WorldWideScience

Sample records for corrosion concrete quality

  1. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  2. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  3. The bacterial corrosion of concretes

    International Nuclear Information System (INIS)

    Tache, G.

    1998-01-01

    Concrete is a material very sensitive to aging effects and to permanent aggressions. It is an evolutive material in which internal hydration reactions and exchange reactions with the external medium are produced. Moreover, its characteristics tightly depends on factors which are bound to its formulation, to the appropriate choice of materials in which it is constituted, to their qualities and to the conditions of its use. Its aging depends then in a large extent of these different factors and of the adequation between its final characteristics and the solicitations in which it is submitted: physical, mechanical, thermal.. or environmental. This chapter deals particularly with the influence of the bacterial phenomena on concrete. Some recalls are at first given on the principles which govern the concrete durability. Then are approached the phenomena mechanisms. (O.M.)

  4. Modeling of Corrosion-induced Concrete Damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Michel, Alexander; Stang, Henrik

    2013-01-01

    In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non...... of corrosion products affects both the time-to cover cracking and the crack width at the concrete surface.......In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non......-uniform formation of corrosion products at the concrete/reinforcement interface, a deterministic approach is used. The model gives good estimates of both deformations in the con-crete/reinforcement interface and crack width when compared to experimental data. Further, it is shown that non-uniform deposition...

  5. Boric Acid Corrosion of Concrete Rebar

    Directory of Open Access Journals (Sweden)

    Yang L.

    2013-07-01

    Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure and compromise the integrity of the structure. Because corrosion rate of carbon steel in concrete in the presence of boric acid is lacking in published literature and available data are equivocal on the effect of boric acid on rebar corrosion, corrosion rate measurements were conducted in this study using several test methods. Rebar corrosion rates were measured in (i borated water flowing in a simulated concrete crack, (ii borated water flowing over a concrete surface, (iii borated water that has reacted with concrete, and (iv 2,400 ppm boric acid solutions with pH adjusted to a range of 6.0 to 7.7. The corrosion rates were measured using coupled multielectrode array sensor (CMAS and linear polarization resistance (LPR probes, both made using carbon steel. The results indicate that rebar corrosion rates are low (~1 μm/yr or lesswhen the solution pH is ~7.1 or higher. Below pH ~7.1, the corrosion rate increases with decreasing pH and can reach ~100 μm/yr in solutions with pH less than ~6.7. The threshold pH for carbon steel corrosion in borated solution is between 6.8 and 7.3.

  6. Corrosion resistant alloys for reinforced concrete [2009

    Science.gov (United States)

    2009-04-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for four-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focus...

  7. Corrosion resistant alloys for reinforced concrete [2007

    Science.gov (United States)

    2007-07-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for 4-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focused ...

  8. Electrokenitic Corrosion Treatment of Concrete

    Science.gov (United States)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  9. Improved concretes for corrosion resistance

    Science.gov (United States)

    1997-07-01

    The deterioration of various reinforced concrete bridge components containing conventional black steel reinforcement is the most important problem facing U.S. highway agencies. A major cause of this concrete deterioration (cracking, delamination, and...

  10. A corrosion monitoring system for existing reinforced concrete structures.

    Science.gov (United States)

    2015-05-01

    This study evaluated a multi-parameter corrosion monitoring system for existing reinforced concrete structures in chloride-laden service environments. The system was fabricated based on a prototype concrete corrosion measurement system that : had bee...

  11. Factors and mechanisms affecting corrosion of steel in concrete

    International Nuclear Information System (INIS)

    Dehqanian, Ch.

    1986-01-01

    Atomic power plants possess reinforced concrete structures which are exposed to sea water or sea atmosphere. Sea water or its surrounding environment contain very corrosive species which cause corrosion of metal in concrete. It should be mentioned that corrosion of steel in concrete is a complex problem that is not completely understood. Some of the factors which influence the corrosion mechanism and can be related to the pore solution composition is discussed. Chloride ion caused problems are the main source of the corrosion damage seen on the reinforced concrete structures. Corrosion rate in concrete varies and depends on the way chloride ion diffuses into concrete. In addition, the associated cations can influence diffusion of chloride into concrete. The type of portland cement and also the concrete mix design all affect the corrosion behaviour of steel in concrete

  12. Corrosion and Cracking of Reinforced Concrete

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of the deterioration of reinforced concrete has in recent years changed from being a deterministic modelling based on experience to be stochastic modelling based on sound and consistent physical, chemical and mechanical principles. In this paper is presented a brief review of modern mod...... for time to initial corrosion, time to initial cracking, and time to a given crack width may be obtained....

  13. Monitoring corrosion in reinforced concrete structures

    Science.gov (United States)

    Kung, Peter; Comanici, Maria I.

    2014-06-01

    Many defects can cause deterioration and cracks in concrete; these are results of poor concrete mix, poor workmanship, inadequate design, shrinkage, chemical and environmental attack, physical or mechanical damage, and corrosion of reinforcing steel (RS). We want to develop a suite of sensors and systems that can detect that corrosion is taking place in RS and inform owners how serious the problem is. By understanding the stages of the corrosion process, we can develop special a sensor that detects each transition. First, moisture ingress can be monitored by a fiber optics humidity sensor, then ingress of Chloride, which acts as a catalyst and accelerates the corrosion process by converting iron into ferrous compounds. We need a fiber optics sensor which can quantify Chloride ingress over time. Converting ferric to ferrous causes large volume expansion and cracks. Such pressure build-up can be detected by a fiber optic pressure sensor. Finally, cracks emit acoustic waves, which can be detected by a high frequency sensor made with phase-shifted gratings. This paper will discuss the progress in our development of these special sensors and also our plan for a field test by the end of 2014. We recommend that we deploy these sensors by visually inspecting the affected area and by identifying locations of corrosion; then, work with the designers to identify spots that would compromise the integrity of the structure; finally, drill a small hole in the concrete and insert these sensors. Interrogation can be done at fixed intervals with a portable unit.

  14. Corrosion of metal materials embedded in concrete

    International Nuclear Information System (INIS)

    Duffo, G.S.; Farina, S.B.; Schulz, F.M.

    2010-01-01

    Carbon steel is the material most frequently used to strengthen reinforced concrete structures; however, stainless steel and galvanized steel reinforcements are also used in construction concretes; and they are not often used in Latin America. Meanwhile, there are other metals that are embedded in the concrete forming part of the openings (aluminum) or in tubing systems (copper and lead). The use of concrete as a cementing material is also useful for immobilizing wastes, such as for example those generated by the nuclear industry. There is a great deal of research and development on the corrosion of steel reinforcements, but the same is not true for the behavior of other metals embedded in concrete and that also undergo corrosive processes. This work aims to study the corrosion of different metals: copper, lead, aluminum, zinc, stainless steel and carbon steel; embedded in concrete with and without the presence of aggressive species for the metal materials. Test pieces were made of mortar containing rods of different materials for testing, and with chlorides added in concentrations of 0; 0.3 % and 1% (mass of chloride per mass of cement). The test pieces were exposed to different conditions; laboratory environment with a relative humidity (RH) of 45%, a controlled atmosphere with 98% RH and submerged in a solution of 3.5% NaCl. The susceptibility to corrosion of the different metals was evaluated using techniques to monitor the corrosion potential, the resistivity of the mortar and the polarization resistance (PR). The rods were weighed before being placed inside the test pieces to later determine the loss of weight generated by the corrosion process. Polarization curves for the metals were also traced in a simulated pore solution (SPS) and in SPS with added chloride. The results obtained to date show that, of all the metals analyzed, aluminum is the most susceptible to corrosion, and that the test specimens with 0% and 1% of chloride exposed to the laboratory

  15. Concrete quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Holz, N. [Harza Engineering Company, Chicago, IL (United States)

    2000-08-01

    This short article reports on progress at the world's largest civil construction project, namely China's Three Gorges hydro project. Work goes on around the clock to put in place nearly 28 M m{sup 3} of concrete. At every stage of the work there is strong emphasis on quality assurance (QA) and concrete is no exception. The US company Harza Engineering has been providing QA since the mid-1980s and concrete QA has been based on international standards. Harza personnel work in the field with supervisors developing educational tools for supervising concrete construction and quality, as well as providing training courses in concrete technology. Some details on flood control, capacity, water quality and environmental aspects are given..

  16. Corrosion of steel in concrete

    International Nuclear Information System (INIS)

    Preece, C.M.

    1982-10-01

    A comparative study has been made of those properties of Massiv and Standard cements which are considered to determine their ability to protect steel reinforcement from corroding. Saturated Massiv cement has a higher evaporabel water content, but a significantly finer pore structure than has saturated Standard cement. This fine structure resulted in an electrical resistivity ten times higher and chloride diffusivity ten times lower than those of Standard cement. Electrochemical measurements have shown that the passive current density of steel in Massiv mortar is higher than that of steel in Standard mortar, but the higher current should lead to a more rapid decrease in potential to a level at which neither chloride attack of hydrogen evolution will occur. Whereas steel in Standard mortar was found to be highly susceptible to crevice corrosion, no such attack has been observed in Massiv mortar. Moreover, the initiation of chloride induced corrosion and the subsequent rates of corrosion were both lower in Massiv mortar than in Standard mortar. Thus, it may be predicted that Massiv cement would provide greater protection for steel reinforcement in underground structures exposed to chloride containing ground water than would Standard cement. (author)

  17. Corrosion of Steel in Concrete, Part I – Mechanisms

    DEFF Research Database (Denmark)

    Küter, André; Møller, Per; Geiker, Mette Rica

    2006-01-01

    prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress...... of depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...... initiation and propagation of corrosion of steel in concrete are outlined....

  18. Corrosion of Steel in Concrete – Thermodynamical Aspects

    DEFF Research Database (Denmark)

    Küter, Andre; Møller, Per; Geiker, Mette Rica

    2004-01-01

    The present understanding of selected corrosion phenomena in reinforced concrete is reviewed. Special emphasis is given to chloride induced corrosion. There is a general acceptance of the basic corrosion mechanism for steel in concrete. However different anodic reactions governing the subsequent...

  19. Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

    NARCIS (Netherlands)

    Lukovic, M.; Šavija, B.; Ye, G.; Schlangen, H.E.J.G.; van Breugel, K.

    2017-01-01

    Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion

  20. Estimation of Concrete Corrosion Due to Attack of Chloride Salt

    Directory of Open Access Journals (Sweden)

    V. V. Babitski

    2005-01-01

    Full Text Available The paper provides results of experimental concrete research under conditions of concentrated chloride salt solutions. General principles of forecasting concrete corrosion resistance under salt physical corrosion are given in the paper. Analytical dependences for quantitative estimation of corroded concrete have been obtained.

  1. Economic effects of full corrosion surveys for aging concrete structures

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.; Raupach, M.; Reichling, K.

    2013-01-01

    This paper investigates the economic effects of full corrosion surveys of concrete structures. The background is that the existing concrete infrastructure is aging, while being exposed to aggressive influences, which increases the occurrence of corrosion and related concrete damage over time. The

  2. Effects of climate and corrosion on concrete behaviour

    Science.gov (United States)

    Ismail, Mohammad; Egba, Ernest Ituma

    2017-11-01

    Corrosion of steel is a damaging agent that reduces the functional and structural responsibilities of reinforced concrete structures. Accordingly, reinforced concrete members in the environments that are prone to concrete carbonation or chloride attack coupled with high temperature and relative humidity suffer from accelerated corrosion of reinforcing material. Also, literature proves that climate influences corrosion of concrete, and suggests investigation of impact of corrosion on concrete based on climate zone. Therefore, this paper presents the effects of climate and corrosion on concrete behavior, using bond strength of concrete as a case study. Concrete specimens were prepared form concrete mix that was infested with 3.5 kgm-3 of sodium chloride to accelerate corrosion. The specimens were cured sodium chloride solution 3.5% by weight of water for 28 days before placing them in the exposure conditions. Pull-out tests were conducted at time intervals for one year to measure the impact of exposure condition and corrosion on bond strength of concrete. The results show reduction of bond strength of concrete by 32%, 28% and 8% after one year of subjection of the specimens to the unsheltered natural climate, sheltered natural climate, and laboratory ambient environment respectively. The findings indicate that the climate influences corrosion, which reduces the interlocking bond between the reinforcing bar and the adjacent concrete.

