in strength of 49%. Grinding with 54 μm was creating chips of 32.2±9.1 μm in average, representing a loss in strength of 23%. Alumina glass-infiltrated ceramic was exposed to chipping after 75 μm (mean chip size=62.4±19.3 μm) and 54 μm grinding (mean chip size=42.8±16.6 μm), with respectively 38% and 25% estimated loss in strength. Alumina-zirconia glass-infiltrated ceramic was mainly affected by 75 μm grinding damage with a chip average size of 56.8±15.1 μm, representing an estimated loss in strength of 34%. All four ceramics were not exposed to critical chipping at 18 μm diamond grinding. Reshaping a

  20. 75 FR 20778 - Security Zone; Portland Rose Festival Fleet Week, Willamette River, Portland, OR

    Science.gov (United States)

    2010-04-21

    ...-AA87 Security Zone; Portland Rose Festival Fleet Week, Willamette River, Portland, OR AGENCY: Coast... during the Portland Rose Festival Fleet Week from June 2, 2010, through June 7, 2010. The security zone... is a need to provide a security zone for the 2010 Portland Rose Festival Fleet Week, and there is...

  1. 77 FR 15263 - Security Zone; Portland Rose Festival on Willamette River; Portland, OR

    Science.gov (United States)

    2012-03-15

    ... Zone; Portland Rose Festival on Willamette River; Portland, OR AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement of regulation. SUMMARY: The Coast Guard will enforce the Portland Rose Festival... Willamette River during the Portland Rose festival. During the enforcement period, no person or vessel may...

  2. Tetraphenylborate Solubility in High Ionic Strength Salt Solutions

    International Nuclear Information System (INIS)

    Serkiz, S.M.; Ginn, J.D.; Jurgensen, A.R.

    1998-04-01

    Solubility of sodium and potassium salts of the tetraphenylborate ion (TPB) in simulated Savannah River Site High Level Waste was investigated. Data generated from this study allow more accurate predictions of TPB solubility at the In-Tank Precipitation (ITP) facility. Because previous research showed large deviations in the observed solubility of TPB salts when compared with model predictions, additional data were generated to better understand the solubility of TPB in more complex systems of high ionic strength and those containing both potassium and sodium. These data allow evaluation of the ability of current models to accurately predict equilibrium TPB concentrations over the range of experimental conditions investigated in this study

  3. Impact strength and abrasion resistance of high strength concrete with rice husk ash and rubber tires

    Directory of Open Access Journals (Sweden)

    M. B. Barbosa

    Full Text Available The paper discusses the application of High Strength Concrete (HSC technology for concrete production with the incorporation of Rice Husk Ash (RHA residues by replacing a bulk of the material caking and rubber tires with partial aggregate volume, assessing their influence on the mechanical properties and durability. For concrete with RHA and rubber, it was possible to reduce the brittleness by increasing the energy absorbing capacity. With respect to abrasion, the RHA and rubber concretes showed lower mass loss than the concrete without residues, indicating that this material is attractive to be used in paving. It is thus hoped that these residues may represent a technological and ecological alternative for the production of concrete in construction works.

  4. Microstructural characterization of high strength and high conductivity nanocomposite wires

    International Nuclear Information System (INIS)

    Dupouy, F.; Snoeck, E.; Casanove, M.J.; Roucau, C.; Peyrade, J.P.; Askenazy, S.; Complexe Scientifique de Rangueil, Toulouse

    1996-01-01

    The generation of high pulsed magnetic fields by non-destructive magnets is a subject of research in several laboratories in the world. Combining copper and niobium seems to be a promising way to develop composites for such application. CuNb nanofilamentary wires with interesting mechanical properties for non-destructive magnets were obtained. For heavily deformed nanofilamentary wires, the fiber size decreases and the TEM studies reveal a strong fiber-matrix orientation relationship. The Cu/Nb interfaces become semi-coherent and almost completely relaxed, with a distance between misfit dislocations in good agreement with the theoretical predictions. As lowering the filament section improves the mechanical properties, one may expect to elaborate wires with larger numbers of dilaments exhibiting enhanced mechanical properties. The subsequent reduction of the filament section may lead to the formation of mono-crystalline Nb fibers and to perfect coherency of the Cu/Nb interfaces over larger distances

  5. Systematics of atom-atom collision strengths at high speeds

    International Nuclear Information System (INIS)

    Gillespie, G.H.; Inokuti, M.

    1980-01-01

    The collision strengths for atom-atom collisions at high speeds are calculated in the first Born approximation. We studied four classes of collisions, distinguished depending upon whether each of the collision partners becomes excited or not. The results of numerical calculations of the collision strengths are presented for all neutral atoms with Z< or =18. The calculations are based on atomic form factors and incoherent scattering functions found in the literature. The relative contribution of each class of collision processes to the total collision cross section is examined in detail. In general, inelastic processes dominate for low-Z atoms, while elastic scattering is more important for large Z. Other systematics of the collision strengths are comprehensively discussed. The relevant experimental literature has been surveyed and the results of this work for the three collision systems H-He, He-He, and H-Ar are compared with the data for electron-loss processes. Finally, suggestions are made for future work in measurements of atom-atom and ion-atom collision cross sections

  6. Properties of High Strength Concrete Applied on Semarang - Bawen Highway

    Science.gov (United States)

    Setiyawan, Prabowo; Antonius; Wedyowibowo, R. Hawik Jenny

    2018-04-01

    To fulfill the needs of highway construction then a high quality concrete is expected to be produced by a short time and high workability, therefore the addition of additive chemicals needs to be conducted. The objective of the study was to find out the properties of high quality concrete including slump value, compressive strength, flexural strength, elasticity modulus and stress-strain diagrams with the addition of fly ash and superplasticizer. There were five types of mixtures were made in this study with a fas (cement water factor) was 0,41 and an additional 15% of fly ash and a varied superplasticizer of 0%, 0.5%, 1%, 2% towards the weight/volume and cement/water. Test samples of cylinders and prisms or beams were tested in the laboratory at 1, 3, 7, 14, and 28 days. The test results were then compared with the test results made without additional additives. Based on the result of this research, it can be concluded that the increase of slump value due to the addition of 15% fly ash is 0,53 cm of the base slump value. The use of superplasticizer causes the weight of the type to be greater. The optimum dose of superplasticizer is 1,2%, it is still in the usage level according to the F-type admixture brochure (water reducing, high-range admixture) such as 0,6 % -1,5 %. All mixture types which use addition materials for flexural strength (fr'=45kg/cm2) can be achieved at 3 days.

  7. TOUGHREACT Testing in High Ionic Strength Brine Sandstone Systems

    International Nuclear Information System (INIS)

    Xu, Tianfu

    2008-01-01

    Deep saline formations and oil and gas reservoirs often contain concentrated brine solutions of ionic strength greater than 1 (I > 1 M). Geochemical modeling, involving high ionic strength brines, is a challenge. In the original TOUGHREACT code (Xu et al., 2004; Xu et al., 2006), activity coefficients of charged aqueous species are computed using an extended Debye-Huckel (DH) equation and parameters derived by Helgeson et al. (1981). The DH model can deal with ionic strengths from dilute to moderately saline water (up to 6 molal for an NaCl-dominant solution). The equations implemented for the DH model are presented in Appendix A. During the course of the Yucca Mountain project, a Pitzer ion-interaction model was implemented into TOUGHREACT. This allows the application of this simulator to problems involving much more concentrated aqueous solutions, such as those involving geochemical processes in and around high-level nuclear waste repositories where fluid evaporation and/or boiling is expected to occur (Zhang et al., 2007). The Pitzer ion-interaction model, which we refer to as the Pitzer virial approach, and associated ion-interaction parameters have been applied successfully to study non-ideal concentrated aqueous solutions. The formulation of the Pitzer model is presented in Appendix B; detailed information can be founded in Zhang et al. (2007). For CO 2 geological sequestration, the Pitzer ion-interaction model for highly concentrated brines was incorporated into TOUGHREACT/ECO2N, then was tested and compared with a previously implemented extended Debye-Hueckel (DH) ion activity model. The comparison was made through a batch geochemical system using a Gulf Coast sandstone saline formation

  8. Diagnostic value of high strength MRCP in the obstructive jaundice

    International Nuclear Information System (INIS)

    Yang Yang; Dong Yuhai; Yin Jie; Lv Guoyi

    2007-01-01

    Objective: To evaluate the diagnostic value of high strength MRCP in patients with obstructive jaundice. Methods: Routine MRI and MRCP examination on 161 patients with obstructive jaundice were carded out with 1.5T Siemens super-conductive magnetic resonance machine. Of them, 103 cases were benign lesions and 58 were malignant after surgical and ERCP pathological confirmation. Results: The diagnostic accuracy of MRCP was 100%, with the qualitative diagnostic accuracy at 90.2%. Conclusion: MRCP was the best method in diagnosing patients with obstructive jaundice, the concerned performances of MRCP could provide the dependable basis for surgical operation project. (authors)

  9. PM alloy 625M for high strength corrosion resistant applications

    International Nuclear Information System (INIS)

    Rizzo, F.J.; Floreen, S.

    1997-06-01

    In applications where the combination of high strength and good corrosion resistance are required, there have been only a few alloys of choice. A new powder metallurgy alloy has been developed, PM 625M, a niobium modification of Alloy 625, as a material to fill this need. One area of particular interest is the nuclear power industry, where many problems have been encountered with bolts, springs, and guidepins. Mechanical properties and stress corrosion cracking data of PM 625M are presented in this paper

  10. Method for providing a low density high strength polyurethane foam

    Science.gov (United States)

    Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

    2013-06-18

    Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

  11. Electrically conductive Portland cement concrete.

    Science.gov (United States)

    1986-01-01

    There is a need for an effective, simple-to-install secondary anode system for use in the cathodic protection of reinforced concrete bridge decks. In pursuit of such a system, carbon fibers and carbon black were incorporated in portland cement concre...

  12. High Temperature Strength of Oxide Dispersion Strengthened Aluminium

    DEFF Research Database (Denmark)

    Clauer, A.H.; Hansen, Niels

    1984-01-01

    constant (except for the material with the lowest oxide content). The high temperature values of the modulus-corrected yield stresses are approximately two-thirds of the low temperature value. During high temperature creep, there is a definite indication of a threshold stress. This threshold stress......The tensile flow stress of coarse-grained dispersion strengthened Al-Al2O3 materials were measured as a function of temperature (77–873 K) and volume fraction (0.19-0.92 vol.%) of aluminium oxide. For the same material, the creep strength was determined as a function of temperature in the range 573......–873 K. The modulus-corrected yield stress (0.01 offset) is found to be temperature independent at low temperature (195–472 K). Between 473 and 573 K, the yield stress starts to decrease with increasing temperature. At high temperatures (573–873 K), the modulus-corrected yield stress is approximately...

  13. Parameters of Alumina Cement and Portland Cement with Addition of Chalcedonite Meal

    Science.gov (United States)

    Kotwa, Anna

    2017-10-01

    Aluminous cement is a quick binder with special properties. It is used primarily to make non-standard monolithic components exposed to high temperatures, + 1300°C. It is also a component of adhesives and mortars. It has a very short setting time. It is characterized by rapid increase in mechanical strength and resistance to aggressive sulphates. It can be used in reinforced concrete structures. Laying of concrete, construction mortar made of alumina cement can be carried out even at temperatures of -10°C. This article discusses a comparison of the parameters of hardened mortar made of alumina cement GÓRKAL 40 and Portland cement CEM I 42.5R. The mortars contain an addition of chalcedonite meal with pozzolanic properties, with particle size of less than 0.063μm. The meal was added in amounts of 5% and 20% of cement weight. Chalcedonite meal used in the laboratory research is waste material, resulting from chalcedonite aggregate mining. It has the same properties as the rock from which it originates. We have compared the parameters of hardened mortar i.e. compressive strength, water absorption and capillarity. The addition of 20% chalcedonite meal to mortars made from aluminous cement will decrease durability by 6.1% relative to aluminous cement mortar without addition of meal. Considering the results obtained during the absorbency tests, it can be stated that the addition of chalcedonite meal reduces weight gains in mortars made with cement CEM I 42.5 R and alumina cement. Use of alumina cement without addition of meal in mortars causes an increase of mass by 248% compared to Portland cement mortars without additions, in the absorption tests. The addition of chalcedonite meal did not cause increased weight gain in the capillary action tests. For the alumina cement mortars, a lesser weight gains of 24.7% was reported, compared to the Portland cement mortar after 28 days of maturing.

  14. High-mechanical-strength single-pulse draw tower gratings

    Science.gov (United States)

    Rothhardt, Manfred W.; Chojetzki, Christoph; Mueller, Hans Rainer

    2004-11-01

    The inscription of fiber Bragg gratings during the drawing process is a very useful method to realize sensor arrays with high numbers of gratings and excellent mechanical strength and also type II gratings with high temperature stability. Results of single pulse grating arrays with numbers up to 100 and definite wavelengths and positions for sensor applications were achieved at 1550 nm and 830 nm using new photosensitive fibers developed in IPHT. Single pulse type I gratings at 1550 nm with more than 30% reflectivity were shown first time to our knowledge. The mechanical strength of this fiber with an Ormocer coating with those single pulse gratings is the same like standard telecom fibers. Weibull plots of fiber tests will be shown. At 830 nm we reached more than 10% reflectivity with single pulse writing during the fiber drawing in photosensitive fibers with less than 16 dB/km transmission loss. These gratings are useful for stress and vibration sensing applications. Type II gratings with reflectivity near 100% and smooth spectral shape and spectral width of about 1 nm are temperature stable up to 1200 K for short time. They are also realized in the fiber drawing process. These gratings are useful for temperature sensor applications.

  15. High strength fused silica flexures manufactured by femtosecond laser

    Science.gov (United States)

    Bellouard, Yves; Said, Ali A.; Dugan, Mark; Bado, Philippe

    2009-02-01

    Flexures are mechanical elements used in micro- and precision-engineering to precisely guide the motion of micro-parts. They consist of slender bodies that deform elastically upon the application of a force. Although counter-intuitive at first, fused silica is an attractive material for flexure. Pending that the machining process does not introduce surface flaws that would lead to catastrophic failure, the material has a theoretically high ultimate tensile strength of several GPa. We report on high-aspect ratio fused silica flexures manufactured by femtosecond laser combined with chemical etching. Notch-hinges with thickness as small as twenty microns and aspect ratios comparable to aspect ratios obtained by Deep- Reactive-Ion-Etching (DRIE) were fabricated and tested under different loading conditions. Multiple fracture tests were performed for various loading conditions and the cracks morphologies were analyzed using Scanning Electron Microscopy. The manufactured elements show outstanding mechanical properties with flexural strengths largely exceeding those obtained with other technologies and materials. Fused silica flexures offer a mean to combine integrated optics with micro-mechanics in a single monolithic substrate. Waveguides and mechanical elements can be combined in a monolithic devices opening new opportunities for integrated opto-mechatronics devices.

  16. Local buckling failure analysis of high-strength pipelines

    Institute of Scientific and Technical Information of China (English)

    Yan Li; Jian Shuai; Zhong-Li Jin; Ya-Tong Zhao; Kui Xu

    2017-01-01

    Pipelines in geological disaster regions typically suffer the risk of local buckling failure because of slender structure and complex load.This paper is meant to reveal the local buckling behavior of buried pipelines with a large diameter and high strength,which are under different conditions,including pure bending and bending combined with internal pressure.Finite element analysis was built according to previous data to study local buckling behavior of pressurized and unpressurized pipes under bending conditions and their differences in local buckling failure modes.In parametric analysis,a series of parameters,including pipe geometrical dimension,pipe material properties and internal pressure,were selected to study their influences on the critical bending moment,critical compressive stress and critical compressive strain of pipes.Especially the hardening exponent of pipe material was introduced to the parameter analysis by using the Ramberg-Osgood constitutive model.Results showed that geometrical dimensions,material and internal pressure can exert similar effects on the critical bending moment and critical compressive stress,which have different,even reverse effects on the critical compressive strain.Based on these analyses,more accurate design models of critical bending moment and critical compressive stress have been proposed for high-strength pipelines under bending conditions,which provide theoretical methods for highstrength pipeline engineering.

  17. Determination of high-strength materials diamond grinding rational modes

    Science.gov (United States)

    Arkhipov, P. V.; Lobanov, D. V.; Rychkov, D. A.; Yanyushkin, A. S.

    2018-03-01

    The analysis of methods of high-strength materials abrasive processing is carried out. This method made it possible to determine the necessary directions and prospects for the development of shaping combined methods. The need to use metal bonded diamond abrasive tools in combination with a different kind of energy is noted to improve the processing efficiency and reduce the complexity of operations. The complex of experimental research on revealing the importance of mechanical and electrical components of cutting regimes, on the cutting ability of diamond tools, as well as the need to reduce the specific consumption of an abrasive wheel as one of the important economic indicators of the processing process is performed. It is established that combined diamond grinding with simultaneous continuous correction of the abrasive wheel contributes to an increase in the cutting ability of metal bonded diamond abrasive tools when processing high-strength materials by an average of 30% compared to diamond grinding. Particular recommendations on the designation of technological factors are developed depending on specific production problems.

  18. Experimental investigation of bond strength under high loading rates

    Directory of Open Access Journals (Sweden)

    Michal Mathias

    2015-01-01

    Full Text Available The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw and the Joint Research Centre (JRC in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.

  19. Guidelines for Stretch Flanging Advanced High Strength Steels

    International Nuclear Information System (INIS)

    Sriram, S.; Chintamani, J.

    2005-01-01

    Advanced High Strength Steels (AHSS) are currently being considered for use in closure and structural panels in the automotive industry because of their high potential for affordable weight reduction and improved performance. AHSS such as dual phase steels are currently being used in some vehicle platforms. From a manufacturing perspective, stretch flanging during stamping is an important deformation mode requiring careful consideration of geometry and the die process. This paper presents some geometric and process guidelines for stretch flanging AHSS. Hole expansion experiments were conducted to determine the failure limit for a sheared edge condition. Effects of punching clearance, prestrain and prior strain path on hole expansion were explored in these experiments. In addition, dynamic explicit FE calculations using LS-DYNA were also conducted for a typical stretch flange by varying some key geometric parameters. The experimental and FEA results were then analyzed to yield process and geometric guidelines to enable successful stretch flanging of AHSS

  20. Thermal Stir Welding of High Strength and High Temperature Alloys for Aerospace Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Keystone and MSU team propose to demonstrate the feasibility of solid-state joining high strength and temperature alloys utilizing the Thermal Stir Welding...

  1. Optimization of calcium chloride content on bioactivity and mechanical properties of white Portland cement

    International Nuclear Information System (INIS)

    Torkittikul, Pincha; Chaipanich, Arnon

    2012-01-01

    This research investigates the optimization of calcium chloride content on the bioactivity and mechanical properties of white Portland cement. Calcium chloride was used as an addition of White Portland cement at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10% by weight. Calcium chloride was dissolved in sterile distilled water and blended with White Portland cement using a water to cement ratio of 0.5. Analysis of the bioactivity and pH of white Portland cement pastes with calcium chloride added at various amounts was carried out in simulated body fluid. Setting time, density, compressive strength and volume of permeable voids were also investigated. The characteristics of cement pastes were examined by X-ray diffractometer and scanning electron microscope linked to an energy-dispersive X-ray analyzer. The result indicated that the addition of calcium chloride could accelerate the hydration of white Portland cement, resulting in a decrease in setting time and an increase in early strength of the pastes. The compressive strength of all cement pastes with added calcium chloride was higher than that of the pure cement paste, and the addition of calcium chloride at 8 wt.% led to achieving the highest strength. Furthermore, white Portland cement pastes both with and without calcium chloride showed well-established bioactivity with respect to the formation of a hydroxyapatite layer on the material within 7 days following immersion in simulated body fluid; white Portland cement paste with added 3%CaCl 2 exhibited the best bioactivity. - Highlights: ► Optimization CaCl 2 content on the bioactivity and mechanical properties. ► CaCl 2 was used as an addition at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10% by weight. ► CaCl 2 resulted in a decrease in setting time and an increase in early strength. ► Addition of 3%CaCl 2 exhibited the optimum formation of hydroxyapatite.

  2. Advanced High Strength Steel in Auto Industry: an Overview

    Directory of Open Access Journals (Sweden)

    N. Baluch

    2014-08-01

    Full Text Available The world’s most common alloy, steel, is the material of choice when it comes to making products as diverse as oil rigs to cars and planes to skyscrapers, simply because of its functionality, adaptability, machine-ability and strength. Newly developed grades of Advanced High Strength Steel (AHSS significantly outperform competing materials for current and future automotive applications. This is a direct result of steel’s performance flexibility, as well as of its many benefits including low cost, weight reduction capability, safety attributes, reduced greenhouse gas emissions and superior recyclability. To improve crash worthiness and fuel economy, the automotive industry is, increasingly, using AHSS. Today, and in the future, automotive manufacturers must reduce the overall weight of their cars. The most cost-efficient way to do this is with AHSS. However, there are several parameters that decide which of the AHSS types to be used; the most important parameters are derived from the geometrical form of the component and the selection of forming and blanking methods. This paper describes the different types of AHSS, highlights their advantages for use in auto metal stampings, and discusses about the new challenges faced by stampers, particularly those serving the automotive industry.

  3. Characteristics of shock propagation in high-strength cement mortar

    Science.gov (United States)

    Wang, Zhanjiang; Li, Xiaolan; Zhang, Ruoqi

    2001-06-01

    Planar impact experiments have been performed on high-strength cement mortar to determine characteristics of shock propagation.The experiments were conducted on a light-gas gun,and permanent-magnet particle velocity gages were used to obtain the sand of 0.5 3.5mm size.A bulk density of 2.31g/cm^3,and a compressive and tensile strength of 82MPa and 7.8MPa,respectively,were determined.Three kinds of experimental techniques were used,including the reverse ballistic configuration.These techniques effectively averaged the measured dynamic compression state over a sensibly large volume of the test sample.The impact velocities were controlled over a range of approximately 80m/s to 0.83km/s.Hugoniot equation of state data were obtained for the material over a pressure range of approximately 0.2 2.0GPa,and its nonlinear constitutive relation were analyzed.The experiment results show that,in higher pressure range provided in the experiment,the shock wave in the material splits into two components of an elastic and a plastic,with the Hugoniot elastic limit 0.4 0.5GPa and the precursor velocity about 4.7km/s,and the material presents a very strong nonlinear dynamic response,and its shock amplitude will greatly decrease in propagation.

  4. Accelerated Creep Testing of High Strength Aramid Webbing

    Science.gov (United States)

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar

    2012-01-01

    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  5. High Strength Concrete Columns under Axial Compression Load: Hybrid Confinement Efficiency of High Strength Transverse Reinforcement and Steel Fibers

    Science.gov (United States)

    Perceka, Wisena; Liao, Wen-Cheng; Wang, Yo-de

    2016-01-01

    Addition of steel fibers to high strength concrete (HSC) improves its post-peak behavior and energy absorbing capability, which can be described well in term of toughness. This paper attempts to obtain both analytically and experimentally the efficiency of steel fibers in HSC columns with hybrid confinement of transverse reinforcement and steel fibers. Toughness ratio (TR) to quantify the confinement efficiency of HSC columns with hybrid confinement is proposed through a regression analysis by involving sixty-nine TRs of HSC without steel fibers and twenty-seven TRs of HSC with hybrid of transverse reinforcement and steel fibers. The proposed TR equation was further verified by compression tests of seventeen HSC columns conducted in this study, where twelve specimens were reinforced by high strength rebars in longitudinal and transverse directions. The results show that the efficiency of steel fibers in concrete depends on transverse reinforcement spacing, where the steel fibers are more effective if the spacing transverse reinforcement becomes larger in the range of 0.25–1 effective depth of the section column. Furthermore, the axial load–strain curves were developed by employing finite element software (OpenSees) for simulating the response of the structural system. Comparisons between numerical and experimental axial load–strain curves were carried out. PMID:28773391

  6. Fatigue crack Behaviour in a High Strength Tool Steel

    DEFF Research Database (Denmark)

    Højerslev, Christian; Carstensen, Jesper V.; Brøndsted, Povl

    2002-01-01

    The influence of microstructure on fatigue crack initiation and crack growth of a hardened and tempered high speed steel was investigated. The evolution of fatigue cracks was followed in four point bending at room temperature. It was found that a carbide damage zone exists above a threshold load...... value of maximally 80% of the yield strength of the steel. The size of this carbide damage zone increases with increasing load amplitude, and the zone is apparently associated with crack nucleation. On fatigue crack propagation plastic deformation of the matrix occurs in a radius of approximately 4...... microns in front of the fatigue crack tip, which is comparable with the relevant mean free carbide spacing....

  7. Recent Niobium Developments for High Strength Steel Energy Applications

    Science.gov (United States)

    Jansto, Steven G.

    Niobium-containing high strength steel materials have been developed for oil and gas pipelines, offshore platforms, nuclear plants, boilers and alternative energy applications. Recent research and the commercialization of alternative energy applications such as windtower structural supports and power transmission gear components provide enhanced performance. Through the application of these Nb-bearing steels in demanding energy-related applications, the designer and end user experience improved toughness at low temperature, excellent fatigue resistance and fracture toughness and excellent weldability. These enhancements provide structural engineers the opportunity to further improve the structural design and performance. For example, through the adoption of these Nb-containing structural materials, several design-manufacturing companies are initiating new windtower designs operating at higher energy efficiency, lower cost, and improved overall material design performance.

  8. Thermal Transport in High-Strength Polymethacrylimide (PMI) Foam Insulations

    Science.gov (United States)

    Qiu, L.; Zheng, X. H.; Zhu, J.; Tang, D. W.; Yang, S. Y.; Hu, A. J.; Wang, L. L.; Li, S. S.

    2015-11-01

    Thermal transport in high-strength polymethacrylimide (PMI) foam insulations is described, with special emphasis on the density and temperature effects on the thermal transport performance. Measurements of the effective thermal conductivity are performed by a freestanding sensor-based 3ω method. A linear relationship between the density and the effective thermal conductivity is observed. Based on the analysis of the foam insulation morphological structures and the corresponding geometrical cell model, the quantitative contribution of the solid conductivity and the gas conductivity as well as the radiative conductivity to the total effective thermal conductivity as a function of the density and temperature is calculated. The agreement between the curves of the results from the developed model and experimental data indicate the model can be used for PMI foam insulating performance optimization.

  9. Corrosion fatigue behavior of high strength brass in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, A.S.; Kassem, M.A.; Ramadan, R.M.; El-Zeky, M.A. [Suez Canal Univ., Dept. of Metallurgy and Materials Engineering (Egypt)

    2000-07-01

    Corrosion fatigue behavior of British Standard high strength brass, CZ 127 has been studied in various environments, 3.5%NaC1 solution and 3.5%NaC1 containing 1000ppm ammonia by applying the reverse bending technique, strain-controlled cyclic, at 67 cycles/min. Characteristics of the produced alloy were studied using differential thermal analysis with applying its results in heat treating of the alloy; metallographic examinations; hardness measurements; X-ray; and electrochemical behavior of the unstressed alloy. CZ 127 was fatigued at three different conditions, solution treated, peak aged, and over aged at a fixed strain amplitude, 0.03 5. Solution treated alloy gave the best fatigue properties in all environments tested among the other materials. Results of the alloy studied were compared with that obtained of 70/30 {alpha}-brass. Fracture surface of the fatigued alloy was examined using optical microscope and scanning electron microscope equipped with EDX. (author)

  10. Corrosion fatigue behavior of high strength brass in aqueous solutions

    International Nuclear Information System (INIS)

    Hamada, A.S.; Kassem, M.A.; Ramadan, R.M.; El-Zeky, M.A.

    2000-01-01

    Corrosion fatigue behavior of British Standard high strength brass, CZ 127 has been studied in various environments, 3.5%NaC1 solution and 3.5%NaC1 containing 1000ppm ammonia by applying the reverse bending technique, strain-controlled cyclic, at 67 cycles/min. Characteristics of the produced alloy were studied using differential thermal analysis with applying its results in heat treating of the alloy; metallographic examinations; hardness measurements; X-ray; and electrochemical behavior of the unstressed alloy. CZ 127 was fatigued at three different conditions, solution treated, peak aged, and over aged at a fixed strain amplitude, 0.03 5. Solution treated alloy gave the best fatigue properties in all environments tested among the other materials. Results of the alloy studied were compared with that obtained of 70/30 α-brass. Fracture surface of the fatigued alloy was examined using optical microscope and scanning electron microscope equipped with EDX. (author)

  11. CO2 laser cutting of advanced high strength steels (AHSS)

    International Nuclear Information System (INIS)

    Lamikiz, A.; Lacalle, L.N. Lopez de; Sanchez, J.A.; Pozo, D. del; Etayo, J.M.; Lopez, J.M.

    2005-01-01

    This article demonstrates the optimum working areas and cutting conditions for the laser cutting of a series of advanced high strength steels (AHSS). The parameters that most influence the cutting of sheet metal have been studied and the results have been divided into two large groups with thickness of more and less than 1 mm. The influence of the material and, more important, the effect of coating have been taken into account. The results, have demonstrate very different behaviours between the thinnest and thickest sheets, whilst the variation of the cutting parameters due to the influence of the material is less relevant. The optimum cutting areas and the quality of the cut evaluated with different criteria are presented. Finally, the best position for the laser beam has been observed to be underneath the sheet

  12. Advanced Gear Alloys for Ultra High Strength Applications

    Science.gov (United States)

    Shen, Tony; Krantz, Timothy; Sebastian, Jason

    2011-01-01

    Single tooth bending fatigue (STBF) test data of UHS Ferrium C61 and C64 alloys are presented in comparison with historical test data of conventional gear steels (9310 and Pyrowear 53) with comparable statistical analysis methods. Pitting and scoring tests of C61 and C64 are works in progress. Boeing statistical analysis of STBF test data for the four gear steels (C61, C64, 9310 and Pyrowear 53) indicates that the UHS grades exhibit increases in fatigue strength in the low cycle fatigue (LCF) regime. In the high cycle fatigue (HCF) regime, the UHS steels exhibit better mean fatigue strength endurance limit behavior (particularly as compared to Pyrowear 53). However, due to considerable scatter in the UHS test data, the anticipated overall benefits of the UHS grades in bending fatigue have not been fully demonstrated. Based on all the test data and on Boeing s analysis, C61 has been selected by Boeing as the gear steel for the final ERDS demonstrator test gearboxes. In terms of potential follow-up work, detailed physics-based, micromechanical analysis and modeling of the fatigue data would allow for a better understanding of the causes of the experimental scatter, and of the transition from high-stress LCF (surface-dominated) to low-stress HCF (subsurface-dominated) fatigue failure. Additional STBF test data and failure analysis work, particularly in the HCF regime and around the endurance limit stress, could allow for better statistical confidence and could reduce the observed effects of experimental test scatter. Finally, the need for further optimization of the residual compressive stress profiles of the UHS steels (resulting from carburization and peening) is noted, particularly for the case of the higher hardness C64 material.

  13. Behaviour of High Strength Steel Endplate Connections in Fire and after Fire

    NARCIS (Netherlands)

    Qiang, X.

    2013-01-01

    The aim of this research is to reveal more information and understanding on behaviour and failure mechanisms of high strength steel endplate connections (combining high strength steel endplates with either mild steel or high strength steel beams and columns in endplate connections) in fire and after

  14. High-strength structural steels; their properties, and the problems encountered during the welding process

    International Nuclear Information System (INIS)

    Uwer, D.

    1978-01-01

    High-strength structural steels, manufacture, properties. Requirements to be met by the welded joints of high-strength structural steels. Influence of the welding conditions on the mechanical properties in the heat-affected zone. Cold-cracking behaviour of welded joints. Economic efficiency of high-strength structural steels. Applications. (orig.) [de

  15. Hybrid Welding of 45 mm High Strength Steel Sections

    Science.gov (United States)

    Bunaziv, Ivan; Frostevarg, Jan; Akselsen, Odd M.; Kaplan, Alexander F.

    Thick section welding has significant importance for oil and gas industry in low temperature regions. Arc welding is usually employed providing suitable quality joints with acceptable toughness at low temperatures with very limited productivity compared to modern high power laser systems. Laser-arc hybrid welding (LAHW) can enhance the productivity by several times due to higher penetration depth from laser beam and combined advantages of both heat sources. LAHW was applied to join 45 mm high strength steel with double-sided technique and application of metal cored wire. The process was captured by high speed camera, allowing process observation in order to identify the relation of the process stability on weld imperfections and efficiency. Among the results, it was found that both arc power and presence of a gap increased penetration depth, and that higher welding speeds cause unstable processing and limits penetration depth. Over a wide range of heat inputs, the welds where found to consist of large amounts of fine-grained acicular ferrite in the upper 60-75% part of welds. At the root filler wire mixing was less and cooling faster, and thus found to have bainitic transformation. Toughness of deposited welds provided acceptable toughness at -50 °C with some scattering.

  16. High carbon microalloyed martensitic steel with ultrahigh strength-ductility

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Shengwei; Liu, Yu; Hao, Qingguo [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Ying [School of Mechanical Engineering, Shanghai Dianji University, Shanghai 200245 (China); Chen, Nailu, E-mail: nlchen@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zuo, Xunwei; Rong, Yonghua [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-04-29

    Based on the idea of rising the mechanical stability of retained austenite by the addition of Si in Fe-Mn based steels, an Fe-0.63C-1.52Mn-1.49Si-0.62Cr-0.036Nb was designed, then its hot rolled plate was successively tread by normalization process as pretreatment of novel quenching-partitioning-tempering (Q-P-T) process. Product of tensile and elongation (PSE) of 53.94 GPa% were obtained for this high carbon Q-P-T martensitic steel, and the PSE (40.18 GPa%) obtained by the conversion of tensile sample size using Oliver formula still is more excellent PSE than those of other microalloyed advanced high strength steels reported. The microstructural characterization reveals origin of ultrahigh PSE resulting from both the increase of considerable and dispersed carbon enriched retained austenite with relative high mechanical stability in volume fraction and the decrease of brittle twin-type martensite with the sensitivity of notch.

  17. 3D printing of high-strength aluminium alloys.

    Science.gov (United States)

    Martin, John H; Yahata, Brennan D; Hundley, Jacob M; Mayer, Justin A; Schaedler, Tobias A; Pollock, Tresa M

    2017-09-20

    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  18. 3D printing of high-strength aluminium alloys

    Science.gov (United States)

    Martin, John H.; Yahata, Brennan D.; Hundley, Jacob M.; Mayer, Justin A.; Schaedler, Tobias A.; Pollock, Tresa M.

    2017-09-01

    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  19. Rice husk ash as a partial replacement of cement in high strength concrete containing micro silica: Evaluating durability and mechanical properties

    Directory of Open Access Journals (Sweden)

    Seyed Alireza Zareei

    2017-12-01

    Full Text Available The preliminary and inevitable interest in the use of partial replacements or by – products as complementary pozzolanic materials was mostly induced by enforcement of air pollution control resulted from cement production industry. Rise husk is by- product taken from rice mill process, with approximately the ratio of 200 kg per one ton of rice, even in high temperature it reduces to 40 kg. This paper presents benefits resulted from various ratios of rice husk ash(RHA on concrete indicators through 5 mixture plans with proportions of 5, 10, 15, 20 and 25% RHA by weight of cement in addition to 10% micro- silica (MS to be compared with a reference mixture with 100% Portland cement. Tests results indicated the positive relationship between 15% replacement of RHA with increase in compressive strengths by about 20%. The optimum level of strength and durability properties generally gain with addition up to 20%, beyond that is associated with slight decrease in strength parameters by about 4.5%. The same results obtained for water absorption ratios likely to be unfavourable. Chloride ions penetration increased with increase in cement replacement by about 25% relative to the initial values (about less than one fifth.

  20. Characteristics in Paintability of Advanced High Strength Steels

    International Nuclear Information System (INIS)

    Park, Ha Sun

    2007-01-01

    It is expected that advanced high strength steels (AHSS) would be widely used for vehicles with better performance in automotive industries. One of distinctive features of AHSS is the high value of carbon equivalent (Ceq), which results in the different properties in formability, weldability and paintability from those of common grade of steel sheets. There is an exponential relation between Ceq and electric resistance, which seems also to have correlation with the thickness of electric deposition (ED) coat. higher value of Ceq of AHSS lower the thickness of ED coat of AHSS. Some elements of AHSS such as silicon, if it is concentrated on the surface, affect negatively the formation of phosphates. In this case, silicon itself doesn't affect the phosphate, but its oxide does. This phenomenon is shown dramatically in the welding area. Arc welding or laser welding melts the base material. In the process of cooling of AHSS melt, the oxides of Si and Mn are easily concentrated on the surface of boundary between welded and non welded area because Si and Mn cold be oxidized easier than Fe. More oxide on surface results in poor phosphating and ED coating. This is more distinctive in AHSS than in mild steel. General results on paintability of AHSS would be reported, being compared to those of mild steel

  1. Portland Public Schools Project Chrysalis: Year 2 Evaluation Report.

    Science.gov (United States)

    Mitchell, Stephanie J.; Gabriel, Roy M.; Hahn, Karen J.; Laws, Katherine E.

    In 1994, the Chrysalis Project in Portland Public Schools received funding to prevent or delay the onset of substance abuse among a special target population: high-risk, female adolescents with a history of childhood abuse. Findings from the evaluation of the project's second year of providing assistance to these students are reported here. During…

  2. portland_me.grd

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to...

  3. Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance

    Science.gov (United States)

    Chen, Irvin Allen

    -belite cement that contained medium C4A3 S¯ and C2S contents showed good dimensional stability, sulfate resistance, and compressive strength development and was considered the optimum phase composition for calcium sulfoaluminate-belite cement in terms of comparable performance characteristics to portland cement. Furthermore, two calcium sulfoaluminate-belite cement clinkers were successfully synthesized from natural and waste materials such as limestone, bauxite, flue gas desulfurization sludge, Class C fly ash, and fluidized bed ash proportioned to the optimum calcium sulfoaluminate-belite cement synthesized from reagent-grade chemicals. Waste materials composed 30% and 41% of the raw ingredients. The two calcium sulfoaluminate-belite cements synthesized from natural and waste materials showed good dimensional stability, sulfate resistance, and compressive strength development, comparable to commercial portland cement.

  4. Effective longitudinal strength of high temperature metal-matrix composites

    International Nuclear Information System (INIS)

    Craddock, J.N.; Savvides, I.

    1991-01-01

    Several models for predicting the longitudinal strength of fiber composites are presented, ranging from a simple netting analysis to a model incorporating curvilinear strain hardening for all the components. Results from these models are presented for tungsten fiber reinforced superalloys, FeCrAlY and MARM200. It is shown that a simple elastic limit micromechanical model does not always adequately describe the useful strength of the composites. The methods proposed here are shown to be more appropriate for predicting the effective composite strength. 2 refs

  5. A new generation of ultra high strength steel pipelines

    International Nuclear Information System (INIS)

    Brozda, J.; Zeman, M.; Weglowski, M.

    2008-01-01

    For many years an increased demand for natural gas can be observed. Ultra high-strength pipelines with higher operating pressures and/or reduced wall thickness are a means to reduce transmission costs. Motivated by reduced investment costs (overcharge a few billion of dollars), tend towards the development of a new grade of pipeline steel with microalloying element for example Nb, that potentially lowers the total cost of long-distance gas pipelines by 5 - 15%. New long distance pipelines have budgets in excess of several billion dollars. This paper describes mechanical properties of new generation of pipelines steel with higher content of niobium and the influence the welding thermal cycles on the microstructure and brittle fracture resistance. The resistance to cold cracking has also been determined. It was found that the new steel has close properties to API X70 grade steels, but is cheaper in manufacturing and installation. The steel has been covered by the amended EN 10028-5 standard and proper modifications will also be made in other European standards. (author)

  6. Fatigue crack retardation of high strength steel in saltwater

    International Nuclear Information System (INIS)

    Tokaji, K.; Ando, Z.; Imai, T.; Kojima, T.

    1983-01-01

    A high strength steel was studied in 3 percent saltwater to investigate the effects of a corrosive environment and sheer thickness on fatigue crack propagation behavior following the application of a single tensile overload. Experiments were carried out under sinusoidally varying loads at a load ratio of 0 and frequency of 10 H /SUB z/ . A single tensile overload was found to cause delayed retardation, and the crack propagation rate at first increased, followed by fairly rapid decrease to a minimum value and then increased gradually to its steady-state value, just as it did in air. The overload affected zone size and the retardation cycles increased with decreasing sheet thickness, just as they did in air. However, the zone size and the cycles were larger in 3 percent saltwater than in air. Since the crack propagation rates through the overload affected zone were not affected by the test environment, the longer retardation cycles in 3 percent saltwater were attributed to an enlargement of the overload affected zone size. The crack propagation behavior following the application of a single tensile overload in 3 percent saltwater was well explained by the crack closure concept

  7. ON THE HIGH TEMPERATURE BENDING STRENGTH OF CASTABLES

    Directory of Open Access Journals (Sweden)

    JIŘÍ HAMÁČEK

    2012-09-01

    Full Text Available The hot moduli of rupture (HMOR measurements have been performed for the low-cement castable (LCC, the ultra-low cement castable (ULCC, and the no-cement castable (NCC. All castables contained SiO2-Al2O3 based aggregates (burned fireclay and kaolin. The experimental data points have been described using the model based on the Varshni approach within the temperature region 1000-1200°C and by the model based on the Adam-Gibbs theory above 1400°C. A smooth but distinct transition between both temperature regions has been observed. The limits and applicability of the models have been analyzed. At lower temperature the loss of strength of castables was attributed to weakening of bonds most probably in the frontal process zone of cracking. At higher temperature, the liquid phase causes slowing down of the crack propagation by formation of the viscous bridging in the following wake region. And finally, at very high temperatures, the castable behaves as very viscous suspension which can be described using models originally developed for molten glasses.

  8. High-strength concrete and the design of power plant structures

    International Nuclear Information System (INIS)

    Puttonen, J.

    1991-01-01

    Based on the literature, the design of high-strength concrete structures and the suitability of high-strength concrete for the power plant structures have been studied. Concerning the behavior of structures, a basic difference between the high-strength concrete and the traditional one is that the ductility of the high-strength concrete is smaller. In the design, the non-linear stress-strain relationship of the high-strength concrete has to be taken into account. The use of the high-strength concrete is economical if the strength of the material can be utilized. In the long term, the good durability and wear resistance of the high-strength concrete increases the economy of the material. Because of the low permeability of the high-strength concrete, it is a potential material in the safety-related structures of nuclear power plants. The study discovered no particular power plant structure which would always be economical to design of high-strength concrete. However, the high-strength concrete was found to be a competitive material in general

  9. High-strength cellular ceramic composites with 3D microarchitecture.

    Science.gov (United States)

    Bauer, Jens; Hengsbach, Stefan; Tesari, Iwiza; Schwaiger, Ruth; Kraft, Oliver

    2014-02-18

    To enhance the strength-to-weight ratio of a material, one may try to either improve the strength or lower the density, or both. The lightest solid materials have a density in the range of 1,000 kg/m(3); only cellular materials, such as technical foams, can reach considerably lower values. However, compared with corresponding bulk materials, their specific strength generally is significantly lower. Cellular topologies may be divided into bending- and stretching-dominated ones. Technical foams are structured randomly and behave in a bending-dominated way, which is less weight efficient, with respect to strength, than stretching-dominated behavior, such as in regular braced frameworks. Cancellous bone and other natural cellular solids have an optimized architecture. Their basic material is structured hierarchically and consists of nanometer-size elements, providing a benefit from size effects in the material strength. Designing cellular materials with a specific microarchitecture would allow one to exploit the structural advantages of stretching-dominated constructions as well as size-dependent strengthening effects. In this paper, we demonstrate that such materials may be fabricated. Applying 3D laser lithography, we produced and characterized micro-truss and -shell structures made from alumina-polymer composite. Size-dependent strengthening of alumina shells has been observed, particularly when applied with a characteristic thickness below 100 nm. The presented artificial cellular materials reach compressive strengths up to 280 MPa with densities well below 1,000 kg/m(3).

  10. Strength and Mechanical Properties of High Strength Cement Mortar with Silica Fume

    OpenAIRE

    川上, 英男; 谷, 康博

    1993-01-01

    Two series of tests were carried out to clarify the effects of silica fume on the strength and mechanical properties of cement mortar. The test specimens of cement mortar were prepared within the flow values between 180 mm and 240 mm which qualifies better workability of the concrete. The fiow values were attained by using superplasticizer. The specimens were tested at the age of 4 weeks. Main results of the experiments are as follows. 1. At a given cement water ratio,the larger volume of sil...

  11. Determination of the leaching rate of radionuclide 134Cs from the solidified radioactive wastes in Syrian Portland cement and cement-microsilica matrixes

    International Nuclear Information System (INIS)

    Ismail Shaaban; Nasim Assi

    2010-01-01

    The suitability of Syrian Portland cement for disposal of solidified low-level radioactive waste was assessed by measuring the leaching rate of 134 Cs. In ordinary cement concrete, a leaching rate of 1.309 x 10 -3 g/cm 2 per day was measured. Mixing this concrete with microsilica reduced significantly the leaching rate to 3.106 x 10 -4 g/cm 2 per day for 1% mixing, and to 9.645 x 10 -5 g/cm 2 per day for 3% mixing. It was also found that the application of a latex paint reduced these leaching rates by about 10%. These results, along with mechanical strength tests (under radiation exposure, high temperature, long water immersion and freeze-thaw cycling) indicate that Syrian Portland cement is suited for the disposal of low-level radioactive waste. (author)

  12. Highly controllable and green reduction of graphene oxide to flexible graphene film with high strength

    International Nuclear Information System (INIS)

    Wan, Wubo; Zhao, Zongbin; Hu, Han; Gogotsi, Yury; Qiu, Jieshan

    2013-01-01

    Graphical abstract: Highly controllable and green reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant. Self-assembly of the as-made CCG sheets results in a flexible CCG film, of which the tensile strength strongly depends on the deoxygenation degree of graphene sheets. - Highlights: • Graphene was synthesized by an effective and environmentally friendly approach. • We introduced a facile X-ray diffraction analysis method to investigate the reduction process from graphene oxide to graphene. • Flexible graphene films were prepared by self-assembly of the graphene sheets. • The strength of the graphene films depends on the reduction degree of graphene. - Abstract: Graphene film with high strength was fabricated by the assembly of graphene sheets derived from graphene oxide (GO) in an effective and environmentally friendly approach. Highly controllable reduction of GO to chemical converted graphene (CCG) was achieved with sodium citrate as a facile reductant, in which the reduction process was monitored by XRD analysis and UV–vis absorption spectra. Self-assembly of the as-made CCG sheets results in a flexible CCG film. This method may open an avenue to the easy and scalable preparation of graphene film with high strength which has promising potentials in many fields where strong, flexible and electrically conductive films are highly demanded

  13. The Statistical Analysis of Relation between Compressive and Tensile/Flexural Strength of High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Kępniak M.

    2016-12-01

    Full Text Available This paper addresses the tensile and flexural strength of HPC (high performance concrete. The aim of the paper is to analyse the efficiency of models proposed in different codes. In particular, three design procedures from: the ACI 318 [1], Eurocode 2 [2] and the Model Code 2010 [3] are considered. The associations between design tensile strength of concrete obtained from these three codes and compressive strength are compared with experimental results of tensile strength and flexural strength by statistical tools. Experimental results of tensile strength were obtained in the splitting test. Based on this comparison, conclusions are drawn according to the fit between the design methods and the test data. The comparison shows that tensile strength and flexural strength of HPC depend on more influential factors and not only compressive strength.

  14. The Estimation of Compaction Parameter Values Based on Soil Properties Values Stabilized with Portland Cement

    Science.gov (United States)

    Lubis, A. S.; Muis, Z. A.; Pasaribu, M. I.

    2017-03-01

    The strength and durability of pavement construction is highly dependent on the properties and subgrade bearing capacity. This then led to the idea of the selection methods to estimate the density of the soil with the proper implementation of the system, fast and economical. This study aims to estimate the compaction parameter value namely the maximum dry unit weight (γd max) and optimum moisture content (wopt) of the soil properties value that stabilized with Portland Cement. Tests conducted in the laboratory of soil mechanics to determine the index properties (fines and liquid limit) and Standard Compaction Test. Soil samples that have Plasticity Index (PI) between 0-15% then mixed with Portland Cement (PC) with variations of 2%, 4%, 6%, 8% and 10%, each 10 samples. The results showed that the maximum dry unit weight (γd max) and wopt has a significant relationship with percent fines, liquid limit and the percentation of cement. Equation for the estimated maximum dry unit weight (γd max) = 1.782 - 0.011*LL + 0,000*F + 0.006*PS with R2 = 0.915 and the estimated optimum moisture content (wopt) = 3.441 + 0.594*LL + 0,025*F + 0,024*PS with R2 = 0.726.

  15. Nuevos conglomerantes complementarios del cemento portland

    OpenAIRE

    Argiz, Cristina; Menéndez, Esperanza; Moragues, Amparo; Sanjuan-Barbudo, Miguel

    2012-01-01

    El desarrollo de nuevos conglomerantes complementarios al cemento portland se presenta como una alternativa que permitirá reciclar residuos, entre otros posibles beneficios. Estos nuevos materiales difícilmente podrán competir con el cemento portland ya que sus aplicaciones son limitadas y su coste, en general, más elevado.

  16. TRP 9904 - Constitutive Behavior of High Strength Multiphase Sheel Steel Under High Strain Rate Deformation

    Energy Technology Data Exchange (ETDEWEB)

    David Matlock; John Speer

    2005-03-31

    The focus of the research project was to systematically assess the strain rate dependence of strengthening mechanisms in new advanced high strength sheet steels. Data were obtained on specially designed and produced Duel Phase and TRIP steels and compared to the properties of automotive steels currently in use.

  17. Processing of a new high strength high toughness steel with duplex microstructure (Ferrite + Austenite)

    International Nuclear Information System (INIS)

    Martis, Codrick J.; Putatunda, Susil K.; Boileau, James

    2013-01-01

    Highlights: ► This new steel has exceptional combination of high strength and fracture toughness. ► Austempering treatment resulted in a very fine scale bainitic ferrite microstructure. ► As the austempering temperature increases yield strength and toughness decreases. ► Maximum fracture toughness of 105 MPa √m is obtained after austempering at 371 °C. ► A relationship between fracture toughness and the parameter σ y (X γ C γ ) 1/2 was observed. - Abstract: In this investigation a new third generation advanced high strength steel (AHSS) has been developed. This steel was synthesized by austempering of a low carbon and low alloy steel with high silicon content. The influence of austempering temperature on the microstructure and the mechanical properties including the fracture toughness of this steel was also examined. Compact tension and cylindrical tensile specimens were prepared from a low carbon low alloy steel and were initially austenitized at 927 °C for 2 h and then austempered in the temperature range between 371 °C and 399 °C to produce different microstructures. The microstructures were characterized by X-ray diffraction, scanning electron microscopy and optical metallography. Test results show that the austempering heat treatment has resulted in a microstructure consisting of very fine scale bainitic ferrite and austenite. A combination of very high tensile strength of 1388 MPa and fracture toughness of 105 MPa √m was obtained after austempering at 371 °C

  18. High-strength high-conductivity Cu-Nb microcomposite sheet fabricated via multiple roll bonding

    International Nuclear Information System (INIS)

    Jha, S.C.; Delagi, R.G.; Forster, J.A.; Krotz, P.D.

    1993-01-01

    Copper-niobium microcomposites are a new class of high-strength high-conductivity materials that have attractive properties for room- and elevated-temperature applications. Since Nb has little solid solubility in Cu, addition of Nb to Cu does not affect its conductivity. Copper-niobium microcomposites are melted and cast so that the microstructure of cast Cu-Nb ingots consists of 1- to 10 μm Nb dendrites uniformly distributed within the copper matrix. Extensive wire drawing with a true processing strain (η> 12) of Cu-Nb alloy leads to refinement and elongation of Nb dendrites into 1- to 10 nm-thick filaments. The presence of such fine Nb filaments causes a significant increase in the strength of Cu-Nb wires. The tensile strength of heavily drawn Cu-Nb wires was determined to be significantly higher than the values predicted by the rule of mixtures. This article reports the fabrication of high-strength Cu-Nb microcomposite sheet by multiple roll bonding. It is difficult and impractical to attain high processing strains (η>3) by simple cold rolling. In most practical cold-rolling operation, the thickness reduction does not exceed 90 pct (η ≅2). Therefore, innovative processing is required to generate high strength in Cu-Nb microcomposite sheet. Multiple roll bonding of Cu-Nb has been utilized to store high processing strain ( η>10) in the material and refine the Nb particle size within the copper matrix. This article describes the microstructure, mechanical properties, and thermal stability of roll-bonded Cu-Nb microcomposite sheet

  19. Influence of the welding process on martensitic high strength steel

    Directory of Open Access Journals (Sweden)

    Petr Hanus

    2014-07-01

    Full Text Available The subject of the study is martensitic 22MnB5 steels, which are used in the automotive industry. The main purpose of the performed analyses is a study of strength differences in heat affected zones of the spot welding. For the needs of the strength decrease assessment, the critical layer of the heat affected area was experimentally simulated. The aim of the work is to determine the most suitable methodology for evaluating the local changes of the elastic-plastic material response. The aim of this work is to determine the optimal methods for the determination of the yield strength and to find a firming trend in these zones.

  20. Ultrafine Structure and High Strength in Cold-Rolled Martensite

    DEFF Research Database (Denmark)

    Huang, Xiaoxu; Morito, S.; Hansen, Niels

    2012-01-01

    Structural refinement by cold rolling (10 to 80 pct reductions) of interstitial free (IF) steel containing Mn and B has been investigated from samples with different initial structures: (a) lath martensite, (b) coarse ferrite (grain size 150 mu m), and (c) fine ferrite (22 mu m). Unalloyed IF steel....... At low to medium strains, lath martensite transforms into a cell block structure composed of cell block boundaries and cell boundaries with only a negligible change in strength. At medium to large strains, cell block structures in all samples refine with increasing strain and the hardening rate...... is constant (stage IV). A strong effect of the initial structure is observed on both the structural refinement and the strength increase. This effect is largest in lath martensite and smallest in unalloyed ferrite. No saturation in structural refinement and strength is observed. The discussion covers...

  1. Heavyweight cement concrete with high stability of strength parameters

    Science.gov (United States)

    Kudyakov, Konstantin; Nevsky, Andrey; Danke, Ilia; Kudyakov, Aleksandr; Kudyakov, Vitaly

    2016-01-01

    The present paper establishes regularities of basalt fibers distribution in movable cement concrete mixes under different conditions of their preparation and their selective introduction into mixer during the mixing process. The optimum content of basalt fibers was defined as 0.5% of the cement weight, which provides a uniform distribution of fibers in the concrete volume. It allows increasing compressive strength up to 51.2% and increasing tensile strength up to 28.8%. Micro-structural analysis identified new formations on the surface of basalt fibers, which indicates the good adhesion of hardened cement paste to the fibers. Stability of concrete strength parameters has significantly increased with introduction of basalt fibers into concrete mix.

  2. Geckolike high shear strength by carbon nanotube fiber adhesives

    Science.gov (United States)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  3. Yield strength of molybdenum, tantalum and tungsten at high strain rates and very high temperatures

    International Nuclear Information System (INIS)

    Škoro, G.P.; Bennett, J.R.J.; Edgecock, T.R.; Booth, C.N.

    2012-01-01

    Highlights: ► New experimental data on the yield strength of molybdenum, tantalum and tungsten. ► High strain rate effects at record high temperatures (up to 2700 K). ► Test of the consistency of the Zerilli–Armstrong model at very high temperatures. - Abstract: Recently reported results of the high strain rate, high temperature measurements of the yield strength of tantalum and tungsten have been analyzed along with new experimental results on the yield strength of molybdenum. Thin wires are subjected to high stress by passing a short, fast, high current pulse through a thin wire; the amplitude of the current governs the stress and the repetition rate of the pulses determines the temperature of the wire. The highest temperatures reached in the experiments were 2100 °C (for molybdenum), 2250 °C (for tantalum) and 2450 °C (for tungsten). The strain-rates in the tests were in the range from 500 to 1500 s −1 . The parameters for the constitutive equation developed by Zerilli and Armstrong have been determined from the experimental data and the results have been compared with the data obtained at lower temperatures. An exceptionally good fit is obtained for the deformation of tungsten.

  4. Nanotechnology-Based Performance Improvements For Portland Cement Concrete - Phase I

    Science.gov (United States)

    2012-08-16

    A fundamental understanding of the nano-structure of Portland cement concrete (PCC) is the key to realizing significant breakthroughs regarding high performance and susta : (MBTC 2095/3004) using molecular dynamics (MD) provided new understanding of ...

  5. Weld Metallurgy and Mechanical Properties of High Manganese Ultra-high Strength Steel Dissimilar Welds

    Science.gov (United States)

    Dahmen, Martin; Lindner, Stefan; Monfort, Damien; Petring, Dirk

    The increasing demand for ultra-high strength steels in vehicle manufacturing leads to the application of new alloys. This poses a challenge on joining especially by fusion welding. A stainless high manganese steel sheet with excellent strength and deformation properties stands in the centre of the development. Similar and dissimilar welds with a metastable austenitic steel and a hot formed martensitic stainless steel were performed. An investigation of the mixing effects on the local microstructure and the hardness delivers the metallurgical features of the welds. Despite of carbon contents above 0.4 wt.% none of the welds have shown cracks. Mechanical properties drawn from tensile tests deliver high breaking forces enabling a high stiffness of the joints. The results show the potential for the application of laser beam welding for joining in assembly of structural parts.

  6. Behaviour of high-strength concrete incorporating ground ...

    African Journals Online (AJOL)

    of tests were carried out on concrete incorporating Ground Granulated Blast Furnace Slag (GGBFS) of “Mittal ... mechanical properties by using the existing materials on the local market and HSC ..... general shape of the curves whether at 28 days ... Figure.7. Residual compressive strength as a function of temperature.

  7. Shear in high strength concrete bridge girders : technical report.

    Science.gov (United States)

    2013-04-01

    Prestressed Concrete (PC) I-girders are used extensively as the primary superstructure components in Texas highway bridges. : A simple semi-empirical equation was developed at the University of Houston (UH) to predict the shear strength of PC I-girde...

  8. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    Science.gov (United States)

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  9. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    Science.gov (United States)

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  10. Interfacial (Fiber-matrix) Properties of High-strength Mortar (150 MPa) from Fiber Pullout

    DEFF Research Database (Denmark)

    Shannag, M.J.; Brincker, Rune; Hansen, Will

    1996-01-01

     The steel fiber-matrix properties of high-strength mortar (150 MPa), such as DSP (densified small particle), are obtained and compared to an ordinary strength mortar (40 MPa) using a specially designed fiber pullout apparatus. A new method for estimating the debonding energy of the interfacial z......-strength DSP mortar has significantly improved interfacial properties compared to ordinary strength mortar. These results are important in the understanding of the role of steel fibers in improving the tensile properties of high-strength, brittle, cement-matrix composites....... The steel fiber-matrix properties of high-strength mortar (150 MPa), such as DSP (densified small particle), are obtained and compared to an ordinary strength mortar (40 MPa) using a specially designed fiber pullout apparatus. A new method for estimating the debonding energy of the interfacial...

  11. Evaluation of creep rupture property of high strength ferritic/martensitic steel (PNC-FMS)

    International Nuclear Information System (INIS)

    Uehira, Akihiro; Mizuno, Tomoyasu; Ukai, Shigeharu; Yoshida, Eiichi

    1999-04-01

    High Strength Ferritic/Martensitic Steel (PNC-FMS : 11Cr-0.5Mo-2W,Nb,V), developed by JNC, is one of the candidate materials for the long-life core of large-scale fast breeder reactor. The material design base standard (tentative) of PNC-FMS was established and the creep rupture strength reduction factor in the standard was determined in 1992. This factor was based on only evaluation of decarburization effect on tensile strength after sodium exposure. In this study, creep rupture properties of PNC-FMS under out of pile sodium exposure and in pile were evaluated, using recent test results as well as previous ones. The evaluation results are summarized as follows : a. Decarburization rate constant of pressurized tubes under sodium exposure is identical with stress free specimens. b. In case of the same decarburization content under out of pile sodium exposure, creep strength tends to decrease more significantly than tensile strength. c. Creep strength under out of pile sodium exposure showed significant decrease in high temperature and long exposure time, but in pile (MOTA) creep strength showed little decrease. A new creep rupture strength reduction factor, which is the ratio of creep rupture strength under sodium exposure or in pile to in air, was made by correlating the creep rupture strength. This new method directly using the ratio of creep rupture strength was evaluated and discussed from the viewpoint of design applicability, compared with the conventional method based on decarburization effect on tensile strength. (author)

  12. High-strength and high-RRR Al-Ni alloy for aluminum-stabilized superconductor

    CERN Document Server

    Wada, K; Sakamoto, H; Yamamoto, A; Makida, Y

    2000-01-01

    The precipitation type aluminum alloys have excellent performance as the increasing rate in electric resistivity with additives in the precipitation state is considerably low, compared to that of the aluminum alloy with additives in the solid-solution state. It is possible to enhance the mechanical strength without remarkable degradation in residual resistivity ratio (RRR) by increasing content of selected additive elements. Nickel is the suitable additive element because it has very low solubility in aluminum and low increasing rate in electric resistivity, and furthermore, nickel and aluminum form intermetallic compounds which effectively resist the motion of dislocations. First, Al-0.1wt%Ni alloy was developed for the ATLAS thin superconducting solenoid. This alloy achieved high yield strength of 79 MPa (R.T.) and 117 MPa (4.2 K) with high RRR of 490 after cold working of 21% in area reduction. These highly balanced properties could not be achieved with previously developed solid-solution aluminum alloys. ...

  13. Modern high strength QT, TM and duplex-stainless steels

    International Nuclear Information System (INIS)

    Bocquet, P.; Luxenburger, G.; Porter, D.; Ericsson, C.

    2003-01-01

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  14. Thermal cyclic strength of molybdenum monocrystal at high temperatures

    International Nuclear Information System (INIS)

    Strizhalo, V.A.; Uskov, E.I.

    1975-01-01

    The results of the investigation of the thermocyclic creep and low-cycle fatigue of a molybdenum single crystal are discussed. The strength of a molybdenum single crystal under nonisothermal stressing has been investigated by using two different regimes of temperature and load variation. The temperature limits of the cycle were the same for the two testing regimes, the maximum temperature being 1700degC and the minimum 350degC. At higher temperatures (above 1500degC) the short-term strength of single-crystal molybdenum is comparable with that of commercial molybdenum and the refractory alloys, while the ductility is considerably higher. It should be noted that the failure of single-crystal molybdenum under rigid alternating loading is preceded by intensive distortion of the specimen, owing to directional cyclic creep of the metal in zones of bulging and thinning

  15. Effect of wastewater on properties of Portland pozzolana cement

    Science.gov (United States)

    Babu, G. Reddy

    2017-07-01

    This paper presents the effect of wastewaters on properties of Portland pozzolana cement (PPC). Fourteen water treatment plants were found out in the Narasaraopet municipality region in Guntur district, Andhra Pradesh, India. Approximately, from each plant, between 3500 and 4000 L/day of potable water is selling to consumers. All plants are extracting ground water and treating through Reverse Osmosis (RO) process. During water treatment, plants are discharging approximately 1,00,000 L/day as wastewater in side drains in Narasaraopet municipality. Physical and chemical analysis was carried out on fourteen plants wastewater and distilled water as per producer described in APHA. In the present work, based on the concentrations of constituent's in wastewater, four typical plants i.e., Narasaraopeta Engineering College (NECWW), Patan Khasim Charitable Trust (PKTWW), Mahmadh Khasim Charitable Trust (MKTWW) and Amara (ARWW) were considered. The performance of four plants wastewater on physical properties i.e., setting times, compressive strength, and flexural strength of Portland pozzolana Cement (PPC) were performed in laboratories and compared same with reference specimens i.e., made with Distilled Water (DW) as mixing water. No significant change was observed in initial and finial setting time but setting times of selected wastewaters were retarded as compared to that of reference water. Almost, no change was observed in 90 days compressive and flexural strengths in four plants wastewaters specimens compared to that of reference water specimens. XRD technique was employed to find out main hydration compounds formed in the process.

  16. Polymer concrete composites for the production of high strength pipe and linings in high temperature corrosive environments

    Science.gov (United States)

    Zeldin, A.; Carciello, N.; Fontana, J.; Kukacka, L.

    High temperature corrosive resistant, non-aqueous polymer concrete composites are described. They comprise about 12 to 20% by weight of a water-insoluble polymer binder polymerized in situ from a liquid monomer mixture consisting essentially of about 40 to 70% by weight of styrene, about 25 to 45% by weight acrylonitrile and about 2.5 to 7.5% by weight acrylamide or methacrylamide and about 1 to 10% by weight of a crosslinking agent. This agent is selected from the group consisting of trimethylolpropane trimethacrylate and divinyl benzene; and about 80 to 88% by weight of an inert inorganic filler system containing silica sand and portland cement, and optionally Fe/sub 2/O/sub 3/ or carbon black or mica. A free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other organic peroxides and combinations thereof to initiate crosspolymerization of the monomer mixture in the presence of said inorganic filler.

  17. Beam Test for Evaluating Applicabillity of High - Strength Reinforcement in Structure of Nuclear Facility

    International Nuclear Information System (INIS)

    Yim, Sangjun; Lee, Byungsoo; Bang, Changjoon

    2014-01-01

    The high-strength rebar which has high yield strength can reduce the amount of rebar in concrete and widen its spacing so that it has better workability and higher economic benefits for the structure. However, the maximum yield strength of rebar is limited to 420MPa in the design criteria for structure of nuclear facility in Korea and USA. Korea Hydro and Nuclear Power is progressing research to revise the limitation in the yield strength of rebar, which is suggested in the criteria of KEPIC and ACI, in order to apply 550 MPa high-strength rebar for the construction of a nuclear facility. This study is to review the applicability of high strength rebar in structure of a nuclear facility through a model beam test. After reviewing the shear capacity and reinforcement yield to assess the applicability of high-strength reinforcement in the structure of a nuclear facility, we make the following conclusions. When using high shear reinforcement with wider spacing, it has a similar shear capacity to normal reinforcement with narrower spacing. This means better workability and economic benefits can be achieved by widening the rebar spacing without brittle fracture in the elements. For future plans, the results of this test and supplementary test will be submitted to ACI349 committee as backup data to revise the standard for yield strength of high-strength rebar

  18. Beam Test for Evaluating Applicabillity of High - Strength Reinforcement in Structure of Nuclear Facility

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Sangjun; Lee, Byungsoo; Bang, Changjoon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

    2014-05-15

    The high-strength rebar which has high yield strength can reduce the amount of rebar in concrete and widen its spacing so that it has better workability and higher economic benefits for the structure. However, the maximum yield strength of rebar is limited to 420MPa in the design criteria for structure of nuclear facility in Korea and USA. Korea Hydro and Nuclear Power is progressing research to revise the limitation in the yield strength of rebar, which is suggested in the criteria of KEPIC and ACI, in order to apply 550 MPa high-strength rebar for the construction of a nuclear facility. This study is to review the applicability of high strength rebar in structure of a nuclear facility through a model beam test. After reviewing the shear capacity and reinforcement yield to assess the applicability of high-strength reinforcement in the structure of a nuclear facility, we make the following conclusions. When using high shear reinforcement with wider spacing, it has a similar shear capacity to normal reinforcement with narrower spacing. This means better workability and economic benefits can be achieved by widening the rebar spacing without brittle fracture in the elements. For future plans, the results of this test and supplementary test will be submitted to ACI349 committee as backup data to revise the standard for yield strength of high-strength rebar.

  19. Cyclic fatigue of a high-strength corrosion-resistant sheet TRIP steel

    Science.gov (United States)

    Terent'ev, V. F.; Alekseeva, L. E.; Korableva, S. A.; Prosvirnin, D. V.; Pankova, M. N.; Filippov, G. A.

    2014-04-01

    The mechanical properties of 0.3- and 0.8-mm-thick high-strength corrosion-resistant TRIP steel having various levels of strength properties are studied during static and cyclic loading in the high-cycle fatigue range. The fatigue fracture surface is analyzed by fractography, and the obtained results demonstrate ductile and quasi-brittle fracture mechanisms of this steel depending on the strength properties of the steel and the content of deformation martensite in it.

  20. Sustainable normal and high strength recycled aggregate concretes using crushed tested cylinders as coarse aggregates

    Directory of Open Access Journals (Sweden)

    Bilal S. Hamad

    2017-12-01

    Full Text Available The paper reports on a research program that was designed at the American University of Beirut (AUB to investigate the fresh and hardened mechanical properties of a high performance concrete mix produced with partial or full substitution of crushed natural lime-stone aggregates with recycled aggregates from crushed tested cylinders in batching plants. Choosing crushed cylinders as source of recycling would result in reusing portion of the waste products of the concrete production industry. An extensive concrete batching and testing program was conducted to achieve two optimum normal and high strength concrete mixes. The variables were the nominal concrete strength (28 or 60 MPa and the percentage replacement of natural coarse aggregates with recycled aggregates from crushed tested cylinders (0, 20, 40, 60, 80, or 100%. Normal strength tested cylinders were used as source of the recycled aggregates for the normal strength concrete (NSC mix and high strength tested cylinders were used for the high strength concrete (HSC mix. Tests on the trial batches included plastic state slump and hardened state mechanical properties including cylinder compressive strength, cylinder splitting tensile strength, modulus of elasticity, and standard beams flexural strength. The results indicated no significant effect on the slump and around 10% average reduction in the hardened mechanical properties for both investigated levels of concrete compressive strength.

  1. Tough hybrid ceramic-based material with high strength

    International Nuclear Information System (INIS)

    Guo, Shuqi; Kagawa, Yutaka; Nishimura, Toshiyuki

    2012-01-01

    This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB 2 -based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB 2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

  2. Advanced nickel base alloys for high strength, corrosion applications

    Science.gov (United States)

    Flinn, J.E.

    1998-11-03

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0--20Fe, 10--30Cr, 2--12Mo, 6 max. Nb, 0.05--3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01--0.08C, less than 0.2N, 0.1 max. 0, bal. Ni. 3 figs.

  3. Stress corrosion in high-strength aluminum alloys

    Science.gov (United States)

    Dorward, R. C.; Hasse, K. R.

    1980-01-01

    Report describes results of stress-corrosion tests on aluminum alloys 7075, 7475, 7050, and 7049. Tests compare performance of original stress-corrosion-resistant (SCR) aluminum, 7075, with newer, higher-strength SCR alloys. Alloys 7050 and 7049 are found superior in short-transverse cross-corrosion resistance to older 7075 alloy; all alloys are subject to self-loading effect caused by wedging of corrosion products in cracks. Effect causes cracks to continue to grow, even at very-low externally applied loads.

  4. Development of high toughness, high strength aluminide-bonded carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Becher, P.F.; Plucknett, K.P.; Tiegs, T.N. [Oak Ridge National Lab., TN (United States)] [and others

    1997-04-01

    Cemented carbides are widely used in applications where resistance to abrasion and wear are important, particularly in combination with high strength and stiffness. In the present case, ductile aluminides have been used as a binder phase to fabricate dense carbide cermets by either sintering of mixed powders or a melt-infiltration sintering process. The choice of an aluminide binder was based on the exceptional high temperature strength and chemical stability exhibited by these alloys. For example, TiC-based composites with a Ni{sub 3}Al binder phase exhibit improved oxidation resistance, Young`s moduli > 375 GPa, high fracture strengths (> 1 GPa) that are retained to {ge} 900{degrees}C, and fracture toughness values of 10 to 15 MPa{radical}m, identical to that measured in commercial cobalt-bonded WC with the same test method. The thermal diffusivity values at 200{degrees}C for these composites are {approximately} 0.070 to 0.075 cm{sup 2}/s while the thermal expansion coefficients rise with Ni3Al content from {approximately} 8 to {approximately}11 x 10{sup {minus}6}/{degrees}C over the range of 8 to 40 vol. % Ni{sub 3}Al. The oxidation and acidic corrosion resistances are quite promising as well. Finally, these materials also exhibit good electrical conductivity allowing them to be sectioned and shaped by electrical discharge machining (EDM) processes.

  5. Microencapsulated phase change materials for enhancing the thermal performance of Portland cement concrete and geopolymer concrete for passive building applications

    International Nuclear Information System (INIS)

    Cao, Vinh Duy; Pilehvar, Shima; Salas-Bringas, Carlos; Szczotok, Anna M.; Rodriguez, Juan F.; Carmona, Manuel; Al-Manasir, Nodar; Kjøniksen, Anna-Lena

    2017-01-01

    Highlights: • Microencapsulated phase change materials give high energy storage capacity concrete. • Microcapsule addition increases the porosity of concrete. • Thermal and mechanical properties are linked to the enhanced concrete porosity. • Agglomerated microcapsules have strong impact on the concrete properties. • Microcapsules caused geopolymer to become more energy efficient than Portland cement. - Abstract: Concretes with a high thermal energy storage capacity were fabricated by mixing microencapsulated phase change materials (MPCM) into Portland cement concrete (PCC) and geopolymer concrete (GPC). The effect of MPCM on thermal performance and compressive strength of PCC and GPC were investigated. It was found that the replacement of sand by MPCM resulted in lower thermal conductivity and higher thermal energy storage, while the specific heat capacity of concrete remained practically stable when the phase change material (PCM) was in the liquid or solid phase. Furthermore, the thermal conductivity of GPC as function of MPCM concentration was reduced at a higher rate than that of PCC. The power consumption needed to stabilize a simulated indoor temperature of 23 °C was reduced after the addition of MPCM. GPC exhibited better energy saving properties than PCC at the same conditions. A significant loss in compressive strength was observed due to the addition of MPCM to concrete. However, the compressive strength still satisfies the mechanical European regulation (EN 206-1, compressive strength class C20/25) for concrete applications. Finally, MPCM-concrete provided a good thermal stability after subjecting the samples to 100 thermal cycles at high heating/cooling rates.