  3. Enhancing corrosion resistance of reinforced concrete structures with hybrid fiber reinforced concrete

    International Nuclear Information System (INIS)

    Blunt, J.; Jen, G.; Ostertag, C.P.

    2015-01-01

    Highlights: • Reinforced concrete beams were subjected to cyclic flexural loading. • Hybrid fiber reinforced composites were effective in reducing corrosion rates. • Crack resistance due to fibers increased corrosion resistance of steel rebar. • Galvanic corrosion measurements underestimated corrosion rates. • Polarization resistance measurements predicted mass loss more accurately. - Abstract: Service loads well below the yield strength of steel reinforcing bars lead to cracking of reinforced concrete. This paper investigates whether the crack resistance of Hybrid Fiber Reinforced Concrete (HyFRC) reduces the corrosion rate of steel reinforcing bars in concrete after cyclic flexural loading. The reinforcing bars were extracted to examine their surface for corrosion and compare microcell and macrocell corrosion mass loss estimates against direct gravimetric measurements. A delay in corrosion initiation and lower active corrosion rates were observed in the HyFRC beam specimens when compared to reinforced specimens containing plain concrete matrices cycled at the same flexural load

  4. Corrosion of steel in cracked concrete: a microscale study

    NARCIS (Netherlands)

    Pacheco, J.; Savija, B.; Schlangen, E.; Polder, R.B.

    2014-01-01

    The influence of concrete cracking upon reinforcement corrosion is complex. Cracks allow fast penetration of chlorides, potentially leading to a shorter initiation period of reinforcement corrosion. Structural regulations control acceptable crack width values based on the exposure class of the

  5. Corrosion performance tests for reinforcing steel in concrete : technical report.

    Science.gov (United States)

    2009-10-01

    The existing test method used to assess the corrosion performance of reinforcing steel embedded in : concrete, mainly ASTM G 109, is labor intensive, time consuming, slow to provide comparative results, : and can be expensive. However, with corrosion...

  6. Corrosion performance tests for reinforcing steel in concrete : test procedures.

    Science.gov (United States)

    2009-09-01

    The existing test method to assess the corrosion performance of reinforcing steel embedded in concrete, mainly : ASTM G109, is labor intensive, time consuming, slow to provide comparative results, and often expensive. : However, corrosion of reinforc...

  7. Performance evaluation of corrosion-affected reinforced concrete ...

    Indian Academy of Sciences (India)

    M B Anoop

    Abstract. A methodology for performance evaluation of reinforced concrete bridge girders in corrosive ... concrete (RC) members of infrastructural systems, espe- ... bility will be useful for making engineering decisions for ...... Water-cement ratio.

  8. Additives as corrosion inhibitors in reinforced concrete

    International Nuclear Information System (INIS)

    Venegas, Ricardo; Vera, Rosa; Carvajal, Ana Maria; Villarroel, Maria; Vera, Enrique; Ortiz, Cesar

    2008-01-01

    This work studies the behavior of two additives as inhibitors of corrosion in reinforced concrete. The presence of Microsilica, a physical inhibitor, in the mixture decreases pore size in structures and improves compression. Calcium Nitrite, a chemical inhibitor, is an oxidizing agent and allows a more homogenous film to form over the steel that becomes more resistant to attacks from aggressive ions like anion chloride and others. Three pairs of concrete test pieces were used without additives and with additives with a/c ration of 0.55. The samples were exposed to an accelerated attack of chlorides, submerging them in a 4.27 M solution of NaCl for 24 hours and then drying them at room temperature for another 24 hours, completing a cycle every 48 hours. The tests were carried out at 1 cycle and 5 cycles of partial moistening and drying. The steel corrosion was evaluated with corrosion potential measurements. Conductivity, pH, chlorides and sulfate profiles were defined depending on the depth of the concrete. The composition of the corrosion products was determined using X-ray diffraction and the morphology of the film by scanning electron microscopy. The results show that for 1 test cycle, the corrosion potential of the steel in the sample with calcium nitrite was -54mV, which was a higher value than that measured in the sample with microsilica (-217.3mV) and without an additive (-159.1mV), corroborating its inhibitory power. The content of the free chlorides in the sample with micros ice allows greater capillary suction by adding high amounts of chloride to the structure (2.6% on the outside up to 2.20% near the steel); while the test pieces with calcium nitrite and without an additive had concentrations lower than 2% in all the evaluated points. After five cycles of exposing the samples to the saline solution the behavior is inverted. The measures of conductivity agreed with the previous results. Meanwhile, the pH of the solutions obtained from the powder from the

  9. Influence of heat treatment on corrosive resistance of concrete steels

    International Nuclear Information System (INIS)

    Woldan, A.; Suliga, I.; Kusinski, J.; Jazowy, R.

    1998-01-01

    The reinforcing bars are essential elements of ferro-concrete structures. During the building structure service the reinforcing bars should co-operate with surrounding concrete. Any bonding defects as well as corrosion induced strength reduction may result in construction failure. The reinforcing steel working environment is determined by concrete chemical and phase composition and surrounding environmental properties. The aggressive corrosive activity of the letter implies necessity of effective ways development to protect elements against corrosion. The effect of heat treatment, increased Si content in steel on corrosion resistance of reinforcing steel in concrete was studied in the current work. Corrosion tests and metallographic examinations proved a positive influence of hardening and Si enrichment on corrosion resistance of reinforcing bars in ferro-concrete structures. (author)

  10. Concrete cover cracking due to uniform reinforcement corrosion

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Michel, Alexander; Geiker, Mette Rica

    2013-01-01

    and reinforcement de-passivation is a frequently used limit state. The present paper investigates an alternative limit state: corrosion-induced cover cracking. Results from numerical simulations of concrete cover cracking due to reinforcement corrosion are presented. The potential additional service life...... is calculated using literature data on corrosion rate and Faraday’s law. The parameters varied comprise reinforcement diameter, concrete cover thickness and concrete material properties, viz. concrete tensile strength and ductility (plain concrete and fibre reinforced concrete). Results obtained from......Service life design (SLD) is an important tool for civil engineers to ensure that the structural integrity and functionality of the structure is not compromised within a given time frame, i.e. the service life. In SLD of reinforced concrete structures, reinforcement corrosion is of major concern...

  11. Corrosion initiation and propagation in cracked concrete - a literature review

    NARCIS (Netherlands)

    Pacheco, J.; Polder, R.

    2012-01-01

    The major degradation mechanism in civil engineering concrete structures is corrosion of reinforcement due to chloride penetration. Corrosion reduces serviceability and safety due to cracking and spalling of concrete and loss of steel cross section. Recently, service life design has moved from

  12. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    Science.gov (United States)

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion. PMID:24558346

  13. Monitoring corrosion of steel bars in reinforced concrete structures.

    Science.gov (United States)

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion.

  14. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Verma

    2014-01-01

    Full Text Available Corrosion of steel bars embedded in reinforced concrete (RC structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP method. This paper also presents few techniques to protect concrete from corrosion.

  15. Advanced modelling of concrete deterioration due to reinforcement corrosion

    International Nuclear Information System (INIS)

    Isgor, O.B.; Razaqpur, A.G.

    2006-01-01

    A comprehensive model is presented for predicting the rate of steel corrosion in concrete structures and the consequent formation and propagation of cracks around the steel reinforcement. The corrosion model considers both the initiation and the propagation stages of corrosion. Processes commencing in the initiation stage, such as the transport of chloride ions and oxygen within the concrete and variation in temperature and moisture, are assumed to continue in the propagation stage while active corrosion is occurring contemporaneously. This allows the model to include the effects of changes in exposure conditions on the corrosion rate and the effects of the corrosion reactions on the transport properties of concrete. The corrosion rates are calculated by applying the finite-element solution of the Laplace equation for electrochemical potential, with appropriate boundary conditions. Because these boundary conditions are nonlinear, a nonlinear solution algorithm is used. The results of the analysis are compared with available test data, and the comparison is found to be satisfactory. (author)

  16. Steel fibre corrosion in cracks:durability of sprayed concrete

    OpenAIRE

    Nordström, Erik

    2000-01-01

    Steel fibre reinforced sprayed concrete is common practice for permanent linings in underground construction. Today there is a demand on "expected technical service life" of 120 years. Thin steel fibres could be expected to discontinue carrying load fast with a decrease of fibre diameter caused by corrosion, especially in cracks. The thesis contains results from inspections on existing sprayed concrete structures and a literature review on corrosion of steel fibres in cracked concrete. To stu...

  17. Predicting concrete corrosion of sewers using artificial neural network.

    Science.gov (United States)

    Jiang, Guangming; Keller, Jurg; Bond, Philip L; Yuan, Zhiguo

    2016-04-01

    Corrosion is often a major failure mechanism for concrete sewers and under such circumstances the sewer service life is largely determined by the progression of microbially induced concrete corrosion. The modelling of sewer processes has become possible due to the improved understanding of in-sewer transformation. Recent systematic studies about the correlation between the corrosion processes and sewer environment factors should be utilized to improve the prediction capability of service life by sewer models. This paper presents an artificial neural network (ANN)-based approach for modelling the concrete corrosion processes in sewers. The approach included predicting the time for the corrosion to initiate and then predicting the corrosion rate after the initiation period. The ANN model was trained and validated with long-term (4.5 years) corrosion data obtained in laboratory corrosion chambers, and further verified with field measurements in real sewers across Australia. The trained model estimated the corrosion initiation time and corrosion rates very close to those measured in Australian sewers. The ANN model performed better than a multiple regression model also developed on the same dataset. Additionally, the ANN model can serve as a prediction framework for sewer service life, which can be progressively improved and expanded by including corrosion rates measured in different sewer conditions. Furthermore, the proposed methodology holds promise to facilitate the construction of analytical models associated with corrosion processes of concrete sewers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Damage induced by continued corrosion in concrete repair systems

    NARCIS (Netherlands)

    Luckovic, M.; Savija, B.; Schlangen, E.

    2014-01-01

    Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. After the repair, corrosion of the steel might continue and even accelerate. While the development of the corrosion cell depends on many parameters and is difficult to control, the occurrence of

  19. The Effect of Fly Ash on the Corrosion Behaviour of Galvanised Steel Rebarsin Concrete

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.

  20. Corrosion of reinforcement bars in steel ibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe

    and the influence of steel fibres on initiation and propagation of cracks in concrete. Moreover, the impact of fibres on corrosion-induced cover cracking was covered. The impact of steel fibres on propagation of reinforcement corrosion was investigated through studies of their impact on the electrical resistivity...... of concrete, which is known to affect the corrosion process of embedded reinforcement. The work concerning the impact of steel fibres on initiation and propagation of cracks was linked to corrosion initiation and propagation of embedded reinforcement bars via additional studies. Cracks in the concrete cover...... are known to alter the ingress rate of depassivating substances and thereby influence the corrosion process. The Ph.D. study covered numerical as well as experimental studies. Electrochemically passive steel fibres are electrically isolating thus not changing the electrical resistivity of concrete, whereas...

  1. Smeared crack modelling approach for corrosion-induced concrete damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie Anusha; Michel, Alexander; Stang, Henrik

    2017-01-01

    In this paper a smeared crack modelling approach is used to simulate corrosion-induced damage in reinforced concrete. The presented modelling approach utilizes a thermal analogy to mimic the expansive nature of solid corrosion products, while taking into account the penetration of corrosion...... products into the surrounding concrete, non-uniform precipitation of corrosion products, and creep. To demonstrate the applicability of the presented modelling approach, numerical predictions in terms of corrosion-induced deformations as well as formation and propagation of micro- and macrocracks were......-induced damage phenomena in reinforced concrete. Moreover, good agreements were also found between experimental and numerical data for corrosion-induced deformations along the circumference of the reinforcement....

  2. Structural Effects of Reinforced Concrete Beam Due to Corrosion

    Science.gov (United States)

    Noh, Hamidun Mohd; Idris, Nur'ain; Noor, Nurazuwa Md; Sarpin, Norliana; Zainal, Rozlin; Kasim, Narimah

    2018-03-01

    Corrosion of steel in reinforced concrete is one of the main issues among construction stakeholders. The main consequences of steel corrosion include loss of cross section of steel area, generation of expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between the steel reinforcing bar and concrete, and deteriorating the strength of the structure. The objective of this study is to investigate the structural effects of corrosion damage on the performance of reinforced concrete beam. A series of corroded reinforced concrete beam with a corrosion rate of 0%, 20% and 40% of rebar corrosion is used in parametric study to assess the influence of different level of corrosion rate to the structural performance. As a result, the used of interface element in the finite element modelling predicted the worst case of corrosion analysis since cracks is induced and generate at this surface. On the other hand, a positive linear relationship was sketched between the increase of expansive pressure and the corrosion rate. Meanwhile, the gradient of the graph is decreased with the increase of steel bar diameter. Furthermore, the analysis shows that there is a significant effect on the load bearing capacity of the structure where the higher corrosion rate generates a higher stress concentration at the mid span of the beam. This study could predict the residual strength of reinforced concrete beam under the corrosion using the finite element analysis. The experimental validation is needed on the next stage to investigate the quantitative relation between the corrosion rate and its influence on the mechanical properties.

  3. Quality inspection of concrete

    International Nuclear Information System (INIS)

    Mellmann, G.

    1983-01-01

    The testing instruction named in the pertinent standards for concrete vary considerably. They can best be judged through comparing their operating characteristic curves. Here it is noticed for the proof of the solidity of the building, that with the compressive resistances derived from the impact test, method-related severe variations influence the evaluation of the results. In the scope of tests carried out by the Federal Institute for Material Testing, through non destructive, ultrasonic echo return measurements and impact tests as well as through combined evaluation with the aid of a multiple linear regression analysis, it could be proven that a greater confidence level can be achieved and thus a more appropriate judgement of the quality of the concrete of a building is possible. (orig.) [de

  4. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  5. Corrosion on reinforced concrete structures. An application for the intermediate level radioactive waste container

    International Nuclear Information System (INIS)

    Arva, Alejandro; Alvarez, Marta G.; Duffo, Gustavo S.

    2003-01-01

    The behavior of steel reinforcement bars (rebars) for a high performance reinforced concrete made of sulfate resistant portland cement was evaluated from the rebars corrosion point of view. The results from the present work will be used to evaluate the materials properties to be used in the construction of the intermediate level radioactive waste disposal containers. The study is carried out evaluating the incidence of chloride and sulfate ions, as well as, concrete carbonation in the rebar corrosion process. The electrochemical parameters that characterize the corrosion process (corrosion potential [E corr ], polarisation resistance [Rp] and concrete electrical resistivity [ρ]) were monitored on specially designed reinforced concrete specimens. The results up to date (about 1000 days of exposure) reveal that the concrete under study provides to the steel reinforcement bars of a passive state against corrosion under the test conditions. An increasing tendency as a function of time of ρ is observed that corroborates the continuous curing process of concrete. The chloride and carbonation diffusion coefficients were also determined, and their values are comparable with those of high quality concrete. (author)

  6. Impact of biofouling on corrosion resistance of reinforced concrete

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, B.T.; Gajendragad, M.R.; Ranganna, G.; Wagh, A.B.; Sudhakaran, T.

    the structure from deterioration; a nonuniform deposit can lead to severe localized pitting corrosion. To study this cylindrical reinforced concrete electrodes were exposed to seawater. They were periodically removed and examined for the presence of fouling...

  7. Evaluation of corrosion resistance of various concrete reinforcing materials.

    Science.gov (United States)

    2013-06-01

    The Vermont Agency of Transportation undertook a simple experiment to determine the corrosion : resistance ability of various reinforcing steels (rebar) that may be used in bridges and other concrete : structures. Eight types of rebar were used in th...

  8. Sensor Systems for Corrosion Monitoring in Concrete Structures

    Directory of Open Access Journals (Sweden)

    K.Kumar

    2006-05-01

    Full Text Available It is a need of permanently embedded corrosion monitoring devices to monitor the progress of corrosion problems on a new or existing reinforced concrete structures before embarking on repair or rehabilitation of the structures. Numerous devices are available for investigating corrosion problems, because no single technique exists which tells an engineer what he needs to know, namely how much damage there is on a structure now and how rapidly the damage will grow with time. In this investigation the studies on the sensors systems based on the measurements of half cell potential of rebars inside the concrete, resistivity of concrete, corrosion rate of rebars by eddy current measurements and sensing of chloride ions are reported. An integrated system consists of above sensors are fabricated and embedded into concrete. The response from each sensor was acquired and analyzed by NI hardware through LabVIEW software.

  9. Maintenance Planning for Chloride Initiated Corrosion in Concrete Structures

    DEFF Research Database (Denmark)

    Engelund, S.; Sørensen, John Dalsgaard

    1998-01-01

    Corrosion of the reinforcement in concrete structures can be initiated when the chloride concentration around the reinforcement exceeds a threshold value. In order to prevent the corrosion from reaching a stage where the load-bearing capacity of a given structure suffers a substantial decrease...

  10. Effect of acid corrosion on crack propagation of concrete beams

    Indian Academy of Sciences (India)

    HU SHAOWEI

    2018-03-10

    Mar 10, 2018 ... sive strength, low price, convenient construction modelling and workability, as well as corrosion ... These test results showed that the elastic modulus and fracture parameters of concrete structures reduced ... due to nonlinear characteristics of concrete materials, the classical linear elastic fracture mechanics.

  11. The anaerobic corrosion of carbon steel in concrete

    International Nuclear Information System (INIS)

    Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

    1991-01-01

    This is the final report of a 2 year programme aimed at (1) determining the rate of anaerobic corrosion of steel in concrete, (2) investigating the nature of the corrosion products formed on carbon steel embedded in cementitious material under anaerobic conditions and (3) evaluating the effect of hydrogen over-pressures on the rate of anaerobic corrosion. All experiments have been carried out at temperatures in the range 20-30 0 C, ie ambient conditions. 4 refs.; 19 figs.; 6 tabs

  12. Stochastic Models for Chloride-Initiated Corrosion in Reinforced Concrete

    DEFF Research Database (Denmark)

    Engelund, Svend; Sørensen, John Dalsgaard

    Corrosion of the reinforcement in concrete structures can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is when the chloride content around the reinforcement exceeds a threshold value. In the present paper a statistical model is developed by which...... the chloride content in a 1reinforced concrete structure can be predicted. The model parameters are estimated on the basis of measurements. The distribution of the time to initiation of corrosion is estimated by FORMISORM-analysis....

  13. Stochastic Models for Chloride-Initiated Corrosion in Reinforced Concrete

    DEFF Research Database (Denmark)

    Engelund, S.; Sørensen, John Dalsgaard

    1996-01-01

    Corrosion of the reinforcement in concrete structures can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is when the chloride content around the reinforcement exceeds a threshold value. In the present paper a statistical model is developed by which...... the chloride content in a reinforced concrete structure can be predicted. The model parameters are estimated on the basis of measurements. The distribution of the time to initiation of corrosion is estimated by FORM/SORM-analysis....

  14. Degradation of normal portland and slag cement concrete under load, due to reinforcement corrosion

    International Nuclear Information System (INIS)

    Philipose, K.E.; Beaudoin, J.J.; Feldman, R.F.

    1992-08-01

    The corrosion of reinforcement is one of the major degradation mechanisms of reinforced concrete elements. The majority of studies published on concrete-steel corrosion have been conducted on unstressed specimens. Structural concrete, however, is subjected to substantial strain near the steel reinforcing bars that resist tensile loads, which results in a system of microcracks. This report presents the initial results of an investigation to determine the effect of applied load and microcracking on the rate of ingress of chloride ion and corrosion of steel in concrete. Simply-supported concrete beam specimens were loaded to give a maximum strain of about 600 με on the tension face. Chloride ion ingress on cores taken from loaded specimens was monitored using energy-dispersive X-ray analysis techniques. Corrosion current and rate measurements using linear polarization electrochemical techniques were also obtained on the same loaded specimens. Variables investigated included two concrete types, two steel cover-depths, three applied load levels, bonded and unbonded rebars and the exposure of tension and compression beam faces to chloride solution. One concrete mixture was made with type 10 Portland cement, the other with 75% blast furnace slag, 22% type 50 cement and 3% silica fume. The rate of chloride ion ingress into reinforced concrete, and hence the time for chloride ion to reach the reinforcing steel, is shown to be dependent on applied load and the concrete quality. The dependence of corrosion process descriptors - passive layer formation, initiation period and propagation period - on the level of applied load is discussed. (Author) (6 refs., 3 tabs., 10 figs.)

  15. Lithuanian Quarry Aggregates Concrete Effects of Alkaline Corrosion Tests

    Directory of Open Access Journals (Sweden)

    Aurimas Rutkauskas

    2016-02-01

    Full Text Available Aggregate alkaline corrosion of cement in concrete is going to respond in sodium and potassium hydroxide (lye with active SiO2 found in some aggregates. During this reaction, the concrete has resulted in significant internal stresses which cause deformation of the concrete, cracking and disintegration. The reaction is slow and concrete signs of decomposition appear only after a few months or years. The study used two different aggregates quarries. Studies show that Lithuania gravel contaminated with reactive particles having amorphous silicon dioxide reacting with cement in sodium and potassium hydroxide and the resulting alkaline concrete corrosion. It was found that, according to AAR 2 large aggregates include Group II – potentially reactive because of their expansion after 14 days, higher than 0.1%.

  16. Chloride-induced corrosion of steel in cracked concrete – Part I: Experimental studies under accelerated and natural marine environments

    International Nuclear Information System (INIS)

    Otieno, M.; Beushausen, H.; Alexander, M.

    2016-01-01

    Parallel corrosion experiments were carried out for 2¼ years by exposing one half of 210 beam specimens (120 × 130 × 375 mm long) to accelerated laboratory corrosion (cyclic wetting and drying) while the other half underwent natural corrosion in a marine tidal zone. Experimental variables were crack width w cr (0, incipient crack, 0.4, 0.7 mm), cover c (20, 40 mm), binder type (PC, PC/GGBS, PC/FA) and w/b ratio (0.40, 0.55). Results show that corrosion rate (i corr ) was affected by the experimental variables in the following manner: i corr increased with increase in crack width, and decreased with increase in concrete quality and cover depth. The results also show that the corrosion performance of concretes in the field under natural corrosion cannot be inferred from its performance in the laboratory under accelerated corrosion. Other factors such as corrosion process should be taken into account.

  17. Evaluation and rehabilitation of corrosion damaged reinforced concrete structures

    International Nuclear Information System (INIS)

    Paul, I.S.

    1999-01-01

    For the last two decades, rehabilitation of corrosion damaged concrete structures has been one of the most important challenges faced by the construction industry throughout the world. The extent of the damage is significant in cold climates and also in hot and humid climates. In both cases, the corrosion is invariably initiated by ingress of salts into the concrete either from de-icing salts used on roads, or from salt-laden air, soils or ground water. However, there is a contrast in sites of distress in the two climatic regions mentioned above. In cold climates, where de-icing salts are used, the damage is generally to superstructures and is therefore visible, but in hot, humid coastal regions damage is primarily in the substructures and may not be so clearly apparent. This paper presents the corrosion mechanism in concrete deterioration, the methods of evaluation of the damaged structures, and rehabilitation strategies. A case history of a concrete rehabilitation project is included together with some lessons learned in rehabilitation of corrosion damaged structures. Recommendations are made for maintenance of concrete structures and a warning is issued that salt run-off from roads in cold climates may cause distress in below ground concrete structures, similar to structures in hot and humid climates with saline groundwater and soils. (author)

  18. Corrosion initiation and service life of concrete structures

    International Nuclear Information System (INIS)

    Byung Hwan Oh; Bong Seok Jang

    2005-01-01

    The Corrosion of steel reinforcements in concrete is of great concern in the view of safety and durability of reinforced concrete structures. The reinforced concrete structures exposed to sea environments suffer from corrosion of steel bars due to chloride ingress. The chloride penetration into concrete is influenced by many parameters such as type of cement, mixture proportions and existence of rebars. The conventional diffusion analyses have neglected the existence of steel bar in concrete. The purpose of the present paper is, therefore, to explore the effects of reinforcement on the chloride diffusion in concrete structures by incorporating realistic diffusion models. To this end, the nonlinear binding isotherm which includes the effects of cement types and mixture proportion has been introduced in the chloride diffusion analysis. The effects of reinforcements on the chloride penetration have been analyzed through finite element analysis. The present study indicates that the chlorides are accumulated in front of a reinforcing bar and the accumulation of chlorides is much more pronounced for the case of larger-size bars. The higher accumulation of chlorides at bar location causes faster corrosion of reinforcing bars. The corrosion initiation time reduces by about 30-40 percent when the existence of rebar is considered in the chloride diffusion analysis. (authors)

  19. Acoustic emission intensity analysis of corrosion in prestressed concrete piles

    Science.gov (United States)

    Vélez, William; Matta, Fabio; Ziehl, Paul

    2014-02-01

    Corrosion of steel strands in prestressed concrete (PC) bridges may lead to substantial damage or collapse well before the end of the design life. Acoustic Emission (AE) is a suitable nondestructive technique to detect and locate corrosion in reinforced and prestressed concrete, which is key to prioritize inspection and maintenance. An effective tool to analyze damage-related AE data is intensity analysis (IA), which is based on two data trends, namely Severity (average signal strength of high amplitude hits) and Historic Index (ratio of the average signal strength of the most recent hits to the average of all hits). IA criteria for corrosion assessment in PC were recently proposed based on empirical evidence from accelerated corrosion tests. In this paper, AE data from prestressed and non-prestressed concrete pile specimens exposed to salt water wet-dry cycling for over 600 days are used to analyze the relation between Severity and Historic Index and actual corrosion. Evidence of corrosion is gained from the inspection of decommissioned specimens. The selection of suitable J and K parameters for IA is discussed, and an IA chart with updated corrosion criteria for PC piles is presented.