  6. Processing of Cu-Cr alloy for combined high strength and high conductivity

    Directory of Open Access Journals (Sweden)

    A.O Olofinjanaa

    2017-11-01

    Full Text Available High strength and high conductivity (HSHC are two intrinsic properties difficult to combine in metallic alloy design because; almost all strengthening mechanisms also lead to reduced conductivity. Precipitation hardening by nano-sized precipitates had proven to be the most adequate way to achieve the optimum combination of strength and conductivity in copper based alloys. However, established precipitation strengthened Cu- alloys are limited to very dilute concentration of solutes thereby limiting the volume proportion hardening precipitates. In this work, we report the investigation of the reprocessing of higher Cr concentration Cu- based alloys via rapid solidification. It is found that the rapid solidification in the as-cast ribbon imposed combined solution extension and ultra-refinement of Cr rich phases. X-ray diffraction evidences suggest that the solid solution extension was up to 6wt%Cr. Lattice parameters determined confirmed the many folds extension of solid solution of Cr in Cu.  Thermal aging studies of the cast ribbons indicated that peak aging treatments occurred in about twenty minutes. Peak aged hardness ranged from about 200 to well over 300Hv. The maximum peak aged hardness of 380Hv was obtained for alloy containing 6wt.%Cr but with conductivity of about 50%IACS. The best combined strength/conductivity was obtained for 4wt.%Cr  alloy with hardness of 350HV and conductivity of 80% IACS. The high strengths observed are attributed to the increased volume proportion of semi-coherent Cr rich nano-sized precipitates that evolved from the supersaturated solid solution of Cu-Cr that was achieved from the high cooling rates imposed by the ribbon casting process. The rapid overaging of the high Cr concentration Cu-Cr alloy is still a cause for concern in optimising the process for reaching peak HSHC properties. It is still important to investigate a microstructural design to slow or severely restrict the overaging process. The optimum

  7. AN EXPERIMENTAL STUDY ON STRENGTH AND PERMEABILITY PROPERTIES OF HIGH STRENGTH CONCRETE

    OpenAIRE

    Yedla Venkatesh * & G. Kalyan

    2017-01-01

    Concrete is the most important engineering material and the addition of some other materials may change the properties of concrete. Mineral additions which are also known as mineral admixtures have been used with cements for many years. There are two types of materials crystalline and non crystalline. High performance concrete (HPC) exceeds the properties and constructability of normal concrete. Micro silica or silica fume is very fine non crystalline material. Silica fume is produced in elec...

  8. Alkyl chitosan film-high strength, functional biomaterials.

    Science.gov (United States)

    Lu, Li; Xing, Cao; Xin, Shen; Shitao, Yu; Feng, Su; Shiwei, Liu; Fusheng, Liu; Congxia, Xie

    2017-11-01

    Biofilm with strong tensile strength is a topic item in the area of tissue engineering, medicine engineering, and so forth. Here we introduced an alkyl chitosan film with strong tensile strength and its possibility for an absorbable anticoagulation material in vivo was tested in the series of blood test, such as dynamic coagulation time, plasma recalcification time and hemolysis. Alkyl chitosan film was a better biomaterial than traditional chitosan film in the anticoagulation, tissue compatibility and cell compatibility. The unique trait of alkyl chitosan film may be for its greater contact angle and hydrophobicity ability to reduce the adsorption capacity for the blood component and the activity of fibrinolytic enzymes, enhance the antibacterial capacity than chitosan film. Moreover, none of chitosan film or butyl chitosan film exhibited quick inflammation or other disadvantage and degraded quickly by implanted test. Therefore, Alkyl chitosan film is of prospective properties as an implantable, absorbable agent for tissue heals, and this material need further research. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3034-3041, 2017. © 2017 Wiley Periodicals, Inc.

  9. Modern high strength QT, TM and duplex-stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Bocquet, P. [Industeel (France); Luxenburger, G. [Aktiengesellschaft der Dillinger Huettenwerke, Dillingen/Saar (Germany); Porter, D. [Rautaruukki (Finland); Ericsson, C. [Avesta Polarit (Sweden)

    2003-07-01

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  10. Effect of Hybrid Fibers on the Mechanical Properties of High Strength Concrete

    Directory of Open Access Journals (Sweden)

    Hamid H. Hussein, Saeed K. Rejeb Hayder T. Abd

    2014-04-01

    Full Text Available In this study, high strength concrete of 75 MPa compressive strength was investigated. The experimental program was designed to study the effect of fibers and hybrid fibers (steel and polypropylene fibers on the fresh (workability and wet density and hardened properties (compressive strength, splitting strength, flexural strength and dry density of high strength concrete. Results show that decreases in slump flow of all concrete mixtures containing steel, polypropylene and hybrid fibers compared with control mix (0% fiber. Hybrid high strength concrete with steel and polypropylene fibers showed superior compressive, splitting, flexural strengths over the others concrete without or with single fibers content. The test results indicate that the maximum increase in compressive and flexural strengths are obtains with the hybridization ratio (70%steel + 30% polypropylene and were equal to 14.54% and 23.34% respectively, compared with the control mix. While, the maximum increase in splitting tensile strength with (100% steel fiber + 0 polypropylene is 21.19%. 

  11. Perbandingan Sifat Fisik Beton Yang Menggunakan Semen Portland Pozzolan Dan Semen Portland Tipe I

    OpenAIRE

    Yusnita, Heni

    2011-01-01

    The research about concrete by using the Portland pozzolan cement and Portland cement type I has been done with the variation of submersion time is 7, 14, 21, and 28 days. The test is done for physics of the concrete. The sample is made from the ingredients 1 cement : 2 sand : 3 pebble. The result of the researching shows that the used of the Portland pozzolan cement can raise the impact of the concrete as much as 9,15% from concrete which uses the Portland cement type I. Orther side for the ...

  12. Translucency and Strength of High-Translucency Monolithic Zirconium-Oxide Materials

    Science.gov (United States)

    2016-05-12

    Capt Todd D. Church APPROVED: Translucency and Strength of High-Translucency Monolithic Zirconium -Oxide Materials C~t) Kraig/[ Vandewalle Date...copyrighted material in the thesis/dissertation manuscript entitled: "Translucency arid Strength of High-Translucency Monolithic Zirconium -Oxide...Translucency Monolithic Zirconium -Oxide Materials Abstract Dental materials manufacturers have developed more translucent monolithic zirconium oxide

  13. Internal and External Oxidation of Manganese in Advanced High Strength Steels

    NARCIS (Netherlands)

    Aghaei Lashgari, V.

    2014-01-01

    Advanced high strength steels (AHSS) have been used extensively in the automotive industries. The main characteristic of these steels is combination of high strength and enhanced formability that makes them very attractive for automotive application. However, the major drawback of these steels is

  14. Continuous, flexible, and high-strength superconducting Nb3Ge and Nb3Sn filaments

    International Nuclear Information System (INIS)

    Ahmad, I.; Heffernan, W.J.

    1976-01-01

    Fabrication of continuous, flexible, and high-strength (1600 MN/m 2 ) composite filaments of Nb 3 Ge (T/subc/ 18 0 K) and Nb 3 Sn is reported, involving chemical vapor deposition of these compounds on Nb-coated high-strength W--1% ThO 2 filaments

  15. Gravity Data for the Greater Portland Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (1,522 records) were compiled by the Portland State University. This data base was received in August 1990. Principal gravity parameters...

  16. Lift : Special Needs Transportation in Portland, Oregon

    Science.gov (United States)

    1978-01-01

    The report covers Portland, Oregon's Special Needs Transportation (SNT) project - the Lift - during its first year of operation. The purposes of this UMTA Service and Methods Demonstration (SMD) is to: (1) test a transit operator's ability to provide...

  17. Recycled materials in Portland cement concrete

    Science.gov (United States)

    2000-06-01

    This report pertains to a comprehensive study involving the use of recycled materials in Portland cement concrete. Three different materials were studied including crushed glass (CG), street sweepings (SS), and recycled concrete (RC). Blast furnace s...

  18. Investigations on the tensile strength of high performance concrete incorporating silica fume

    International Nuclear Information System (INIS)

    Santanu Bhanja; Bratish Sengupta

    2005-01-01

    Though the literature is rich in reporting on silica fume concrete the technical data on tensile strength is quite limited. The present paper is directed towards developing a better understanding on the isolated contribution of silica fume on the tensile strengths of High Performance Concrete. Extensive experimentation was carried out over water-binder ratios ranging from 0.26 to 0.42 and silica fume binder ratios from 0.0 to 0.3. For all the mixes compressive, flexural and split tensile strengths were determined at 28 days. The results of the present investigation indicate that silica fume incorporation results in significant improvements in the tensile strengths of concrete. It is also observed that the optimum replacement percentage, which led to maximization of strength, is not a constant one but depends on the water- cementitious material ratio of the mix. Compared to split tensile strengths, flexural strengths have exhibited greater percentage gains in strength. Increase in split tensile strength beyond 15% silica fume replacement is almost insignificant whereas sizeable gains in flexural tensile strength have occurred even up to 25% replacements. For the present investigation transgranular failure of concrete was observed which indicate that silica fume incorporation results in significant improvements in the strength of both paste and transition zone. (authors)

  19. An Experimental Study of High Strength-High Volume Fly Ash Concrete for Sustainable Construction Industry

    Science.gov (United States)

    Kate, Gunavant K.; Thakare, Sunil B., Dr.

    2017-08-01

    Concrete is the most widely used building material in the construction of infrastructures such as buildings, bridges, highways, dams, and many other facilities. This paper reports the development, the basic idea, the main properties of high strength-high volume fly ash with application in concrete associated with the development and implementation of Sustainable Properties of High Volume Fly Ash Concrete (HVFAC) Mixtures and Early Age Shrinkage and mechanical properties of concrete for 7,28,56 and 90days. Another alternative to make environment-friendly concrete is the development of high strength-high-volume fly ash concrete which is an synthesized from materials of geological origin or by-product materials such as fly ash which is rich in silicon and aluminum. In this paper 6 concrete mixtures were produced to evaluate the effect of key parameters on the mechanical properties of concrete and its behavior. The study key parameters are; binder material content, cement replacement ratios, and the steel fibers used to High Volume Fly Ash mixtures for increasing performance of concrete.

  20. Thermodynamic modelling of the effect of temperature on the hydration and porosity of Portland cement

    International Nuclear Information System (INIS)

    Lothenbach, Barbara; Matschei, Thomas; Moeschner, Goeril; Glasser, Fred P.

    2008-01-01

    The composition of the phase assemblage and the pore solution of Portland cements hydrated between 0 and 60 deg. C were modelled as a function of time and temperature. The results of thermodynamic modelling showed a good agreement with the experimental data gained at 5, 20, and 50 deg. C. At 5 and at 20 deg. C, a similar phase assemblage was calculated to be present, while at approximately 50 deg. C, thermodynamic calculations predicted the conversion of ettringite and monocarbonate to monosulphate. Modelling showed that in Portland cements which have an Al 2 O 3 /SO 3 ratio of > 1.3 (bulk weight), above 50 deg. C monosulphate and monocarbonate are present. In Portland cements which contain less Al (Al 2 O 3 /SO 3 < 1.3), above 50 deg. C monosulphate and small amounts of ettringite are expected to persist. A good correlation between calculated porosity and measured compressive strength was observed

  1. Analyses of heavy metals in mineral trioxide aggregate and Portland cement.

    Science.gov (United States)

    Schembri, Matthew; Peplow, George; Camilleri, Josette

    2010-07-01

    Portland cement is used in the construction industry as a binder in concrete. It is manufactured from chalk, limestone, and clay, which are clinkered at very high temperatures and ground with gypsum to form Portland cement. The raw materials and the manufacturing process can result in the inclusion of heavy metals in Portland cement. Portland cement with a four to one addition of bismuth oxide is marketed as mineral trioxide aggregate (MTA), which is used mainly as a dental material. Heavy metal inclusion can be of concern because MTA is in contact with hard and soft tissues. Measurements of arsenic, lead, and chromium in hydrated gray and white Portland cement, ProRoot MTA, and MTA Angelus were conducted with graphite furnace atomic absorption spectrophotometry after acid digestion on the hydrated material. The leaching of the metal ions from the solid material in water and simulated body fluid (SBF) was also determined. All cement types showed high relative values of leached chromium compared with arsenic and lead in both the total metal content and leached species. The gray Portland cement showed the highest total amount of metal. The white Portland and both MTAs had lower values for all the leached metal ions. Both MTAs released more arsenic than the amount specified in ISO 9917-1 (2007). Portland cements and MTAs showed evidence of heavy metals in the acid-soluble form as well as leaching in deionized water and SBF. MTA contained levels of arsenic higher than the safe limit specified by the ISO 9917-1 (2007). Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Evaluation of a highway bridge constructed using high strength lightweight concrete bridge girders.

    Science.gov (United States)

    2011-04-01

    The use of high performance concretes to provide longer bridge spans has been limited due to the capacity of existing infrastructure to handle the load of the girders during transportation. The use of High Strength Lightweight Concrete (HSLW) can pro...

  3. Failure analysis of high strength pipeline with single and multiple corrosions

    International Nuclear Information System (INIS)

    Chen, Yanfei; Zhang, Hong; Zhang, Juan; Li, Xin; Zhou, Jing

    2015-01-01

    Highlights: • We study failure of high strength pipelines with single corrosion. • We give regression equations for failure pressure prediction. • We propose assessment procedure for pipelines with multiple corrosions. - Abstract: Corrosion will compromise safety operation of oil and gas pipelines, accurate determination of failure pressure finds importance in residual strength assessment and corrosion allowance design of onshore and offshore pipelines. This paper investigates failure pressure of high strength pipeline with single and multiple corrosions using nonlinear finite element analysis. On the basis of developed regression equations for failure pressure prediction of high strength pipeline with single corrosion, the paper proposes an assessment procedure for predicting failure pressure of high strength pipeline with multiple corrosions. Furthermore, failure pressures predicted by proposed solutions are compared with experimental results and various assessment methods available in literature, where accuracy and versatility are demonstrated

  4. Three-Sheet Spot Welding of Advanced High-Strength Steels

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Friis, Kasper Storgaard; Zhang, W.

    2011-01-01

    The automotive industry has introduced the three-layer weld configuration, which represents new challenges compared to normal two-sheet lap welds. The process is further complicated by introducing high-strength steels in the joint. The present article investigates the weldability of thin, low....... The weld mechanisms are analyzed numerically and compared with metallographic analyses showing how the primary bonding mechanism between the thin, low-carbon steel sheet and the thicker sheet of high-strength steel is solid-state bonding, whereas the two high-strength steels are joined by melting, forming...... a weld nugget at their mutual interface. Despite the absence of the typical fusion nugget through the interface between the low-carbon steel and high-strength steel, the weld strengths obtained are acceptable. The failure mechanism in destructive testing is ductile fracture with plug failure....

  5. The evaluation on clamping force of high strength bolts by length parameter

    International Nuclear Information System (INIS)

    Kim, Kang-Seok; Nah, Hwan-Seon; Lee, Hyeon-Ju; Lee, Kang-Min

    2009-01-01

    It has been reported that the length parameter of high strength bolts results in the variance in tension loads. The required turn for each length is specified in AISC RCSC specification. This study was focused on evaluating any influence on the clamping torque subjected to length parameter of high strength bolts. The two kinds of high strength bolts of specimen are as follows; High Strength Hexagon bolt defined on ASTM A490 and Torque Shear Bolt on KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut and the clamping force were analyzed to review whether length parameter can be affected on the required tension load. To test whether the length parameter has an impact on the torque and turn of nut for the required strength and clamping force, statistical analysis is carried out. (author)

  6. Thermophysical properties of blends from Portland and sulfoaluminate-belite cements

    International Nuclear Information System (INIS)

    Mojumdar, S.C.; Janotka, I.

    2002-01-01

    The behavior of mortars with blends consisting of sulfoaluminate-belite cements and ordinary Portland cement made with cement to sand ratio of 1:3 by weight and w/c = 0.5 maintained for 90 days at 20 0 C either at 60% relative humidity - dry air or 100% relative humidity - wet air. The results show insufficient character of hydraulic activity of sulfoaluminate-belite cements. Their quality has been improved. The replacement of 15 wt % of sulfoaluminate-belite cement by ordinary Portland cement influences strength positively and elasticity modulus values as well as hydrated phases and pore structure development of sulfoaluminate-belite/ordinary Portland cement blends relative to pure sulfoaluminate-belite cement systems. The above statements confirm the possible making technologies, when improvements in sulfoaluminate-belite cements quality will be achieved. One would then anticipate the competition in usages between sulfoaluminate-belite/ordinary Portland cement and blast furnace-slag Portland cement systems in the practice. It is important to consider because sulfoaluminate-belite cements are of great advantage from the viewpoint of energy savings and quantity of CO 2 released during their production. Thermal characteristics of the samples were studied by thermogravimetry and differential thermal analysis from room temperature to 1000 0 C in air atmosphere. Generally, four significant temperature regions on thermogravimetry curves with the respective differential thermal analysis peak temperature for all types of samples are observed (Authors)

  7. Gradient twinned 304 stainless steels for high strength and high ductility

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Aiying [School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai (China); Liu, Jiabin; Wang, Hongtao [Institute of Applied Mechanics, Zhejiang University, Hangzhou (China); Lu, Jian, E-mail: jianlu@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Wang, Y. Morris, E-mail: ymwang@llnl.gov [Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2016-06-14

    Gradient materials often have attractive mechanical properties that outperform uniform microstructure counterparts. It remains a difficult task to investigate and compare the performance of various gradient microstructures due to the difficulty of fabrication, the wide range of length scales involved, and their respective volume percentage variations. We have investigated four types of gradient microstructures in 304 stainless steels that utilize submicrotwins, nanotwins, nanocrystalline-, ultrafine- and coarse-grains as building blocks. Tensile tests reveal that the gradient microstructure consisting of submicrotwins and nanotwins has a persistent and stable work hardening rate and yields an impressive combination of high strength and high ductility, leading to a toughness that is nearly 50% higher than that of the coarse-grained counterpart. Ex- and in-situ transmission electron microscopy indicates that nanoscale and submicroscale twins help to suppress and limit martensitic phase transformation via the confinement of martensite within the twin lamellar. Twinning and detwinning remain active during tensile deformation and contribute to the work hardening behavior. We discuss the advantageous properties of using submicrotwins as the main load carrier and nanotwins as the strengthening layers over those coarse and nanocrystalline grains. Our work uncovers a new gradient design strategy to help metals and alloys achieve high strength and high ductility.

  8. Novel boride base cermets with very high strength

    International Nuclear Information System (INIS)

    Ken-ichi Takagi; Mari Yonetsu; Yuji Yamasaki

    2001-01-01

    Mo 2 NiB 2 boride base cermets consist of a Mo 2 NiB 2 type complex boride as a hard phase and a Ni base binder. The addition of Cr and V to the cermets changed the boride structure from orthorhombic to tetragonal and resulted in the improvement of mechanical properties and microstructural refinement. The tetragonal Mo 2 NiB 2 was formed through the orthorhombic Mo 2 NiB 2 by the solid state reaction during sintering and not formed directly from the raw material powders. Ni-4.5B-46.9Mo-12.5V-xMn (wt.%) model cermets with five levels of Mn content from 0 to 10 wt.% were prepared to investigate the effects of Mn on the mechanical properties and microstructure Of Mo 2 NiB 2 base cermets. The transverse rupture strength (TRS) of the cermets depended strongly on the microstructure, which varied significantly with Mn content. The maximum TRS obtained at 2.5 wt.%Mn were 3.5 Gpa with hardness of 87 R A . (author)

  9. An Experimental Investigation on the Effect of Addition of Ternary Blend on the Mix Design Characteristics of High Strength Concrete using Steel Fibre

    Science.gov (United States)

    Sinha, Deepa A., Dr; Verma, A. K., Dr

    2017-08-01

    This paper presents the results of M60 grade of concrete. M60 grade of concrete is achieved by maximum density technique. Concrete is brittle and weak in tension and develops cracks during curing and due to thermal expansion / contraction over a period ot time. Thus the effect of addition of 1% steel fibre is studied. For ages, concrete has been one of the widely used materials for construction. When cement is manufactured, every one ton of cement produces around one ton of carbon dioxide leading to global warming and also as natural resources are finishing, so use of supplementary cementitious material like alccofine and flyash is used as partial replacement of cement is considered. The effect of binary and ternary blend on the strength characteristics is studied. The results indicate that the concrete made with alccofine and flyash generally show excellent fresh and hardened properties. The ternary system that is Portland cement-fly ash-Alccofine concrete was found to increase the strength of concrete when compared to concrete made with Portland cement or even from Portland cement and fly ash.

  10. Effects of cathodic protection on cracking of high-strength pipeline steels

    Energy Technology Data Exchange (ETDEWEB)

    Elboujdaini, M.; Revie, R. W.; Attard, M. [CANMET Materials Technology Laboratory, Ottawa, ON(Canada)], email: melboujd@nrcan.gc.ca

    2010-07-01

    Four strength levels of pipeline steels, ranging from X-70 to X-120, were compared to determine whether higher strength materials are more susceptible to hydrogen embrittlement under cathodic protection. Ductility was measured in a solution at four protection levels, going from no cathodic protection to 500 mV of overprotection. All four steels showed loss of ductility under cathodic protection. Under cathodic polarization, the loss of ductility increased with the strength of the steel and the activity of the potential. After slow-strain-rate experiments conducted in air and examination of fracture surfaces, it is concluded that application of cathodic potentials, cathodic overprotection, higher strength of steel, and exposure to aqueous solution are factors that decrease the ductility of steel. Hydrogen reduction seems to be an important factor in ductility reduction and fractures. Observations suggest that high-strength pipelines need better control of cathodic protection than lower-strength pipelines.

  11. Production of small diameter high-temperature-strength refractory metal wires

    Science.gov (United States)

    Petrasek, D. W.; Signorelli, R. A.; King, G. W.

    1973-01-01

    Special thermomechanical techniques (schedules) have been developed to produce small diameter wire from three refractory metal alloys: colombian base alloy, tantalum base alloy, and tungsten base alloy. High strengths of these wires indicate their potential for contributing increased strength to metallic composites.

  12. Pressure vessels fabricated with high-strength wire and electroformed nickel

    Science.gov (United States)

    Roth, B.

    1966-01-01

    Metal pressure vessels of various shapes having high strength-to-weight ratios are fabricated by using known techniques of filament winding and electroforming. This eliminates nonuniform wall thickness and unequal wall strength which resulted from welding formed vessel segments together.

  13. Design of high-temperature high-strength Al-Ti-V-Zr alloys

    International Nuclear Information System (INIS)

    Lee, H.M.

    1990-01-01

    This paper reports that it seems plausible to develop high-strength Al-base alloys useful up to 698K in view of the behavior of nickel base superalloys which resist degradation of mechanical properties to 75 pct of their absolute melting temperature. For high temperature Al alloys, the dispersed hardening phase must not undergo phase transformation to an undesirable phase during long time exposure at the temperature of interest. An additional factor to be considered is the stability of the hardening phase with respect to Ostwald ripening. This coarsening resistance is necessary so that the required strength level can be maintained after the long-time service at high temperatures. The equilibrium crystal structures of Al 3 Ti, Al 3 V and Al 3 Zr are tetragonal D0 22 , D0 22 and D0 23 , respectively. At the temperatures of interest, around 698K, vanadium and titanium are mutually substitutable in the form of Al 3 (Ti, V). Much of titanium and vanadium can be substituted for zirconium in the D0 23 - type Al 3 Zr compound, creating Al 3 (Ti, Zr) and Al 3 (V, Zr), respectively. In particular, it has been reported that fcc L1 2 -structured Al 3 M dispersoids form in the rapidly solidified Al-V-Zr and Al-Ti-Zr systems and both L1 2 and D0 23 -structured Al 3 M phases showed slow coarsening kinetics

  14. High-lying neutron hole strengths observed in pick-up reactions

    International Nuclear Information System (INIS)

    Gales, S.

    1980-01-01

    Neutron-hole states in orbits well below the Fermi surface have been observed in a number of medium-heavy nuclei from A=90 to 209 using one nucleon pick-up reactions. The excitation energies, angular distributions of such broad and enhanced structures will be discussed. The fragmentation of the neutron-hole strengths as well as the spreading of such simple mode of excitations into more complex states are compared to recent calculations within the quasiparticle-phonon or the single particle-vibration coupling nuclear models. We report on recent measurements of J for inner-hole states in 89 Zr and 115 Sn 119 Sn using the analyzing power of the (p,d) and (d,t) reactions. Large enhancement of cross-sections are observed at high excitation energy in the study of the (p,t) reactions on Zr, Cd, Sn, Te and Sm isotopes. The systematic features of such high-lying excitation are related to the ones observed in one neutron pick-up experiments. The origin of such concentration of two neutron-hole strengths in Cd and Sn isotopes will be discussed. Preliminary results obtained in the study of the (α, 6 He) reaction at 218 MeV incident energy on 90 Zr, 118 Sn and 208 Pb targets are presented and compared to the (p,t) results. Finally the properties of hole-analog states populated in neutron pick-up reactions (from 90 Zr to 208 Pb) will be presented

  15. A feasibility study of high-strength Bi-2223 conductor for high-field solenoids

    Science.gov (United States)

    Godeke, A.; Abraimov, D. V.; Arroyo, E.; Barret, N.; Bird, M. D.; Francis, A.; Jaroszynski, J.; Kurteva, D. V.; Markiewicz, W. D.; Marks, E. L.; Marshall, W. S.; McRae, D. M.; Noyes, P. D.; Pereira, R. C. P.; Viouchkov, Y. L.; Walsh, R. P.; White, J. M.

    2017-03-01

    We performed a feasibility study on a high-strength Bi{}2-xPb x Sr2Ca2Cu3O{}10-x(Bi-2223) tape conductor for high-field solenoid applications. The investigated conductor, DI-BSCCO Type HT-XX, is a pre-production version of Type HT-NX, which has recently become available from Sumitomo Electric Industries. It is based on their DI-BSCCO Type H tape, but laminated with a high-strength Ni-alloy. We used stress-strain characterizations, single- and double-bend tests, easy- and hard-way bent coil-turns at various radii, straight and helical samples in up to 31.2 T background field, and small 20-turn coils in up to 17 T background field to systematically determine the electro-mechanical limits in magnet-relevant conditions. In longitudinal tensile tests at 77 K, we found critical stress- and strain-levels of 516 MPa and 0.57%, respectively. In three decidedly different experiments we detected an amplification of the allowable strain with a combination of pure bending and Lorentz loading to ≥slant 0.92 % (calculated elastically at the outer tape edge). This significant strain level, and the fact that it is multi-filamentary conductor and available in the reacted and insulated state, makes DI-BSCCO HT-NX highly suitable for very high-field solenoids, for which high current densities and therefore high loads are required to retain manageable magnet dimensions.

  16. Properties of Portland-Composite Cements with metakaolin: Commercial and manufactured by Thermal Activation of Serbian Kaolin Clay

    Directory of Open Access Journals (Sweden)

    Mitrovic A.

    2012-09-01

    Full Text Available Portland-composite cements (CEM II were prepared with addition of 5 to 35% of metakaolin (MK, manufactured by thermal activation/calcination of Serbian kaolin clay, and commercial matakaolin (CMK. Performance of the composite cements was evaluated, through the setting time (initial and final, compressive strengths (for ages 2, 7, 28, 90 and 180 days and soundness, and compared with control cement (Portland cement – CEM I. Setting time (initial and final is accelerated in Portlandcomposite cements, for both metakaolins used. The acceleration is higher in cement with addition of commercial metakaolin. Lower compressive strength is obtained after 2 days of curing for all Portland-composite cements in comparison with control cement, since pozzolanic reaction still did not show its effect. After 7 days, pozzolanic reaction show its effect, manifested as compressive strength increase of Portland-composite cements with addition of up to 35% of CMK, and 25% in the case of cements with MK. After 28 days compressive strength was higher than that for control cement for cements prepared with addition of CMK, and with addition of up to 25% MK. After 90 days increased compressive strength was noticed with addition of 10 - 20% of CMK, and with 10 and 15% of MK, while after 180 days addition of both metakaolins influences compressive strength decrease. The results of the soundness, 0.5 mm for CEM I, and 1.0 mm in most Portland-composite cements indicate soundness increase with addition of metakaolins. Generally, better performance of Portland-composite cements was obtained with addition of commercial metakaolin, which may be attributed to the differences in the pozzolanic activity of the applied metakaolins, 20.5 MPa and 14.9 MPa for CMK and MK, respectively. By our previous findings pozzolanic activity of the thermally activated clay may be increased by subsequent milling of the metakaolin manufactured by thermal activation process.

  17. Unitarity corrections and high field strengths in high energy hard collisions

    International Nuclear Information System (INIS)

    Kovchegov, Y.V.; Mueller, A.H.

    1997-01-01

    Unitarity corrections to the BFKL description of high energy hard scattering are viewed in large N c QCD in light-cone quantization. In a center of mass frame unitarity corrections to high energy hard scattering are manifestly perturbatively calculable and unrelated to questions of parton saturation. In a frame where one of the hadrons is initially at rest unitarity corrections are related to parton saturation effects and involve potential strengths A μ ∝1/g. In such a frame we describe the high energy scattering in terms of the expectation value of a Wilson loop. The large potentials A μ ∝1/g are shown to be pure gauge terms allowing perturbation theory to again describe unitarity corrections and parton saturation effects. Genuine nonperturbative effects only come in at energies well beyond those energies where unitarity constraints first become important. (orig.)

  18. Laser beam welding of new ultra-high strength and supra-ductile steels

    OpenAIRE

    Dahmen, M.

    2015-01-01

    Ultra-high strength and supra-ductile are entering fields of new applications. Those materials are excellent candidates for modern light-weight construction and functional integration. As ultra-high strength steels the stainless martensitic grade 1.4034 and the bainitic steel UNS 53835 are investigated. For the supra-ductile steels stand two high austenitic steels with 18 and 28 % manganese. As there are no processing windows an approach from the metallurgical base on is required. Adjusting t...

  19. Connections in Precast Buildings using Ultra High-Strength Fibre Reinforced Concrete

    DEFF Research Database (Denmark)

    Hansen, Lars Pilegaard

    1995-01-01

    Ultra high-strength concrete adds new dimensions to the design of concrete structures. It is a brittle material but introducing fibres into the matrix changes the material into a highly ductile material. Furthermore, the fibre reinforcement increases the anchorage of traditional reinforcement bar...... and the fire resistance. Such a fibre reinforced ultra high-strength material has been used to develop a simple joint solution between slab elements in a column - slab building system....

  20. Corrosion Assessment Guidance for High Strength Steels (Phase 1)

    Science.gov (United States)

    2009-08-01

    The continuing worldwide demand for natural gas presents major challenges to pipeline operators. There is increasing need to construct long distance, high capacity transmission pipelines, particularly in the more remote areas of Arctic North America,...

  1. Root perforations treatment using mineral trioxide aggregate and Portland cements.

    Science.gov (United States)

    Silva Neto, José Dias da; Brito, Rafael Horácio de; Schnaider, Taylor Brandão; Gragnani, Alfredo; Engelman, Mírian; Ferreira, Lydia Masako

    2010-12-01

    Clinical, radiological and histological evaluation of root perforations treated with mineral trioxide aggregate (MTA) or Portland cements, and calcium sulfate barrier. One molar and 11 premolar teeth of a male mongrel dog received endodontic treatment and furcations were perforated with a high-speed round bur and treated with a calcium sulfate barrier. MTA, Portland cement type II (PCII) and type V (PCV), and white Portland cement (WPC) were used as obturation materials. The teeth were restored with composite resin and periapical radiographs were taken. The animal was euthanized 120 days post-surgery for treatment evaluation. Right lower first premolar (MTA), right lower third premolar (PCV), left lower second premolar (MTA), and right lower second premolar (WPC): clinically normal, slightly radio-transparent area on the furcation, little inflammatory infiltrate, and new-bone formation. Left lower third premolar (PCII), right upper first premolar (WPC), right upper third premolar (PCII), and left upper first molar (PCV): clinically normal, radiopaque area on the furcation, and new-bone formation. Right upper second premolar (MTA), left upper second premolar (WPC), left upper third premolar (PCII): presence of furcation lesion, large radiolucent area, and intense inflammatory infiltrate. All obturation materials used in this study induced new-bone formation.

  2. Binding of chloride and alkalis in Portland cement systems

    International Nuclear Information System (INIS)

    Nielsen, Erik P.; Herfort, Duncan; Geiker, Mette R.

    2005-01-01

    A thermodynamic model for describing the binding of chloride and alkalis in hydrated Portland cement pastes has been developed. The model is based on the phase rule, which for cement pastes in aggressive marine environment predicts multivariant conditions, even at constant temperature and pressure. The effect of the chloride and alkalis has been quantified by experiments on cement pastes prepared from white Portland cements containing 4% and 12% C 3 A, and a grey Portland cement containing 7% C 3 A. One weight percent calcite was added to all cements. The pastes prepared at w/s ratio of 0.70 were stored in solutions of different Cl (CaCl 2 ) and Na (NaOH) concentrations. When equilibrium was reached, the mineralogy of the pastes was investigated by EDS analysis on the SEM. A well-defined distribution of chloride was found between the pore solution, the C-S-H phase, and an AFm solid solution phase consisting of Friedel's salt and monocarbonate. Partition coefficients varied as a function of iron and alkali contents. The lower content of alkalis in WPC results in higher chloride contents in the C-S-H phase. High alkali contents result in higher chloride concentrations in the pore solution

  3. Development of high yield strength non-magnetic steels for the equipments of nuclear fusion research

    International Nuclear Information System (INIS)

    Matsuoka, Hidenori; Mukai, Tetsuya; Ohtani, Hiroo; Tsuruki, Takanori; Okada, Yasutaka

    1979-01-01

    Recently, activity of nuclear fusion research and so forth increase the demand of non-magnetic materials for various equipments and structures. For these usage, very low magnetic permeability as well as high strength are required under high magnetic field. Based on fundamental research, middle C-17% Cr-7% Ni-N non-magnetic steel has been developed. The developed steel shows more stable austenite phase and possesses higher yield strength and endurance limit of more than 10 kg/mm 2 , compared with 18% Cr-8% Ni austenitic steel. Also the developed steel has good ductility and toughness in spite of the high yield strength and shows better machinability than usual high Mn non- magnetic steels. The large forgings of this newly developed steel are manufactured in the works for the equipments of nuclear fusion research and confirmed good mechanical properties, high fatigue strength and low permeability. (author)

  4. Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2018-01-01

    Full Text Available The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

  5. A study of high-strength bolts after dephosphoring

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2016-03-01

    Full Text Available A wide variety of fasteners are produced, including those for the automobile industry, household electrical appliances industry, architectural engineering, and even the aviation industry. The effects of the high-tensile bolt dephosphoring process on the entire fastener manufacturing process and its organizational characteristics and mechanical properties are analyzed and discussed in this study. Our experimental results reveal that the bolt dephosphoring process must be completed before heat treatment, which can be confirmed with a dephosphoring reagent or metallographic observation. Once bolt heat treatment is completed, bolts without dephosphoring appear to be coated with δ ferrite (delta ferrite composed of a phosphate coating and a phosphatizing coating, which are not easily removed. Heat treatment with phosphorus results in grain boundary segregation, causing embrittlement and a reduction in lattice bonding forces and resulting in a high risk of fracturing when bolts are used in high-temperature environments or undergo multiaxial stresses.

  6. Development of the Portland cement slurries with diatomaceous earth to the oil industry; Desenvolvimento de pastas de cimento Portland com adicao de diatomita para a industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Brito, Roseane A; Melo, Dulce M.A.; Martinelli, Antonio E.; Simao, Cristina A.; Paiva, Maria D.M. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Melo, Marcus A.F. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    The class-G Portland cement has been used with success in oil well cementing. The material is usually shipped to the Northeast Brazil, because the only plant that manufactures class-G is located in Cantagalo/RJ. The present work investigates the influence of the partial substitution of Portland cement by diatomaceous earth, aiming at reducing the costs in oil well cementing, improving the slurry properties and using local raw material. The diatomaceous earth has pozzolanic properties and can be used as extenders of cement slurries. This properties added to the lower cost and availability of this material in Northeast Brazil, make the diatomaceous earth a candidate material to produce light cements, to well conditions in advanced phases of production. It were evaluated the rheological properties of the slurries (at 25 and 52 deg C), volume of free water, compressive strength after curing for 8, 24 and 48 h at 38 deg C, and consistometry tests. The results show that the diatomaceous earth maintain the viscosity values and gel force suitable for use in oil well cementing. No free water was observed in the formulations. It was also verified that the compressive strength of slurries hardened with diatomaceous earth is similar to those with only Portland cement and that the minimum compressive strength of 300 psi, after curing for 8 h was reached. The thickening time was longer than the average value and the application value. (author)

  7. Experimental Study on Artificial Cemented Sand Prepared with Ordinary Portland Cement with Different Contents

    Directory of Open Access Journals (Sweden)

    Dongliang Li

    2015-07-01

    Full Text Available Artificial cemented sand test samples were prepared by using ordinary Portland cement (OPC as the cementing agent. Through uniaxial compression tests and consolidated drained triaxial compression tests, the stress-strain curves of the artificial cemented sand with different cementing agent contents (0.01, 0.03, 0.05 and 0.08 under various confining pressures (0.00 MPa, 0.25 MPa, 0.50 MPa and 1.00 MPa were obtained. Based on the test results, the effect of the cementing agent content (Cv on the physical and mechanical properties of the artificial cemented sand were analyzed and the Mohr-Coulomb strength theory was modified by using Cv. The research reveals that when Cv is high (e.g., Cv = 0.03, 0.05 or 0.08, the stress-strain curves of the samples indicate a strain softening behavior; under the same confining pressure, as Cv increases, both the peak strength and residual strength of the samples show a significant increase. When Cv is low (e.g., Cv = 0.01, the stress-strain curves of the samples indicate strain hardening behavior. From the test data, a function of Cv (the cementing agent content with c′ (the cohesion force of the sample and Δϕ′ (the increment of the angle of shearing resistance is obtained. Furthermore, through modification of the Mohr-Coulomb strength theory, the effect of cementing agent content on the strength of the cemented sand is demonstrated.