  20. Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

    Science.gov (United States)

    Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

    2013-03-01

    Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

  1. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    OpenAIRE

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-01-01

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete u...

  2. The anaerobic corrosion of carbon steel in concrete

    International Nuclear Information System (INIS)

    Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

    1990-11-01

    The report describes the work of a two year programme investigating the anaerobic corrosion of carbon steel embedded in a range of candidate repository cements and concretes at laboratory temperatures. The factors investigated in the study were the rate of the anaerobic corrosion reaction, the effect of hydrogen overpressure on the reaction rate and the form of the corrosion product. Both electrochemical and sample weight loss corrosion rate measurements were used. The cements and concretes used were prepared both with and without small additions of chloride (2% by weight of mix water). The results indicate that the corrosion rate is low, < 1 μm/year, the effect of hydrogen overpressure is not significant over the range of pressures investigated, 1-100 atmospheres, and that the corrosion product is dependent on the cement used to cast the samples. Magnetite was identified in the case of blast furnace slag replacement cements but for pulverised fuel ash and ordinary Portland cements no corrosion product was evident either from X-ray diffraction or laser Raman measurements. Further work is presently underway to investigate the effects of elevated temperatures and chloride levels on the anaerobic corrosion reaction and the rate of hydrogen gas production. (author)

  3. Corrosion of Modified Concrete with Sugar Cane Bagasse Ash

    Directory of Open Access Journals (Sweden)

    R. E. Núñez-Jaquez

    2012-01-01

    Full Text Available Concrete is a porous material and the ingress of water, oxygen, and aggressive ions, such as chlorides, can cause the passive layer on reinforced steel to break down. Additives, such as fly ash, microsilica, rice husk ash, and cane sugar bagasse ash, have a size breakdown that allows the reduction of concrete pore size and, consequently, may reduce the corrosion process. The objective of this work is to determine the corrosion rate of steel in reinforced concrete by the addition of 20% sugar cane bagasse ash by weight of cement. Six prismatic specimens (7×7×10 cm with an embedded steel rod were prepared. Three contained 20% sugar cane bagasse ash by weight of cement and the other three did not. All specimens were placed in a 3.5% NaCl solution and the corrosion rate was determined using polarization resistance. The results showed that reinforced concrete containing sugar cane bagasse ash has the lowest corrosion rates in comparison to reinforced concrete without the additive.

  4. The Effect of Corrosive Environment on Geopolymer Concrete Tensile Strength

    Directory of Open Access Journals (Sweden)

    Bayuaji Ridho

    2017-01-01

    Full Text Available This study has the purpose to explore the potential of geopolymer concrete tensile strength in particular on the effects of corrosive environments. Geopolymer concrete, concrete technology used no OPC that has advantages, one of which is durability, especially for corrosive seawater environment. In addition, geopolymer concrete with polymerization mechanism does not require large energy consumption or an environmentally friendly concept. Geopolymer concrete in this study is using a type C fly ash from PT. International Power Mitsui Operation & Maintenence Indonesia (IPMOMI Paiton. The type of alkaline activator used NaOH (14 molar and Na2SiO3. Coarse and fine aggregate used are local aggregate. Geopolymer concrete molded test specimen with dimensions of (10 × 20 cm cylinder, further heating and without heating, then maintained at room temperature and seawater up to 28 days. Then to determine the mechanical properties, the tensile strength testing is done with reference. This result of study indicates the curing of geopolymer concrete at 60 ° C for 24 hours to raise the tensile strength of geopolymer concrete.

  5. EMBEDDED CAPACITOR SENSOR FOR MONITORING CORROSION OF REINFORCEMENT IN CONCRETE

    Directory of Open Access Journals (Sweden)

    SITI FATIMAH ABDUL RAHMAN

    2012-04-01

    Full Text Available Corrosion of reinforcement can affect durability and integrity of reinforced concrete structures. Repair cost for a badly corroded structure can be very costly and time consuming. In this paper, several capacitor sensors were developed to monitor corrosion potential of reinforcement in concrete. The impedance capacitive of sensors was tested in various acid and alkali solutions using Agilent 4284A Precision LCR meter. The other sensors were tied to reinforcements and embedded in concrete specimen contaminated with 5% chloride to measure corrosion potential. The specimens were exposed to the corrosion chamber and indoor environments. From the research, it was found that the sensor can measure the impedance capacitive at different frequencies in the aggressive solutions. Besides, it was observed that the patterns of corrosion potential shown by the embedded sensors were similar to the SRI sensor. The output values from embedded sensor are in a range of recommendation by the ASTM-C876. Eventually, the bars were found corroded from the broken specimens that confirmed the detection of corrosion activities as recorded by the sensors.

  6. Early corrosion monitoring of prestressed concrete piles using acoustic emission

    Science.gov (United States)

    Vélez, William; Matta, Fabio; Ziehl, Paul H.

    2013-04-01

    The depassivation and corrosion of bonded prestressing steel strands in concrete bridge members may lead to major damage or collapse before visual inspections uncover evident signs of damage, and well before the end of the design life. Recognizing corrosion in its early stage is desirable to plan and prioritize remediation strategies. The Acoustic Emission (AE) technique is a rational means to develop structural health monitoring and prognosis systems for the early detection and location of corrosion in concrete. Compelling features are the sensitivity to events related to micro- and macrodamage, non-intrusiveness, and suitability for remote and wireless applications. There is little understanding of the correlation between AE and the morphology and extent of early damage on the steel surface. In this paper, the evidence collected from prestressed concrete (PC) specimens that are exposed to salt water is discussed vis-à-vis AE data from continuous monitoring. The specimens consist of PC strips that are subjected to wet/dry salt water cycles, representing portions of bridge piles that are exposed to tidal action. Evidence collected from the specimens includes: (a) values of half-cell potential and linear polarization resistance to recognize active corrosion in its early stage; and (b) scanning electron microscopy micrographs of steel areas from two specimens that were decommissioned once the electrochemical measurements indicated a high probability of active corrosion. These results are used to evaluate the AE activity resulting from early corrosion.

  7. The anaerobic corrosion of carbon steel in concrete

    International Nuclear Information System (INIS)

    Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

    1990-11-01

    The report describes the work of a two year programme investigating the anaerobic corrosion of carbon steel embedded in a range of candidate repository cements and concretes at laboratory ambient temperatures. The factors investigated in the study were the rate of the anaerobic corrosion reaction, the effect of hydrogen overpressure on the reaction rate and the form of the corrosion product. Both electrochemical and sample weight loss corrosion rate measurements were used. The cements and concretes used were prepared both with and without small additions of chloride (2% by weight of mix water). The results indicate that the corrosion rate is low, <1 μm/year, the effect of hydrogen overpressure is not significant over the range of pressures investigated, 1-100 atmospheres, and that the corrosion product is dependent on the cement used to cast the samples. Magnetite was identified in the case of blast furnace slag replacement cements but for pulverised fuel ash and ordinary Portland cements no corrosion product was evident either from X-ray diffraction or laser Raman measurements. (Author)

  8. Durability evaluation method on rebar corrosion of reinforced concrete

    International Nuclear Information System (INIS)

    Kitsutaka, Yoshinori

    2013-01-01

    In this paper, method on the durability evaluation in nuclear power plant concrete structures was investigated. In view of the importance of evaluating the degree of deterioration of reinforced concrete structures, relationships should be formulated among the number of years elapsed, t, the amount of action of a deteriorative factor, F, the degree of material deterioration, D, and the performance of the structure, P. Evaluation by PDFt diagrams combining these relationships may be effective. A detailed procedure of durability evaluation for a reinforced concrete structure using PDFt concept is presented for the deterioration of rebar corrosion caused by neutralization and penetration of salinity by referring to the recent papers. (author)

  9. FORMULATION OF MATHEMATICAL PROBLEM DESCRIBING PHYSICAL AND CHEMICAL PROCESSES AT CONCRETE CORROSION

    Directory of Open Access Journals (Sweden)

    Sergey V. Fedosov

    2017-06-01

    Full Text Available The article deals with the relevance of new scientific research focused on modeling of physical and chemical processes occurring in the cement concrete at their exploitation. The basic types of concrete corrosion are described. The problem of mass transfer processes in a flat reinforced concrete wall at concrete corrosion of the first and the second types has been mathematically formulated.

  10. Initiation and propagation of rebar corrosion in carbonated and cracked concrete

    International Nuclear Information System (INIS)

    Ghantous, Rita-Maria

    2016-01-01

    the influence of the steel/binder interface quality on the corrosion products layer distribution. a decrease in the iron mass dissolution rate is a common observation for all the above mentioned conditions. This traduces the decrease of corrosion kinetics with time. Additionally, when performed, free corrosion potentials drops down at the beginning of the corrosion test then increases to reach the potential of a passivated rebar. Moreover, the corrosion products fill the de-passivated (carbonated) area and remain localized around the crack. all these observations lead to predict that carbonation-induced corrosion deep in the crack is not the most harmful parameter for the structure sustainability due to a possible rebar re-passivation. Additionally, the position of the rebar impacts significantly the corrosion process. The highest rebar with respect to casting direction shows the highest corrosion thickness on its lower part due to the voids and defects induced by the materials settlement and bleeding (Top bar effect). Finally, it is deduced that the corrosion conditions have an influence on the crystallinity state of the corrosion products. Corrosion products with a good crystallinity state are detected for the conditions having the lowest saturation degree (40 C, 3 min rain, natural environment). This is important to note because the mechanical resistance of corrosion products is dependent from their crystallinity. Based on these conclusions, a phenomenological corrosion model is proposed for steels located in cracked and carbonated concrete in this study based on the obtained results and on the literature review. (author) [fr

  11. Corrosion of steel in locally deficient concrete.

    Science.gov (United States)

    2009-02-28

    This investigation confirmed prior noted trends of extensive preferential chloride intrusion at preexisitng cracks in a majority of cases of substructure members in Florida bridges built with low permeability conventional concrete.

  12. Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

    Directory of Open Access Journals (Sweden)

    Mladena Luković

    2017-01-01

    Full Text Available Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion cell is difficult to control, the damage can be possibly delayed and controlled by use of a suitable repair material. The lattice fracture model is used in this paper to investigate the performance of strain hardening cementitious composite (SHCC in concrete repair systems exposed to ongoing corrosion. Numerical results were verified by experimental tests when SHCC, nonreinforced material (repair mortar, and commercial repair mortar are used as repair materials. In experiments, reinforcement bars (surrounded by a repair material were exposed to accelerated corrosion tests. The influence of the substrate surface preparation, the type of repair material, the interface, and the substrate strength on the resulting damage and failure mode of repair systems are discussed. In general, SHCC repair enables distributed cracking with small crack widths, up to several times smaller compared to repair mortar. Furthermore, more warning signs prior to the final failure are present in the SHCC repair system.

  13. Quality assurance of polymer concrete

    International Nuclear Information System (INIS)

    Schulz, H.

    1984-01-01

    With polymer concrete, a whole range of organisational and functional measures have to be met in order to assure the required quality with an economic expenditure. Quality assurance begins in the design and does not end in the production, rather includes all fields of the enterprise. The following deals with a particular range of the total complex, the inspection methods for assuring the quality of machine components of polymer concrete, particularly machine tool bases, this being through the control of the raw material, the production and the finished product. (orig.) [de

  14. Full surface inspection methods regarding reinforcement corrosion of concrete structures

    International Nuclear Information System (INIS)

    Reichling, K.; Raupach, M.; Broomfield, J.; Gulikers, J.; L'Hostis, Valerie

    2013-01-01

    For reinforced concrete structures a localisation of all significant critical areas can only be done by a full surface inspection. The economic advantages are obvious: uncritical areas have not to be repaired expensively.The first step of the assessment should always be a visual inspection. The range of deterioration causes can be limited and the degree of deterioration may be estimated roughly. The inspection program can be adjusted to the requirements. By means of a full surface potential mapping areas with a high risk for chloride induced reinforcement corrosion can be localised, although no deteriorations are visually detectable at the concrete surface. In combination with concrete cover depth and resistivity measurements areas with corrosion promoting exposure conditions can be localised even if the reinforcement is not yet de-passivated. The following publication gives an overview about the essential full surface investigation methods to localise critical areas regarding corrosion of steel in concrete. The selection of methods is based on the inspection procedure given in reference 2. (authors)

  15. New Findings in Hydrogen Sulfide Related Corrosion of Concrete Sewers

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Hvitved-Jacobsen, Thorkild

    2009-01-01

    This paper summarizes major findings of a long-term study of hydrogen sulfide gas (H2S) adsorption and oxidation on concrete and plastic sewer pipe surfaces. The processes have been studied using a pilot-scale setup designed to replicate conditions in a gravity sewer located downstream of a force...... main. H2S related concrete corrosion and odor is often observed at such locations. The experiments showed that the rate of H2S oxidation was significantly faster on concrete pipe surfaces than on plastic pipe surfaces. Steady state calculations based on the kinetic data demonstrated that the gas phase...... H2S concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henrys law. In plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on these surfaces. Finally...

  16. A new corrosion sensor to determine the start and development of embedded rebar corrosion process at coastal concrete.

    Science.gov (United States)

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-09-30

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

  17. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    Directory of Open Access Journals (Sweden)

    Weiliang Jin

    2013-09-01

    Full Text Available The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

  18. Quantifying movements of corrosion products in reinforced concrete using x-ray attenuation measurements

    DEFF Research Database (Denmark)

    Pease, Bradley Justin; Michel, Alexander; Stang, Henrik

    2011-01-01

    Corrosion of steel reinforcement, embedded in concrete, may substantially degrade concrete structures due to the expansive nature of corrosion products. Expansion of corrosion products cause tensile stresses to develop and cracks to form in concrete. Extensive research has focused on corrosion...... of corrosion products move into the concrete without generating tensile stresses and cracks in the concrete. Typically, corrosion products are thought to occupy pores, interfacial defects, and/or air voids located near the concrete-steel interface and stresses develop only after filling of these pores. Further....... X-ray attenuation measurements are also capable of detecting cracks. Therefore, this approach provides a direct measurement of the amount and location of reinforcement corrosion products required to induce cracking. Results of a parametric investigation on the impact of water-to-cement ratio (0...

  19. Interferences in Prompt {gamma} Analysis of corrosive contaminants in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, KFUPM Box 1815, Dhahran-31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, KFUPM Box 1815, Dhahran-31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2006-12-21

    An accelerator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup has been developed to measure the concentration of corrosive chloride and sulfate contaminants in concrete. The Minimum Detectable Concentration (MDC) limit of chlorine and sulfur in the concrete depends upon the {gamma}-ray used for elemental analysis. For more interfering {gamma}-rays, the MDC limit is higher than that for less interfering {gamma}-rays. The MDC limit of sulfur in concrete measured for the KFUPM PGNAA setup was calculated to be 0.60{+-}0.19 wt%. The MDC limit is equal to the upper limit of sulfur concentration in concrete set by the British Standards. The MDC limit of chlorine in concrete for the KFUPM PGNAA setup, which was calculated for less interfering 1.165 MeV {gamma}-rays, was found to be 0.075{+-}0.025 wt%. The lower limits of the MDC of chlorine in concrete was 73% higher than the limit set by American Concrete Institute. The limit of the MDC can be improved to the desired standard by increasing the intensity of neutron source. For moreinterfering 5.715 and 6.110 MeV chlorine {gamma}-rays the MDC limit was found to be 2-3 times larger than that of 1.165 MeV {gamma}-rays. When normalized to the same intensity of the neutron source, the MDC limits of chlorine and sulfur in concrete from the KFUPM PGNAA setup are better than MDC limits of chlorine in concrete obtained with the {sup 241}Am-Be source-based PGNAA setup. This study has shown that an accelerator-based PGNAA setup can be used in chlorine and sulfur analysis of concrete samples.

  20. Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

    Directory of Open Access Journals (Sweden)

    P. T. C. Mendes

    Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

  1. Measurement of reinforcement corrosion in concrete structures. Betonirakenteiden raudoituksen korroosion tutkiminen

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, A

    1992-03-01

    Ageing and aggressive enviromental conditions of concrete structures will result in deterioration of concrete and corrosion of steel in concrete. Corrosion of steel will in time result in the end of the service life or expensive renovations, unless corrosion of steel is noticed and renovated in time. Corrosion of steel in concrete can be found out by the present corrosion measurement methods, so that renovation can be started in right time. The report presents mainly on the basis of the literature references the following corrosion measurement methods: polarisation resistance, AC-impedance, electrical resistance probe, electrochemical noice and half-cell potential mapping. The half-cell potential mapping will be presented more precisely than the other corrosion measurement methods, for the potential mapping is the most used method. Concrete and Soils Laboratory of Imatran Voima Oy uses in the measurement of reinforcement corrosion the English, eight channel potential measuring equipment.

  2. Measurement of reinforcement corrosion in concrete structures; Betonirakenteiden raudoituksen korroosion tutkiminen

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, A

    1992-03-01

    Ageing and aggressive enviromental conditions of concrete structures will result in deterioration of concrete and corrosion of steel in concrete. Corrosion of steel will in time result in the end of the service life or expensive renovations, unless corrosion of steel is noticed and renovated in time. Corrosion of steel in concrete can be found out by the present corrosion measurement methods, so that renovation can be started in right time. The report presents mainly on the basis of the literature references the following corrosion measurement methods: polarisation resistance, AC-impedance, electrical resistance probe, electrochemical noice and half-cell potential mapping. The half-cell potential mapping will be presented more precisely than the other corrosion measurement methods, for the potential mapping is the most used method. Concrete and Soils Laboratory of Imatran Voima Oy uses in the measurement of reinforcement corrosion the English, eight channel potential measuring equipment.

  3. Advances in concrete materials for sewer systems affected by microbial induced concrete corrosion: A review.

    Science.gov (United States)

    Grengg, Cyrill; Mittermayr, Florian; Ukrainczyk, Neven; Koraimann, Günther; Kienesberger, Sabine; Dietzel, Martin

    2018-05-01

    Microbial induced concrete corrosion (MICC) is recognized as one of the main degradation mechanisms of subsurface infrastructure worldwide, raising the demand for sustainable construction materials in corrosive environments. This review aims to summarize the key research progress acquired during the last decade regarding the understanding of MICC reaction mechanisms and the development of durable materials from an interdisciplinary perspective. Special focus was laid on aspects governing concrete - micoorganisms interaction since being the central process steering biogenic acid corrosion. The insufficient knowledge regarding the latter is proposed as a central reason for insufficient progress in tailored material development for aggressive wastewater systems. To date no cement-based material exists, suitable to withstand the aggressive conditions related to MICC over its entire service life. Research is in particular needed on the impact of physiochemical material parameters on microbial community structure, growth characteristics and limitations within individual concrete speciation. Herein an interdisciplinary approach is presented by combining results from material sciences, microbiology, mineralogy and hydrochemistry to stimulate the development of novel and sustainable materials and mitigation strategies for MICC. For instance, the application of antibacteriostatic agents is introduced as an effective instrument to limit microbial growth on concrete surfaces in aggressive sewer environments. Additionally, geopolymer concretes are introduced as highly resistent in acid environments, thus representing a possible green alternative to conventional cement-based construction materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Corrosion resistance of steel fibre reinforced concrete - A literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2017-01-01

    Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of civil infrastructure. However, there are inconsistencies among international standards and guidelines regarding the consideration of carbon-steel fibres for the structural verification of SFRC exposed...... of the mechanisms governing the corrosion of carbon-steel fibres in cracks and its effects on the fracture behaviour of SFRC are not fully understood....

  5. Influence of cracks on rebar corrosion in carbonated concretes

    International Nuclear Information System (INIS)

    Ghantous, R.M.; L'Hostis, V.; Poyet, S.; Francois, R.; Tran, N.C.

    2015-01-01

    This paper presents an experimental program allowing the determination of the effect of pre-cracks and their orientations on both initiation and propagation of reinforcement steel corrosion due to carbonation in different environmental conditions, in order to propose an operational model allowing the evaluation of the kinetic of corrosion of the reinforcement steel in cooling towers of nuclear power plants. The cracking mode that generates cracks which are representative of those appearing on the cooling towers is a three-point bending test performed on prismatic samples of 7*7*28 cm 3 size with 6 mm steel bars. The length of damaged steel / concrete interface, which appears following a three-point bending test, is then quantified. This length could be determining in the initiation and the propagation of corrosion. Results show that this length is dependent on the residual crack opening and that the length of damaged interface in its lower part is larger than that on the upper part due to the Top Bar effect. After cracking, the samples will be exposed to carbon dioxide to ensure carbonation of the steel bar localized at the bottom of the crack and the concrete/steel interface, damaged by the load applied during the three-point bending test. After carbonation of the interface, samples will be submitted to corrosion in different environmental conditions whose effect on the kinetics of corrosion will be determined. The work done so far permits the definition of the cracking protocol (three points bending) that allows obtaining cracks which are representative of those existing on cooling towers. Moreover, the length of steel/concrete damaged interface with respect to crack opening is quantified. It was found that this length is proportional to the crack opening. In addition, it was shown that the Top Bar effect increases the damaged interface length at the lower part of steel bars

  6. Influence of reactive fillers on concrete corrosion resistance

    Science.gov (United States)

    Rakhimbayev, Sh M.; Tolypina, N. M.; Khakhaleva, E. N.

    2018-03-01

    Contact surfaces represent the weakest link in a conglomerate structure of materials. They ensure the diffusion of aggressive agents inside the material. To reduce the conductivity of contact surfaces it is advisable to use reactive fillers, which interact with cement matrix via certain mechanisms, which in turn, reduces the permeability of the contact layer and fosters durability of products. The interaction of reactive fillers with calcium hydroxide of a concrete liquid phase in a contact area leads to the formation of hydrated calcium silicates of a tobermorite group. Such compounds, being settled in pores and capillaries of a product, colmatage and clog them to some extent thus leading to diffusion delay (inhibition) with regard to aggressive components of external media inside porous material, which in turn inhibits the corrosion rate. The authors studied and compared the corrosion of cement concrete with a standard filler (quartz sand) and a reactive filler (perlite and urtit). The experiments confirmed the positive influence of active fillers on concrete corrosion resistance.

  7. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    KAUST Repository

    Serdar, Marijana

    2015-05-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  8. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    KAUST Repository

    Serdar, Marijana; Meral, Cagla; Kunz, Martin; Bjegovic, Dubravka; Wenk, Hans-Rudolf; Monteiro, Paulo J.M.

    2015-01-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  9. Corrosion rate of steel in concrete - Evaluation of confinement techniques for on-site corrosion rate

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica; Elsener, Bernhard

    2009-01-01

    Earlier on-site investigations and laboratory studies have shown that varying corrosion rates are obtained when different commercially available instruments are used. The different confinement techniques, rather than the different electrochemical techniques used in the instruments, are considered...... to be the main reason for the discrepancies. This paper presents a method for the quantitative assessment of confinement techniques based on monitoring the operation of the corrosion rate instrument and the current distribution between the electrode assembly on the concrete surface and a segmented reinforcement...... bar embedded in the concrete. The applicability of the method was demonstrated on two commercially available corrosion rate instruments based on different confinement techniques. The method provided an explanation of the differences in performance of the two instruments. Correlated measurements...

  10. Corrosion of steel tendons used in prestressed concrete pressure vessels

    International Nuclear Information System (INIS)

    Griess, J.C.; Naus, D.J.