  8. Experimental Study on Artificial Cemented Sand Prepared with Ordinary Portland Cement with Different Contents.

    Science.gov (United States)

    Li, Dongliang; Liu, Xinrong; Liu, Xianshan

    2015-07-02

    Artificial cemented sand test samples were prepared by using ordinary Portland cement (OPC) as the cementing agent. Through uniaxial compression tests and consolidated drained triaxial compression tests, the stress-strain curves of the artificial cemented sand with different cementing agent contents (0.01, 0.03, 0.05 and 0.08) under various confining pressures (0.00 MPa, 0.25 MPa, 0.50 MPa and 1.00 MPa) were obtained. Based on the test results, the effect of the cementing agent content ( C v ) on the physical and mechanical properties of the artificial cemented sand were analyzed and the Mohr-Coulomb strength theory was modified by using C v . The research reveals that when C v is high (e.g., C v = 0.03, 0.05 or 0.08), the stress-strain curves of the samples indicate a strain softening behavior; under the same confining pressure, as C v increases, both the peak strength and residual strength of the samples show a significant increase. When C v is low (e.g., C v = 0.01), the stress-strain curves of the samples indicate strain hardening behavior. From the test data, a function of C v (the cementing agent content) with c ' (the cohesion force of the sample) and Δϕ' (the increment of the angle of shearing resistance) is obtained. Furthermore, through modification of the Mohr-Coulomb strength theory, the effect of cementing agent content on the strength of the cemented sand is demonstrated.

  9. On the performance of circular concrete-filled high strength steel columns under axial loading

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmoud El-Heweity

    2012-06-01

    Full Text Available This work presents a numerical study to investigate the performance of circular high-strength steel tubes filled with concrete (CFT under monotonic axial loading. A model is developed to implement the material constitutive relationships and non-linearity. Calibration against previous experimental data shows good agreement. A parametric study is then conducted using the model and compared with codes provisions. Strength and ductility of confined concrete are of primary concern. Variables considered are yield stress of steel tube and column diameter. The assessment of column performance is based on axial load carrying capacities and enhancements of both strength and ductility due to confinement. Two parameters namely strength enhancement factor (Kf and ductility index (μ are clearly defined and introduced for assessment. Results indicate that both concrete strength and ductility of CFT columns are enhanced but to different extents. The ductile behaviors are significantly evident. The increase in yield stress of steel tube has a minimal effect on concrete strength but pronounced effect on concrete ductility. However, reduction in ductility is associated with using high-tensile steel of Grade 70. The overall findings indicate that the use of high-strength tube in CFT columns is not promising. This finding may seriously be considered in seismic design.

  10. Dualism of precipitation morphology in high strength low alloy steel

    International Nuclear Information System (INIS)

    Chih-Yuan, Chen; Chien-Chon, Chen; Jer-Ren, Yang

    2015-01-01

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  11. Dualism of precipitation morphology in high strength low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Chih-Yuan, Chen, E-mail: chen6563@gmail.com [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chien-Chon, Chen [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Jer-Ren, Yang, E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-02-25

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  12. Utilization of steel slag for Portland cement clinker production.

    Science.gov (United States)

    Tsakiridis, P E; Papadimitriou, G D; Tsivilis, S; Koroneos, C

    2008-04-01

    The aim of the present research work is to investigate the possibility of adding steel slag, a by-product of the conversion of iron to steel process, in the raw meal for the production of Portland cement clinker. Two samples of raw meals were prepared, one with ordinary raw materials, as a reference sample ((PC)(Ref)), and another with 10.5% steel slag ((PC)(S/S)). Both raw meals were sintered at 1450 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the steel slag did not affect the mineralogical characteristics of the so produced Portland cement clinker. Furthermore, both clinkers were tested by determining the grindability, setting times, compressive strengths and soundness. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of the steel slag did not negatively affect the quality of the produced cement.

  13. Splitting in Dual-Phase 590 high strength steel plates

    International Nuclear Information System (INIS)

    Yang Min; Chao, Yuh J.; Li Xiaodong; Tan Jinzhu

    2008-01-01

    Charpy V-notch impact tests on 5.5 mm thick, hot-rolled Dual-Phase 590 (DP590) steel plate were evaluated at temperatures ranging from 90 deg. C to -120 deg. C. Similar tests on 2.0 mm thick DP590 HDGI steel plate were also conducted at room temperature. Splitting or secondary cracks was observed on the fractured surfaces. The mechanisms of the splitting were then investigated. Fracture surfaces were analyzed by optical microscope (OM) and scanning electron microscope (SEM). Composition of the steel plates was determined by electron probe microanalysis (EPMA). Micro Vickers hardness of the steel plates was also surveyed. Results show that splitting occurred on the main fractured surfaces of hot-rolled steel specimens at various testing temperatures. At temperatures above the ductile-brittle-transition-temperature (DBTT), -95 deg. C, where the fracture is predominantly ductile, the length and amount of splitting decreased with increasing temperature. At temperatures lower than the DBTT, where the fracture is predominantly brittle, both the length and width of the splitting are insignificant. Splitting in HDGI steel plates only appeared in specimens of T-L direction. The analysis revealed that splitting in hot-rolled plate is caused by silicate and carbide inclusions while splitting in HDGI plate results from strip microstructure due to its high content of manganese and low content of silicon. The micro Vickers hardness of either the inclusions or the strip microstructures is higher than that of the respective base steel

  14. Synergic Adsorption–Biodegradation by an Advanced Carrier for Enhanced Removal of High-Strength Nitrogen and Refractory Organics

    KAUST Repository

    Ahmad, Muhammad; Liu, Sitong; Mahmood, Nasir; Mahmood, Asif; Ali, Muhammad; Zheng, Maosheng; Ni, Jinren

    2017-01-01

    Coking wastewater contains not only high-strength nitrogen but also toxic biorefractory organics. This study presents simultaneous removal of high-strength quinoline, carbon, and ammonium in coking wastewater by immobilized bacterial communities

  15. High-impact strength acrylic denture base material processed by autoclave.

    Science.gov (United States)

    Abdulwahhab, Salwan Sami

    2013-10-01

    To investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of high-impact strength acrylic denture base material. High Impact Acryl was the heat-cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: control groups in which high-impact strength acrylic resins processed by conventional water-bath processing technique (74°C for 1.5 h then boil for 30 min) and experimental groups in which high-impact strength acrylic resins processed by autoclave at 121°C, 210 kPa .The experimental groups were divided into (fast) groups for 15 min, and (slow) groups for 30 min. To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (Charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. In ANOVA test, there were highly significant differences between the results of the processing techniques in transverse, impact, hardness, and porosity test. The LSD test showed a significant difference between control and fast groups in transverse and hardness tests and a non-significant difference in impact test and a highly significant difference in porosity test; while, there were a highly significant differences between control and slow groups in all examined tests; finally, there were a non-significant difference between fast and slow groups in transverse and porosity tests and a highly significant difference in impact and hardness tests. In the autoclave processing technique, the slow (long) curing cycle improved the tested physical and mechanical properties as compared with the fast (short) curing cycle. The autoclave processing technique improved the tested physical and mechanical properties of High Impact Acryl. Copyright © 2013 Japan Prosthodontic Society

  16. The rupture strength of dissimilar joints in high temperature

    International Nuclear Information System (INIS)

    Groenwall, B.

    1992-05-01

    In dissimilar joints between austenitic stainless steels and ferritic steels the heat affected zone in the ferritic steel always is the weakest link. Two different joints where the ferritic steel has been 10CrMo910 (2.25Cr1Mo) and X20CrMoV121 respectively (162Cr1Mo0.3V) has been investigated through thermal cycling and isothermal creep testing. In this case the purpose has been to investigate the weakest link and therefore both 10CrMo910 and X20CrMoV121 have been welded to themselves using the TIG-method with Inconel 82 (70Cr20Cr3Mn2). 5Nb as filler wire. Crossweld specimens have been taken from the joints. To accelerate the testing the tip temperature at thermal cycling and the temperature at isothermal creep testing has been in the region 600-650 degrees C. Low ductile fracture, which is typical for failures in practice, has been obtained by using a moderate tensile stress, 63 N/mm 2 . In the high temperature range, 650 degrees C, the thermal cycling compared to the isothermal testing had no influence but in lower temperatures the cycling caused decreased time to rupture. The time to rupture in thermal cycling as well as in isothermal testing as a function of testing temperature can be fitted to exponential curve of type t = a x e bT (where t and T are time and temperature respectively). Through extrapolation of the measured data it has been found that 10CrMo910 in hard conditions that is thermal cycling has a life time at 500 degrees C of about 100 000 h. If the operational temperature is constant the life time will be about four times longer. The X20CrMoV121 on the other hand has a life time at thermal cycling at 500 degrees C and moderate tensile stress of about 3 000 000 h. This means that the tensile stress can be increased considerably. The cracks appear in 10CrMo910 closely to the fusion line but in the X20CrMoV121 steel cracking and fracture arise in the heat affected zone some millimeters from the fusion line. (au)

  17. Synthesis of pure Portland cement phases

    DEFF Research Database (Denmark)

    Wesselsky, Andreas; Jensen, Ole Mejlhede

    2009-01-01

    Pure phases commonly found in Portland cement clinkers are often used to test cement hydration behaviour in simplified experimental conditions. The synthesis of these phases is covered in this paper, starting with a description of phase relations and possible polymorphs of the four main phases...... in Portland cement, i.e. tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium alumino ferrite. Details of the The process of solid state synthesis are is described in general including practical advice on equipment and techniques. Finally In addition, some exemplary mix compositions...

  18. Possibility of using waste tire rubber and fly ash with Portland cement as construction materials.

    Science.gov (United States)

    Yilmaz, Arin; Degirmenci, Nurhayat

    2009-05-01

    The growing amount of waste rubber produced from used tires has resulted in an environmental problem. Recycling waste tires has been widely studied for the last 20 years in applications such as asphalt pavement, waterproofing systems and membrane liners. The aim of this study is to evaluate the feasibility of utilizing fly ash and rubber waste with Portland cement as a composite material for masonry applications. Class C fly ash and waste automobile tires in three different sizes were used with Portland cement. Compressive and flexural strength, dry unit weight and water absorption tests were performed on the composite specimens containing waste tire rubber. The compressive strength decreased by increasing the rubber content while increased by increasing the fly ash content for all curing periods. This trend is slightly influenced by particle size. For flexural strength, the specimens with waste tire rubber showed higher values than the control mix probably due to the effect of rubber fibers. The dry unit weight of all specimens decreased with increasing rubber content, which can be explained by the low specific gravity of rubber particles. Water absorption decreased slightly with the increase in rubber particles size. These composite materials containing 10% Portland cement, 70% and 60% fly ash and 20% and 30% tire rubber particles have sufficient strength for masonry applications.

  19. Garnet Yield Strength at High Pressures and Implications for Upper Mantle and Transition Zone Rheology

    International Nuclear Information System (INIS)

    Kavner, A.

    2008-01-01

    Garnet helps control the mechanical behavior of the Earth's crust, mantle, and transition zone. Here, measurements are presented suggesting that garnet, long considered to be a high-viscosity phase, is actually weaker than the other dominant components in the transition zone. The mechanical behavior of garnet at high pressures was examined using radial diffraction techniques in the diamond anvil cell. The yield strength of grossular garnet was inferred from synchrotron X-ray measurements of differential lattice strains. The differential stress was found to increase from 1.3 (±0.6) GPa at a hydrostatic pressure 5.8 (±1.1) GPa to 4.1 (±0.4) GPa at 15.7 (±1.0) GPa, where it was level to 19 GPa. The strength results are consistent with inferred strength values for majorite garnet from measurements in the diamond cell normal geometry, bolstering the idea that garnet-structured materials may all have similar strengths. In this low-temperature, high differential stress regime, garnet is shown to be significantly weaker than anhydrous ringwoodite and to have a strength similar to hydrous ringwoodite. This result suggests that the presence of water in the transition zone may not be required to explain a weak rheology, and therefore models of transition zone behavior built assuming that garnet is the high-strength phase may need to be revised.

  20. Development of strength evaluation method for high-pressure ceramic components

    Energy Technology Data Exchange (ETDEWEB)

    Takegami, Hiroaki, E-mail: takegami.hiroaki@jaea.go.jp; Terada, Atsuhiko; Inagaki, Yoshiyuki

    2014-05-01

    Japan Atomic Energy Agency is conducting R and D on nuclear hydrogen production by the Iodine-Sulfur (IS) process. Since highly corrosive materials such as sulfuric and hydriodic acids are used in the IS process, it is very important to develop components made of corrosion resistant materials. Therefore, we have been developing a sulfuric acid decomposer made of a ceramic material, that is, silicon carbide (SiC), which shows excellent corrosion resistance to sulfuric acid. One of the key technological challenges for the practical use of a ceramic sulfuric acid decomposer made of SiC is to be licensed in accordance with the High Pressure Gas Safety Act for high-pressure operations of the IS process. Since the strength of a ceramic material depends on its geometric form, etc., the strength evaluation method required for a pressure design is not established. Therefore, we propose a novel strength evaluation method for SiC structures based on the effective volume theory in order to extend the range of application of the effective volume. We also developed a design method for ceramic apparatus with the strength evaluation method in order to obtain a license in accordance with the High Pressure Gas Safety Act. In this paper, the minimum strength of SiC components was calculated by Monte Carlo simulation, and the minimum strength evaluation method of SiC components was developed by using the results of simulation. The method was confirmed by fracture test of tube model and reference data.

  1. Evaluation of acceptance strength tests for concrete pavements.

    Science.gov (United States)

    2005-06-30

    The North Carolina Department of Transportation has used traditionally flexural strength tests for acceptance : testing of Portland cement concrete pavements. This report summarizes a research project implemented to : investigate the feasibility of u...

  2. Compressive Strength Characteristics of Carbon, Palm Kernel and ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2018-03-15

    Mar 15, 2018 ... reinforced concrete was one of the topics of interest. Once the health risks ... over the Portland cement concrete, some of which includes higher strength ... be used in the construction industry as a binder for aggregates.

  3. STOCHASTIC MODELING OF COMPRESSIVE STRENGTH OF PHOSPHORUS SLAG CONTENT CEMENT

    Directory of Open Access Journals (Sweden)

    Ali Allahverdi

    2016-07-01

    Full Text Available One of the common methods for quick determination of compressive strength as one of the most important properties for assessment of cement quality is to apply various modeling approaches. This study is aimed at finding a model for estimating the compressive strength of phosphorus slag content cements. For this purpose, the compressive strengths of chemically activated high phosphorus slag content cement prepared from phosphorus slag (80 wt.%, Portland cement (14 wt.% and a compound chemical activator containing sodium sulfate and anhydrite (6 wt.% were measured at various Blaine finenesses and curing times. Based on the obtained results, a primary stochastic model in terms of curing time and Blaine fineness has been developed. Then, another different dataset was used to incorporate composition variable including weight fractions of phosphorus slag, cement, and activator in the model. This model can be effectively used to predict the compressive strength of phosphorus slag content cements at various Blaine finenesses, curing times, and compositions.

  4. Evolution of Durable High-Strength Flowable Mortar Reinforced with Hybrid Fibers

    OpenAIRE

    Dawood, Eethar Thanon; Ramli, Mahyuddin

    2012-01-01

    The production and use of durable materials in construction are considered as one of the most challenging things for the professional engineers. Therefore, this research was conducted to investigate the mechanical properties and the durability by using of different percentages of steel fiber with high-strength flowable mortar (HSFM) and also the use of the hybridization of steel fibers, palm fibers, and synthetic fiber (Barchip). Different experimental tests (compressive strength, splitting t...

  5. Crystallization of high-strength nano-scale leucite glass-ceramics.

    Science.gov (United States)

    Theocharopoulos, A; Chen, X; Wilson, R M; Hill, R; Cattell, M J

    2013-11-01

    Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength. An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied. Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048-0.055 μm(2)) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p0.05) strength difference. All other groups' mean BFS and characteristic strengths were found to be significantly different (pglass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Deschner, Florian, E-mail: florian.deschner@gmail.com [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Lothenbach, Barbara; Winnefeld, Frank [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Neubauer, Jürgen [GeoZentrum Nordbayern, Mineralogy, University of Erlangen-Nuremberg, 91054 Erlangen (Germany)

    2013-10-15

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H.

  7. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    International Nuclear Information System (INIS)

    Deschner, Florian; Lothenbach, Barbara; Winnefeld, Frank; Neubauer, Jürgen

    2013-01-01

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H

  8. STABILISASI TANAH LIAT SANGAT LUNAK DENGAN GARAM DAN PC (PORTLAND CEMENT

    Directory of Open Access Journals (Sweden)

    Tirta Djusman Arief

    2006-01-01

    Full Text Available Adding sodium chloride, as admixture, and Portland Cement, as stabilizer, to a very soft clay increase its plasticity index (PI, Californian Bearing Ratio (CBR, and Unconfined Compression Strength (UCS. This paper presents the results of testings done to very soft clay from Margomulyo, Surabaya. The results show a promising tendency. Anyhow a wider and comprehensive research is still needed to ensure the long-term effect of the soil stabilization. Abstract in Bahasa Indonesia : Penambahan garam (sodium chloride dan PC (Portland Cement meningkatkan PI (Plasticity Index, CBR (Californian Bearing Ratio, dan UCS (Unconfined Compression Strength dari tanah lempung sangat lunak. Dalam makalah ini disajikan hasil pengujian yang dilakukan terhadap lempung sangat lunak dari daerah Margomulyo, Surabaya. Hasilnya menunjukkan kecenderungan yang menggembirakan, namun penelitian yang luas dan komprehensif masih diperlukan untuk peningkatan stabilitas tanah dalam jangka panjang.

  9. High-Strength Low-Alloy Steel Strengthened by Multiply Nanoscale Microstructures

    Science.gov (United States)

    Shen, Y. F.; Zuo, L.

    Recently, we have being focused on improving the strength without sacrificing ductility of High-strength low-alloy (HSLA) steels by designing nanostructures. Several developments have been obtained, summarized as the following three parts: (a) Depressively nanoscale precipitates: A ferritic steel with finely dispersed precipitates reveals a yield strength of 760 MPa, approximately three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels, and its ultimate tensile strength reaches 850 MPa with an elongation-to-failure value of 18%. The finely dispersed TiC precipitates in the matrix provide matrix strengthening. The estimated magnitude of precipitation strengthening is around 458 MPa. The effects of the particle size, particle distribution and intrinsic particle strength have been investigated through dislocation dynamics (DD) simulations. The DD results show that strengthening is not only a function of the density of the nano-scale precipitates but also of their size. (b) Ultrafinely ferritic plate: An interstitial-free (IF) steel sheet with a cold-rolling reduction of 75% shows a high tensile strength (710MPa) while preserving a considerable plastic strain (13%). The ductility recovery with increasing the rolling reduction up to 75% is related with the decreasing both in lamellar spacings and cell blocks sizes. (c) Parallel nano-laminated austenite: A composite microstructure consisting of ferrite, bainitic ferrite (BF) laths and retained austenite (RA) platelets has been found for the steel with a chemical composition of 0.19C-0.30Si-1.76Mn-1.52Al (in mass fraction), processed with annealing and bainitic holding. The sample annealed at 820oC (for 120s) and partitioned at 400oC (for 300s) has the best combination of ultimate tensile strength (UTS, 682 MPa) and elongation to failure ( 70%) with about 26% of BF plates 16% RA in its microstructure.

  10. Effects of chemical and mineral additives and the water/cement ratio on the thermal resistance of Portland cement concrete

    International Nuclear Information System (INIS)

    Cesar, Leandro Cesar Dias; Morelli, Arnaldo C.; Baldo, Joao Baptista

    1998-01-01

    The exposure of Portland concrete to high temperatures (>250 deg C) can damage drastically the microstructural integrity of the material. Since the water/cement ratio as well as the inclusion of superplasticizers and mineral additives (silica fume) can alter constitutively and micro structurally the material, in this work it was investigated per effect of these additions on the damage resistance of portland concrete after exposure to high temperatures. (author)

  11. Portland cement concrete air content study.

    Science.gov (United States)

    1987-04-20

    This study took the analysis of Portland cement concrete air content. Based on the information gathered, this study hold the results were : 1) air-entrained concrete was more durable than non-air entrained concrete all other factors being equal; 2) A...

  12. Alkali binding in hydrated Portland cement paste

    NARCIS (Netherlands)

    Chen, Wei; Brouwers, Jos

    2010-01-01

    The alkali-binding capacity of C–S–H in hydrated Portland cement pastes is addressed in this study. The amount of bound alkalis in C–S–H is computed based on the alkali partition theories firstly proposed by Taylor (1987) and later further developed by Brouwers and Van Eijk (2003). Experimental data

  13. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on tunable functionalized copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

    2015-01-01

    system, with respect to functionalization, is achieved. It is investigated how the different functionalization variables affect essential DE properties, including dielectric permittivity, dielectric loss, elastic modulus and dielectric breakdown strength, and the optimal degree of chemical......%) was obtained without compromising other vital DE properties such as elastic modulus, gel fraction, dielectric and viscous loss and electrical breakdown strength....

  14. Fatigue in Welded High-Strength Steel Plate Elements under Stochastic Loading

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

    1999-01-01

    The present project is a part of an investigation on fatigue in offshore structures in high-strength steel. The fatigue life of plate elements with welded attachments is studied. The material used has a yield stress of ~ 810-840 MPa, and high weldability and toughness properties. Fatigue test...... series with constant amplitude loading and with various types of stochastic loading have been carried through on test specimens in high-strength steel, and - for a comparison - on test specimens in conventional offshore structural steel with a yield stress of ~ 400-410 MPa.A comparison between constant...... amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those...

  15. EXPERIMENTAL TESTS OF VANADIUM STRENGTH MODELS AT HIGH PRESSURES AND STRAIN RATES

    Energy Technology Data Exchange (ETDEWEB)

    Park, H; Barton, N R; Becker, R C; Bernier, J V; Cavallo, R M; Lorenz, K T; Pollaine, S M; Remington, B A; Rudd, R E

    2010-03-02

    Experimental results showing significant reductions from classical in the Rayleigh-Taylor (RT) instability growth rate due to high pressure material strength or effective lattice viscosity in metal foils are presented. On the Omega Laser in the Laboratory for Laser Energetics, University of Rochester, target samples of polycrystalline vanadium are compressed and accelerated quasi-isentropically at {approx}1 Mbar pressures, while maintaining the samples in the solid-state. Comparison of the results with constitutive models for solid state strength under these conditions show that the measured RT growth is substantially lower than predictions using existing models that work well at low pressures and long time scales. High pressure, high strain rate data can be explained by the enhanced strength due to a phonon drag mechanism, creating a high effective lattice viscosity.

  16. Laser beam welding of new ultra-high strength and supra-ductile steels

    Science.gov (United States)

    Dahmen, Martin

    2015-03-01

    Ultra-high strength and supra-ductile are entering fields of new applications. Those materials are excellent candidates for modern light-weight construction and functional integration. As ultra-high strength steels the stainless martensitic grade 1.4034 and the bainitic steel UNS 53835 are investigated. For the supra-ductile steels stand two high austenitic steels with 18 and 28 % manganese. As there are no processing windows an approach from the metallurgical base on is required. Adjusting the weld microstructure the Q+P and the QT steels require weld heat treatment. The HSD steel is weldable without. Due to their applications the ultra-high strength steels are welded in as-rolled and strengthened condition. Also the reaction of the weld on hot stamping is reflected for the martensitic grades. The supra-ductile steels are welded as solution annealed and work hardened by 50%. The results show the general suitability for laser beam welding.

  17. High-capacity, high-strength trailer designs for the GA-4/GA-9 casks

    International Nuclear Information System (INIS)

    Rickard, N.D.; Kissinger, J.A.; Taylor, C.; Zimmer, A.

    1991-01-01

    General Atomics (GA) is developing final designs for two dedicated legal-weight trailers to transport the GA-4 and GA-9 Spent-Fuel Casks. The basic designs for these high-capacity, high-strength trailers are essentially identical except for small modifications to account for the differences in cask geometry. The authors are designing both trailers to carry a 55,000 lb (24,900 kg) payload and to withstand a 2.5 g vertical design load. The GA-4 and GA-9 trailers are designed for significantly higher loads than are typical commercial semitrailers, which are designed to loads in the range of 1.7 to 2.0 g. To meet the federal gross vehicle weight limit for legal-weight trucks, GA has set a target design weight for the trailers of 9000 lb (4080 kg). This weight includes the personnel barrier, cask tiedowns, and impact limiter removal and storage system. Based on the preliminary trailer designs, the final design weight will to be very close to this target weight

  18. High-capacity, high-strength trailer designs for the GA-4/GA-9 Casks

    International Nuclear Information System (INIS)

    Kissinger, J.A.; Rickard, N.D.; Taylor, C.; Zimmer, A.

    1991-01-01

    General Atomics (GA) is developing final designs for two dedicated legal-weight trailers to transport the GA-4 and GA-9 Spent-Fuel Casks. The basic designs for these high-capacity, high-strength trailers are essentially identical except for small modifications to account for the differences in cask geometry. We are designing both trailers to carry a 55,000 lb (24,900 kg) payload and to withstand a 2.5 g vertical design load. The GA-4 and GA-9 trailers are designed for significantly higher loads than are typical commercial semitrailers, which are designed to loads in the range of 1.7 to 2.0 g. To meet the federal gross vehicle weight limit for legal-weight trucks, GA has set a target design weight for the trailers of 9000 lb (4080 kg). This weight includes the personnel barrier, cask tiedowns, and impact limiter removal and storage system. Based on the preliminary trailer designs, the final design weight is expected to be very close to this target weight. 3 refs., 3 figs

  19. Radioactive waste-Portland cement systems: I, radionuclide distribution

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Glasser, F.P.; Lachowski, E.E.

    1984-01-01

    Crystal chemical stabilization of radioactive wastes can be achieved during clinkering of, or with, ordinary portland cement. Waste loadings of 20 to 30 wt% are achieved by dilute solid solution of waste ions into cementitious host lattices. Higher waste loadings result in compatible noncementitious radiophases. The cementitious phases hydrate without loss of compressive strength. Crystallochemical relationships predict that the radionuclide partitioning in the anhydrous clinkered phases will be maintained in the hydration products. These cementitious hydroxylated radiophases would be in internal equilibrium under anticipated repository conditions. The radionuclide distributions observed are described in the context of established phase equilibria for commercial waste cement systems, but are applicable to transuranic, medium- and low-level wastes

  20. Effect of surface decarburization on the mechanical properties of high strength low alloy steel

    International Nuclear Information System (INIS)

    Saqib, S.

    1993-01-01

    An attempt has been made to study the relationship of mechanical properties with the microstructure of a high strength low alloy steel. A thorough investigation was conducted on the steel sheet and variation in mechanical properties was observed across its thickness with a change in the microstructure. Change in hardness and tensile strength at the surface compare to the core of the material is attributed to decarburization. The current research indicates that the correlation between hardness and tensile strength is not valid for steels if the hardness is determined on the surface only. Great care should be taken at the time of determination of tensile strength by using conversion charts/tables on the basis of hardness values obtained by practical means. (author)

  1. Fracture and fatigue of high strength filaments. Final report, September 25, 1974--August 30, 1975

    International Nuclear Information System (INIS)

    Holt, N.L.; Finnie, I.

    1975-01-01

    The history of high strength filamentary materials is traced and it is seen that their use has been widespread. It is shown that today's demands upon these materials require a better understanding of their behavior than is presently available. Current theories for both the static and fatigue strength of filamentary materials are reviewed. An analysis of static strength tests on short filaments is presented that explains seemingly anomalous test behavior which has been reported in the literature. The proposed approach is supported by experiments and computer analysis. A new machine for the fatigue testing of filaments or wires was designed and is described in detail. Results are presented for fatigue tests on tungsten wire, graphite filaments and glass filaments. Graphite filaments showed an unexpected deterioration in strength after very many cycles (10 8 ). An explanation of this effect is offered and supported by scanning electron microscope observations. The work concludes with some suggestions for further research

  2. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels

    Science.gov (United States)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-02-01

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400-450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0-1.2 GPa at room temperature, which is nearly 3-5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry.

  3. Preparation and Physical Assessment of Portland Cement Base Composites Containing Nano Particles

    OpenAIRE

    Amir Mahmoudi

    2015-01-01

    In this research the effects of adding silica and alumina nanoparticles on flow ability and compressive strength of cementitious composites based on Portland cement were investigated. In the first stage, the rheological behavior of different samples containing nanosilica, nanoalumina and polypropylene, polyvinyl alcohol and polyethylene fibers were evaluated. With increasing of nanoparticles in fresh samples, the slump flow diameter reduced. Fibers reduced the flow abilit...

  4. Thermal analysis of borogypsum and its effects on the physical properties of Portland cement

    International Nuclear Information System (INIS)

    Elbeyli, Iffet Yakar; Derun, Emek Moeroeydor; Guelen, Jale; Piskin, Sabriye

    2003-01-01

    Borogypsum, which consists mainly of gypsum crystals, B 2 O 3 and some impurities, is formed during the production of boric acid from colemanite, which is an important borate ore. In this study, the effect of borogypsum and calcined borogypsum on the physical properties of ordinary Portland cement (OPC) has been investigated. The calcination temperature and transformations in the structures of borogypsum and natural gypsum were determined by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. Thermal experiments were carried out between ambient temperature and 500 deg. C in an air atmosphere at a heating rate of 10 deg. C min -1 . After calculation of enthalpy and determination of conversion temperatures, borogypsum (5% and 7%), hemihydrate borogypsum (5%) and natural gypsum (5%) were added separately to Portland cement clinker and cements were ground in the laboratory. The final products were tested for chemical analysis, compressive strength, setting time, Le Chatelier expansion and fineness properties according to the European Standard (EN 196). The results show that increasing the borogypsum level in Portland cement from 5% to 7% caused an increase in setting time and a decrease in soundness expansion and compressive strength. The cement prepared with borogypsum (5%) was found to have similar strength properties to those obtained with natural gypsum, whereas a mixture containing 5% of hemihydrate borogypsum was found to develop 25% higher compressive strength than the OPC control mixtures at 28 days. For this reason, utilization of calcined borogypsum in cement applications is expected to give better results than untreated borogypsum. It is concluded that hemihydrate borogypsum could be used as a retarder for Portland cement as an industrial side. This would play an important role in reducing environmental pollution

  5. Utilization of Local Ingredients for the Production of High-Early-Strength Engineered Cementitious Composites

    Directory of Open Access Journals (Sweden)

    Hanwen Deng

    2018-01-01

    Full Text Available The rapid repair and retrofitting of existing transportation infrastructure requires dimensional stability and ductile repair material that can obtain sufficiently high strength in a few hours to accommodate the large loading and deformation at an early age. Engineering cementitious composites (ECCs is a class representative of the new generation of high-performance fiber-reinforced cement-based composites (HPFRCC with medium fiber content. The unique properties of tremendous ductility and tight multiple crack behavior indicate that ECC can be used as an effective retrofit material. The wide application of this material in China will require the use of all local ingredients. In this study, based on Chinese domestic ingredients, including matrix materials and all fibers, high-early-strength ECC (HES-ECC was designed under the guidance of strain-hardening criterion of ECC. The matrix properties and fiber/matrix interfacial micromechanics properties were obtained from three-point-bending test and single-fiber pullout test. The mechanical properties of HES-ECC were achieved by direct tensile test. The experimental results show that HES-ECC was successfully developed by using all Chinese materials. When using the domestic PVA fiber at 2%, the strength requirement can be achieved but only a low ductility. When using the domestic PE fiber at 0.8%, the strength and deformation requirement both can be obtained. The HES-ECC developed in this study exhibited compressive strength of more than 25 MPa within 6 hours, and an ultimate tensile strength of 5-6 MPa and tensile strain capacity of 3-4% after 60 days. Moreover, the cost of using domestic fiber can be largely reduced compared with using imported fiber, up to 70%; it is beneficial to the promotion of these high-early-strength ECCs in the Chinese market.

  6. The behavior of high-strength unidirectional composites under tension with superposed hydrostatic pressure

    NARCIS (Netherlands)

    Zinoviev, P.A.; Tsvetkov, S.V.; Kulish, G.G.; Berg, van den R.W.; Schepdael, van L.J.M.M.

    2001-01-01

    Three types of high-strength unidirectional composite materials were studied under longitudinal tension with superposed high hydrostatic pressure. Reinforcing fibers were T1000G carbon, S2 glass and Zylon PBO fibers; the Ciba 5052 epoxy resin was used as matrix. The composites were tested under

  7. Alternative Fuel for Portland Cement Processing

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E; Davis, Edward W; Zee, Ralph H; Bransby, David I; Hopkins, Carla; Thompson, Rutherford L; Duan, Jingran; ; Venkatasubramanian, Vignesh; Stephen, Giles

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted

  8. Effect of tension lap splice on the behavior of high strength concrete (HSC beams

    Directory of Open Access Journals (Sweden)

    Ahmed El-Azab

    2014-12-01

    Full Text Available In the recent years, many research efforts have been carried out on the bond strength between normal strength concrete (NSC and reinforcing bars spliced in tension zones in beams. Many codes gave a minimum splice length for tension and compression reinforcement as a factor of the bar diameter depending on many parameters such as concrete strength, steel yield stress, shape of bar end, shape of bar surface and also bar location. Also, codes gave another restriction about the percentage of total reinforcement to be spliced at the same time. Comparatively limited attention has been directed toward the bond between high strength concrete (HSC and reinforcing bars spliced in tension zones in beams. HSC has high modulus of elasticity, high density and long-term durability. This research presents an experimental study on the bond between high strength concrete (HSC and reinforcing bars spliced in tension zones in beams. It reports the influence of several parameters on bond in splices. The parameters covered are casting position, splice length as a factor of bar diameter, bar diameter and reinforcement ratio. The research involved tests on sixteen simply-supported beams of 1800 mm span, 200 mm width and 400 mm thickness made of HSC. In each beam, the total tensile steel bars were spliced in the constant moment zone. Crack pattern, crack propagation, cracking load, failure load and mi span deflection were recorded and analyzed to study the mentioned parameters effect.

  9. Damage Analysis and Evaluation of High Strength Concrete Frame Based on Deformation-Energy Damage Model

    Directory of Open Access Journals (Sweden)

    Huang-bin Lin

    2015-01-01

    Full Text Available A new method of characterizing the damage of high strength concrete structures is presented, which is based on the deformation energy double parameters damage model and incorporates both of the main forms of damage by earthquakes: first time damage beyond destruction and energy consumption. Firstly, test data of high strength reinforced concrete (RC columns were evaluated. Then, the relationship between stiffness degradation, strength degradation, and ductility performance was obtained. And an expression for damage in terms of model parameters was determined, as well as the critical input data for the restoring force model to be used in analytical damage evaluation. Experimentally, the unloading stiffness was found to be related to the cycle number. Then, a correction for this changing was applied to better describe the unloading phenomenon and compensate for the shortcomings of structure elastic-plastic time history analysis. The above algorithm was embedded into an IDARC program. Finally, a case study of high strength RC multistory frames was presented. Under various seismic wave inputs, the structural damages were predicted. The damage model and correction algorithm of stiffness unloading were proved to be suitable and applicable in engineering design and damage evaluation of a high strength concrete structure.

  10. Improvement of formability of high strength steel sheets in shrink flanging

    International Nuclear Information System (INIS)

    Hamedon, Z; Abe, Y; Mori, K

    2016-01-01

    In the shrinkage flanging, the wrinkling tends to occur due to compressive stress. The wrinkling will cause a difficulty in assembling parts, and severe wrinkling may leads to rupture of parts. The shrinkage flange of the ultra-high strength steel sheets not only defects the product by the occurrence of the wrinkling but also causes seizure and wear of the dies and shortens the life of dies. In the present study, a shape of a punch having gradual contact was optimized in order to prevent the wrinkling in shrinkage flanging of ultra-high strength steel sheets. The sheet was gradually bent from the corner of the sheet to reduce the compressive stress. The wrinkling in the shrink flanging of the ultra-high strength steel sheets was prevented by the punch having gradual contact. It was found that the punch having gradual contact is effective in preventing the occurrence of wrinkling in the shrinkage flanging. (paper)

  11. Statistical approach to predict compressive strength of high workability slag-cement mortars

    International Nuclear Information System (INIS)

    Memon, N.A.; Memon, N.A.; Sumadi, S.R.

    2009-01-01

    This paper reports an attempt made to develop empirical expressions to estimate/ predict the compressive strength of high workability slag-cement mortars. Experimental data of 54 mix mortars were used. The mortars were prepared with slag as cement replacement of the order of 0, 50 and 60%. The flow (workability) was maintained at 136+-3%. The numerical and statistical analysis was performed by using database computer software Microsoft Office Excel 2003. Three empirical mathematical models were developed to estimate/predict 28 days compressive strength of high workability slag cement-mortars with 0, 50 and 60% slag which predict the values accurate between 97 and 98%. Finally a generalized empirical mathematical model was proposed which can predict 28 days compressive strength of high workability mortars up to degree of accuracy 95%. (author)

  12. Methodological aspects of functional neuroimaging at high field strength: a critical review

    International Nuclear Information System (INIS)

    Scheef, L.; Landsberg, M.W.; Boecker, H.