    The purpose of this investigation was to determine the corrosion behavior of a high strength steel (ASTM A416-74 grade 270), typical of those used as tensioning tendons in prestressed concrete pressure vessels, in several corrosive environments and to demonstrate the protection afforded by coating the steel with either of two commercial petroleum-base greases or Portland Cement grout. In addition, the few reported incidents of prestressing steel failures in concrete pressure vessels used for containment of nuclear reactors are reviewed. The susceptibility of the steel to stress corrosion cracking and hydrogen embrittlement and its general corrosion rate were determined in several salt solutions. Wires coated with the greases and grout were soaked for long periods in the same solutions and changes in their mechanical properties were subsequently determined. All three coatings appeared to give essentially complete protection but small flaws in the grease coatings were detrimental; flaws or cracks less than 1 mm wide in the grout were without effect

  11. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Serdar, Marijana [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Meral, Cagla [Middle East Technical University, Department of Civil Engineering, Ankara (Turkey); Kunz, Martin [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Bjegovic, Dubravka [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Wenk, Hans-Rudolf [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM.

  12. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    International Nuclear Information System (INIS)

    Serdar, Marijana; Meral, Cagla; Kunz, Martin; Bjegovic, Dubravka; Wenk, Hans-Rudolf; Monteiro, Paulo J.M.

    2015-01-01

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM

  13. Reinforcement steel corrosion in passive state and by carbonation: Consideration of galvanic currents and interface steel - concrete defaults

    International Nuclear Information System (INIS)

    Nasser, A.

    2010-01-01

    This thesis aims to study the durability of nuclear waste deep storage structures. The work carried out is essentially an experimental study, and focuses on the corrosion of steel in the passive state with aerated or non-aerated conditions on the one hand, and the corrosion of steel in carbonated concrete during the propagation phase on the other hand. Indeed, the pore solution of concrete in contact with the metal is alkaline (pH between 12 and 13). Under these conditions, steel reinforced concrete remains passive by forming a stable and protective oxide layer (corrosion of steel in the passive state). This passive layer limits the steel corrosion rate at very low values (negligible on a short life time) but not null. For the nuclear waste storage structures due to a very long life time (up to several hundred years), this low corrosion rate can become a risk. Therefore, it is necessary to study the evolution of the oxide layer growth over time. The objectives of the thesis are to study the influence of the steel-concrete interface quality on reinforcement corrosion in passive and active state, and the possible occurrence of galvanic corrosion currents between different reinforcement steel areas. (author)

  14. Integrated modelling of corrosion-induced deterioration in rein-forced concrete structures

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, M.R.; Stang, Henrik

    2013-01-01

    at the reinforcement surface, a FEM based me-chanical model was used to simulate corrosion-induced concrete damage. Both FEM models were fully coupled, i.e. information, such as corrosion current density, dam-age state of concrete cover, etc., were constantly exchanged between the models. To demonstrate the potential......An integrated finite element based modelling approach is presented, which allows for fully coupled simulation of reinforcement corrosion and corrosion-induced concrete damage. While a finite element method (FEM) based corrosion model was used to describe electrochemical processes...... use of the modelling approach, a numerical example is presented which illustrates full coupling of formation of corrosion cells, propagation of corrosion, and subsequent development of corrosion-induced concrete damage....

  15. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II : Properties of Steel Surface Layers

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

  16. Corrosion of steel in cracked concrete : Chloride microanalysis and service life predictions

    NARCIS (Netherlands)

    Pacheco Farias, J.

    2015-01-01

    Reinforcement corrosion is frequently considered as the predominant degradation mechanism affecting reinforced concrete structures. Reinforced concrete structures are commonly subject to harsh environmental and loading conditions in which aggressive species can penetrate. Chlorides, present in

  17. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    International Nuclear Information System (INIS)

    Khan, Inamullah; François, Raoul; Castel, Arnaud

    2014-01-01

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied

  18. Quantitative estimation on delaying of onset of corrosion of rebar in surface treated concrete using sealers

    Directory of Open Access Journals (Sweden)

    A. Sivasankar

    2013-12-01

    Full Text Available Surface treatment on the concrete surface using sealers reduces the rate of permeability of chloride and moisture through the concrete. The delaying of onset of corrosion is evaluated for surface treated and untreated concrete using electrochemical techniques. After conducting rapid chloride permeability test (RCPT, using Nernst–Plank equation, the diffusion coefficient of chloride (Deff is calculated. Substituting threshold chloride concentration of rebar (Cth from cyclic polarization test in the ficks second law, the time to initiation of corrosion (Ti is arrived. From the results it is found that the treated concrete with alkyltrialkoxy silane sealer delays the onset of corrosion by four times than that of untreated concrete.

  19. Experimental investigation of the relation between damage at the concrete-steel interface and initiation of reinforcement corrosion in plain and fibre reinforced concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Solgaard, Anders Ole Stubbe; Pease, Bradley Justin

    2013-01-01

    Cracks in covering concrete are known to hasten initiation of steel corrosion in reinforced concrete structures. To minimise the impact of cracks on the deterioration of reinforced concrete structures, current approaches in (inter)national design codes often limit the concrete surface crack width....... Recent investigations however, indicate that the concrete-reinforcement interfacial condition is a more fundamental criterion related to reinforcement corrosion. This work investigates the relation between macroscopic damage at the concrete-steel interface and corrosion initiation of reinforcement...... embedded in plain and fibre reinforced concrete. Comparisons of experimental and numerical results indicate a strong correlation between corrosion initiation and interfacial condition....

  20. Effect Of Age And Concrete Cover Thickness On Steel Reinforcement Corrosion At Splash Zone In Reinforced Concrete Hydraulic Structures

    Directory of Open Access Journals (Sweden)

    Nada M. Al- Galawi

    2015-08-01

    Full Text Available Corrosion of reinforcing steel bars in reinforced concrete is considered as one of the biggest problems that face countries overlooking to the Arabian Gulf including Iraq. The research aims to study the effect of the corrosion of steel bars in concrete structures that are exposed to wetting and drying via waves. Reinforced concrete samples were exposed to marine simulated environment for 90 days using prepared system for this purpose. At the end of exposure period polarization test was implemented to measure the actual corrosion rate in each sample. After that the corrosion process was accelerated using impressed current technique by applying a constant electric current DC to the reinforcing bars. Depending on the corrosion current in natural conditions which was measured in polarization test periods of exposing samples to accelerated corrosion current so as to maintain virtual exposure ages of 5 and 25 years of exposure to natural corrosion were calculated. The results showed a remarkable increase in the corrosion current of steel bars in samples that had lower concrete cover thickness. The increase in the cover thickness from 20mm to 40 and 65 mm had a significant effect on reducing the corrosion current at the age of 90 days to about 70 of its original value in both cases. At the virtual exposure age of 5 years the reduction percentage in the corrosion current resulted from increasing cover thickness from 20mm to 40 and 65 mm were 43 and 79 respectively.

  1. Corrosion resistance of steel fibre reinforced concrete – a literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2016-01-01

    Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding...... the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing...... the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated...

  2. Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuhui [College of Civil Engineering and Mechanics, Xiangtan University, 411105 Xiangtan (China); School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Wang, Lei, E-mail: leiwlei@hotmail.com [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Zhang, Jianren; Ma, Yafei [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Liu, Yongming [School for Engineering of Matter, Transport and Energy, Arizona State University, 85281 Tempe, AZ (United States)

    2017-03-15

    Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

  3. Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

    International Nuclear Information System (INIS)

    Zhang, Xuhui; Wang, Lei; Zhang, Jianren; Ma, Yafei; Liu, Yongming

    2017-01-01

    Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

  4. Corrosion and protection in reinforced concrete : Pulse cathodic protection: an improved cost-effective alternative

    NARCIS (Netherlands)

    Koleva, D.A.

    2007-01-01

    Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved cost-effective alternative. The aim of the research project was to study the possibilities for establishing a new or improved electrochemical method for corrosion prevention/protection for reinforced concrete.

  5. Natural Corrosion Inhibitors for Steel Reinforcement in Concrete — a Review

    Science.gov (United States)

    Raja, Pandian Bothi; Ghoreishiamiri, Seyedmojtaba; Ismail, Mohammad

    2015-04-01

    Reinforced concrete is one of the widely used construction materials for bridges, buildings, platforms and tunnels. Though reinforced concrete is capable of withstanding a large range of severe environments including marine, industrial and alpine conditions, there are still a large number of failures in concrete structures for many reasons. Either carbonation or chloride attack is the main culprit which is due to depassivation of reinforced steel and subsequently leads to rapid steel corrosion. Among many corrosion prevention measures, application of corrosion inhibitors play a vital role in metal protection. Numerous range of corrosion inhibitors were reported for concrete protection that were also used commercially in industries. This review summarizes the application of natural products as corrosion inhibitors for concrete protection and also scrutinizes various factors influencing its applicability.

  6. FEM Modelling of the Evolution of Corrosion Cracks in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion of the concr......Corrosion cracks are caused by the increasing volume of corrosion products during the corrosion of the reinforcement. After corrosion initiation the rust products from the corroded reinforcement will initially fill the porous zone near the reinforcement and the result in an expansion...... of the concrete near the reinforcement. Tensile stresses are then initiated in the concrete. With increasing corrosion, the tensile stresses will at a certain time reach a critical value and cracks will be developed. The increase of the crack with after formation of the initial crack is the subject of this paper...

  7. On the application of thermodynamics of corrosion for service life design of concrete structures

    DEFF Research Database (Denmark)

    Küter, Andre; Geiker, Mette Rica; Møller, Per

    2010-01-01

    There are unexploited possibilities in the application of thermodynamics of corrosion for service life design (SLD) of concrete structures. Thermodynamics provides means for insightful descriptions of corrosion mechanisms and of corrosion protection mechanisms. Strategies for corrosion protection...... of the application of thermodynamics for SLD and gives examples of two applications: description of corrosion processes and design of countermeasures. Emphasis is set on chloride induced corrosion....... can be based on thermodynamically consistent corrosion mechanisms and evaluation of existing and design of new countermeasures can be performed using thermodynamics. Similarly, materials concepts for embedded electrodes can be designed using thermodynamics. The present paper provides a brief outline...

  8. Multi-physical and multi-scale deterioration modelling of re-inforced concrete: modelling corrosion-induced concrete damage

    DEFF Research Database (Denmark)

    Michel, Alexander; Lepech, Michael; Stang, Henrik

    2016-01-01

    for the discretization of the concrete domain. To model the expansive nature of solid corrosion products, a thermal analogy is used. The modelling approach further accounts for the penetration of solid corrosion products into the available pore space of the surrounding cementitious materials and non-uniform distribution...

  9. Electrochemical techniques to detect corrosion in concrete structures in nuclear installations - Technical note

    International Nuclear Information System (INIS)

    2002-01-01

    The mechanism of corrosion in aqueous media is of electrochemical nature. This means that the oxidation of the metal is counterbalanced by the reduction of another substance in another region of the metallic surface. Therefore, zones (anodes and cathodes) with different electrochemical potential, develop. In the case of concrete the electrolyte is constituted by the pore solution, which is very alkaline. This pore solution is formed by mainly a mixture of KOH and NaOH presenting pH values ranging between 12.6-14. The solution is saturated in Ca(OH) 2 . Steel embedded in concrete is naturally protected by this high alkalinity and by the barrier effect of the cover itself. The two main causes of electrochemical corrosion are carbonation and the presence of chlorides. Carbonation usually induces a generalized corrosion while chloride will lead into pitting or localized attack. The corrosion can be easily recognized by the rust presence on the rebar and by the appearance of cracks running parallel to the rebars. The objective of this report is to describe the electrochemical non-destructive techniques that can be used in real size reinforced concrete structures to assess the corrosion condition of their reinforcement. These techniques can be used indistinctly in conventional civil engineering structures or in those of nuclear installations. Electrochemical techniques are used to detect electrochemical corrosion activity of metallic reinforcements. They cannot quantify stress corrosion cracking or hydrogen embrittlement although may give some qualitative information about them. The aims of their applications may be one of the following circumstances: 1. Quality control of new constructions; 2. Condition evaluation of existing structures for: - Identification of steel de-passivation, - Detecting corroding areas for rehabilitation purposes, - Calculation of residual load-bearing capacity of the structure, - Prediction of the damage evolution, - Determination of the

  10. Corrosion Measurements in Reinforced Fly Ash Concrete Containing Steel Fibres Using Strain Gauge Technique

    Directory of Open Access Journals (Sweden)

    V. M. Sounthararajan

    2013-01-01

    Full Text Available Corrosion of steel bars in concrete is a serious problem leading to phenomenal volume expansion and thereby leading to cover concrete spalling. It is well known that the reinforced concrete structures subjected to chloride attack during its service life cause these detrimental effects. The early detection of this damage potential can extend the service life of concrete. This study reports the comprehensive experimental studies conducted on the identification of corrosion mechanism in different types of reinforced concrete containing class-F fly ash and hooked steel fibres. Fly ash replaced concrete mixes were prepared with 25% and 50% fly ash containing steel fibres at 0.5%, 1.0%, and 1.5% by volume fraction. Corrosion process was investigated in an embedded steel bar (8 mm diameter reinforced in concrete by passing an impressed current in sodium chloride solution. Strain gauge attached to the rebars was monitored for electrical measurements using strain conditioner. Strain gauge readings observed during the corrosion process exhibited the volume changes of the reinforcement embedded inside the concrete. The corrosion potential of different steel fibre reinforced concrete mixes with fly ash addition showed higher resistance towards the corrosion initiation.