    2007-01-01

    The last few years have proven that high field magnetic resonance imaging (MRI) is superior in nearly every way to conventional equipment up to 1.5 tesla (T). Following the global success of 3T-scanners in research institutes and medical practices, a new generation of MRI devices with field strengths of 7T and higher is now on the horizon. The introduction of ultra high fields has brought MRI technology closer to the physical limitations and increasingly greater costs are required to achieve this goal. This article provides a critical overview of the advantages and problems of functional neuroimaging using ultra high field strengths. This review is principally limited to T2*-based functional imaging techniques not dependent on contrast agents. The main issues include the significance of high field technology with respect to SNR, CNR, resolution, and sequences, as well as artifacts, noise exposure, and SAR. Of great relevance is the discussion of parallel imaging, which will presumably determine the further development of high and ultra high field strengths. Finally, the importance of high field strengths for functional neuroimaging is explained by selected publications. (orig.)

  13. Assessment of ECISS draft standard for derivation of high temperature proof strength values

    Energy Technology Data Exchange (ETDEWEB)

    Linde, L.; Sandstroem, R.

    1996-03-01

    New European material standards are under development and modern data evaluation techniques must be able to supply these standards with accurate design values. A draft standard for the derivation of high temperature proof strength values has been proposed. This standard (EDS) has been used to calculate strength values for six steels; one unalloyed steel, one 12 % Cr steel and four austenitic stainless steels. Although large data sets were available, it was not possible to satisfy the requirement in the EDS of 80 % temperature coverage in the proof strength data for several steels. It suggests that temperature coverage specified in the EDS is unrealistically high. Due to the limited number of heats satisfying the temperature coverage requirements for each steel, the statistical error in the derived values exceeds 10-20 % which must be considered as unacceptably high. Instead it is recommended that the full data sets are used irrespective of temperature coverage. The variation of proof strength values represented by the analysed heats did not cover the corresponding variation in the larger data set available. This was the case even for the steel where 16 heats satisfied the temperature coverage requirement. Thus a limited number of heats can not be expected to be a good representation of more complete data sets. This has the consequence that absolute strength values can not be derived without access to a standardised proof strength at room temperature. Two derivation methods investigated in this report are both based on the ISO 2605/III procedure for proof strength assessments at elevated temperature. Method I and II use an essentially temperature independent and temperature dependent reduction term respectively. The methods have been assessed by the same data sets for the six steels. One or both methods gave satisfactory results for most of the investigated steels. Presented results are based on work carried out in ECISS TC22 WG1. 17 refs, 20 figs, 7 tabs.

  14. Coseismic landslides reveal near-surface rock strength in a high-relief tectonically active setting

    Science.gov (United States)

    Gallen, Sean F.; Clark, Marin K.; Godt, Jonathan W.

    2014-01-01

    We present quantitative estimates of near-surface rock strength relevant to landscape evolution and landslide hazard assessment for 15 geologic map units of the Longmen Shan, China. Strength estimates are derived from a novel method that inverts earthquake peak ground acceleration models and coseismic landslide inventories to obtain material proper- ties and landslide thickness. Aggregate rock strength is determined by prescribing a friction angle of 30° and solving for effective cohesion. Effective cohesion ranges are from 70 kPa to 107 kPa for 15 geologic map units, and are approximately an order of magnitude less than typical laboratory measurements, probably because laboratory tests on hand-sized specimens do not incorporate the effects of heterogeneity and fracturing that likely control near-surface strength at the hillslope scale. We find that strength among the geologic map units studied varies by less than a factor of two. However, increased weakening of units with proximity to the range front, where precipitation and active fault density are the greatest, suggests that cli- matic and tectonic factors overwhelm lithologic differences in rock strength in this high-relief tectonically active setting.

  15. Tensile strength and durability characteristics of high-performance fiber reinforced concrete

    International Nuclear Information System (INIS)

    Ramadoss, P.; Nagamani, K.

    2008-01-01

    This paper presents investigations towards developing a better understanding of the contribution of steel fibers to the tensile strength of high-performance fiber reinforced concrete (HPFRC). For 32 series of mixes, flexural and splitting tensile strengths were determined at 28 days. The variables investigated were fiber volume fraction (0%, 0.5%, 1% and 1.5% with an aspect of 80), silica fume replacement level (SF/CM=0.05 and 0.10) and matrix composition (w/cm ratios ranging from 0.25 t 0.40). The influence of fiber content in terms of fiber reinforcing index on the flexural and splitting tensile strengths of HPFRC is presented. Comparative studies were performed on the tensile behavior of SFRC measured by two different loading tests: flexural test and splitting test. Based on the test results, using the least square method, empirical expressions were developed to predict 28-day tensile strength of HPFRC in terms of fiber reinforcing index. Durability tests were carried out to examine the performance of the SFRC. Relationship between flexural and splitting tensile strengths has been developed using regression analysis. The experimental values of previous researchers were compared with the values predicted by the empirical equations and the absolute variation obtained was within 6% and 5% for flexural and splitting tensile strengths respectively. (author)

  16. [The effect of 24 weeks of moderate-to-high intensity strength training on the elderly].

    Science.gov (United States)

    Solà Serrabou, Marta; López del Amo, José Luis; Valero, Oliver

    2014-01-01

    Strength programs have been seen to be useful in minimizing the effects of sarcopenia, although intervention protocols may vary in their content and characteristics. The aim of this study was to demonstrate the influence of a particular strength protocol for the elderly. A total of 35 individuals took part in the study, with 18 in the exercise group (4 men and 14 women), and 17 in the control group (4 men and 13 women). The average age was 73. The exercise group carried out a strength training program at moderate to high intensity over 24 weeks. Strength was evaluated using the chair stand test, 2-minute step and 2 vertical jumps-squat jump (SJ), and countermovement jump (CMJ). Falls in both groups were also compared before and after the intervention, as well as their relationship with the chair stand variable. A tendency towards improvement was observed in all tests, with the exception of CMJ; while the control group showed a tendency in the opposite direction. Contrast between the two groups at the end of the intervention was notable in all the tests. An inverse relationship between the chair stand strength variable and the number of falls was evident. According to the results achieved, the training was perceived to exercise a positive influence on both the strength of the elderly people and a reduction of the number of falls. The gap between the two groups widened towards the end of the intervention. Copyright © 2013 SEGG. Published by Elsevier Espana. All rights reserved.

  17. Friction stir weld assisted diffusion bonding of 5754 aluminum alloy to coated high strength steels

    International Nuclear Information System (INIS)

    Haghshenas, M.; Abdel-Gwad, A.; Omran, A.M.; Gökçe, B.; Sahraeinejad, S.; Gerlich, A.P.

    2014-01-01

    Highlights: • Successful lap joints of Al 5754 sheet to coated DP600 and 22MnB5 steels. • Negligible effect of welding speed on mechanical properties of Al 5754/22MnB5 joints. • Lower strength of Al 5754/22MnB5 joints compared with Al 5754/DP600 joints. - Abstract: In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 aluminum alloy to coated high strength steels (DP600 and 22MnB5) by promoting diffusion bonding in an overlap configuration. Mechanical performance and microstructures of joints were analyzed by overlap shear testing, metallography, and X-ray diffraction. Our results show that the strength of joint is dependent upon tool travel speed and the depth of the tool pin relative to the steel surface. The thickness and types of intermetallic compounds formed at the interface play a significant role in achieving a joint with optimum performance. That is, the formation of high aluminum composition intermetallic compounds (i.e. Al 5 Fe 2 ) at the interface of the friction stir lap joint appeared to have a more negative effect on joint strength compared to the presence of high iron composition intermetallic phases (i.e. FeAl). This is in agreement with previously reported findings that FeAl intermetallic can improve the fracture toughness and interface strength in Al/St joints

  18. The influence of cellular structures on flow stress of high strength components manufactured using SLM

    DEFF Research Database (Denmark)

    Mahshid, Rasoul; Hansen, Hans Nørgaard; Loft Højbjerre, Klaus

    2016-01-01

    Additive manufacturing has shown significant improvement in material and machines for high-quality solid freeform fabrication processes such as selective laser melting (SLM). In particular, manufacturing lattice structures using the SLM procedure is of interest. This research examines the effect...... of cellular materials on compression strength. The specimens are manufactured additively using industrial 3D printing systems from high-strength alloy. The material has the right mechanical properties for manufacturing tool components. This includes samples with solid and lattice structures. The Compression...

  19. Hot ductility behavior of a low carbon advanced high strength steel (AHSS) microalloyed with boron

    OpenAIRE

    Mejía, Ignacio; Bedolla Jacuinde, Arnoldo; Maldonado, Cuauhtémoc; Cabrera Marrero, José M.

    2011-01-01

    The current study analyses the influence of boron addition on the hot ductility of a low carbon advanced high strength NiCrVCu steel. For this purpose hot tensile tests were carried out at different temperatures (650, 750, 800, 900 and 1000 ◦C) at a constant true strain rate of 0.001 s−1. Experimental results showed a substantial improvement in hot ductility for the low carbon advanced high strength steel when microalloyed with boron compared with that without boron addition. Nevertheless,...

  20. Achieving Hydrogen Storage Goals through High-Strength Fiber Glass - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong [PPG Industries, Inc., Cheswick, PA (United States); Johnson, Kenneth I. [PPG Industries, Inc., Cheswick, PA (United States); Newhouse, Norman L. [PPG Industries, Inc., Cheswick, PA (United States)

    2017-06-05

    Led by PPG and partnered with Hexagon Lincoln and Pacific Northwest National Laboratory (PNNL), the team recently carried out a project “Achieving Hydrogen Storage Goals through High-Strength Fiber Glass”. The project was funded by DOE’s Fuel Cell Technologies office within the Office of Energy Efficiency and Renewable Energy, starting on September 1, 2014 as a two-year project to assess technical and commercial feasibilities of manufacturing low-cost, high-strength glass fibers to replace T700 carbon fibers with a goal of reducing the composite total cost by 50% of the existing, commercial 700 bar hydrogen storage tanks used in personal vehicles.

  1. Propriedades mecânicas de materiais compósitos à base de cimento Portland e resina epoxi Mechanical properties of composite materials based on portland cement and epoxy resin

    Directory of Open Access Journals (Sweden)

    T. H. Panzera

    2010-03-01

    Full Text Available O estudo de materiais de alto desempenho e multifuncionais, como os compósitos poliméricos cimentícios, tem sido o foco de inúmeras pesquisas na indústria da construção civil. Este trabalho investiga o efeito da combinação de uma fase polimérica termorrígida, uma resina epóxi, com cimento Portland branco estrutural, seguido da avaliação da resistência à compressão e módulo de elasticidade. Este compósito, quando comparado individualmente com as suas matérias-prima originais, promove um aumento da resistência mecânica à compressão, redução da massa específica e, também uma mudança significativa do comportamento mecânico. As mudanças nas propriedades mecânicas estão associadas à hidratação da fase cimentícia na presença da resina, fato comprovado através da análise espectroscópica na região do infravermelho.The study of multi-functional materials of high performance, as the polymeric-cementitious composites, has been the focus of several researches in the industry of the civil engineering. This work investigates the effect of the combination of a thermorigid epoxy phase and the white Portland cement, followed by the evaluation of its compressive strength and modulus of elasticity. This composite, when the phases are individually compared, provides an increase of the compressive strength, a reduction of the density, and a significant change of the mechanical behaviour. The changes in mechanical behaviour are associated with the hydration of cement in the presence of resin, which was evident after infrared spectroscopy analysis.

  2. Comparison of Post Weld Treatment of High Strength Steel Welded Joints in Medium Cycle Fatigue

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard

    2010-01-01

    This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel...... the stress range can exceed the yield-strength of ordinary structural steel, especially when considering positive stress ratios (R > 0). Fatigue experiments and qualitative evaluation of the different post-weld treatments leads to the selection of TIG dressing. The process of implementing TIG dressing...... in mass production and some inherent initial problems are discussed. The treatment of a few critical welds leads to a significant increase in fatigue performance of the entire structure and the possibility for better utilization of very high-strength steel....

  3. High strength H2S resistant steels and alloys for oil field tubular products

    International Nuclear Information System (INIS)

    Straatmann, J.A.; Grobner, P.J.

    1976-01-01

    New sources of oil and natural gas are more frequently occurring at greater depths in hostile surface and underground environments. The materials utilized in drilling and completing the wells require higher strength along with improved resistance to corrosive/embrittling attack by contaminants present in the deep, high pressure-high temperature formations. Higher strength steels having yield strengths in excess of 690 MPa and possessing improved resistance to sulfide stress corrosion cracking (SSC) have been developed and are currently being evaluated by the oil industry. The research to develop these new steels combined modifications of chemical compositions, heat treatment and processing variables. For most severe SSC environments and deep wells, it was necessary to provide even better alloys for tubular materials. The successful solution to the problem was found with the utilization of nickel-base alloys. These materials are being evaluated in commercial applications

  4. Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

    International Nuclear Information System (INIS)

    Long-Chao, Zhuo; Shu-Jie, Pang; Hui, Wang; Tao, Zhang

    2009-01-01

    Based on a new approach for designing glassy alloy compositions, bulk Al-based alloys with good glass-forming ability (GFA) are synthesized. The cast Al 86 Si 0.5 Ni 4.06 Co 2.94 Y 6 Sc 0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod. The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 GPa and maximum strength of 1.27 GPa as well as an obvious plastic strain of about 2.4% during compressive deformation. This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability. (condensed matter: structure, mechanical and thermal properties)

  5. Effects of Pelvic and Core Strength Training on High School Cross-Country Race Times.

    Science.gov (United States)

    Clark, Anne W; Goedeke, Maggie K; Cunningham, Saengchoy R; Rockwell, Derek E; Lehecka, Bryan J; Manske, Robert C; Smith, Barbara S

    2017-08-01

    Clark, AW, Goedeke, MK, Cunningham, SR, Rockwell, DE, Lehecka, BJ, Manske, RC, and Smith, BS. Effects of pelvic and core strength training on high school cross-country race times. J Strength Cond Res 31(8): 2289-2295, 2017-There is only limited research examining the effect of pelvic and core strength training on running performance. Pelvic and core muscle fatigue is believed to contribute to excess motion along frontal and transverse planes which decreases efficiency in normal sagittal plane running motions. The purpose of this study was to determine whether adding a 6-week pelvic and core strengthening program resulted in decreased race times in high school cross-country runners. Thirty-five high school cross-country runners (14-19 years old) from 2 high schools were randomly assigned to a strengthening group (experimental) or a nonstrengthening group (control). All participants completed 4 standardized isometric strength tests for hip abductors, adductors, extensors, and core musculature in a test-retest design. The experimental group performed a 6-week pelvic and core strengthening program along with their normal training. Participants in the control group performed their normal training without additional pelvic and core strengthening. Baseline, 3-week, and 6-week race times were collected using a repeated measures design. No significant interaction between experimental and control groups regarding decreasing race times and increasing pelvic and core musculature strength occurred over the 6-week study period. Both groups increased strength and decreased overall race times. Clinically significant findings reveal a 6-week pelvic and core stability strengthening program 3 times a week in addition to coach led team training may help decrease race times.

  6. Hydration kinetics modeling of Portland cement considering the effects of curing temperature and applied pressure

    International Nuclear Information System (INIS)

    Lin Feng; Meyer, Christian

    2009-01-01

    A hydration kinetics model for Portland cement is formulated based on thermodynamics of multiphase porous media. The mechanism of cement hydration is discussed based on literature review. The model is then developed considering the effects of chemical composition and fineness of cement, water-cement ratio, curing temperature and applied pressure. The ultimate degree of hydration of Portland cement is also analyzed and a corresponding formula is established. The model is calibrated against the experimental data for eight different Portland cements. Simple relations between the model parameters and cement composition are obtained and used to predict hydration kinetics. The model is used to reproduce experimental results on hydration kinetics, adiabatic temperature rise, and chemical shrinkage of different cement pastes. The comparisons between the model reproductions and the different experimental results demonstrate the applicability of the proposed model, especially for cement hydration at elevated temperature and high pressure.

  7. Properties of Fresh and Hardened High Strength Steel Fibres Reinforced Self-Compacted Concrete

    Directory of Open Access Journals (Sweden)

    Saad Ali Al-Ta'an

    2016-10-01

    Full Text Available Fresh and hardened properties of high strength steel fibrous self-compacted concrete were studied in this investigation. One reference high strength self-compacted concrete mix is used, with five percent (by weight of cement silica fume and eight percent of the cement replaced by limestone powder. Three steel fibres percentages by volume of concrete are used (0.4, 0.8, and 1.2. The used steel fibres were a shelled Harex type with irregular cross-section, equivalent diameter of 0.9278 mm, and 32 mm long. Super plasticizer was used to improve the workability and flow ability of the mixes. The test results showed that the presence of steel fibres decrease the flow ability, and increase the time of spreading, segregation, and passing ability of the fresh concrete. For the fibres percentages used, the fresh properties were within the recommended specifications for the self-compacted concrete. The test results showed an early strength development rate more than that for plain normal concrete due to the presence of the fine materials. As for normal concrete, the test results showed also that the increase in the splitting strength is more than the increase in the compressive strength due to the presence of the steel fibres. The brittle mode of failure of the plain unreinforced specimens changed to a ductile one due to the presence of the steel fibres.

  8. Creep Behavior of High-Strength Concrete Subjected to Elevated Temperatures.

    Science.gov (United States)

    Yoon, Minho; Kim, Gyuyong; Kim, Youngsun; Lee, Taegyu; Choe, Gyeongcheol; Hwang, Euichul; Nam, Jeongsoo

    2017-07-11

    Strain is generated in concrete subjected to elevated temperatures owing to the influence of factors such as thermal expansion and design load. Such strains resulting from elevated temperatures and load can significantly influence the stability of a structure during and after a fire. In addition, the lower the water-to-binder (W-B) ratio and the smaller the quantity of aggregates in high-strength concrete, the more likely it is for unstable strain to occur. Hence, in this study, the compressive strength, elastic modulus, and creep behavior were evaluated at target temperatures of 100, 200, 300, 500, and 800 °C for high-strength concretes with W-B ratios of 30%, 26%, and 23%. The loading conditions were set as non-loading and 0.33f cu . It was found that as the compressive strength of the concrete increased, the mechanical characteristics deteriorated and transient creep increased. Furthermore, when the point at which creep strain occurred at elevated temperatures after the occurrence of transient creep was considered, greater shrinkage strain occurred as the compressive strength of the concrete increased. At a heating temperature of 800 °C, the 80 and 100 MPa test specimens showed creep failure within a shrinkage strain range similar to the strain at the maximum load.

  9. Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

    Science.gov (United States)

    Stalheim, Douglas G.; Peimao, Fu; Linhao, Gu; Yongqing, Zhang

    Structural steels with yield strength requirements greater or equal to 690 MPa can be produced through controlled recrystallization hot rolling coupled with precipitation strengthening or purposeful heat treatment through quench and tempering (Q&T). High strength structural steel and wear/abrasion resistant requirements greater or equal to 360 Brinell hardness (BHN) are produced by the development of microstructures of tempered lower bainite and/or martensite through the Q&T process. While these Q&T microstructures can produce very high strengths and hardness levels making them ideal for 690 MPa plus yield strength or wear/abrasion resistant applications, they lack toughness/ductility and hence are very brittle and prone to cracking. While tempering the microstructures helps in improving the toughness/ductility and reducing the brittleness, strength and hardness can be sacrificed. In addition, these steels typically consist of alloy designs containing boron with carbon equivalents (CE) greater than 0.50 to achieve the desired microstructures. The higher CE has a negative influence on weldability.

  10. Crack Arrest Toughness of Two High Strength Steels (AISI 4140 and AISI 4340)

    Science.gov (United States)

    Ripling, E. J.; Mulherin, J. H.; Crosley, P. B.

    1982-04-01

    The crack initiation toughness ( K c ) and crack arrest toughness ( K a ) of AISI 4140 and AISI 4340 steel were measured over a range of yield strengths from 965 to 1240 MPa, and a range of test temperatures from -53 to +74°C. Emphasis was placed on K a testing since these values are thought to represent the minimum toughness of the steel as a function of loading rate. At the same yield strengths and test temperatures, K a for the AISI 4340 was about twice as high as it was for the AISI 4140. In addition, the K a values showed a more pronounced transition temperature than the K c values, when the data were plotted as a function of test temperature. The transition appeared to be associated with a change in fracture mechanism from cleavage to dimpled rupture as the test temperature was increased. The occurrence of a “pop-in” behavior at supertransition temperatures has not been found in lower strength steels, and its evaluation in these high strength steels was possible only because they are not especially tough at their supertransition temperatures. There is an upper toughness limit at which pop-in will not occur, and this was found for the AISI 4340 steel when it was tempered to its lowest yield strength (965 MPa). All the crack arrest data were identified as plane strain values, while only about one-half of the initiation values could be classified this way.

  11. Creep Behavior of High-Strength Concrete Subjected to Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Minho Yoon

    2017-07-01

    Full Text Available Strain is generated in concrete subjected to elevated temperatures owing to the influence of factors such as thermal expansion and design load. Such strains resulting from elevated temperatures and load can significantly influence the stability of a structure during and after a fire. In addition, the lower the water-to-binder (W–B ratio and the smaller the quantity of aggregates in high-strength concrete, the more likely it is for unstable strain to occur. Hence, in this study, the compressive strength, elastic modulus, and creep behavior were evaluated at target temperatures of 100, 200, 300, 500, and 800 °C for high-strength concretes with W–B ratios of 30%, 26%, and 23%. The loading conditions were set as non-loading and 0.33fcu. It was found that as the compressive strength of the concrete increased, the mechanical characteristics deteriorated and transient creep increased. Furthermore, when the point at which creep strain occurred at elevated temperatures after the occurrence of transient creep was considered, greater shrinkage strain occurred as the compressive strength of the concrete increased. At a heating temperature of 800 °C, the 80 and 100 MPa test specimens showed creep failure within a shrinkage strain range similar to the strain at the maximum load.

  12. Development of high strength steel sheets for crashworthiness; Shototsu anzen`yo kokyodo usu koban no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, K; Yamamoto, M; Mizui, N; Hirose, Y; Kojima, K [Sumitomo Metal Industries, Ltd. Osaka (Japan)

    1997-10-01

    For frontal or rear members of automotive body, the most suitable high strength steel was investigated. Dynamic tensile test at strain-rate of 2000/s and crash test of hat-shape column at 4m/s were conducted for steel sheets with tensile strength ranging from 290 to 980 MPa. Dynamic tensile strength increases with increasing static one but the ratio of dynamic tensile strength to static one decreases. Tensile strength remarkably affects crash energy absorption of column and TRIP steel is superior to other steels with same tensile strength. 7 refs., 16 figs., 1 tab.

  13. Martensitic transformations, structure, and strengthness of processed high-nitrogen and high-carbon ferrous alloys

    Science.gov (United States)

    Kaputkina, L. M.; Prokoshkina, V. G.

    2003-10-01

    Structures and properties of metastable austenitic alloys Fe-18Cr-16Ni-I2Mn-(0.17 to 0. 50)N, Fe-18Cr-12Mn-(0.48 to 1.12)N, Fe-18Cr-(0.1 to 1.18)N, and Fe-(12 to 20)Ni-(0.6 to 1.3)C, Fe-(6 to 8)Mn-(0.6 to 1.0)C, Fe-(5 to 6)Cr-(4 to 5)Mn-(0.6 to 0.8)C, Fe-6Cr-(1.0 to 1.3)C resulting from martensitic transformations under cooling and cold deformation (CD), as well as following tempering processes, were studied by magnetometry, X-ray and electron microscopy analyses, hardness measurements and mechanical properties tests. Martensite with a b.c.t. lattice was formed in all alloys with M_s{>}-196^circC during cooling. Under CD transformations of γ{to}α, γ{to}\\varepsilon{to}α, or γ{to}\\varepsilon types were realized depending on the alloy composition. Carbon increased but nitrogen decreased stacking fault energy. Thus carbon assists α-martensite formation but nitrogen promotese. As CD level and/or concentration of carbon and nitrogen increase residual stresses resulting from the CD also increase. The martensitic transformation during CD can decrease the residual stresses. Kinetic of tempering of b.c.t. thermal martensite differs from those of CD-induced martensite. In the second case, deformation aging, texture, and residual stresses are more visible. The maximal strengthening under CD takes place in (Mn+N)-steels. (Cr+N) and (Cr+Mn+N)-steels are high-strength, non-magnetic and corrosion resistant and are easily hardened by a low level of plastic deformation.

  14. Phase transformation and mechanical behavior of thermomechanically controlled processed high strength ordnance steel

    International Nuclear Information System (INIS)

    Bandyopadhyay, P.S.; Ghosh, S.K.; Kundu, S.; Chatterjee, S.

    2013-01-01

    A new low carbon titanium and niobium microalloyed steel has been thermomechanically processed in a pilot plant unit. Phase transformation phenomenon of the above steel during continuous cooling has been assessed. Evolution of microstructure and mechanical properties has also been studied at different finish rolling temperatures. A mixture of intragranular ferrite with granular bainite and bainitic ferrite along with inter-lath and intra-lath precipitation of (Ti, Nb)CN particles are the characteristic microstructural feature of air cooled steel. However, mixture of lower bainite and lath martensitic structure along with similar type (Ti, Nb)CN precipitate is observed in water quenched steel. High yield strength (896–948 MPa) with high tensile strength (974–1013 MPa) has been achieved with moderate ductility (16–17%) for the selected range of finish rolling temperature for air cooled steel. However, the water quenched steel yields higher yield strength (1240–1260 MPa) as well as higher tensile strength (1270–1285 MPa) but with lower ductility (13–14%) for the selected range of finish rolling temperature. Fairly good impact toughness values in the range of 50–89 J are obtained for the air cooled steel which are marginally higher than those of water quenched steel (42–81 J). - Highlights: ► New high strength steel has been processed in a pilot plant scale. ► Primarily granular bainite and bainitic ferrite are obtained in air cooled steel. ► Mixture of lower bainite and lath martensite is obtained in water quenched steel. ► (Ti, Nb)CN precipitate is obtained for both air cooled and water quenched steels. ► Highest strength with reasonable ductility has been achieved after water quenching

  15. Phase transformation and mechanical behavior of thermomechanically controlled processed high strength ordnance steel

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyay, P.S. [Ordnance Development Centre, Metal and Steel Factory, Ishapore 743 144 (India); Ghosh, S.K., E-mail: skghosh@metal.becs.ac.in [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India); Kundu, S.; Chatterjee, S. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India)

    2013-02-15

    A new low carbon titanium and niobium microalloyed steel has been thermomechanically processed in a pilot plant unit. Phase transformation phenomenon of the above steel during continuous cooling has been assessed. Evolution of microstructure and mechanical properties has also been studied at different finish rolling temperatures. A mixture of intragranular ferrite with granular bainite and bainitic ferrite along with inter-lath and intra-lath precipitation of (Ti, Nb)CN particles are the characteristic microstructural feature of air cooled steel. However, mixture of lower bainite and lath martensitic structure along with similar type (Ti, Nb)CN precipitate is observed in water quenched steel. High yield strength (896–948 MPa) with high tensile strength (974–1013 MPa) has been achieved with moderate ductility (16–17%) for the selected range of finish rolling temperature for air cooled steel. However, the water quenched steel yields higher yield strength (1240–1260 MPa) as well as higher tensile strength (1270–1285 MPa) but with lower ductility (13–14%) for the selected range of finish rolling temperature. Fairly good impact toughness values in the range of 50–89 J are obtained for the air cooled steel which are marginally higher than those of water quenched steel (42–81 J). - Highlights: ► New high strength steel has been processed in a pilot plant scale. ► Primarily granular bainite and bainitic ferrite are obtained in air cooled steel. ► Mixture of lower bainite and lath martensite is obtained in water quenched steel. ► (Ti, Nb)CN precipitate is obtained for both air cooled and water quenched steels. ► Highest strength with reasonable ductility has been achieved after water quenching.

  16. Investigation of Ti-Fe-Co bulk alloys with high strength and enhanced ductility

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Kato, Hidemi; Inoue, Akihisa

    2005-01-01

    High-strength Ti-Fe-Co alloys were produced in the shape of arc-melted ingots with the dimensions of about 20-25mm in diameter and 7-10mm in height. The structure of the Ti-Fe-Co alloys (at Fe/Co ratio >1) studied by X-ray diffractometry and scanning electron microscopy consisted of an ordered Pm3-bar m Ti(FeCo) compound and a disordered body-centered cubic Im3-bar m β-Ti solid solution. The optimization of the Ti-Fe-Co alloy composition is performed from the viewpoint of both high strength and ductility. The strongest Ti-Fe-Co alloys have a hypereutectic structure and exhibit a high strength of about 2000MPa and a plastic deformation of 15%. The high strength and ductility values can be achieved without using the injection mould casting or rapid solidification procedure. The deformation behavior and the fractography of Ti-Fe-Co alloys are studied in detail

  17. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  18. USE OF HIGH-STRENGTH BAINITIC CAST IRON FOR PRODUCING GEAR WHEELS

    Directory of Open Access Journals (Sweden)

    A. I. Pokrovskiy

    2015-01-01

    Full Text Available The advantages and drawbacks of high-strength cast irons with bainitic structure are reviewed basing on the authors’ own experience in the production of critical partsfrom this material and on the analysis of world trends. A possibility of the replacement of alloy steels by bainitic cast iron in manufacturing critical machine parts is discussed.

  19. Development of Ferrium S53 High-Strength, Corrosion-Resistant Steel

    Science.gov (United States)

    2009-01-01

    or any other high-strength steel. No special tools or grinding wheels are required. The only significant differences with S53 are  Machining... runout point and ** point) Fit for 4330 in Air (w/o runout points) Fit for S53 in Salt Fit for 300M in Salt Fit for 4330 in Salt MIL HNBK 5 for 300M in

  20. Fatigue properties of high-strength materials used in cold-forging tools

    DEFF Research Database (Denmark)

    Brøndsted, P.; Skov-Hansen, P.

    1998-01-01

    In the present work classical analytical models are used to describe the static stress–strain curves, low-cycle fatigue properties and fatigue crack growth behaviour of high-strength materials for use in tools for metal-forming processes such as cold forging and extrusion. The paper describes the...

  1. CD 1550 – bread wheat cultivar with high gluten strength for the cooler regions of Brazil

    Directory of Open Access Journals (Sweden)

    Francisco de Assis Franco

    2015-03-01

    Full Text Available Cultivar CD 1550 is well-suited for the wheat-growing regions 1 and 2 of Rio Grande do Sul, Santa Catarina and Paraná and 3 of Paraná. It has the characteristics of bread wheat and high gluten strength. The average potential yield is 3828 kg ha-1, 7% higher than that of the controls.

  2. Defect enhanced diffusion process and hydrogen delayed fracture in high strength steels

    International Nuclear Information System (INIS)

    Lung, C.W.; Mu Zaiqin.

    1985-10-01

    A defect enhanced diffusion model for hydrogen delayed fracture in high strength steels is suggested. It is shown that the rate of crack growth is dependent on the square or higher power of the stress intensity factor which is consistent with recent experiments. (author)

  3. Numerical Analysis on the High-Strength Concrete Beams Ultimate Behaviour

    Science.gov (United States)

    Smarzewski, Piotr; Stolarski, Adam

    2017-10-01

    Development of technologies of high-strength concrete (HSC) beams production, with the aim of creating a secure and durable material, is closely linked with the numerical models of real objects. The three-dimensional nonlinear finite element models of reinforced high-strength concrete beams with a complex geometry has been investigated in this study. The numerical analysis is performed using the ANSYS finite element package. The arc-length (A-L) parameters and the adaptive descent (AD) parameters are used with Newton-Raphson method to trace the complete load-deflection curves. Experimental and finite element modelling results are compared graphically and numerically. Comparison of these results indicates the correctness of failure criteria assumed for the high-strength concrete and the steel reinforcement. The results of numerical simulation are sensitive to the modulus of elasticity and the shear transfer coefficient for an open crack assigned to high-strength concrete. The full nonlinear load-deflection curves at mid-span of the beams, the development of strain in compressive concrete and the development of strain in tensile bar are in good agreement with the experimental results. Numerical results for smeared crack patterns are qualitatively agreeable as to the location, direction, and distribution with the test data. The model was capable of predicting the introduction and propagation of flexural and diagonal cracks. It was concluded that the finite element model captured successfully the inelastic flexural behaviour of the beams to failure.

  4. The electric strength of high-voltage transformers insulation at effect of partial dischargers

    International Nuclear Information System (INIS)

    Khoshravan, E.; Zeraatparvar, A.; Gashimov, A.M.; Mehdizadeh, R.N.

    2001-01-01

    Full text : In paper the change of electric strength of high-voltage transformers insulation at the effect of partial discharges with space charge accumulation was investigated. It is revealed that the effect of partial discharges of insulation materials results the reduction of their pulsing electric strength which can restore the own initial value at releasing of saved charge the volume of a material under condition of absence the ineversible structural changes in it. Researches of high-voltage transformers insulation's non-failure operation conditions show, that at increasing of insulation work time in a strong electrical field the reduction of average breakdown voltages with simultaneous increasing of spread in discharge voltage values takes place. It authentically testifies to reduction of short-time discharge voltage of insulation materials during their electrical aging. As the basic reason of insulation electrical aging the partial discharges occurring in gas cavities inside insulation were considered. It is known that the space charges will be formed in insulation elements of high-voltage devices which effects in dielectrical property of these elements including the electric strength and the space charge formation can occur also at partial discharges in an alternating voltage while the service of high-voltage transformers. In the given work the experiments in revealing separate influence partial discharges in pulsing electric strength of insulation materials at presence and at absence inside them the space charge were spent

  5. High strength reinforcing steel bars : concrete shear friction interface : final report : Part A.

    Science.gov (United States)

    2017-03-01

    High-strength steel (HSS) reinforcement, specifically ASTM A706 Grade 80 (550), is now permitted by the AASHTO LRFD Bridge Design Specifications for use in reinforced concrete bridge components in non-seismic regions. Using Grade 80 (550) steel reinf...

  6. Effects of high-intensity interval cycling performed after resistance training on muscle strength and hypertrophy.

    Science.gov (United States)

    Tsitkanou, S; Spengos, K; Stasinaki, A-N; Zaras, N; Bogdanis, G; Papadimas, G; Terzis, G

    2017-11-01

    Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P high-intensity interval cycling performed after heavy-resistance exercise may not inhibit resistance exercise-induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Compact cross-sections of mild and high-strength steel hollow-section beams

    NARCIS (Netherlands)

    Pavlovic, M.; Veljkovic, M.

    2017-01-01

    The Eurocode 3 rules for the high-strength steel (HSS: fy > 460 MPa) limit the analysis of beams to elastic global analysis and grades up to S700. In order to fully exploit the potential to design lightweight and sustainable steel structures, plastic analysis and the use of higher

  8. Development of high-mechanical strength electrical insulations for tokamak toroidal field coils

    International Nuclear Information System (INIS)

    Burke, C.

    1977-01-01

    The electrical insulation for the TF (Toroidal Field) coils is subjected to a high interlaminar shear, tensile and compressive stresses. Two candidate epoxy/glass fiber systems using prepreg and vacuum impregnation techniques were evaluated. Specimens were prepared and processed under controlled conditions to simulate specification manufacturing procedures. The strengths of the insulation were measured in interlaminar shear, tension, compression, and combined shear and compression statically. Shear modulus determinations were also made. Various techniques of surface treatments to increase bond strengths with three resin primers were tested

  9. Properties of Galvanized and Galvannealed Advanced High Strength Hot Rolled Steels

    Energy Technology Data Exchange (ETDEWEB)

    V.Y. Guertsman; E. Essadiqi; S. Dionne; O. Dremmailova; R. Bouchard; B. Voyzelle; J. McDermid; R. Fourmentin

    2008-04-01

    The objectives of the project were (i) to develop the coating process information to achieve good quality coatings on 3 advanced high strength hot rolled steels while retaining target mechanical properties, (ii) to obtain precise knowledge of the behavior of these steels in the various forming operations and (iii) to establish accurate user property data in the coated conditions. Three steel substrates (HSLA, DP, TRIP) with compositions providing yield strengths in the range of 400-620 MPa were selected. Only HSLA steel was found to be suitable for galnaizing and galvannealing in the hot rolled condition.

  10. Neptunium(V) Adsorption to Bacteria at Low and High Ionic Strength

    Science.gov (United States)

    Ams, D.; Swanson, J. S.; Reed, D. T.

    2010-12-01

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO2+ aquo and associated complexed species, is readily soluble, interacts weakly with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface containment. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO2+) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacteria/Np mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria used were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. The observed adsorption behavior may be linked to similarities and differences in the characteristics of the moieties between the cell walls of common gram-negative soil and halophilic bacteria. Moreover, differences in adsorption behavior may also reflect ionic

  11. Neptunium(V) adsorption to bacteria at low and high ionic strength

    International Nuclear Information System (INIS)

    Ams, David A.; Swanson, Juliet S.; Reed, Donald T.; Fein, Jeremy B.