  11. Prediction of Corrosion Resistance of Concrete Containing Natural Pozzolan from Compressive Strength

    Science.gov (United States)

    al-Swaidani, A. M.; Ismat, R.; Diyab, M. E.; Aliyan, S. D.

    2015-11-01

    A lot of Reinforced Concrete (RC) structures in Syria have suffered from reinforcement corrosion which shortened significantly their service lives. Probably, one of the most effective approaches to make concrete structures more durable and concrete industry on the whole - more sustainable is to substitute pozzolan for a portion of Portland cement (PC). Syria is relatively rich in natural pozzolan. In the study, in order to predict the corrosion resistance from compressive strength, concrete specimens were produced with seven cement types: one plain Portland cement (control) and six natural pozzolan-based cements with replacement levels ranging from 10 to 35%. The development of the compressive strengths of concrete cube specimens with curing time has been investigated. Chloride penetrability has also been evaluated for all concrete mixes after three curing times of 7, 28 and 90 days. The effect on resistance of concrete against damage caused by corrosion of the embedded reinforcing steel has been investigated using an accelerated corrosion test by impressing a constant anodic potential for 7, 28 and 90 days curing. Test results have been statistically analysed and correlation equations relating compressive strength and corrosion performance have been developed. Significant correlations have been noted between the compressive strength and both rapid chloride penetrability and corrosion initiation times. So, this prediction could be reliable in concrete mix design when using natural pozzolan as cement replacement.

  12. Monitoring the corrosion process of reinforced concrete using BOTDA and FBG sensors.

    Science.gov (United States)

    Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

    2015-04-15

    Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions.

  13. Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

    Directory of Open Access Journals (Sweden)

    Ahmed A. Abouhussien

    2014-01-01

    Full Text Available Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

  14. Vertical impedance measurements on concrete bridge decks for assessing susceptibility of reinforcing steel to corrosion

    Science.gov (United States)

    Bartholomew, Paul D.; Guthrie, W. Spencer; Mazzeo, Brian A.

    2012-08-01

    Corrosion is a pressing problem for aging concrete infrastructure, especially bridge decks. Because of its sensitivity to factors that affect corrosion of reinforcing steel in concrete, resistivity is an important structural health indicator for reinforced concrete structures. In this research, an instrument was developed to measure vertical impedance on concrete bridge decks. Measurements of vertical impedance on slabs prepared in the laboratory, on slabs removed from decommissioned bridge decks, and on an in-service bridge deck in the field demonstrate the utility of the new apparatus.

  15. Corrosion potential: influence of moisture, water-cement ratio, chloride content and concrete cover

    Directory of Open Access Journals (Sweden)

    M. H. F. Medeiros

    Full Text Available ABSTRACT The method of measuring the corrosion potential is used as an electrochemical tool for helping the monitoring of the corrosion of reinforcements of concrete structures. As a criterion for evaluating results it is common to use intervals of corrosion potential and their correlation with corrosion probability, as precognizes ASTM C 876:2015. With this criterion, it is possible to establish an overview of the thermodynamic situation of corrosion in the structure or in the test specimen in laboratory. However, the method is influenced by several factors related with the concrete, the environment and with procedures adopted at the moment of executing the readings. Aiming to provide information to guide the technical and scientific environment regarding the right use of this type of non-destructive testing, the objective of this work is to evaluate some possible factors influencing the reading of corrosion potential, such as: moisture content of the concrete, water/cement ratio, thickness of the concrete cover and degree of contamination by chlorides. Results indicate that moisture and degree of contamination of the concrete by chloride ions had a tendency of making the corrosion potential more electronegative. Besides, it was verified that the influence of the cover is different for the case of contaminated concrete (1% of chlorides by mass of cement and not contaminated with chlorides: the influence of the thickness of the cover, in the case of concrete contaminated by chlorides, was inversely proportional, in other words, the greater the cover thickness is, the less electronegative the value of the corrosion potential will be. On the other hand, in cases of concretes without chlorides, the effect of the cover thickness in the readings or corrosion potential was irrelevant. All this information was proved with 95% of statistical significance.

  16. Corrosion Mechanism and Bond-Strength Study on Galvanized Steel in Concrete Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kouril, M.; Pokorny, P.; Stoulil, J. [University of Chemistry and Technology, Prague (Czech Republic)

    2017-04-15

    Zinc coating on carbon steels give the higher corrosion resistance in chloride containing environments and in carbonated concrete. However, hydrogen evolution accompanies the corrosion of zinc in the initial activity in fresh concrete, which can lead to the formation of a porous structure at the reinforcement -concrete interface, which can potentially reduce the bond-strength of the reinforcement with concrete. The present study examines the mechanism of the corrosion of hot-dip galvanized steel in detail, as in the model pore solutions and real concrete. Calcium ion plays an important role in the corrosion mechanism, as it prevents the formation of passive layers on zinc at an elevated alkalinity. The corrosion rate of galvanized steel decreases in accordance with the exposure time; however, the reason for this is not the zinc transition into passivity, but the consumption of the less corrosion-resistant phases of hot-dip galvanizing in the concrete environment. The results on the electrochemical tests have been confirmed by the bond-strength test for the reinforcement of concrete and by evaluating the porosity of the cement adjacent to the reinforcement.

  17. Resistance to Corrosion of Reinforcement of High Volume Fly Ash Concrete

    International Nuclear Information System (INIS)

    Kwon, S. O.; Bae, S. H.; Lee, H. J.; Lee, K. M.; Jung, S. H.

    2014-01-01

    Due to the increasing of interest about the eco-friendly concrete, it is increased to use concretes containing by-products of industry such as fly ash(FA), ground granulated blast furnace slag(GGBFS), silica fume(SF), and etc. Especially, these are well known for improving the resistances to reinforcement corrosion in concrete and decreasing chloride ion penetration. The purpose of this experimental research is to evaluate the resistance against corrosion of reinforcement of high volume fly ash(HVFA) concrete which is replaced with high volume fly ash for cement volume. For this purpose, the concrete test specimens were made for various strength level and replacement ratio of FA, and then the compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91, and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that the compressive strength of HVFA concrete was decreased with increasing replacement ratio of FA but long-term resistances against reinforcement corrosion and chloride ion penetration of that were increased

  18. Influence of Changes in Water-to-Cement Ratio, Alkalinity, Concrete Fluidity, Voids, and Type of Reinforcing Steel on the Corrosion Potential of Steel in Concrete.

    Science.gov (United States)

    2014-04-01

    "Research on steel corrosion has demonstrated that the concentrations of chloride and hydroxide ion at the concrete/steel : interface influence the susceptibility of the steel to corrosive attack. This study used electrochemical means and changes in ...

  19. Coated steel rebar for enhanced concrete-steel bond strength and corrosion resistance.

    Science.gov (United States)

    2010-10-01

    This report summarizes the findings and recommendations on the use of enamel coating in reinforced concrete structures both for bond strength and : corrosion resistance of steel rebar. Extensive laboratory tests were conducted to characterize the pro...

  20. Structural design guidelines for concrete bridge decks reinforced with corrosion-resistant reinforcing bars.

    Science.gov (United States)

    2014-10-01

    This research program develops and validates structural design guidelines and details for concrete bridge decks with : corrosion-resistant reinforcing (CRR) bars. A two-phase experimental program was conducted where a control test set consistent : wi...

  1. Possibilities for improving corrosion protection of reinforced concrete by modified hydrotalcites: a literature review

    NARCIS (Netherlands)

    Yang, Z.; Fischer, H.R.; Polder, R.B.

    2012-01-01

    Modified Hydrotalcites (MHTs) represent a group of technologically promising materials for improving corrosion protection in concrete owing to their low cost, relative simplicity of preparation, and plenty of composition variables. Numerous academic and commercial studies on MHTs have been carried

  2. Effect of Fly-Ash on Corrosion Resistance Characteristics of Rebar Embedded in Recycled Aggregate Concrete

    Science.gov (United States)

    Revathi, Purushothaman; Nikesh, P.

    2018-04-01

    In the frame of an extended research programme dealing with the utilization of recycled aggregate in concrete, the corrosion resistance characteristics of rebars embedded in recycled aggregate concrete is studied. Totally five series of concrete mixtures were prepared with fly-ash as replacement for cement in the levels of 10-30% by weight of cement. Corrosion studies by 90 days ponding test, linear polarization test and impressed voltage tests were carried out, in order to investigate whether corrosion behaviour of the rebars has improved due to the replacement of cement with fly-ash. Results showed that the replacement of cement with fly-ash in the range of 20-30% improves the corrosion resistance characteristics of recycled aggregate concrete.

  3. Effect of red mud addition on the corrosion parameters of reinforced concrete evaluated by electrochemical methods

    Directory of Open Access Journals (Sweden)

    D.V. Ribeiro

    Full Text Available Red mud, the main waste generated in aluminum and alumina production from bauxite ore by the Bayer process, is considered "hazardous" due to its high pH. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect of concrete. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its corrosion potential and increasing its electrical resistivity. Red mud proved to be a promising additive for concrete to inhibit the corrosion process.

  4. Materials and methods for corrosion control of reinforced and prestressed concrete structures in new construction

    Science.gov (United States)

    2000-08-01

    Salt-induced reinforcing steel corrosion in concrete bridges has undoubtedly become a considerable economic burden to many State and local transportation agencies. Since the iron in the steel has a natural tendency to revert eventually to its most st...

  5. Inspection of Buildings in Rio de Janeiro-Brazil: Proving the greater tendency of corrosion at the base of reinforced concrete columns using potential corrosion technique

    OpenAIRE

    Marcelo Henrique Farias de Medeiros

    2013-01-01

    Monitoring the corrosion of steel embedded in concrete is a way to assess the degradation of civil structures. A technique used for this is the measurement of corrosion potential, which includes the use of a reference electrode, connected to a high input impedance voltmeter. There are many factors influencing the measurement of corrosion potential, such as: degree of concrete moisture content, the oxygen access, existence of micro fissures, chloride penetration, carbonation and concrete cover...

  6. Propagation of steel corrosion in concrete: Experimental and numerical investigations

    DEFF Research Database (Denmark)

    Michel, Alexander; Otieno, M.; Stang, Henrik

    2016-01-01

    This paper focuses on experimental and numerical investigations of the propagation phase of reinforcement corrosion to determine anodic and cathodic Tafel constants and exchange current densities, from corrosion current density and corrosion potential measurements. The experimental program includ...

  7. Protection of Steel Corrosion in Concrete Members by the Combination of Galvanic Anode and Nitrite Penetration

    Directory of Open Access Journals (Sweden)

    Minobu Aoyama

    2014-01-01

    Full Text Available Chloride induced-corrosion of steel bars in concrete can make cracks and exfoliation in near-surface regions in reinforced concrete structures. In this paper, we described the basic concept and practice of steel bars corrosion protection method by the combination of galvanic anode (zinc wire and the penetration of nitrite ions from mortar layers containing a large amount of lithium nitrite.