    2010-01-01

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO 2 + aquo and associated complexed species, is readily soluble, weakly interacting with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface contaminant. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO 2 + ) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacterialNp mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight the key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. Similarities in adsorption behavior may be linked to similarities in the characteristics of the moieties between all bacterial cell walls. Differences in adsorption behavior may reflect differences in ionic strength effects, rather than differences in bacteria

  12. Neptunium(V) adsorption to bacteria at low and high ionic strength

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory; Swanson, Juliet S [Los Alamos National Laboratory; Reed, Donald T [Los Alamos National Laboratory; Fein, Jeremy B [UNIV OF NOTRE DAME

    2010-12-08

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO{sub 2}{sup +} aquo and associated complexed species, is readily soluble, weakly interacting with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface contaminant. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO{sub 2}{sup +}) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacterialNp mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight the key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. Similarities in adsorption behavior may be linked to similarities in the characteristics of the moieties between all bacterial cell walls. Differences in adsorption behavior may reflect differences in ionic strength effects, rather than

  13. Fractographic investigation of stress corrosion cracking of steels for high-strength bolts

    International Nuclear Information System (INIS)

    Gladshtejn, L.I.; Goritskij, V.M.; Evtushenko, N.A.; Sokolov, S.P.; Panfilova, L.M.

    1980-01-01

    By the methods of quantitative fractography studied is the effect of chemical composition on stress corrosion cracking resistance in the mean agressive medium (pH=2.2) and the fracture structure of cylindrical delta samples with the notch (K=2.75) of high-strength chromium steel. It is shown that the alloying of the 40 steel with Cr, Si, V increases its strength under short-time loading but leads to forming of brittle areas in fracture under long time effect of corrosion medium

  14. Effect of tempering time on the ballistic performance of a high strength armour steel

    OpenAIRE

    Jena, Pradipta Kumar; Senthil P., Ponguru; K., Siva Kumar

    2016-01-01

    The investigation describes and analyses the effect of tempering time on the mechanical and ballistic performance of a high strength armour steel. The steel is subjected to tempering at 300 °C for 2, 24 and 48 h. A marginal variation in strength and hardness is observed with increase in tempering time, whereas ductility and Charpy impact values are found to be decreasing. Ballistic performance of the samples are evaluated by impacting 7.62 mm and 12.7 mm armour piercing projectiles at 0° angl...

  15. High strength and utilizable ductility of bulk ultrafine-grained Cu-Al alloys

    Science.gov (United States)

    An, X. H.; Han, W. Z.; Huang, C. X.; Zhang, P.; Yang, G.; Wu, S. D.; Zhang, Z. F.

    2008-05-01

    Lack of plasticity is the main drawback for nearly all ultrafine-grained (UFG) materials, which restricts their practical applications. Bulk UFG Cu-Al alloys have been fabricated by using equal channel angular pressing technique. Its ductility was improved to exceed the criteria for structural utility while maintaining a high strength by designing the microstructure via alloying. Factors resulting in the simultaneously enhanced strength and ductility of UFG Cu-Al alloys are the formation of deformation twins and their extensive intersections facilitating accumulation of dislocations.

  16. Hydrolysis, formation and ionization constants at 250C, and at high temperature-high ionic strength

    International Nuclear Information System (INIS)

    Phillips, S.L.; Phillips, C.A.; Skeen, J.

    1985-02-01

    Thermochemical data for nuclear waste disposal are compiled. The resulting computerized database consists of critically evaluated data on Gibbs energy of formation, enthalpy of formation, entropy and heat capacity of selected substances for about 16 elements at 25 0 C and zero ionic strength. Elements covered are Am, As, Br, C, Cl, F, I, Mo, Np, N, O, P, Pu, Si, Sr, S, and U. Values of these thermodynamic properties were used to calculate equilibrium quotients for hydrolysis, complexation and ionization reactions up to 300 0 C and 3 ionic strength, for selected chemical reactions

  17. High-Strength Composite Fabric Tested at Structural Benchmark Test Facility

    Science.gov (United States)

    Krause, David L.

    2002-01-01

    Large sheets of ultrahigh strength fabric were put to the test at NASA Glenn Research Center's Structural Benchmark Test Facility. The material was stretched like a snare drum head until the last ounce of strength was reached, when it burst with a cacophonous release of tension. Along the way, the 3-ft square samples were also pulled, warped, tweaked, pinched, and yanked to predict the material's physical reactions to the many loads that it will experience during its proposed use. The material tested was a unique multi-ply composite fabric, reinforced with fibers that had a tensile strength eight times that of common carbon steel. The fiber plies were oriented at 0 and 90 to provide great membrane stiffness, as well as oriented at 45 to provide an unusually high resistance to shear distortion. The fabric's heritage is in astronaut space suits and other NASA programs.

  18. Applicability of newly developed 610MPa class heavy thickness high strength steel to boiler pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Norihiko; Kaihara, Shoichiro; Ishii, Jun [Ishikawajima-Harima Heavy Industries Corp., Yokohama (Japan); Kajigaya, Ichiro [Ishikawajima-Harima Heavy Industries Corp., Tokyo (Japan); Totsuka, Takehiro; Miyazaki, Takashi [Ishikawajima-Harima Heavy Industries Corp., Aioi (Japan)

    1995-11-01

    Construction of a 350 MW Class PFBC (Pressurized Fluidized Bed Combustion) boiler plant is under planning in Japan. Design temperature and pressure of the vessel are maximum 350 C and 1.69 MPa, respectively. As the plate thickness of the vessel exceeds over 100 mm, high strength steel plate of good weldability and less susceptible to reheat cracking was required and developed. The steel was aimed to satisfy the tensile strength over 610 MPa at 350 C after postweld heat treatment (PWHT), with good notch toughness. The authors investigated the welding performances of the newly developed steel by using 150 mm-thick plate welded by pulsed-MAG and SAW methods. It was confirmed that the newly developed steel and its welds possess sufficient strength and toughness after PWHT, and applicable to the actual pressure vessel.

  19. Effect of thermal ageing on mechanical properties of a high-strength ODS alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Hoon; Kim, Sung Hwan; Jang, Chang Heui [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Tae Kyu [Nuclear Materials DivisionKorea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    A new high-strength ODS alloy, ARROS, was recently developed for the application as the cladding material of a Sodium-cooled fast reactor (SFR). To assess the long-term integrity under thermal ageing, ARROS was thermally aged in air at 650°C for 1000 h. The degree of thermal ageing was assessed by mechanical tests such as uniaxial tensile, hardness, and small punch tests at from room temperature to 650°C. Tensile strength was slightly decreased but elongation, hardness, and small punch energy were hardly changed at all test temperatures for the specimen aged at 650°C for 1000 h. However, the variation in mechanical properties such as hardness and small punch energy increased after thermal ageing. Using the test results, the correlation between tensile strength and maximum small punch load was established.

  20. Behavior of bonded and unbonded prestressed normal and high strength concrete beams

    Directory of Open Access Journals (Sweden)

    O.F. Hussien

    2012-12-01

    This paper presents an experimental program conducted to study the behavior of bonded and unbounded prestressed normal strength (NSC and high strength concrete (HSC beams. The program consists of a total of nine beams; two specimens were reinforced with non-prestressed reinforcement, four specimens were reinforced with bonded tendons, and the remaining three specimens were reinforced with unbonded tendons. The overall dimensions of the beams are 160 × 340 × 4400-mm. The beams were tested under cyclic loading up to failure to examine its flexural behavior. The main variables in this experimental program are nominal concrete compressive strength (43, 72 and 97 MPa, bonded and unbonded tendons and prestressing index (0%, 70% and 100%. Theoretical analysis using rational approach was also carried out to predict the flexural behavior of the specimens. Evaluation of the analytical work is introduced and compared to the results of the experimental work.

  1. A design method for two-layer beams consisting of normal and fibered high strength concrete

    International Nuclear Information System (INIS)

    Iskhakov, I.; Ribakov, Y.

    2007-01-01

    Two-layer fibered concrete beams can be analyzed using conventional methods for composite elements. The compressed zone of such beam section is made of high strength concrete (HSC), and the tensile one of normal strength concrete (NSC). The problems related to such type of beams are revealed and studied. An appropriate depth of each layer is prescribed. Compatibility conditions between HSC and NSC layers are found. It is based on the shear deformations equality on the layers border in a section with maximal depth of the compression zone. For the first time a rigorous definition of HSC is given using a comparative analysis of deformability and strength characteristics of different concrete classes. According to this definition, HSC has no download branch in the stress-strain diagram, the stress-strain function has minimum exponent, the ductility parameter is minimal and the concrete tensile strength remains constant with an increase in concrete compression strength. The application fields of two-layer concrete beams based on different static schemes and load conditions make known. It is known that the main disadvantage of HSCs is their low ductility. In order to overcome this problem, fibers are added to the HSC layer. Influence of different fiber volume ratios on structural ductility is discussed. An upper limit of the required fibers volume ratio is found based on compatibility equation of transverse tensile concrete deformations and deformations of fibers

  2. Alloy and composition dependence of hydrogen embrittlement susceptibility in high-strength steel fasteners

    Science.gov (United States)

    Brahimi, S. V.; Yue, S.; Sriraman, K. R.

    2017-06-01

    High-strength steel fasteners characterized by tensile strengths above 1100 MPa are often used in critical applications where a failure can have catastrophic consequences. Preventing hydrogen embrittlement (HE) failure is a fundamental concern implicating the entire fastener supply chain. Research is typically conducted under idealized conditions that cannot be translated into know-how prescribed in fastener industry standards and practices. Additionally, inconsistencies and even contradictions in fastener industry standards have led to much confusion and many preventable or misdiagnosed fastener failures. HE susceptibility is a function of the material condition, which is comprehensively described by the metallurgical and mechanical properties. Material strength has a first-order effect on HE susceptibility, which increases significantly above 1200 MPa and is characterized by a ductile-brittle transition. For a given concentration of hydrogen and at equal strength, the critical strength above which the ductile-brittle transition begins can vary due to second-order effects of chemistry, tempering temperature and sub-microstructure. Additionally, non-homogeneity of the metallurgical structure resulting from poorly controlled heat treatment, impurities and non-metallic inclusions can increase HE susceptibility of steel in ways that are measurable but unpredictable. Below 1200 MPa, non-conforming quality is often the root cause of real-life failures. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  3. High efficient and continuous surface modification of carbon fibers with improved tensile strength and interfacial adhesion

    Science.gov (United States)

    Sun, Jingfeng; Zhao, Feng; Yao, Yue; Jin, Zhen; Liu, Xu; Huang, Yudong

    2017-08-01

    Most of the surface modification technologies for carbon fibers, no matter in laboratory scale or for commercial manufacture, are accompanied by a simultaneous decrease in tensile strength. In this paper, a feasible and high efficient strategy for carbon fiber treatment which could obviously improve both tensile strength and interfacial adhesion was proposed. Continuously moving carbon fibers were treated with atmospheric helium plasma for 1 min, followed by a 5 min pyrolytic carbon deposition using ethanol as precursor at 800 °C. The effects of the new approach were characterized by SEM, AFM, nanoindentation, XPS, Raman, wettability analysis, single fiber tensile strength testing and single fiber pull-out testing. After modification, pyrolytic carbon coating was deposited on the fiber surface uniformly, and the roughness and surface energy increased significantly. The single fiber tensile testing results indicate that the resulting fiber strength increased 15.7%, rising from 3.13 to 3.62 GPa. Meanwhile, the interfacial shear strength of its epoxy composites increased from 65.3 to 83.5 MPa. The comparative studies of carbon fibers modified with commercial anodic oxidation and sizing were also carried out. The results demonstrate that the new method can be utilized in the carbon fiber manufacture process and is more efficient than the traditional approaches.

  4. High-Strength Low-Alloy (HSLA) Mg-Zn-Ca Alloys with Excellent Biodegradation Performance

    Science.gov (United States)

    Hofstetter, J.; Becker, M.; Martinelli, E.; Weinberg, A. M.; Mingler, B.; Kilian, H.; Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-04-01

    This article deals with the development of fine-grained high-strength low-alloy (HSLA) magnesium alloys intended for use as biodegradable implant material. The alloys contain solely low amounts of Zn and Ca as alloying elements. We illustrate the development path starting from the high-Zn-containing ZX50 (MgZn5Ca0.25) alloy with conventional purity, to an ultrahigh-purity ZX50 modification, and further to the ultrahigh-purity Zn-lean alloy ZX10 (MgZn1Ca0.3). It is shown that alloys with high Zn-content are prone to biocorrosion in various environments, most probably because of the presence of the intermetallic phase Mg6Zn3Ca2. A reduction of the Zn content results in (Mg,Zn)2Ca phase formation. This phase is less noble than the Mg-matrix and therefore, in contrast to Mg6Zn3Ca2, does not act as cathodic site. A fine-grained microstructure is achieved by the controlled formation of fine and homogeneously distributed (Mg,Zn)2Ca precipitates, which influence dynamic recrystallization and grain growth during hot forming. Such design scheme is comparable to that of HSLA steels, where low amounts of alloying elements are intended to produce a very fine dispersion of particles to increase the material's strength by refining the grain size. Consequently our new, ultrapure ZX10 alloy exhibits high strength (yield strength R p = 240 MPa, ultimate tensile strength R m = 255 MPa) and simultaneously high ductility (elongation to fracture A = 27%), as well as low mechanical anisotropy. Because of the anodic nature of the (Mg,Zn)2Ca particles used in the HSLA concept, the in vivo degradation in a rat femur implantation study is very slow and homogeneous without clinically observable hydrogen evolution, making the ZX10 alloy a promising material for biodegradable implants.

  5. High strength and large ductility in spray-deposited Al–Zn–Mg–Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hongchun, E-mail: hcyu@hnu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Wang, Mingpu; Jia, Yanlin [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Xiao, Zhu, E-mail: xiaozhu8417@gmail.com [School of Engineering, University of Liverpool, Liverpool L69 3GH (United Kingdom); Chen, Chang; Lei, Qian; Li, Zhou; Chen, Wei [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Zhang, Hao [Jiangsu Haoran Spray Forming Alloys Co., Ltd., Zhengjiang 212009, Jiangsu (China); Wang, Yanguo; Cai, Canying [School of Physics and Microelectronics, Hunan University, Changsha 410082, Hunan (China)

    2014-07-15

    Highlights: • Spray deposition process was used to produce Al alloys with excellent performance. • The deposited alloys exhibited a high strength of 690 MPa and elongation up to 17.2%. • The η′ phase was coherent with α-Al and their orientation relationship was studied. • The interface misfits and the transition matrixes of two phases were calculated. - Abstract: The mechanical properties and microstructure of large-scale Al–Zn–Mg–Cu alloys fabricated by spray deposition/rapid solidification technology were investigated in detail. The as-extruded alloys under peak-aging temper exhibited ultimate tensile strength (UTS), yield strength (YS) and elongation of 690 MPa, 638 MPa and 17.2%, respectively. The simultaneous coexisting of high strength and large tensile ductility of the alloys were achieved in our experiment. It was considered that the high-density nano-precipitates distributed uniformly in the peak-aged alloys may be responsible for the high strength and improved ductility. Orientation relationship between η′ precipitates and α-Al matrix were verified by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction patterns (SADPs) observations. The η′ phases in the alloy were fully coherent with the aluminum matrix, with the orientation relationship of (101{sup ¯}0){sub η{sup ′}}//{110}{sub Al} and [1{sup ¯}21{sup ¯}0]{sub η{sup ′}}//<1{sup ¯}12>{sub Al}. The relationship between the lattice parameters of η′ phase and the related plane-spacing of the aluminum were a{sub η{sup ′}}=3d{sub (112){sub A{sub l}}} and c{sub η{sup ′}}=6d{sub (111){sub A{sub l}}}. Based on obtained orientation relationship, the transition matrix of η′ phases were also calculated.

  6. Effect of water absorption by the aggregate on properties of high-strength lightweight concrete

    Energy Technology Data Exchange (ETDEWEB)

    Punkki, J

    1996-12-31

    Recently, high-strength lightweight concrete has become an interesting building material for the offshore oil industry. This doctoral thesis presents an experimental investigation of the effect of water absorption by three different types of lightweight aggregates. One type did not show any water absorption ability at all and so represented no problem to the concrete production. For the two other high-strength aggregates, which were of more conventional types, the water absorption depended not only on the properties of the aggregates, but also on the concrete mixing procedure and the properties of the fresh cement paste. When water absorbing lightweight aggregate was used in a dry condition, the workability of the concrete was significantly reduced by the water absorption of the aggregate. This effect was not present when prewetted aggregate was used. The water absorption by the lightweight aggregate also affected the early compressive strength of concrete. After one day, dry aggregate gave on the average 10 MPa higher compressive strength than did prewetted aggregate. The strength-density ratio was affected by the moisture condition of the aggregate. Dry lightweight aggregate gave 9 MPa higher compressive strength at a density of 2000 kg/m{sup 3} compared to that of prewetted aggregate. The water absorption by the lightweight also affected the microstructure of the hardened concrete. Dry lightweight aggregate gave a slightly better microstructure than normal weight aggregate. The results indicate that the use of prewetted aggregate adversely affected the transition zone between the aggregate and the cement paste. 69 refs., 58 figs., 42 tabs.

  7. Effect of water absorption by the aggregate on properties of high-strength lightweight concrete

    Energy Technology Data Exchange (ETDEWEB)

    Punkki, J.

    1995-12-31

    Recently, high-strength lightweight concrete has become an interesting building material for the offshore oil industry. This doctoral thesis presents an experimental investigation of the effect of water absorption by three different types of lightweight aggregates. One type did not show any water absorption ability at all and so represented no problem to the concrete production. For the two other high-strength aggregates, which were of more conventional types, the water absorption depended not only on the properties of the aggregates, but also on the concrete mixing procedure and the properties of the fresh cement paste. When water absorbing lightweight aggregate was used in a dry condition, the workability of the concrete was significantly reduced by the water absorption of the aggregate. This effect was not present when prewetted aggregate was used. The water absorption by the lightweight aggregate also affected the early compressive strength of concrete. After one day, dry aggregate gave on the average 10 MPa higher compressive strength than did prewetted aggregate. The strength-density ratio was affected by the moisture condition of the aggregate. Dry lightweight aggregate gave 9 MPa higher compressive strength at a density of 2000 kg/m{sup 3} compared to that of prewetted aggregate. The water absorption by the lightweight also affected the microstructure of the hardened concrete. Dry lightweight aggregate gave a slightly better microstructure than normal weight aggregate. The results indicate that the use of prewetted aggregate adversely affected the transition zone between the aggregate and the cement paste. 69 refs., 58 figs., 42 tabs.

  8. Assessment and optimization of thermal and fluidity properties of high strength concrete via genetic algorithm

    Directory of Open Access Journals (Sweden)

    Barış Şimşek

    2016-12-01

    Full Text Available This paper proposes a Response Surface Methodology (RSM based Genetic Algorithm (GA using MATLAB® to assess and optimize the thermal and fluidity of high strength concrete (HSC. The overall heat transfer coefficient, slump-spread flow and T50 time was defined as thermal and fluidity properties of high strength concrete. In addition to above mentioned properties, a 28-day compressive strength of HSC was also determined. Water to binder ratio, fine aggregate to total aggregate ratio and the percentage of super-plasticizer content was determined as effective factors on thermal and fluidity properties of HSC. GA based multi-objective optimization method was carried out by obtaining quadratic models using RSM. Having excessive or low ratio of water to binder provides lower overall heat transfer coefficient. Moreover, T50 time of high strength concrete decreased with the increasing of water to binder ratio and the percentage of superplasticizer content. Results show that RSM based GA is effective in determining optimal mixture ratios of HSC.

  9. Experimental Investigation and FE Analysis on Constitutive Relationship of High Strength Aluminum Alloy under Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Yuanqing Wang

    2016-01-01

    Full Text Available Experiments of 17 high strength aluminum alloy (7A04 specimens were conducted to investigate the constitutive relationship under cyclic loading. The monotonic behavior and hysteretic behavior were focused on and the fracture surface was observed by scanning electron microscope (SEM to investigate the microfailure modes. Based on Ramberg-Osgood model, stress-strain skeleton curves under cyclic loading were fitted. Parameters of combined hardening model including isotropic hardening and kinematic hardening were calibrated from test data according to Chaboche model. The cyclic tests were simulated in finite element software ABAQUS. The test results show that 7A04 aluminum alloy has obvious nonlinearity and ultra-high strength which is over 600 MPa, however, with relatively poor ductility. In the cyclic loading tests, 7A04 aluminum alloy showed cyclic hardening behavior and when the compressive strain was larger than 1%, the stiffness degradation and strength degradation occurred. The simulated curves derived by FE model fitted well with experimental curves which indicates that the parameters of this combined model can be used in accurate calculation of 7A04 high strength aluminum structures under cyclic loading.

  10. Adsorption of Sr on kaolinite, illite and montmorillonite at high ionic strengths

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, J.J.; Langmuir, D. (Colorado School of Mines, Golden (USA). Dept. of Chemistry and Geochemistry)

    1991-01-01

    Experimental measurements of Sr adsorption onto kaolinite, illite and montmorillonite in up to 4.0 mol/kg NaCl solutions, were modelled with the surface ionization and complexation triple-layer (SIC) model (Davis et al.) to determine if model adjustments were required for high ionic strengths. Improved model fits to the adsorption data were obtained at high ionic strengths, reflecting a lowered sensitivity of the model. A general reduction in Sr adsorption with increasing ionic strength was caused by an increase in the outer layer surface charge, rather than by a drop in the number of available adsorption sites. Sensitivity analysis showed that the range of values of model constants yielding acceptable fits was as large as variations reported in the literature for these constants. The study demonstrates that adsorption will not retard Sr migration in brines, and that it is unnecessary to introduce a Pitzer ion interaction subroutine in the SIC model when considering adsorption at high ionic strengths. (orig.).

  11. Impact of high strength electromagnetic fields generated by Tesla transformer on plant cell ultrastructure

    Directory of Open Access Journals (Sweden)

    Anna Rusakova

    2017-09-01

    Full Text Available Non-thermal effects of direct electric fields and alternating electromagnetic fields (EMF have been successfully used in a number of studies and applications in agriculture and biotechnology. Among different kinds of high strength EMF generators, the Tesla transformer (TT is known as a widely applied, low cost, and troubleproof device, which generates EMF in the range of 2–8 MHz. Despite of a number of developed and perspective applications of high strength EMFs in agriculture and biotechnology, the EMFs generated by TT, as well as the 1–50 MHz range of high strength EMF still remain unexplored in the fields of plant physiology, ultrastructure studies and biochemistry. In this work, we have shown that TT-EMFs (4 MHz induced fast stem and petiole bending, disappearance of cell organelles, vacuolar membranes, and increase of a non-photochemical chlorophyll fluorescence quenching in petioles. It is intriguing that such fatal effects can be evoked in plants by EMFs which are well known as harmless for man at the applied strength and frequency.

  12. Immobilisation Of Spent Ion Exchange Resins Using Portland Cement Blending With Organic Material

    International Nuclear Information System (INIS)

    Zalina Laili; Mohd Abdul Wahab; Nur Azna Mahmud

    2014-01-01

    Immobilisation of spent ion exchange resins (spent resins) using Portland cement blending with organic material for example bio char was investigated. The performance of cement-bio char matrix for immobilisation of spent ion exchange resins was evaluated based on their compression strength and leachability under different experimental conditions. The results showed that the amount of bio char and spent resins loading effect the compressive strength of the waste form. Several factors affecting the leaching behaviour of immobilised spent resins in cement-bio char matrix. (author)

  13. Technical Developments and Trends of Earthquake Resisting High-Strength Reinforcing Steel Bars

    International Nuclear Information System (INIS)

    Hwang, Byoungchul; Shim, Jae-Hyeok; Lee, Myoung-Gyu; Lee, Joonho; Jung, Jun-Ho; Kim, Bo-Sung; Won, Sung-Bin

    2016-01-01

    Since reconstruction of old town in Korea requires high-rise and seismic design construction, many attentions have been paid to high strength seismic reinforced steel bar. In the present paper, technical developments and trends are summarized for developing next-generation seismic reinforced steel bar of grade 700 MPa. Steelmaking process requires high energy efficiency and refining ability. Effects of alloying elements are explained, and alloy design based on computational thermodynamics is introduced. On the other hand, it is considered that grain size refinement by the controlled rolling and low temperature transformation structures formed by the accelerated cooling are effective to obtain acceptable mechanical properties with high strength. Finite element simulation analysis is also useful to understand plastic deformation by rolling, internal and external heat transfer, and corresponding phase transformation of austenite phase to various low-temperature transformation structures.

  14. Technical Developments and Trends of Earthquake Resisting High-Strength Reinforcing Steel Bars

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Byoungchul [Seoul National University of Science and Technology, Seoul (Korea, Republic of); Shim, Jae-Hyeok [Korea Institute of Science and Technology, Seoul (Korea, Republic of); Lee, Myoung-Gyu; Lee, Joonho [Korea University, Seoul (Korea, Republic of); Jung, Jun-Ho [Hyundai Steel, Incheon (Korea, Republic of); Kim, Bo-Sung [Daehan Steel, Busan (Korea, Republic of); Won, Sung-Bin [Dongkuk Steel, Kyungju (Korea, Republic of)

    2016-12-15

    Since reconstruction of old town in Korea requires high-rise and seismic design construction, many attentions have been paid to high strength seismic reinforced steel bar. In the present paper, technical developments and trends are summarized for developing next-generation seismic reinforced steel bar of grade 700 MPa. Steelmaking process requires high energy efficiency and refining ability. Effects of alloying elements are explained, and alloy design based on computational thermodynamics is introduced. On the other hand, it is considered that grain size refinement by the controlled rolling and low temperature transformation structures formed by the accelerated cooling are effective to obtain acceptable mechanical properties with high strength. Finite element simulation analysis is also useful to understand plastic deformation by rolling, internal and external heat transfer, and corresponding phase transformation of austenite phase to various low-temperature transformation structures.

  15. Biodegradability oriented treatability studies on high strength segregated wastewater of a woolen textile dyeing plant.

    Science.gov (United States)

    Baban, Ahmet; Yediler, Ayfer; Ciliz, NilgunKiran; Kettrup, Antonius

    2004-11-01

    Textile dyeing and finishing industry involves considerable amount of water usage as well as polluted and highly colored wastewater discharges. Biological treatability by means of mineralization, nitrification and denitrification of high strength woolen textile dye bathes, first- and second-rinses is presented. COD fractionation study was carried out and kinetic parameters were determined. Biodegradability of organic compounds in highly loaded composite wastewater after segregation and the effluent of applied biological treatment of high strength composite wastewater were measured by determining oxygen consumption rates. The results were used in terms of assessing an alternative method for inert COD fractionation. The study implied that about 80% soluble COD, 50% color and 75% toxicity reduction were possible by single sludge biological processes. Sixteen per cent of total COD was found to be initially inert. Inert fraction was increased to 22% by production of soluble and particulate microbial products through biological treatment. copyright 2004 Elsevier Ltd.

  16. Fatigue testing of weldable high strength steels under simulated service conditions

    Science.gov (United States)

    Tantbirojn, Natee

    There have been concerns over the effect of Cathodic Protection (CP) on weldable high strength steels employed in Jack-up production platform. The guidance provided by the Department of Energy HSE on higher strength steels, based on previous work, was to avoid overprotection as this could cause hydrogen embrittlement. However, the tests conducted so far at UCL for the SE702 type high strength steels (yields strength around 690 MPa) have shown that the effect of over protection on high strength steels may not be as severe as previously thought. For this thesis, SE702 high strength steels have been investigated in more detail. Thick (85mm) parent and ground welded plates were tested under constant amplitude in air and seawater with CP. Tests were also conducted on Thick (40mm) T-butt welded plates under variable amplitude loading in air and seawater with two CP levels (-800mV and -1050mV). Different backing materials (ceramic and metallic) for the welding process of the T-butt plates were also investigated. The variable amplitude sequences employed were generated using the Jack-up Offshore Standard load History (JOSH). The fatigue results are presented as crack growth and S/N curves. They were compared to the conventional offshore steel (BS 4360 50D). The results suggested that the fatigue life of the high strength steels was comparable to the BS 4360 50D steels. The effect of increasing the CP was found to be detrimental to the fatigue life but the effect was not large. The effect of CP was less noticeable in T-butt welded plates. However, in general, the effect of overprotection is not as detrimental to the Jack-up steels as previously thought. The load histories generated by JOSH were found to have some unfavourable characteristics. The framework is based on Markov Chain method and pseudo-random number generator for selecting sea-states. A study was carried out on the sequence generated by JOSH. The generated sequences were analysed for their validity for fatigue

  17. Chemically vapor-deposited tungsten: its high temperature strength and ductility

    International Nuclear Information System (INIS)

    Bryant, W.A.

    1977-01-01

    The high temperature tensile ductility (as measured by total elongation normal to the growth direction) of chemically vapor-deposited tungsten was found to be significantly greater than previously reported. A correlation was found between ductility and void content. However, voids were found to have essentially no effect on the high temperature strength of this material, which is considerably weaker than powder metallurgy tungsten. (Auth.)

  18. Stress corrosion cracking of several high strength ferrous and nickel alloys

    Science.gov (United States)

    Nelson, E. E.

    1971-01-01

    The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

  19. Effect of addition of Sikament-R superplasticizer on the hydration characteristics of portland cement pastes

    Directory of Open Access Journals (Sweden)

    Safaa.M. El Gamal

    2012-08-01

    Full Text Available The effect of addition of Sikament-R superplasticizer (modified lignosulphonate base on the hydration characteristics of hardened Portland cement pastes were studied at different curing conditions. Four mixtures were prepared using 0, 0.2, 0.4 and 0.6 wt% addition of Sikament-R superplasticizer (SR of cement. These pastes were hydrated under two different conditions; (i normal curing at room temperature; 25 °C up to 90 days periods and (ii hydrothermal curing at a pressure of 8 atm. of saturated steam up to 24 h. The compressive strength, combined water content, free lime content, gel/space ratio and microstructure of hardened cement pastes were studied. The results revealed that addition of SR superplasticizer promote the dispersion of cement particles and interacts with Ca(OH2. The addition of SR superplasticizer exhibits Portland cement better workability during the preparation of pastes. In addition, amore compact structure were obtained leading to higher values of compressive strength for all the hardened hydrated pastes under both normal and hydrothermal curing. The results indicated that the addition of SR superplasticizer to Portland cement does not alter the types of hydration products formed during normal or hydrothermal conditions; only it caused a decrease in the degree of the porosity of the formed pastes.

  20. High temperature strength and aging behavior of 12%Cr-15%Mn austenitic steels

    International Nuclear Information System (INIS)

    Miyahara, Kazuya; Bae, Dong-Su; Sakai, Hidenori; Hosoi, Yuzo

    1993-01-01

    High Mn-Cr austenitic steels are still considered to be an important high temperature structural material from the point of view of reduced radio-activation. The objective of the present study is to make a fundamental research of mechanical properties and microstructure of 12%Cr-15%Mn austenitic steels. Especially the effects of alloying elements of V and Ti on the mechanical properties and microstructure evolution of high Mn-Cr steels were studied. Precipitation behaviors of carbides, nitrides and σ phase are investigated and their remarkable effects on the high temperature strength are found. The addition of V was very effective for strengthening the materials with the precipitation of fine VN. Ti was also found to be beneficial for the improvement of high temperature strength properties. The results of high temperature strengths of the 12Cr-15Mn austenitic steels were compared with those of the other candidate and/or reference materials, for example, JFMS (modified 9Cr-2Mo ferritic stainless steel) and JPCAs (modified 316 austenitic stainless steels). (author)

  1. Prediction of compression strength of high performance concrete using artificial neural networks

    International Nuclear Information System (INIS)

    Torre, A; Moromi, I; Garcia, F; Espinoza, P; Acuña, L

    2015-01-01

    High-strength concrete is undoubtedly one of the most innovative materials in construction. Its manufacture is simple and is carried out starting from essential components (water, cement, fine and aggregates) and a number of additives. Their proportions have a high influence on the final strength of the product. This relations do not seem to follow a mathematical formula and yet their knowledge is crucial to optimize the quantities of raw materials used in the manufacture of concrete. Of all mechanical properties, concrete compressive strength at 28 days is most often used for quality control. Therefore, it would be important to have a tool to numerically model such relationships, even before processing. In this aspect, artificial neural networks have proven to be a powerful modeling tool especially when obtaining a result with higher reliability than knowledge of the relationships between the variables involved in the process. This research has designed an artificial neural network to model the compressive strength of concrete based on their manufacturing parameters, obtaining correlations of the order of 0.94

  2. Time-Dependent Behavior of High-Strength Kevlar and Vectran Webbing

    Science.gov (United States)

    Jones, Thomas C.; Doggett, William R.

    2014-01-01

    High-strength Kevlar and Vectran webbings are currently being used by both NASA and industry as the primary load-bearing structure in inflatable space habitation modules. The time-dependent behavior of high-strength webbing architectures is a vital area of research that is providing critical material data to guide a more robust design process for this class of structures. This paper details the results of a series of time-dependent tests on 1-inch wide webbing including an initial set of comparative tests between specimens that underwent realtime and accelerated creep at 65 and 70% of their ultimate tensile strength. Variability in the ultimate tensile strength of the webbings is investigated and compared with variability in the creep life response. Additional testing studied the effects of load and displacement rate, specimen length and the time-dependent effects of preconditioning the webbings. The creep test facilities, instrumentation and test procedures are also detailed. The accelerated creep tests display consistently longer times to failure than their real-time counterparts; however, several factors were identified that may contribute to the observed disparity. Test setup and instrumentation, grip type, loading scheme, thermal environment and accelerated test postprocessing along with material variability are among these factors. Their effects are discussed and future work is detailed for the exploration and elimination of some of these factors in order to achieve a higher fidelity comparison.

  3. Effect of steel fibres on mechanical properties of high-strength concrete

    International Nuclear Information System (INIS)

    Holschemacher, K.; Mueller, T.; Ribakov, Y.

    2010-01-01

    Steel fibre reinforced concrete (SFRC) became in the recent decades a very popular and attractive material in structural engineering because of its good mechanical performance. The most important advantages are hindrance of macrocracks' development, delay in microcracks' propagation to macroscopic level and the improved ductility after microcracks' formation. SFRC is also tough and demonstrates high residual strengths after appearing of the first crack. This paper deals with a role of steel fibres having different configuration in combination with steel bar reinforcement. It reports on results of an experimental research program that was focused on the influence of steel fibre types and amounts on flexural tensile strength, fracture behaviour and workability of steel bar reinforced high-strength concrete beams. In the frame of the research different bar reinforcements (2o6 mm and 2o12 mm) and three types of fibres' configurations (two straight with end hooks with different ultimate tensile strength and one corrugated) were used. Three different fibre contents were applied. Experiments show that for all selected fibre contents a more ductile behaviour and higher load levels in the post-cracking range were obtained. The study forms a basis for selection of suitable fibre types and contents for their most efficient combination with regular steel bar reinforcement.

  4. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    Science.gov (United States)

    Kara, P.; Csetényi, L. J.; Borosnyói, A.

    2016-04-01

    In the present work, soda-lime glass cullet (flint, amber, green) and special glass cullet (soda-alkaline earth-silicate glass coming from low pressure mercury-discharge lamp cullet and incandescent light bulb borosilicate glass waste cullet) were ground into fine powders in a laboratory planetary ball mill for 30 minutes. CEM I 42.5N Portland cement was applied in mortar mixtures, substituted with waste glass powder at levels of 20% and 30%. Characterisation and testing of waste glass powders included fineness by laser diffraction particle size analysis, specific surface area by nitrogen adsorption technique, particle density by pycnometry and chemical analysis by X-ray fluorescence spectrophotometry. Compressive strength, early age shrinkage cracking and drying shrinkage tests, heat of hydration of mortars, temperature of hydration, X-ray diffraction analysis and volume stability tests were performed to observe the influence of waste glass powder substitution for Portland cement on physical and engineering properties of mortar mixtures.

  5. XRF analysis of portland cement for major and trace elements

    International Nuclear Information System (INIS)

    Abdunnabi, A. R.

    2012-12-01

    Libyan portland cement produced in several factories around the country, in Lip tis, Zoltan, Souq-Elkamis, Dernah and El-Fatach, were analyzed for quantitative major and trace elements and mineral content, which were compered with those imported from Spain, Romania, Cyprus, and Egypt. X-ray fluorescence spectro X lab 2000 spectrometer equipped with Rh-and X-ray tube was used for the analysis of various samples. The detector Si(Li) with a resolution of 148 eV at Mn K-a=5.9 keV facilitates the determination of a wide range of elements from sodium to uranium, with a detection limit at sub levels. Cement samples in the powder form were analyzed using the pellet-technique. The pellets were prepared by mixing 4g of the cement powder with 0.9 g of binder (HWC) and pressed at high pressure. A ful analysis including, background counting, matrix correction and all relevant corrections were achieved automatically by XLAB 2000 software package. For major and trace elements X RF results were higher for most of the elements than those analyzed with atomic absorption spectrometry. The mineral content showed that Libyan cement is comparable to the imported ones, also the Libyan cement meets the requirements of the international specifications of the portland cement. (Author)

  6. Effect of microstructure on the impact toughness of high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, I.

    2014-07-01

    One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design. (Author)

  7. Influence of laser cutting on the fatigue limit of two high strength steels

    International Nuclear Information System (INIS)

    Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep

    2015-01-01

    Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

  8. Influence of laser cutting on the fatigue limit of two high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Mateo, Antonio; Fargas, Gemma; Calvo, Jessica; Roa, Joan Josep [Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering

    2015-02-01

    Laser cutting is widely used in the metal industry, particularly when components of high strength steel sheets are produced. However, the roughness of cut edges produced by laser differs from that obtained by other methods, such as mechanical blanking, and this fact influences the fatigue performance. In the present investigation, specimens of two grades of high strength austenitic steels, i.e. AISI 301LN and TWIP17Mn, were cut by laser and tested in the high cycle fatigue regime to determine their corresponding fatigue limits. A series of fatigue specimens were tested without polishing and other series after a careful polishing of the cut edges, in order to assess the influence of the cut edges condition. Results indicate a significant influence of the edge roughness, more distinctive for AISI 301LN than for TWIP steel.

  9. Rock Strength Anisotropy in High Stress Conditions: A Case Study for Application to Shaft Stability Assessments

    Directory of Open Access Journals (Sweden)

    Watson Julian Matthew

    2015-03-01

    Full Text Available Although rock strength anisotropy is a well-known phenomenon in rock mechanics, its impact on geotechnical design is often ignored or underestimated. This paper explores the concept of anisotropy in a high stress environment using an improved unified constitutive model (IUCM, which can account for more complex failure mechanisms. The IUCM is used to better understand the typical responses of anisotropic rocks to underground mining. This study applies the IUCM to a proposed rock shaft located in high stress/anisotropic conditions. Results suggest that the effect of rock strength anisotropy must be taken into consideration when assessing the rock mass response to mining in high stress and anisotropic rock conditions.

  10. Development of Low Carbon Niobium Bearing High Strength F-B Dual Phase Steel with High Hole Expansion Property

    Science.gov (United States)

    Zhang, Lin; Xia, Ming-sheng; Xiong, Zi-liu; Du, Yan-bing; Qiao, Zhi-ming; Zhang, Hong-bo

    In the study a low carbon niobium bearing high strength F-B dual phase automobile steel with high hole expansion property has been investigated. Steels of different chemical composition have been investigated by simulation experiments of controlled rolling and cooling process to study the influences of chemical elements, especially for C,Nb and Ti, and cooling pattern on the mechanical properties, flangeability and microstructure of strips. So-called 3-stages cooling pattern was adopted in simulation experiments, combining ultra fast cooling in first stage, air cooling in middle stage and fast cooling in the last stage, and at the end of run-out table the temperature of rolled pieces drop to below Bs point. Optical microstructure and SEM morphology have been observed. Results indicate that it is possible to obtain dual phase microstructure of polygonal ferrite plus bainite in adopting 3-stages cooling pattern. The low temperature coiling method using 3-step controlled cooling pattern after hot rolling is effective to produce low carbon Nb bearing steel with high balance of strength-ductility-flangeability, in addition, higher carbon content of steel tend to be detrimental to flangeability of steel, due to much carbide precipitation at ferrite boundary. Based on the results of simulation experiments mill trial has been carried out and hot rolled high strength steel with tensile strength higher as 600Mpa and hole expansion ratio higher as 100% has been developed successfully.

  11. Behavior of hybrid high-strength fiber reinforced concrete slab-column connections under the effect of high tempera

    Directory of Open Access Journals (Sweden)

    Reham H. Ahmed

    2016-04-01

    Full Text Available Concrete can be modified to perform in a more ductile form by the addition of randomly distributed discrete fibers in the concrete matrix. The combined effect of the addition of two types of fibers (steel fiber and polypropylene fiber with different percentages to concrete matrix, which is called hybrid effect is currently under investigation worldwide. The current research work presents the conducted experimental program to observe the behavior of hybrid high strength reinforced concrete slab-column connections under the effect of high temperature. For this purpose, ten slab-column connections were casted and tested. The experimental program was designed to investigate the effect of different variables such as concrete mixture, column location and temperature fighting system. All specimens were exposed to a temperature of 500 °C for duration of two hours. To observe the effect of each variable, specimens were divided into four groups according to the studied parameters. The test results revealed that using hybrid high strength concrete HFHSC produced more strength in punching failure compared with high strength concrete HSC when exposed to elevated temperature. Fighting by air had higher initial crack load compared with that for without fighting and fighting by water. On the other hand, fighting by water decreased the ultimate load.

  12. Mechanical properties of ground state structures in substitutional ordered alloys: High strength, high ductility and high thermal stability

    International Nuclear Information System (INIS)

    Tawancy, H.M.; Aboelfotoh, M.O.

    2014-01-01

    We have studied the effect of atom arrangements in the ground state structures of substitutional ordered alloys on their mechanical properties using nickel–molybdenum-based alloys as model systems. Three alloys with nominal compositions of Ni–19.43 at% Mo, Ni–18.53 at% Mo–15.21 at% Cr and Ni–18.72 at% Mo–6.14 at% Nb are included in the study. In agreement with theoretical predictions, the closely related Pt 2 Mo-type, DO 22 and D1 a superlattices with similar energies are identified by electron diffraction of ground state structures, which can directly be derived from the parent disordered fcc structure by minor atom rearrangements on {420} fcc planes. The three superlattices are observed to coexist during the disorder–order transformation at 700 °C with the most stable superlattice being determined by the exact chemical composition. Although most of the slip systems in the parent disordered fcc structure are suppressed, many of the twinning systems remain operative in the superlattices favoring deformation by twinning, which leads to considerable strengthening while maintaining high ductility levels. Both the Pt 2 Mo-type and DO 22 superlattices are distinguished by high strength and high ductility due to their nanoscale microstructures, which have high thermal stability. However, the D1 a superlattice is found to exhibit poor thermal stability leading to considerable loss of ductility, which has been correlated with self-induced recrystallization by migration of grain boundaries

  13. Strength Assessment of Controlled Low Strength Materials (CLSM) Utilizing Recycled Concrete Aggregate and Waste Paper Sludge Ash

    OpenAIRE

    Ridzuan, Ahmad Ruslan Mohd; Fauzi, Mohd Azrizal; Ghazali, Ezliana; Arshad, Mohd Fadzil; Fauzi, Mohd Afiq; Mohd Fauzi, Mohd Afiq

    2013-01-01

    This paper studies the strength development of low-strength material (CLSM) is controlled by using waste paper sludge ash (WPSA) in CLSM mixtures without adding Portland cement. Series of four (4) compounds which is the CLSM containing 5%, 10%, 20% and 30% of waste paper sludge ash (WPSA) as a substitute for Portland cement. CLSM cubes the sizes of 100mm x 100mm x 100mm compressive strength were tested at age 7, 14 and 28days. It was found that this activity contributes to strength developmen...

  14. Effects of high NH4+ on K+ uptake, culm mechanical strength and grain filling in wheat

    Directory of Open Access Journals (Sweden)

    Lingan eKong

    2014-12-01

    Full Text Available It is well established that a high external NH4+ concentration depresses many processes in plant development, but the underlying mechanisms are still not well understood. To determine whether the negative effects of high levels of NH4+ are related to competitive cation uptake, wheat was grown in a field with moderate (18 g N m-2 and high (30 g N m-2 supplies of NH4+ in the presence or absence of additional K+ (6 g K2O m-2 to examine culm mechanical strength, the main components of the vascular bundle, nitrogen (N remobilization and the grain-filling rate. The results indicated that an excessive supply of NH4+ significantly decreased culm mechanical strength, the cellulose and lignin contents of vascular bundles, the N remobilization efficiency (NRE and the grain-filling rate compared with a moderate level of NH4+. The additional provision of K+ considerably alleviated these negative effects of high NH4+, resulting in a 19.41%-26.95% increase in culm mechanical strength during grain filling and a 34.59% increase in the NRE. An assay using the scanning ion-selective electrode technique (SIET showed that the net rate of transmembrane K+ influx decreased by 84.62%, and measurements using flame photometry demonstrated that the K+ content decreased by 36.13% in wheat plants subjected to high NH4+. This study indicates that the effects of high NH4+ on culm mechanical strength, cellulose and lignin contents, the NRE and the grain-filling rate are probably associated with inhibition of K+ uptake in wheat.

  15. Optimisation of hybrid high-modulus/high-strength carbon fiber reinforced plastic composite drive

    OpenAIRE

    Montagnier, Olivier; Hochard, Christian

    2011-01-01

    International audience; This study deals with the optimisation of hybrid composite drive shafts operating at subcritical or supercritical speeds, using a genetic algorithm. A formulation for the flexural vibrations of a composite drive shaft mounted on viscoelastic supports including shear effects is developed. In particular, an analytic stability criterion is developed to ensure the integrity of the system in the supercritical regime. Then it is shown that the torsional strength can be compu...

  16. Sulfate resistance of nanosilica contained Portland cement mortars

    Science.gov (United States)

    Batilov, Iani B.

    Soils, sea water and ground water high in sulfates are commonly encountered hostile environments that can attack the structure of concrete via chemical and physical mechanisms which can lead to costly repairs or replacement. Sulfate attack is a slow acting deteriorative phenomenon that can result in cracking, spalling, expansion, increased permeability, paste-to-aggregate bond loss, paste softening, strength loss, and ultimately, progressive failure of concrete. In the presented research study, Portland cement (PC) mortars containing 1.5% to 6.0% nanosilica (nS) cement replacement by weight were tested for sulfate resistance through full submersion in sodium sulfate to simulate external sulfate attack. Mortars with comparable levels of cement replacement were also prepared with microsilica (mS). Three cement types were chosen to explore nS' effectiveness to reduce sulfate expansion, when paired with cements of varying tricalcium aluminate (C3A) content and Blaine fineness, and compare it to that of mS. Mortars were also made with combined cement replacement of equal parts nS and mS to identify if they were mutually compatible and beneficial towards sulfate resistance. Besides sulfate attack expansion of mortar bars, the testing program included investigations into transport and microstructure properties via water absorption, sulfate ion permeability, porosimetry, SEM with EDS, laser diffraction, compressive strength, and heat of hydration. Expansion measurements indicated that mS replacement mortars outperformed both powder form nS, and nS/mS combined replacement mixtures. A negative effect of the dry nS powder replacement attributed to agglomeration of its nanoparticles during mixing negated the expected superior filler, paste densification, and pozzolanic activity of the nanomaterial. Agglomerated nS was identified as the root cause behind poor performance of nS in comparison to mS for all cement types, and the control when paired with a low C3A sulfate resistant

  17. Effect of effective grain size on Charpy impact properties of high-strength bainitic steels

    International Nuclear Information System (INIS)

    Shin, Sang Yong; Han, Seung Youb; Lee, Sung Hak; Hwang, Byoung Chul; Lee, Chang Gil

    2008-01-01

    This study is concerned with the effect of Cu and B addition on microstructure and mechanical properties of high-strength bainitic steels. Six kinds of steels were fabricated by varying alloying elements and hot-rolling conditions, and their microstructures and tensile and Charpy impact properties were investigated. Their effective grain sizes were also characterized by the electron back-scatter diffraction analysis. The tensile test results indicated that the B- or Cu-containing steels had the higher yield and tensile strengths than the B- or Cu-free steels because their volume fractions of bainitic ferrite and martensite were quite high. The B- or Cu-free steels had the higher upper shelf energy than the B- or Cu-containing steels because of their higher volume fraction of granular bainite. In the steel containing 10 ppm B without Cu, the best combination of high strengths, high upper shelf energy, and low energy transition temperature could be obtained by the decrease in the overall effective grain size due to the presence of bainitic ferrite having smaller effective grain size

  18. Analysis of local warm forming of high strength steel using near infrared ray energy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W. H., E-mail: whyang21@hyundai.com [Hyundai Motor Company, 700 Yeompo-ro, Buk-Gu, Ulsan, 683-791 (Korea, Republic of); Lee, K., E-mail: klee@deform.co.kr [Solution Lab, 502, 102, Dunsan-daero 117 beon-gil, Seo-Gu, Daejeon, 302-834 (Korea, Republic of); Lee, E. H., E-mail: mtgs2@kaist.ac.kr, E-mail: dyyang@kaist.ac.kr; Yang, D. Y., E-mail: mtgs2@kaist.ac.kr, E-mail: dyyang@kaist.ac.kr [KAIST, Science Town291, Daehak-ro, Yuseong-Gu, Daejeon 305-701 (Korea, Republic of)

    2013-12-16

    The automotive industry has been pressed to satisfy more rigorous fuel efficiency requirements to promote energy conservation, safety features and cost containment. To satisfy this need, high strength steel has been developed and used for many different vehicle parts. The use of high strength steels, however, requires careful analysis and creativity in order to accommodate its relatively high springback behavior. An innovative method, called local warm forming with near infrared ray, has been developed to help promote the use of high strength steels in sheet metal forming. For this method, local regions of the work piece are heated using infrared ray energy, thereby promoting the reduction of springback behavior. In this research, a V-bend test is conducted with DP980. After springback, the bend angles for specimens without local heating are compared to those with local heating. Numerical analysis has been performed using the commercial program, DEFORM-2D. This analysis is carried out with the purpose of understanding how changes to the local stress distribution will affect the springback during the unloading process. The results between experimental and computational approaches are evaluated to assure the accuracy of the simulation. Subsequent numerical simulation studies are performed to explore best practices with respect to thermal boundary conditions, timing, and applicability to the production environment.

  19. Analysis of local warm forming of high strength steel using near infrared ray energy

    International Nuclear Information System (INIS)

    Yang, W. H.; Lee, K.; Lee, E. H.; Yang, D. Y.

    2013-01-01

    The automotive industry has been pressed to satisfy more rigorous fuel efficiency requirements to promote energy conservation, safety features and cost containment. To satisfy this need, high strength steel has been developed and used for many different vehicle parts. The use of high strength steels, however, requires careful analysis and creativity in order to accommodate its relatively high springback behavior. An innovative method, called local warm forming with near infrared ray, has been developed to help promote the use of high strength steels in sheet metal forming. For this method, local regions of the work piece are heated using infrared ray energy, thereby promoting the reduction of springback behavior. In this research, a V-bend test is conducted with DP980. After springback, the bend angles for specimens without local heating are compared to those with local heating. Numerical analysis has been performed using the commercial program, DEFORM-2D. This analysis is carried out with the purpose of understanding how changes to the local stress distribution will affect the springback during the unloading process. The results between experimental and computational approaches are evaluated to assure the accuracy of the simulation. Subsequent numerical simulation studies are performed to explore best practices with respect to thermal boundary conditions, timing, and applicability to the production environment

  20. Effect of sodium fluorosilicate on the properties of Portland cement.

    Science.gov (United States)

    Appelbaum, Keith S; Stewart, Jeffrey T; Hartwell, Gary R

    2012-07-01

    Mineral trioxide aggregate (MTA) satisfies most of the ideal properties of a surgical root-end filling and perforation repair material. It has been found to be nontoxic, noncarcinogenic, nongenotoxic, biocompatible, insoluble in tissue fluids, and dimensionally stable and promotes cementogenesis. The major disadvantages are its long setting time and difficult handling characteristics during placement when performing endodontic procedures. MTA is similar to Portland cement (PC) in both composition and properties. The cement industry has used many additives to decrease the setting time of PC. Proprietary formulas of PC additives include fluorosilicates, which decrease setting time. The purpose of this pilot study was to determine whether sodium fluorosilicate (SF) could be used to decrease the setting time without adversely affecting the compressive strength of PC. To determine the most appropriate amount of SF to add to PC to decrease its setting time, 1%, 2%, 3%, 4%, 5%, 10%, and 15% SF by weight were added to PC and compared with PC without SF. Setting times were measured by using a Gilmore needle, and compressive strengths were determined by using a materials testing system at 24 hours and 21 days. Statistical analysis was performed by using one-way analysis of variance with post hoc Games-Howell test. None of the percentages of SF were effective in changing the setting time of PC (P > .05), and the SF additives were found to decrease the compressive strength of PC (P < .001). On the basis of the conditions of this study, SF should not be used to decrease setting time and increase the compressive strength of PC and as such does not warrant further testing with MTA. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Influence of Internal Sulfate Attack on Some Properties of High Strength Concrete

    Directory of Open Access Journals (Sweden)

    Nada Mahdi Fawzi

    2015-08-01

    Full Text Available One of the most important problems that faces the concrete industry in Iraq is the deterioration due to internal sulfate attack , since it reduces the compressive strength and increases the expansion of concrete. Consequently, the concrete structure may be damage .The effects of total and total effective sulfate contents on high strength concrete (HSC have been studied in the present study. The research studied the effect of sulfate content in cement , sand and gravel , as well as comparing the total sulfate content with the total effective SO3 content. Materials used were divided into two groups of SO3 in cement ,three groups of SO3 in sand ,and two groups of SO3 in gravel. The results show that considering the total effective sulfate content is better than the total content of sulfates since the effect of sulfate in each constituent of concrete, depends on it's granular size .The smaller the particle size of the material the more effective is the sulfate in it. Therefore, it is recommended to follow the Iraqi specification for total effective sulfate content, because it gives more flexibility to the use of sand and gravel with higher sulfate content. The results of compressive strength at 90-days show that the effect of total effective SO3 content of ( 2.647% , 2.992% , 3.424% that correspond to total sulfate of ( 3.778%, 3.294%, 4.528% decrease the compressive strength by (7.53%, 11.44%, 14.59% respectively.

  2. Behavior of Reinforced Concrete Hybrid Trapezoidal Box Girders Using Ordinary and Highly Strength Concrete

    Directory of Open Access Journals (Sweden)

    Nameer A. Alawsh

    2018-03-01

    Full Text Available In this paper, the general behavior of reinforced concrete hybrid box girders is studied by experimental and numerical investigation. Experimental work is included casting monolithically five specimens of box girders with trapezoidal cross section and testing it as simply supported under two point loading. Two specimens were cast as homogenous box girders (full normal strength concrete (NSC (about 35 MPa and full high strength concrete (HSC (about 55 MPa and three specimens were cast as hybrid box girders (HSC in upper flange only, HSC in upper flange and half depth of webs, and HSC in bottom flange and total depth of webs. Experimental results showed significant effects of concrete hybridization on the structural behavior of box girders specimens such as: cracking loads, cracking patterns, ultimate strengths, and failure modes. The ultimate strength of Hybrid box girders increased by 23% as average when compared with the homogenous box girder (full NSC and decreased by 9% as average when compared with homogenous box girder (full HSC. In numerical investigation, the tested specimens were modeled and analyzed using three dimensional non-linear finite element analysis. The analysis was carried out by using a computer program (ANSYS V16.1. The numerical results showed an acceptable agreement with the experimental work with difference about (3.12% and 9.588% as average for ultimate load and deflection, respectively.

  3. High strength oil palm shell concrete beams reinforced with steel fibres

    Directory of Open Access Journals (Sweden)

    S. Poh-Yap

    2017-10-01

    Full Text Available The utilization of lightweight oil palm shell to produce high strength lightweight sustainable material has led many researchers towards its commercialization as structural concrete. However, the low tensile strength of Oil Palm Shell Concrete (OPSC has hindered its development. This study aims to enhance the mechanical properties and flexural behaviours of OPSC by the addition of steel fibres of up to 3% by volume, to produce oil palm shell fibre-reinforced concrete (OPSFRC. The experimental results showed that the steel fibres significantly enhanced the mechanical properties of OPSFRC. The highest compressive strength, splitting tensile and flexural strengths of 55, 11.0 and 18.5 MPa, respectively, were achieved in the OPSFRC mix reinforced with 3% steel fibres. In addition, the flexural beam testing on OPSFRC beams with 3% steel fibres showed that the steel fibre reinforcement up to 3% produced notable increments in the moment capacity and crack resistance of OPSFRC beams, but accompanied by reduction in the ductility.

  4. High strength nanostructured Al-based alloys through optimized processing of rapidly quenched amorphous precursors.

    Science.gov (United States)

    Kim, Song-Yi; Lee, Gwang-Yeob; Park, Gyu-Hyeon; Kim, Hyeon-Ah; Lee, A-Young; Scudino, Sergio; Prashanth, Konda Gokuldoss; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

    2018-01-18

    We report the methods increasing both strength and ductility of aluminum alloys transformed from amorphous precursor. The mechanical properties of bulk samples produced by spark-plasma sintering (SPS) of amorphous Al-Ni-Co-Dy powders at temperatures above 673 K are significantly enhanced by in-situ crystallization of nano-scale intermetallic compounds during the SPS process. The spark plasma sintered Al 84 Ni 7 Co 3 Dy 6 bulk specimens exhibit 1433 MPa compressive yield strength and 1773 MPa maximum strength together with 5.6% plastic strain, respectively. The addition of Dy enhances the thermal stability of primary fcc Al in the amorphous Al-TM -RE alloy. The precipitation of intermetallic phases by crystallization of the remaining amorphous matrix plays important role to restrict the growth of the fcc Al phase and contributes to the improvement of the mechanical properties. Such fully crystalline nano- or ultrafine-scale Al-Ni-Co-Dy systems are considered promising for industrial application because their superior mechanical properties in terms of a combination of very high room temperature strength combined with good ductility.

  5. Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

    Directory of Open Access Journals (Sweden)

    Ashkan Saradar

    2018-02-01

    Full Text Available Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP, steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%.

  6. An investigation on fatigue in high-strength steel offshore structures

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

    1998-01-01

    of the investigation, fatigue test series were carried out on both full scale tubular joints and smaller welded plate test specimens in high-strength steel as well as in conventional offshore structural steel. This paper gives a summary of the main results presented in two recent research reports [15, 16], from...... these investigations. A comparison between constant amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula.Furthermore, in general longer fatigue lives were obtained for the test...... specimens in high-strength steel than those obtained in corresponding tests on joints in conventional offshore structural steel....

  7. An Investigation on Fatigue in High-Strength Steel Offshore Structures

    DEFF Research Database (Denmark)

    Agerskov, Henning; Petersen, R.I.; Lopez Martinez, L.

    1997-01-01

    . In the experimental part of the investigation, fatigue test series have been carried through on both full-scale tubular joints and smaller welded plate test specimens, in high-strength steel as well as in conventional offshore structural steel. The present document gives a summary of the main results presented in two...... recent research reports, Refs. 15 and 16, from these investigations.A comparison between constant amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore......, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those obtained in corresponding tests on joints in conventional offshore structural steel....

  8. Load carrying capacity of shear wall t-connections reinforced with high strength wire ropes

    DEFF Research Database (Denmark)

    Jørgensen, Henrik B.; Bryndom, Thor; Larsen, Michael

    2016-01-01

    -friendly solution. The wire ropes have no bending stiffness and therefore allow for an easier vertical installation of the wall elements. During the last 10 – 15 years, a number of shear tests on plane wire rope connections have been carried out. However, to the best knowledge of the authors, tests on wire rope......Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction...... connections for assembly of precast elements in different planes, such as T- and L-connections, have not yet been published. This paper presents the results of a large test series recently conducted at the University of Southern Denmark to study the shear behaviour of high strength wire rope T...

  9. Application and validation of the notch master curve in medium and high strength structural steels

    Energy Technology Data Exchange (ETDEWEB)

    Cicero, Sergio; Garcia, Tiberio [Universidad de Cantabria, Santander (Spain); Madrazo, Virginia [PCTCAN, Santander (Spain)

    2015-10-15

    This paper applies and validates the Notch master curve in two ferritic steels with medium (steel S460M) and high (steel S690Q) strength. The Notch master curve is an engineering tool that allows the fracture resistance of notched ferritic steels operating within their corresponding ductile-to-brittle transition zone to be estimated. It combines the Master curve and the Theory of critical distances in order to take into account the temperature and the notch effect respectively, assuming that both effects are independent. The results, derived from 168 fracture tests on notched specimens, demonstrate the capability of the Notch master curve for the prediction of the fracture resistance of medium and high strength ferritic steels operating within their ductile-to-brittle transition zone and containing notches.

  10. Load carrying capacity of keyed joints reinforced with high strength wire rope loops

    DEFF Research Database (Denmark)

    Jørgensen, Henrik B.; Hoang, Linh Cao

    2015-01-01

    friendly shear connection can be obtained by replacing the U-bars with high strength looped wire ropes. The wire ropes have the advantage of being flexible (they have virtually no bending stiffness) which makes installation of wall elements much easier. The looped wire ropes are usually pre-installed in so......-called wire boxes which are embedded in the precast wall elements. Once the joint is grouted with mortar, the boxes will function as shear keys and the overlapping wire loops will function as transverse reinforcement that replaces the U-bars. This paper presents a rigid-plastic upper bound model to determine...... the shear capacity of wire loop connections. Tests have shown that the shear capacity of such joints – due to the relatively high tensile strength of the wire ropes - is more prone to be governed by fracture of the joint mortar in combination with yielding of the locking bar. To model this type of failure...

  11. Near-surface modifications for improved crack tolerant behavior of high strength alloys: trends and prospects

    International Nuclear Information System (INIS)

    Hettche, L.R.; Rath, B.B.

    1982-01-01

    The purpose of this chapter is to examine the potential of surface modifications in improving the crack tolerant behavior of high strength alloys. Provides a critique of two of the most promising and versatile techniques: ion implantation and laser beam surface processing. Discusses crack tolerant properties; engineering characterization; publication trends and Department of Defense interests; and emergent surface modification techniques. Finds that the efficiency with which high strength alloys can be incorporated into a structure or component is dependent on the following crack tolerant properties: fracture toughness, fatigue resistance, sustained loading cracking resistance, fretting fatigue resistance, and hydrogen embrittlement resistance. Concludes that ion implantation and laser surface processing coupled with other advanced metallurgical procedures and fracture mechanic analyses provide the means to optimize both the bulk and surface controlled crack tolerant properties

  12. Boron enhances strength and alters mineral composition of bone in rabbits fed a high energy diet.

    Science.gov (United States)

    Hakki, Sema S; Dundar, Niyazi; Kayis, Seyit Ali; Hakki, Erdogan E; Hamurcu, Mehmet; Kerimoglu, Ulku; Baspinar, Nuri; Basoglu, Abdullah; Nielsen, Forrest H

    2013-04-01

    An experiment was performed to determine whether boron had a beneficial effect on bone strength and composition in rabbits with apparent adiposity induced by a high energy diet. Sixty female New Zealand rabbits, aged 8 months, were randomly divided into five groups with the following treatments for seven months: control 1, fed alfalfa hay only (5.91 MJ/kg); control 2, high energy diet (11.76 MJ and 3.88 mg boron/kg); B10, high energy diet+10 mg/kg body weight boron gavage/96 h; B30, high energy diet+30 mg/kg body weight boron gavage/96 h; B50, high energy diet+50mg/kg body weight boron gavage/96 h. Bone boron concentrations were lowest in rabbits fed the high energy diet without boron supplementation, which suggested an inferior boron status. Femur maximum breaking force was highest in the B50 rabbits. Tibia compression strength was highest in B30 and B50 rabbits. All boron treatments significantly increased calcium and magnesium concentrations, and the B30 and B50 treatments increased the phosphorus concentration in tibia of rabbits fed the high energy diet. The B30 treatment significantly increased calcium, phosphorus and magnesium concentrations in femur of rabbits fed the high energy diet. Principal component analysis of the tibia minerals showed that the three boron treatments formed a separate cluster from controls. Discriminant analysis suggested that the concentrations of the minerals in femur could predict boron treatment. The findings indicate boron has beneficial effects on bone strength and mineral composition in rabbits fed a high energy diet. Copyright © 2012 Elsevier GmbH. All rights reserved.

  13. Manufacture of high-strength composite materials from prepregs prepared by radiation processing

    International Nuclear Information System (INIS)

    Laricheva, V.P.; Korotkij, A.F.

    2008-01-01

    Scientific principles of the manufacture of high-strength heat-resistant polymer composite materials with the successive ionizing-radiation and heat treatment (via the step of long-lived prepregs) were developed. Methods for the selection of components for the preparation of long-lived prepregs, as well as for the determination of the optimal curing conditions, were proposed. The mechanical properties of the materials were studied [ru

  14. Fabrication of high strength PVA/SWCNT composite fibers by gel spinning

    OpenAIRE

    Xu, Xuezhu; Uddin, Ahmed Jalal; Aoki, Kenta; Gotoh, Yasuo; Saito, Takeshi; Yumura, Motoo

    2010-01-01

    High-strength composite fibers were prepared from polyvinyl alcohol (PVA) (Degree of polymerization: 1500) reinforced by single-walled carbon nanotubes (SWCNTs) containing few defects. The SWCNTs were dispersed in a 10 wt.% PVA/dimethylsulfoxide solution using a mechanical homogenizer that reduced the size of SWCNT aggregations to smaller bundles. The macroscopically homogeneous dispersion was extruded into cold methanol to form fibers by gel spinning followed by a hot-drawing. The tensile st...

  15. Load carrying capacity of keyed joints reinforced with high strength wire rope loops

    OpenAIRE

    Jørgensen, Henrik B.; Hoang, Linh Cao

    2015-01-01

    Vertical shear connections between precast concrete wall elements are usually made as keyed joints reinforced with overlapping U-bars. The overlapping U-bars form a cylindrical core in which the locking bar is placed and the connection is subsequently grouted with mortar. A more construction friendly shear connection can be obtained by replacing the U-bars with high strength looped wire ropes. The wire ropes have the advantage of being flexible (they have virtually no bending stiffness) which...

  16. Failure Assessment for the High-Strength Pipelines with Constant-Depth Circumferential Surface Cracks

    OpenAIRE

    X. Liu; Z. X. Lu; Y. Chen; Y. L. Sui; L. H. Dai

    2018-01-01

    In the oil and gas transportation system over long distance, application of high-strength pipeline steels can efficiently reduce construction and operation cost by increasing operational pressure and reducing the pipe wall thickness. Failure assessment is an important issue in the design, construction, and maintenance of the pipelines. The small circumferential surface cracks with constant depth in the welded pipelines are of practical interest. This work provides an engineering estimation pr...

  17. Fracture toughness of welded joints of a high strength low alloy steel

    International Nuclear Information System (INIS)

    Veiga, S.M.B. da; Bastian, F.L.; Pope, A.M.

    1985-10-01

    The fracture toughness of the different regions of welded joints of a high strength low alloy steel, Niocor 2, was evaluated at different temperatures and compared with the toughness of the base metal. The studied regions were: the weld metal, fusion boundary and heat affected zone. The welding process used was the manual metal arc. It is shown that the weld metal region has the highest toughness values. (Author) [pt

  18. Treatment of high organic strength waste waters; Tratamiento de aguas residuales de alta carga

    Energy Technology Data Exchange (ETDEWEB)

    Marti Duran, J.; Leyda Escoruela, L. [COMSA, S.A., Madrid (Spain)

    1995-11-01

    A biological treatment process is likely to be the preferred and main stage for the treatment of high strength waste waters. In some instance the wastes will contain a fraction of toxic or non-biodegradable organic constituents which affects the implementation of the central biological process. Two different technologies using tower-shape reactors are described, together with a Low Pressure Chemical Oxidation process technology used in the pretreatment of poorly biodegradable wastes.

  19. Ductile failure analysis of high strength steel in hot forming based on micromechanical damage model

    OpenAIRE

    Ying Liang; Liu Wenquan; Wang Dantong; Hu Ping

    2016-01-01

    The damage evolution of high strength steel at elevated temperature is investigated by using the Gurson-Tvergaard-Needleman (GTN) model. A hybrid method integrated thermal tensile test and numerical technique is employed to identify the damage parameters. The analysis results show that the damage parameters are different at different temperature as the variation of tested material microstructure. Furthermore, the calibrated damage parameters are implemented to simulate a bugling forming at el...

  20. Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

    International Nuclear Information System (INIS)

    Law, M.; Bowie, G.

    2007-01-01

    Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted

  1. Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

    Energy Technology Data Exchange (ETDEWEB)

    Law, M. [Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia)]. E-mail: mlx@ansto.gov.au; Bowie, G. [BlueScope Steel Ltd., Level 11, 120 Collins St, Melbourne, Victoria 3000 (Australia)

    2007-08-15

    Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted.

  2. Effects of Silica in Rice Husk Ash (RHA) in producing High Strength Concrete

    OpenAIRE

    Kartini, K; Nurul Nazierah, M.Y; Zaidahtulakmal, M.Z; Siti Aisyah, G

    2012-01-01

    High strength concrete (HSC) are known to have a higher amount of cement binder in the mix design properties with low w/b ratio. The high mass of cement content produced substantial heat liberation in the concrete due to the reaction between cement and water, which can lead to cracking. Additive likes silica fume is too expensive to use in the HSC in order to overcome the problems, however, the initiative of utilizing the rice husk ash (RHA) which have high silica content are apply for the de...

  3. Measurements of Bauschinger effect and transient behavior of a quenched and partitioned advanced high strength steel

    International Nuclear Information System (INIS)

    Zang, Shun-lai; Sun, Li; Niu, Chao

    2013-01-01

    In recent decades, the needs for new advanced high strength steels (AHSS) with high ductility and strength have rapidly increased to achieve the targets of more fuel-efficient and safer vehicles in automotive industry. However, several undesirable phenomena are experimentally observed during the forming of such materials, particularly with complex loading and large plastic deformation. Springback is one of the most important problems that should be compensated in sheet metal forming process. In this paper, we investigated the hardening behavior of a Q and P (quench and partitioning) steel designated by QP980CR, which is a new third generation advance high strength steel, from the Baosteel Group Corp. in Shanghai, China. The uni-axial tensile and cyclic simple shear tests were conducted. The uni-axial tensile tests were performed on the specimens at 0°, 45° and 90° to rolling direction (RD). The flow stress and transverse strain evolution were obtained in view of the digital image correlation (DIC) measurement. The plastic anisotropy was optimized from the uni-axial tensile tests and thereafter incorporated into the simulations of cyclic simple shear tests. The cyclic simple shear tests were conducted with three prestrains to measure the Bauschinger effect, transient behavior and permanent softening, and to determine the material parameters of the combined isotropic-kinematic hardening model

  4. Measurements of Bauschinger effect and transient behavior of a quenched and partitioned advanced high strength steel

    Energy Technology Data Exchange (ETDEWEB)

    Zang, Shun-lai, E-mail: shawn@mail.xjtu.edu.cn [School of Mechanical Engineering, Xi' an Jiaotong University, No. 28, Xianning Road, Xi' an, Shaanxi (China); Sun, Li [Manufacturing Process Research, General Motors China Science Lab, No. 56, Jinwan Road, Shanghai (China); Niu, Chao [School of Mechanical Engineering, Xi' an Jiaotong University, No. 28, Xianning Road, Xi' an, Shaanxi (China)

    2013-12-01

    In recent decades, the needs for new advanced high strength steels (AHSS) with high ductility and strength have rapidly increased to achieve the targets of more fuel-efficient and safer vehicles in automotive industry. However, several undesirable phenomena are experimentally observed during the forming of such materials, particularly with complex loading and large plastic deformation. Springback is one of the most important problems that should be compensated in sheet metal forming process. In this paper, we investigated the hardening behavior of a Q and P (quench and partitioning) steel designated by QP980CR, which is a new third generation advance high strength steel, from the Baosteel Group Corp. in Shanghai, China. The uni-axial tensile and cyclic simple shear tests were conducted. The uni-axial tensile tests were performed on the specimens at 0°, 45° and 90° to rolling direction (RD). The flow stress and transverse strain evolution were obtained in view of the digital image correlation (DIC) measurement. The plastic anisotropy was optimized from the uni-axial tensile tests and thereafter incorporated into the simulations of cyclic simple shear tests. The cyclic simple shear tests were conducted with three prestrains to measure the Bauschinger effect, transient behavior and permanent softening, and to determine the material parameters of the combined isotropic-kinematic hardening model.

  5. An overview of advanced high-strength nickel-base alloys for LWR applications

    International Nuclear Information System (INIS)

    Prybylowski, J.; Ballinger, R.G.

    1989-01-01

    This paper reviews our current understanding of the behavior of high strength nickel base alloys used in light water reactor (LWR) applications. Emphasis is placed on understanding the fundamental mechanisms controlling crack propagation in these environments. To provide a foundation for this survey, general mechanisms of stress corrosion cracking and hydrogen embrittlement are first reviewed. The behavior of high strength nickel base alloys in LWR environments, as well as in other relevant environments is then reviewed. Suggested mechanisms of crack propagation are discussed. Alternate alloys and microstructural modifications that may result in improved behavior are presented. It is now clear that, at temperatures near 100C, alloy X-750, the predominant high strength nickel base alloy used today in LWR applications, is susceptible to hydrogen embrittlement. A review of published data from hydrogen embrittlement studies of nickel base superalloys during electrolytic charging and in hydrogen sulfide/brine solutions suggests that other nickel base superalloys are available possessing resistance to hydrogen embrittlement superior to that of alloy X-750. Available results of tests in gaseous hydrogen suggest that reduced grain boundary precipitation and a fine distribution of intragranular precipitates that act as irreversible hydrogen traps is the optimum microstructure for hydrogen embrittlement resistance. 42 refs., 2 figs., 5 tabs

  6. The variability and controls of rock strength along rocky coasts of central Spitsbergen, High Arctic

    Science.gov (United States)

    Strzelecki, Mateusz Czesław

    2017-09-01

    This paper presents the results of the Schmidt Hammer Rock Tests (SHRTs) across a range of rocky coastal landforms. Northern Billefjorden (central Spitsbergen), represents typical High Arctic microtidal fjord environment. Sheltered location and prolonged sea-ice conditions limit wave action. Coastal cliffs, shore platforms and skerries are developed in various rock types including limestone, sandstone, anhydrite/gypsum, dolomite and metamorphic outcrops. SHRT demonstrated a broad variety of relationships between rock strength and distance from shoreline, presence of sediment cover, distribution of snow patches and icefoot, and accumulations of seaweed and driftwood. In general, rock cliff surfaces were the most resistant in their lower and middle zones, that are thermally insulated by thick winter snowdrifts. More exposed cliff tops were fractured and weathered. The differences in rock strength observed along the shore platforms were highly dependent on thickness of sediment cover and shoreline configuration promoting stronger rock surfaces in areas exposed to the longest wave fetch and washed from gravel deposits. Rock strength of skerry islands is influenced by tidal action controlling the duration of tide inundation and movement of sea-ice scratching boulder surfaces. The results presented in this paper emphasize the richness of rock coast geomorphology and processes operating in High Arctic settings.

  7. 3D printing of high-strength bioscaffolds for the synergistic treatment of bone cancer

    Science.gov (United States)

    Ma, Hongshi; Li, Tao; Huan, Zhiguang; Zhang, Meng; Yang, Zezheng; Wang, Jinwu; Chang, Jiang; Wu, Chengtie

    2018-04-01

    The challenges in bone tumor therapy are how to repair the large bone defects induced by surgery and kill all possible residual tumor cells. Compared to cancellous bone defect regeneration, cortical bone defect regeneration has a higher demand for bone substitute materials. To the best of our knowledge, there are currently few bifunctional biomaterials with an ultra-high strength for both tumor therapy and cortical bone regeneration. Here, we designed Fe-CaSiO3 composite scaffolds (30CS) via 3D printing technique. First, the 30CS composite scaffolds possessed a high compressive strength that provided sufficient mechanical support in bone cortical defects; second, synergistic photothermal and ROS therapies achieved an enhanced tumor therapeutic effect in vitro and in vivo. Finally, the presence of CaSiO3 in the composite scaffolds improved the degradation performance, stimulated the proliferation and differentiation of rBMSCs, and further promoted bone formation in vivo. Such 30CS scaffolds with a high compressive strength can function as versatile and efficient biomaterials for the future regeneration of cortical bone defects and the treatment of bone cancer.

  8. Hollow-fiber membrane bioreactor for the treatment of high-strength landfill leachate

    KAUST Repository

    Rizkallah, Marwan

    2013-07-15

    Performance assessment of membrane bioreactor (MBR) technology for the treatability of high-strength landfill leachate is relatively limited or lacking. This study examines the feasibility of treating high-strength landfill leachate using a hollow-fiber MBR. For this purpose, a laboratory-scale MBR was constructed and operated to treat leachate with a chemical oxygen demand (COD) of 9000-11,000 mg/l, a 5-day biochemical oxygen demand (BOD5) of 4000-6,000 mg/l, volatile suspended solids (VSS) of 300-500 mg/l, total nitrogen (TN) of 2000-6000 mg/l, and an ammonia-nitrogen (NH3-N) of 1800-4000 mg/l. VSS was used with the BOD and COD data to simulate the biological activity in the activated sludge. Removal efficiencies > 95-99% for BOD5, VSS, TN and NH3-N were attained. The coupled experimental and simulation results contribute in filling a gap in managing high-strength landfill leachate and providing guidelines for corresponding MBR application. © The Author(s) 2013.

  9. Testing of High Thermal Cycling Stability of Low Strength Concrete as a Thermal Energy Storage Material

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2016-09-01

    Full Text Available Concrete has the potential to become a solution for thermal energy storage (TES integrated in concentrating solar power (CSP systems due to its good thermal and mechanical properties and low cost of material. In this study, a low strength concrete (C20 is tested at high temperatures up to 600 °C. Specimens are thermally cycled at temperatures in the range of 400–300 °C, 500–300 °C, and 600–300 °C, which TES can reach in operation. For comparison, specimens also cycled at temperature in the range of 400–25 °C (room temperature, 500–25 °C, and 600–25 °C. It is found from the test results that cracks are not observed on the surfaces of concrete specimens until the temperature is elevated up to 500 °C. There is mechanical deterioration of concrete after exposure to high temperature, especially to high thermal cycles. The residual compressive strength of concrete after 10 thermal cycles between 600 °C and 300 °C is about 58.3%, but the specimens remain stable without spalling, indicating possible use of low strength concrete as a TES material.

  10. Load Carrying Capacity of Shear Wall T-Connections Reinforced with High Strength Wire Ropes

    DEFF Research Database (Denmark)

    Jørgensen, Henrik Brøner; Bryndum, Thor; Larsen, Michael

    2017-01-01

    Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction-friendly so......Traditionally, U-bar loop connections with keyed joints have been used in vertical shear connections between precast concrete wall elements. However, in the recent years, connections with looped high strength wire ropes instead of U-bar loops have proven to be a much more construction......-friendly solution. The wire ropes have no bending stiffness and therefore allow for an easier vertical installation of the wall elements. During the last 10 – 15 years, a number of shear tests on plane wire rope connections have been carried out. However, to the best knowledge of the authors, tests on wire rope...... connections for assembly of precast elements in different planes, such as T- and L-connections, have not yet been published. This paper presents the results of a large test series recently conducted at the University of Southern Denmark to study the shear behaviour of high strength wire rope T...

  11. High-Strength Aluminium Alloys and Their Use in Foundry Industry of Nickel Superalloys

    Directory of Open Access Journals (Sweden)

    Pysz S.

    2014-08-01

    Full Text Available Of great importance in the selection of materials for cast structures is keeping a proper balance between the mechanical and plastic properties, while preserving the relevant casting properties. This study has been devoted to an analysis of the choice and application of high-strength aluminium-based alloys maintaining sufficient level of casting properties. The high level of tensile strength (Rm > 500 MPa matched with satisfactory elongation (A > 3% is important because materials of this type are used for cast parts operating in the aerospace, automotive, and military industries. These beneficial relationships between the high tensile strength and toughness are relatively easy to obtain in the Al-Zn-Mg-Cu alloys subjected to plastic forming and proper heat treatment. In gravity cast products, on the other hand, whether poured into sand moulds or metal moulds (dies, obtaining this favourable combination of properties poses a number of research problems (mostly resulting from the alloy chemical composition as well as technical and technological difficulties.

  12. High strength films from oriented, hydrogen-bonded "graphamid" 2D polymer molecular ensembles.

    Science.gov (United States)

    Sandoz-Rosado, Emil; Beaudet, Todd D; Andzelm, Jan W; Wetzel, Eric D

    2018-02-27

    The linear polymer poly(p-phenylene terephthalamide), better known by its tradename Kevlar, is an icon of modern materials science due to its remarkable strength, stiffness, and environmental resistance. Here, we propose a new two-dimensional (2D) polymer, "graphamid", that closely resembles Kevlar in chemical structure, but is mechanically advantaged by virtue of its 2D structure. Using atomistic calculations, we show that graphamid comprises covalently-bonded sheets bridged by a high population of strong intermolecular hydrogen bonds. Molecular and micromechanical calculations predict that these strong intermolecular interactions allow stiff, high strength (6-8 GPa), and tough films from ensembles of finite graphamid molecules. In contrast, traditional 2D materials like graphene have weak intermolecular interactions, leading to ensembles of low strength (0.1-0.5 GPa) and brittle fracture behavior. These results suggest that hydrogen-bonded 2D polymers like graphamid would be transformative in enabling scalable, lightweight, high performance polymer films of unprecedented mechanical performance.

  13. High temperature creep strength of Advanced Radiation Resistant Oxide Dispersion Strengthened Steels

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling well occurred to 120dpa at high temperatures and this leads the decrease of the mechanical properties and dimensional stability. Compared to this, ferritic/martensitic steel is a good solution because of excellent thermal conductivity and good swelling resistance. Unfortunately, the available temperature range of ferritic/martensitic steel is limited up to 650 .deg. C. ODS steel is the most promising structural material because of excellent creep and irradiation resistance by uniformly distributed nano-oxide particles with a high density which is extremely stable at the high temperature in ferritic/martensitic matrix. In this study, high temperature strength of advanced radiation resistance ODS steel was investigated for the core structural material of next generation nuclear systems. ODS martensitic steel was designed to have high homogeneity, productivity and reproducibility. Mechanical alloying, hot isostactic pressing and hot rolling processes were employed to fabricate the ODS steels, and creep rupture test as well as tensile test were examined to investigate the behavior at high temperatures. ODS steels were fabricated by a mechanical alloying and hot consolidation processes. Mechanical properties at high temperatures were investigated. The creep resistance of advanced radiation resistant ODS steels was more superior than those of ferritic/ martensitic steel, austenitic stainless steel and even a conventional ODS steel.

  14. Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

  15. Thermal Processing Effects on the Adhesive Strength of PS304 High Temperature Solid Lubricant Coatings

    Science.gov (United States)

    DellaCorte, Christopher; Edmonds, Brian J.; Benoy, Patricia A.

    2001-01-01

    In this paper the effects of post deposition heat treatments on the cohesive and adhesive strength properties of PS304, a plasma sprayed nickel-chrome based, high temperature solid lubricant coating deposited on stainless steel, are studied. Plasma spray deposited coating samples were exposed in air at temperatures from 432 to 650 C for up to 500 hr to promote residual stress relief, enhance particle to particle bonding and increase coating to substrate bond strength. Coating pull-off strength was measured using a commercial adhesion tester that utilizes 13 mm diameter aluminum pull studs attached to the coating surface with epoxy. Pull off force was automatically recorded and converted to coating pull off strength. As deposited coating samples were also tested as a baseline. The as-deposited (untreated) samples either delaminated at the coating-substrate interface or failed internally (cohesive failure) at about 17 MPa. Samples heat treated at temperatures above 540 C for 100 hr or at 600 C or above for more than 24 hr exhibited strengths above 31 MPa, nearly a two fold increase. Coating failure occurred inside the body of the coating (cohesive failure) for nearly all of the heat-treated samples and only occasionally at the coating substrate interface (adhesive failure). Metallographic analyses of heat-treated coatings indicate that the Nickel-Chromium binder in the PS304 appears to have segregated into two phases, a high nickel matrix phase and a high chromium precipitated phase. Analysis of the precipitates indicates the presence of silicon, a constituent of a flow enhancing additive in the commercial NiCr powder. The exact nature and structure of the precipitate phase is not known. This microstructural change is believed to be partially responsible for the coating strength increase. Diffusion bonding between particles may also be playing a role. Increasing the heat treatment temperature, exposure time or both accelerate the heat treatment process. Preliminary

  16. High-intensity intermittent exercise and its effects on heart rate variability and subsequent strength performance

    Directory of Open Access Journals (Sweden)

    Valéria Leme Gonçalves Panissa

    2016-03-01

    Full Text Available PRUPOSE: To investigate the effects of a 5-km high-intensity interval exercise (HIIE on heart rate variability (HRV and subsequent strength performance. METHODS: nine trained males performed a control session composed of a half-squat strength exercise (4 x 80% of one repetition maximum – 1RM in isolation and 30-min, 1-, 4-, 8- and 24-h after an HIIE (1-min at the velocity peak:1-min passive recovery. All experimental sessions were performed on different days. The maximum number of repetitions and total weight lifted during the strength exercise were registered in all conditions; in addition, prior to each session, HRV were assessed [beat-to-beat intervals (RR and log-transformed of root means square of successive differences in the normal-to-normal intervals (lnRMSSD]. RESULTS: Performance in the strength exercise dropped at 30-min (31% and 1-h (19% post-HIIE concomitantly with lower values of RR (781±79 ms; 799±134 ms, respectively in the same recovery intervals compared to the control (1015±197 ms. Inferential analysis did not detect any effect of condition on lnRMSSD, however, values were lower after 30-min (3.5±0.4 ms and 1-h (3.3±0.5 ms with moderate and large effect sizes (0.9 and 1.2, respectively compared with the control condition (3.9±0.4 ms. CONCLUSION: Both RR and lnRMSSD seem to be associated with deleterious effects on strength performance, although further studies should be conducted to clarify this association.

  17. Neptunium (V) Adsorption to a Halophilic Bacterium Under High Ionic Strength Conditions: A Surface Complexation Modeling Approach

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory

    2012-06-11

    Rationale for experimental design: Np(V) -- important as analog for Pu(V) and for HLW scenarios; High ionic strength -- relevant to salt-based repositories such as the WIPP; Halophilic microorganisms -- representative of high ionic strength environments. For the first time showed: Significant adsorbant to halophilic microorganisms over entire pH range under high ionic strength conditions; Strong influence of ionic strength with increasing adsorption with increasing ionic strength (in contrast to trends of previous low ionic strength studies); Effect of aqueous Np(V) and bacterial surface site speciation on adsorption; and Developed thermodynamic models that can be incorporated into geochemical speciation models to aid in the prediction of the fate and transport of Np(V) in more complex systems.

  18. Effect of Cement Composition in Lampung on Concrete Strength

    OpenAIRE

    Riyanto, Hery

    2014-01-01

    The strength and durability of concrete depends on the composition of its constituent materials ie fine aggregate, coarse aggregate, cement, water and other additives. The cement composition is about 10% acting as a binder paste material fine and coarse aggregates. In the Lampung market there are several brands of portland cement used by the community to make concrete construction. Although there is a standard of the government of portland cement composition, yet each brand of cement has diff...

  19. High-throughput design of low-activation, high-strength creep-resistant steels for nuclear-reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Qi; Zwaag, Sybrand van der [Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Xu, Wei, E-mail: xuwei@ral.neu.edu.cn [State Key Laboratory of Rolling and Automation, Northeastern University, 110819, Shenyang (China); Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands)

    2016-02-15

    Reduced-activation ferritic/martensitic steels are prime candidate materials for structural applications in nuclear power reactors. However, their creep strength is much lower than that of creep-resistant steel developed for conventional fossil-fired power plants as alloying elements with a high neutron activation cannot be used. To improve the creep strength and to maintain a low activation, a high-throughput computational alloy design model coupling thermodynamics, precipitate-coarsening kinetics and an optimization genetic algorithm, is developed. Twelve relevant alloying elements with either low or high activation are considered simultaneously. The activity levels at 0–10 year after the end of irradiation are taken as optimization parameter. The creep-strength values (after exposure for 10 years at 650 °C) are estimated on the basis of the solid-solution strengthening and the precipitation hardening (taking into account precipitate coarsening). Potential alloy compositions leading to a high austenite fraction or a high percentage of undesirable second phase particles are rejected automatically in the optimization cycle. The newly identified alloys have a much higher precipitation hardening and solid-solution strengthening at the same activity level as existing reduced-activation ferritic/martensitic steels.

  20. Preparation and properties of high-strength recycled concrete in cold areas

    Directory of Open Access Journals (Sweden)

    Haitao, Y.

    2015-06-01

    Full Text Available Concrete waste was processed into recycled coarse aggregate (RCA, subsequently used to prepare high-strength (> 50 MPa recycled concrete. The resulting material was tested for mechanical performance (ULS. The recycled concrete was prepared to the required design strength by adjusting the water/cement ratio. Concrete containing 0, 20, 50, 80 and 100% recycled aggregate was prepared and studied for workability, deformability and durability. The ultimate aim of the study was to prepare high-strength recycled concrete apt for use in cold climates as a theoretical and experimental basis for the deployment of recycled high-strength concrete in civil engineering and building construction.En este estudio se preparó un hormigón de altas resistencias (> 50 MPa utilizando residuos de hormigón como árido grueso reciclado (RCA. El material resultante se ensayó para determinar sus prestaciones mecánicas (ULS. Para adaptarse a los requerimientos resistentes, se ajustó la relación agua/cemento del hormigón reciclado. Se estudió la trabajabilidad, deformabilidad y durabilidad del hormigón con contenidos del 0, 20, 50, 80 y 100% de árido reciclado. El objetivo final del estudio fue preparar hormigón reciclado de altas resistencias apto para su uso en climas fríos como base teórica y experimental para el desarrollo de este tipo de materiales en obra civil y edificación.

  1. Strain rate dependent tensile behavior of advanced high strength steels: Experiment and constitutive modeling

    International Nuclear Information System (INIS)

    Kim, Ji-Hoon; Kim, Daeyong; Han, Heung Nam; Barlat, F.; Lee, Myoung-Gyu

    2013-01-01

    High strain rate tensile tests were conducted for three advanced high strength steels: DP780, DP980 and TRIP780. A high strain rate tensile test machine was used for applying the strain rate ranging from 0.1/s to 500/s. Details of the measured stress–strain responses were comparatively analyzed for the DP780 and TRIP780 steels which show similar microstructural feature and ultimate tensile strength, but different strengthening mechanisms. The experimental observations included: usual strain rate dependent plastic flow stress behavior in terms of the yield stress (YS), the ultimate tensile strength (UTS), the uniform elongation (UE) and the total elongation (TE) which were observed for the three materials. But, higher strain hardening rate at early plastic strain under quasi-static condition than that of some increased strain rates was featured for TRIP780 steel, which might result from more active transformation during deformation with lower velocity. The uniform elongation that explains the onset of instability and the total elongation were larger in case of TRIP steel than the DP steel for the whole strain rate range, but interestingly the fracture strain measured by the reduction of area (RA) method showed that the TRIP steel has lower values than DP steel. The fractographs using scanning electron microscopy (SEM) at the fractured surfaces were analyzed to relate measured fracture strain and the microstructural difference of the two materials during the process of fracture under various strain rates. Finally, constitutive modeling for the plastic flow stresses under various strain rates was provided in this study. The proposed constitutive law could represent both Hollomon-like and Voce-like hardening laws and the ratio between the two hardening types was efficiently controlled as a function of strain rate. The new strength model was validated successfully under various strain rates for several grades of steels such as mild steels, DP780, TRIP780, DP980 steels.

  2. High strength alloys for high temperature service in liquid-salt cooled energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

    2017-01-10

    An essentially cobalt-free alloy consists essentially of, in terms of weight percent: 6.3 to 7.2 Cr, 0.5 to 2 Al, 0 to 5 Fe, 0.7 to 0.8 Mn, 9 to 12.5 Mo, 0 to 6 Ta, 0.75 to 3.5 Ti, 0.01 to 0.25 Nb, 0.2 to 0.6 W, 0.02 to 0.04 C, 0 to 0.001 B, 0.0001 to 0.002 N, balance Ni. The alloy is characterized by a .gamma.' microstructural component in the range of 3 to 17.6 weight percent of the total composition. The alloy is further characterized by, at 850.degree. C., a yield strength of at least 60 Ksi, a tensile strength of at least 70 Ksi, a creep rupture life at 12 Ksi of at least 700 hours, and a corrosion rate, expressed in weight loss [g/(cm.sup.2sec)]10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 5.5 to 17.

  3. High strength alloys for high temperature service in liquid-salt cooled energy systems

    Science.gov (United States)

    Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

    2017-01-10

    An essentially cobalt-free alloy consists essentially of, in terms of weight percent: 6.3 to 7.2 Cr, 0.5 to 2 Al, 0 to 5 Fe, 0.7 to 0.8 Mn, 9 to 12.5 Mo, 0 to 6 Ta, 0.75 to 3.5 Ti, 0.01 to 0.25 Nb, 0.2 to 0.6 W, 0.02 to 0.04 C, 0 to 0.001 B, 0.0001 to 0.002 N, balance Ni. The alloy is characterized by a .gamma.' microstructural component in the range of 3 to 17.6 weight percent of the total composition. The alloy is further characterized by, at 850.degree. C., a yield strength of at least 60 Ksi, a tensile strength of at least 70 Ksi, a creep rupture life at 12 Ksi of at least 700 hours, and a corrosion rate, expressed in weight loss [g/(cm.sup.2sec)]10.sup.-11 during a 1000 hour immersion in liquid FLiNaK at 850.degree. C., in the range of 5.5 to 17.

  4. Mechanical properties of ground state structures in substitutional ordered alloys: High strength, high ductility and high thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Tawancy, H.M., E-mail: tawancy@kfupm.edu.sa [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, KFUPM Box 1639, Dhahran 31261 (Saudi Arabia); Aboelfotoh, M.O., E-mail: oaboelfotoh@gmail.com [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27606 (United States)

    2014-05-01

    We have studied the effect of atom arrangements in the ground state structures of substitutional ordered alloys on their mechanical properties using nickel–molybdenum-based alloys as model systems. Three alloys with nominal compositions of Ni–19.43 at% Mo, Ni–18.53 at% Mo–15.21 at% Cr and Ni–18.72 at% Mo–6.14 at% Nb are included in the study. In agreement with theoretical predictions, the closely related Pt{sub 2}Mo-type, DO{sub 22} and D1{sub a} superlattices with similar energies are identified by electron diffraction of ground state structures, which can directly be derived from the parent disordered fcc structure by minor atom rearrangements on {420}{sub fcc} planes. The three superlattices are observed to coexist during the disorder–order transformation at 700 °C with the most stable superlattice being determined by the exact chemical composition. Although most of the slip systems in the parent disordered fcc structure are suppressed, many of the twinning systems remain operative in the superlattices favoring deformation by twinning, which leads to considerable strengthening while maintaining high ductility levels. Both the Pt{sub 2}Mo-type and DO{sub 22} superlattices are distinguished by high strength and high ductility due to their nanoscale microstructures, which have high thermal stability. However, the D1{sub a} superlattice is found to exhibit poor thermal stability leading to considerable loss of ductility, which has been correlated with self-induced recrystallization by migration of grain boundaries.

  5. TIG-dressing of High Strength Steel Butt Welded Connections. Part 1 : Weld Toe Geometry and Local Hardness

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2014-01-01

    This paper presents the results of extensive measurements on weld toe geometry of as-welded and TIG-dressed butt welded connections in high strength steels S460, S690 and very high strength steels S890 and S1100. Descriptions of the measurement techniques and data analysis are presented. Four weld

  6. TIG-dressing of high strength steel butt welded connections - Part 1: weld toe geometry and local hardness

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2013-01-01

    This paper presents the results of extensive measurements on weld toe geometry of as-welded and TIG-dressed butt welded connections in high strength steels S460, S690 and very high strength steels S890 and S1100. Descriptions of the measurement techniques and data analysis are presented. Four weld

  7. Potencialidades da metacaolinita e do tijolo queimado moído como substitutos parciais do cimento Portland Potentialities of metakaolin and crushed waste calcined clay brick as partial replacement of Portland cement

    Directory of Open Access Journals (Sweden)

    João de Farias Filho

    2000-12-01

    Full Text Available Avalia-se, neste trabalho, a potencialidade do uso da metacaolinita e dos resíduos de produção de tijolos cerâmicos queimados finamente moídos, como substitutos parciais do cimento Portland. Os materiais foram caracterizados física, química e mineralogicamente, além de determinado o índice de atividade pozolânica com cimento Portland. A evolução da resistência a compressão e a flexão das argamassas foi avaliada até as idades de, respectivamente, 365 e 208 dias. As porcentagens de substituição do cimento Portland, em peso, pelos materiais pozolânicos, variaram de 20 a 50%, enquanto o fator água/cimento variou de 0,37 a 0,45. Os resultados obtidos indicaram que a metacaolinita e o tijolo moído queimado possuem elevada atividade pozolânica e que a resistência a compressão, aos 28 dias, das argamassas mistas, foi superior à das argamassas de cimento Portland para os níveis de substituição e fatores água/cimento estudados. Um modelo matemático para predição da resistência à compressão das argamassas mistas é proposto com base em um desenho fatorial de experimentos.This paper evaluates the potentiality of metakaolin and crushed waste fired clay brick as cement replacement materials. They were characterised physically, chemically and mineralogically and their activity with Portland cement determined. The influence of the partial replacement of Portland cement on the development of compressive and flexural strength was evaluated until the age of, respectively, 365 and 208 days. The percentage of cement replacement, in weight, ranged from 20 to 50%, whereas the water/cement ratio ranged from 0.37 to 0.45. The results obtained show that the metakaolin and crushed calcined clay brick presented a good pozolanic activity and that the compressive strength of the blended mortars after 28 days of cure was higher than that observed for the reference Portland cement for all levels of cement replacement and water/cement ratio. A

  8. Development and Application of High Strength TMCP Plate for Coal Mining Machinery

    Science.gov (United States)

    Yongqing, Zhang; Aimin, Guo; Liandeng, Yao

    Coal, as the most major energy in China, accounted for about 70% of China's primary energy production and consumption. While the percentage of coal as the primary energy mix would drop in the future due to serious smog pollution partly resulted from coal-burning, the market demand of coal will maintain because the progressive process of urbanization. In order to improve productivity and simultaneously decrease safety accidents, fully-mechanized underground mining technology based on complete equipment of powered support, armored face conveyor, shearer, belt conveyor and road-header have obtained quick development in recent years, of which powered support made of high strength steel plate accounts for 65 percent of total equipment investment, so, the integrated mechanical properties, in particular strength level and weldability, have a significant effects on working service life and productivity. Take hydraulic powered supports as example, this paper places priority to introduce the latest development of high strength steel plates of Q550, Q690 and Q890, as well as metallurgical design conception and production cost-benefits analysis between QT plate and TMCP plate. Through production and application practice, TMCP or DQ plate demonstrate great economic advantages compared with traditional QT plate.

  9. Adhesive bond strength evaluation in composite materials by laser-generated high amplitude ultrasound

    International Nuclear Information System (INIS)

    Perton, M; Blouin, A; Monchalin, J-P

    2011-01-01

    Adhesive bonding of composites laminates is highly efficient but is not used for joining primary aircraft structures, since there is presently no nondestructive inspection technique to ensure the quality of the bond. We are developing a technique based on the propagation of high amplitude ultrasonic waves to evaluate the adhesive bond strength. Large amplitude compression waves are generated by a short pulse powerful laser under water confinement and are converted after reflection by the assembly back surface into tensile waves. The resulting tensile stresses can cause a delamination inside the laminates or at the bond interfaces. The adhesion strength is evaluated by increasing the laser pulse energy until disbond. A good bond is unaffected by a certain level of stress whereas a weaker one is damaged. The method is shown completely non invasive throughout the whole composite assembly. The sample back surface velocity is measured by an optical interferometer and used to estimate stress history inside the sample. The depth and size of the disbonds are revealed by a post-test inspection by the well established laser-ultrasonic technique. Experimental results show that the proposed method is able to differentiate weak bond from strong bonds and to estimate quantitatively their bond strength.

  10. High-temperature strength of TiC-coated SUS316 stainless steel

    International Nuclear Information System (INIS)

    Kaneko, K.; Furuya, Y.; Kikuchi, M.

    1992-01-01

    Some ceramics-coated metals are nominated as first-wall material. TiC-coated type 316 stainless steel is expected to be superior to other materials in high-temperature strength and in its endurance properties at heavy irradiation. Delamination between ceramics layer and base-metal is considered to be one of the most important problems when such ceramics-coated metals are used in a temperature field with a gradient such as that of the first wall. In this report, the high-temperature strength of TiC-coated type 316 stainless steel, which should be that of the first wall of the fusion reactor, is investigated experimentally and computationally. A simple and precise thermal-stress testing system is developed. The effects of surface roughness as well as of the thermal stress and the residual stress on the bonding strength are investigated. The experimental and numerical results on the residual-stress distribution are compared with each other to confirm the reliability of the inelastic analysis using the finite-element method (FEM). It is expected that a suitable surface roughness makes the residual stress in the coated film small. The optimum range for the TiC-coating temperature is found using inelastic FEM analysis at the heating conditions used in the experiments. (orig.)

  11. Investigation on dissimilar laser welding of advanced high strength steel sheets for the automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Rossini, M., E-mail: matteo.rossini@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Spena, P. Russo, E-mail: pasquale.russospena@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Cortese, L., E-mail: luca.cortese@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Matteis, P., E-mail: paolo.matteis@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Firrao, D., E-mail: donato.firrao@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2015-03-25

    To support the use of advanced high strength steels in car body design and fabrication, an investigation was carried out on dissimilar butt laser welding between TWinning Induced Plasticity (TWIP) steels, Dual Phase (DP) steels, hot stamping boron (22MnB5) steels, and TRansformation Induced Plasticity (TRIP) steels. The base materials and the weldments were fully characterized by means of metallography, microhardness, and tensile tests. Digital image analysis was also used to provide additional information on the local strain field in the joint during the tensile tests. Fractographic examination was finally performed on the fracture surfaces of the tensile samples. The dissimilar joints between the DP, 22MnB5, and TRIP steels exhibit good resistance properties. On the contrary, the dissimilar joints encompassing the TWIP steel exhibit poor mechanical strength and fail along the weld seam by intergranular fracture, probably due to presence of Mn segregations. Therefore, the laser welding of TWIP steel with other advanced high strength steels is not recommended without the use of proper metal fillers. Dissimilar laser welding of DP, TRIP and 22MnB5 combinations, on the contrary, can be a solution to assemble car body parts made of these steel grades.

  12. Isolation of aramid nanofibers for high strength multiscale fiber reinforced composites

    Science.gov (United States)

    Lin, Jiajun; Patterson, Brendan A.; Malakooti, Mohammad H.; Sodano, Henry A.

    2018-03-01

    Aramid fibers are famous for their high specific strength and energy absorption properties and have been intensively used for soft body armor and ballistic protection. However, the use of aramid fiber reinforced composites is barely observed in structural applications. Aramid fibers have smooth and inert surfaces that are unable to form robust adhesion to polymeric matrices due to their high crystallinity. Here, a novel method to effectively integrate aramid fibers into composites is developed through utilization of aramid nanofibers. Aramid nanofibers are prepared from macroscale aramid fibers (such as Kevlar®) and isolated through a simple and scalable dissolution method. Prepared aramid nanofibers are dispersible in many polymers due to their improved surface reactivity, meanwhile preserve the conjugated structure and likely the strength of their macroscale counterparts. Simultaneously improved elastic modulus, strength and fracture toughness are observed in aramid nanofiber reinforced epoxy nanocomposites. When integrated in continuous fiber reinforced composites, aramid nanofibers can also enhance interfacial properties by forming hydrogen bonds and π-π coordination to bridge matrix and macroscale fibers. Such multiscale reinforcement by aramid nanofibers and continuous fibers results in strong polymeric composites with robust mechanical properties that are necessary and long desired for structural applications.

  13. Long-lived, high-strength states of ICAM-1 bonds to beta2 integrin, II

    DEFF Research Database (Denmark)

    Kinoshita, Koji; Leung, Andrew; Simon, Scott

    2010-01-01

    Using single-molecule force spectroscopy to probe ICAM-1 interactions with recombinant alphaLbeta2 immobilized on microspheres and beta2 integrin on neutrophils, we quantified an impressive hierarchy of long-lived, high-strength states of the integrin bond, which start from basal levels with acti......Using single-molecule force spectroscopy to probe ICAM-1 interactions with recombinant alphaLbeta2 immobilized on microspheres and beta2 integrin on neutrophils, we quantified an impressive hierarchy of long-lived, high-strength states of the integrin bond, which start from basal levels......-out and outside-in signaling in neutrophils on the lifetimes and mechanical strengths of ICAM-1 bonds to beta2 integrin on the cell surface. Even though ICAM-1 bonds to recombinant alphaLbeta2 on microspheres in Mg2+ or Mn2+ can live for long periods of time under slow pulling, here we show that stimulation...... of neutrophils in Mg2+ plus the chemokine IL-8 (i.e., inside-out signaling) induces several-hundred-fold longer lifetimes for ICAM-1 attachments to LFA-1, creating strong bonds at very slow pulling speeds where none are perceived in Mg2+ or Mn2+ alone. Similar changes are observed with outside-in signaling, i...

  14. Microbial Activity in Peat Soil Treated With Ordinary Portland Cement (OPC) and Coal Ashes

    Science.gov (United States)

    Rahman, J. A.; Mohamed, R. M. S. R.; Al-Gheethi, A. A.

    2018-04-01

    Peat soil is a cumulative of decayed plant fragment which developed as a result of microbial activity. The microbes degrade the organic matter in the peat soils by the production of hydrolysis enzyme. The least decomposed peat, known as fibric peat has big particles and retain lots of water. This made peat having high moisture content, up to 1500 %. The most decomposed peat known as sapric peat having fines particles and less void ratio. The present study aimed to understand the effects of solidification process on the bacterial growth and cellulase (CMCase) enzyme activity. Two types of mixing were designed for fibric, hemic and sapric peats; (i) Ordinary Portland cement (OPC) at an equal amount of dry peat, with 25 % of fly ash (FA) and total of coarse particle, a combination of bottom ash and fibre of 22 – 34 %, (ii) fibric peat was using water-to-binder ratio (w/b) = 1, 50% OPC, 25 % bottom ash (BA) and 25 % FA. For hemic and sapric peat, w/b=3 with 50 % OPC and 50 % BA were used. All samples were prepared triplicates, and were cured for 7, 14, 28 and 56 days in a closed container at room temperature. The results revealed that the first mix design giving a continuous strength development. However, the second mix design shows a decreased in strength pattern after day 28. The influence of the environment factors such as alkaline pH, reduction of the water content and peat temperature has no significant on the reduction amount of native microbes in the peat. The microbes survived in the solidified peat but the amount of microbes were found reduced for all types of mixing Fibric Mixed 1 (FM1), Hemic Mixed 1(HM1) and Sapric Mixed 1 (SM1) were having good strength increment for about 330 – 1427 % with enzymatic activity recorded even after D56. Nevertheless, with increase in the strength development through curing days, the enzymatic activities were reduced. For the time being, it can be concluded that the microbes have the ability to adapt with new environment

  15. The Evolution of Plate and Extruded Products with High Strength and Fracture Toughness

    Science.gov (United States)

    Denzer, D. K.; Rioja, R. J.; Bray, G. H.; Venema, G. B.; Colvin, E. L.

    From the first use of 2017-T74 on the Junkers F13, improvements have been made to plate and extruded products for applications requiring the highest attainable strength and adequate fracture toughness. One such application is the upper wing of large aircraft. The progression of these product improvements achieved through the development of alloys that include 7075-(T6 & T76), 7150-(T6 & T77) and 7055-(T77 & T79) and most recently 7255-(T77 & T79) is reviewed. The most current advancements include aluminum-copper-lithium, alloy 2055 plate and extruded products that can attain strength equivalent to that of 7055-T77 with higher modulus, similar fracture toughness and improved fatigue, fatigue crack growth and corrosion performance. The achievement of these properties is explained in terms of the several alloy design principles. The highly desired and balanced characteristics make these products ideal for upper wing applications.

  16. Aerospace Patented High-Strength Aluminum Alloy Used in Commercial Industries

    Science.gov (United States)

    2004-01-01

    NASA structural materials engineers at Marshall Space Flight Center (MSFC) in Huntsville, Alabama developed a high-strength aluminum alloy for aerospace applications with higher strength and wear-resistance at elevated temperatures. The alloy is a solution to reduce costs of aluminum engine pistons and lower engine emissions for the automobile industry. The Boats and Outboard Engines Division at Bombardier Recreational Products of Sturtevant, Wisconsin is using the alloy for pistons in its Evinrude E-Tec outboard, 40-90 horsepower, engine line. The alloy pistons make the outboard motor quieter and cleaner, while improving fuel mileage and increasing engine durability. The engines comply with California Air resources Board emissions standards, some of the most stringent in the United States. (photo credit: Bombardiier Recreational Products)

  17. Re-usage of waste foundry sand in high-strength concrete.

    Science.gov (United States)

    Guney, Yucel; Sari, Yasin Dursun; Yalcin, Muhsin; Tuncan, Ahmet; Donmez, Senayi

    2010-01-01

    In this study, the potential re-use of waste foundry sand in high-strength concrete production was investigated. The natural fine sand is replaced with waste foundry sand (0%, 5%, 10%, and 15%). The findings from a series of test program has shown reduction in compressive and tensile strengths, and the elasticity modulus which is directly related to waste foundry inclusion in concrete. Nevertheless the concrete with 10% waste foundry sand exhibits almost similar results to that of the control one. The slump and the workability of the fresh concrete decreases with the increase of the waste foundry sand ratio. Although the freezing and thawing significantly reduces the mechanical and physical properties of the concrete. The obtained results satisfies the acceptable limits set by the American Concrete Institute (ACI). 2010 Elsevier Ltd. All rights reserved.

  18. Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions

    International Nuclear Information System (INIS)

    Hoche, Holger; Oechsner, Matthias

    2017-01-01

    Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

  19. Optimum tungsten content in high strength 9 to 12% chromium containing creep resistant steels

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Muraki, T.; Mimura, H.

    2000-01-01

    Tungsten containing ferritic creep resistant steels are the candidate materials for ultra-super-critical fossil power plant because of their high creep rupture strength. But the strengthening mechanisms by tungsten addition have not yet been completely studied. In this report, creep rupture time and creep strain rate measurement decided the optimum tungsten content in 9 to 12% chromium ferritic steels. The precipitation behavior of Laves phase and the precise discussion of creep strain rate analyses explain the contribution of Laves phase at the lath boundary and the contribution of tungsten in solid solution. P92 contains the optimum amount of tungsten and chromium, 1.8 mass% and 9 mass% respectively judging from the creep rupture strength point of view. (orig.)

  20. Welding of high-strength stainless steel 03Kh12N10MT for cryogenic engineering

    International Nuclear Information System (INIS)

    Pustovit, A.I.

    1989-01-01

    Consideration is being given to weld resistance to cold and hot cracking at 93 and 77K and to mechanical properties of welded joints of high-strength stainless steel 03Kh12N10MT, produced under the fluxes AN-17M, AN-18, AN-26, AN-45, ANF-5, 48-OF-6, ANK-45 and ANK-49 in combination with various welding wires. It is shown that welds on 03Kh12N10MT steel meet the requirements only when using 48-OF-6 or ANK-49 flux. It is noted that impact strength of welds at 77K is sufficiently affected by the volume fraction of non-metallic inclusions in weld metal