  8. Influence of reinforcement's corrosion into hyperstatic reinforced concrete beams: a probabilistic failure scenarios analysis

    Directory of Open Access Journals (Sweden)

    G. P. PELLIZZER

    Full Text Available AbstractThis work aims to study the mechanical effects of reinforcement's corrosion in hyperstatic reinforced concrete beams. The focus is the probabilistic determination of individual failure scenarios change as well as global failure change along time. The limit state functions assumed describe analytically bending and shear resistance of reinforced concrete rectangular cross sections as a function of steel and concrete resistance and section dimensions. It was incorporated empirical laws that penalize the steel yield stress and the reinforcement's area along time in addition to Fick's law, which models the chloride penetration into concrete pores. The reliability theory was applied based on Monte Carlo simulation method, which assesses each individual probability of failure. The probability of global structural failure was determined based in the concept of failure tree. The results of a hyperstatic reinforced concrete beam showed that reinforcements corrosion make change into the failure scenarios modes. Therefore, unimportant failure modes in design phase become important after corrosion start.

  9. Approach to the effect of concrete resistivity in the corrosion of rebars in concrete

    Directory of Open Access Journals (Sweden)

    Andrade, C.

    1987-09-01

    Full Text Available The concrete resistivity has been considered as a factor which affects the corrosion rate of the rebars. Untill now the only relation found has been stablished between potentials and resistivity for steel embedded in Chloride contaminated concrete. In this paper a comparison between corrosion rate of rebars, determined from Polarization Resistance method, and Electrical Resistance data measured through the electronic compensation of the ohmic drop are given. The results of icorr and Rohm has been measured for rebars embedded in mortar made with three different types of cement. The specimens were submited to an accelerated carbonation. The relation between icorr and Rohm is quite similar in all the cases and suggests that the concrete electrical resistivity may be a controling factor of the corrosion rate of the rebars.

    La resistividad del hormigón se ha venido considerando como uno de los factores que afectan a la velocidad de corrosión de las armaduras, aunque, hasta ahora, la única relación encontrada ha sido la establecida entre los potenciales y la resistividad para acero embebido en hormigón contaminado por cloruros. En este trabajo se establecen comparaciones entre velocidad de corrosión de las armaduras, medida a través del método de determinación de la Resistencia de Polarización, y los datos de resistencia eléctrica medidos a través de la compensación de caída óhmica. Los resultados de icorr y Rohm se han medido en armaduras embebidas en mortero fabricado con tres tipos de cemento a los que se ha sometido a un proceso de carbonatación acelerada. La relación entre icorr y Rohm es muy similar en todos los casos y sugiere que la resistencia del hormigón puede actuar como un factor controlante de la velocidad de corrosión de las armaduras.

  10. Relationship between Corrosion Level of Rebar Embedded in Concrete, Corrosion Potential and Current Density Measured by Non-destructive Test Method

    International Nuclear Information System (INIS)

    Chung, Lan; Cho, Seung Ho; Roh, Young Sook; Kim, Joong Koo

    2004-01-01

    The purpose of this study is to identify corrosion mechanism and develop qualitative measurement method of corrosion level. Fist of all, structural behavior of each different level of corrosion states have been evaluated. And mathematical models that can predict corrosion level in terms of electric potential and corrosion intensity are proposed. Corrosion rate in reinforcing bar was investigated in this study using accelerated corrosion method due to electric potential differences based on Faradays law. Total 288 measurement spots were designed in terms of corrosion rates, diameter of reinforcing bars, and concrete cover thickness. Corrosion current densities and corrosion potentials of concrete were measured on these specimens using Gecor device. This study suggested the relationship between corrosion levels, and measured electric current density as follows

  11. Experimental investigation on the threshold chloride concentration for corrosion initiation in reinforced concrete structures

    International Nuclear Information System (INIS)

    Byung Hwan Oh; Seung Yup Jang

    2005-01-01

    The corrosion of steel reinforcements in concrete is of great importance in the view of safety and durability of reinforced concrete structures. This study is focused on the corrosion behavior of steel bars induced by internal chlorides in concrete. The main objective of this study is to determine the threshold chloride concentration causing depassivation and active corrosion of steel reinforcement in concrete. To examine the threshold concentration of chloride ion, the half-cell potential, the chemical composition of extracted pore solutions of concrete and the extent of corroded area of the specimens were measured. Major test variables include the added amount of chlorides in concrete, type of binder, and water-to-binder ratios. From the present comprehensive test results, the factors influencing threshold chloride concentration are investigated, and the rational ranges of threshold chloride concentration causing active corrosion of steels are proposed. The present study provides the realistic chloride limit for corrosion initiation of reinforced concrete structures, which can be used efficiently in the future technical specification. (authors)

  12. A Probabilistic Model for Chloride-Ingress and Initation of Corrosion in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Engelund, S.; Sørensen, John Dalsgaard

    1998-01-01

    Corrosion of the reinforcement is a major problem for a large number of reinforced concrete structures because it can lead to a substantial decrease of the load-bearing capacity. One mode of corrosion initiation is that the chloride content around the reinforcement exceeds a critical threshold va...

  13. Experimental investigations on macro cell corrosion in chloride-contaminated concrete

    NARCIS (Netherlands)

    Gulikers, J.J.W.

    1996-01-01

    Chloride-induced reinforcement corrosion in concrete is characterised by the action of so-called macrocells. The associated localised form of corrosion results from the strong electrochemical interaction between the relatively small pitting sites acting as anodes and the large passive steel areas

  14. A degradation model for stray current induced corrosion in underground reinforced concrete structures

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.

    2003-01-01

    This paper describes the effects of stray currents on durability and reinforcement corrosion of underground concrete structures. Cathodic protection of underground pipelines are stationary sources of stray current interference with concrete, and rail traction systems are non-stationary sources. The

  15. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    Science.gov (United States)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  16. The repair and protection of reinforced concrete with migrating corrosion inhibitors

    International Nuclear Information System (INIS)

    Stefanescu, D.

    2016-01-01

    The concrete is a very durable construction material and his use is based on the principle that concrete is an ideal environment for steel if properly proportioned and placed. In general, reinforced concrete has proved to be successful in terms of both structural performance and durability. However, there are instances of premature failure of reinforced concrete components due to corrosion of the reinforcement. Experience has shown that there are certain portions of exposed concrete structures more vulnerable than others. Methodology for concrete repair it addresses to suggestions of the types of repair methods and materials and a detailed description of the uses, limitations, materials, and procedures for Repair of Concrete. At same the time the methodology presents recommendation on materials, methods of mixing, application, curing and precautions to be exercised during placement. This work presents guidelines for managing reinforced concrete components and specifies the repair strategy with inhibitors incorporating. (authors)

  17. Application of potential relaxation transient measurements to corrosion of steel in concrete

    International Nuclear Information System (INIS)

    Benjamin, S.E.; Skyes, J.M.

    1993-01-01

    Corrosion of steel in concrete is an electrochemical process that involves the process occurring at the interface and also in the bulk diffusion of species. This paper present studies on corrosion of Swedish Iron in concrete utilizing potential relaxation transients. This rapid new D.C. technique (developed at Oxford University, U.K.) analyzes the decay in terms of different resistor (R) - capacitor(c) combinations, thus identifying the individual processes as their time constants(tau). The resistance of the concrete is also separated. The merits and demerits of the technique are discussed. (author)

  18. The design of an instrumented rebar for assessment of corrosion in cracked reinforced concrete

    DEFF Research Database (Denmark)

    Pease, Bradley Justin; Geiker, Mette Rica; Stang, Henrik

    2011-01-01

    rebar with 17 electronically isolated corrosion sensors. Instrumented and standard rebars were cast into concrete beams and bending cracks were induced and held open using steel frames. Epoxy impregnation was used to assess and compare cracks in the concrete around the instrumented and standard rebar...... between the steel and concrete. Cracked beams with cast-in instrumented and standard rebars were ponded with a 10\\% chloride solution and the open circuit corrosion potential (OCP) of the 17 sensors was measured for up to 62 days. Measurements from the individual sensors indicate when and where active...

  19. Corrosion of reinforcing bars embedded in alkali-activated slag concrete subjected to chloride attack

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2012-02-01

    Full Text Available Steel bar embedded in an alkali-activated slag (AAS concrete was tested under complete immersion, in 3.5% NaCl solution by weight of the slag. Ordinary Portland cement (OPC was also tested for comparative purposes and exposed to the same solution. Monitoring of open-circuit potential, polarization resistance measurement and electrochemical impedance spectroscopy (EIS were used to evaluate the corrosion behavior of steel bar. The corrosion resistances of AAS and OPC concretes were performed at 0, 3, 6, 9 and 12 months. Electrochemical measurements shows that AAS concrete presents passive corrosion behavior the first 3 months, after this period of time, it presents corrosion resistance decreased due to the chlorides presence at the steel/AAS interface. For 0 months immersion (28 days of curing the AAS and OPC concretes presented a 10% of corrosion probability. After 3 months of immersion the tested AAS and OPC concretes showed similar behavior, the active potentials in the range from "0.2 to "0.6 V vs. Cu/CuSO4, indicate a 90% probability of corrosion.

  20. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures.

    Science.gov (United States)

    Angst, Ueli M; Elsener, Bernhard

    2017-08-01

    Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation ( C crit ). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that C crit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable C crit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of C crit . It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform C crit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures.

  1. Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment.

    Science.gov (United States)

    Ann, Ki Yong; Cho, Chang-Geun

    2014-01-28

    The present study concerns a development of calcium aluminate cement (CAC) concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC), ranging from 5% to 15%, as a binder. As a result, it was found that an increase in the CAC in binder resulted in a dramatic decrease in the setting time of fresh concrete. However, the compressive strength was lower, ranging about 20 MPa, while OPC indicated about 30-35 MPa at an equivalent age. When it comes to chloride transport, there was only marginal variation in the diffusivity of chloride ions. The corrosion resistance of CAC mixture was significantly enhanced: its chloride threshold level for corrosion initiation exceeded 3.0% by weight of binder, whilst OPC and CAC concrete indicated about 0.5%-1.0%.

  2. Field Testing of Rapid Electrokinetic Nanoparticle Treatment for Corrosion Control of Steel in Concrete

    Science.gov (United States)

    Cardenas, Henry E.; Alexander, Joshua B.; Kupwade-Patil,Kunal; Calle, Luz Marina

    2009-01-01

    This work field tested the use of electrokinetics for delivery of concrete sealing nanoparticles concurrent with the extraction of chlorides. Several cylinders of concrete were batched and placed in immersion at the Kennedy Space Center Beach Corrosion Test Site. The specimens were batched with steel reinforcement and a 4.5 wt.% (weight percent) content of sodium chloride. Upon arrival at Kennedy Space Center, the specimens were placed in the saltwater immersion pool at the Beach Corrosion Test Site. Following 30 days of saltwater exposure, the specimens were subjected to rapid chloride extraction concurrent with electrokinetic nanoparticle treatment. The treatments were operated at up to eight times the typical current density in order to complete the treatment in 7 days. The findings indicated that the short-term corrosion resistance of the concrete specimens was significantly enhanced as was the strength of the concrete.

  3. Influence of Freeze-Thaw Damage on the Steel Corrosion and Bond-Slip Behavior in the Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Fangzhi Zhu

    2016-01-01

    Full Text Available This paper mainly studies the behavior of steel corrosion in various reinforced concrete under freeze-thaw environment. The influence of thickness of concrete cover is also discussed. Additionally, the bond-slip behavior of the reinforced concrete after suffering the freeze-thaw damage and steel corrosion has also be presented. The results show that the freeze-thaw damage aggravates the steel corrosion in concrete, and the results become more obvious in the concrete after suffering serious freeze-thaw damage. Compared with the ordinary concrete, both air entrained concrete and waterproofing concrete possess better resistance to steel corrosion under the same freeze-thaw environment. Moreover, increasing the thicknesses of concrete cover is also an effective method of improving the resistance to steel corrosion. The bond-slip behavior of reinforced concrete with corroded steel decreases with the increase of freeze-thaw damage, especially for the concrete that suffered high freeze-thaw cycles. Moreover, there exists a good correlation between the parameters of bond-slip and freeze-thaw cycles. The steel corrosion and bond-slip behavior of reinforced concrete should be considered serious under freeze-thaw cycles environment, which significantly impact the durability and safety of concrete structure.

  4. Preliminary study of life cycle cost of preventive measures and repair options for corrosion in concrete infrastructurecorrosion in concrete infrastructure

    NARCIS (Netherlands)

    Polder, R.B.; Pan, Yifan; Courage, Wim; Peelen, Willy H A

    2016-01-01

    Maintenance costs of reinforced concrete infrastructure (bridges, tunnels, harbours, parking structures) are increasing due to aging of structures under aggressive exposure. Corrosion of reinforcement due to chloride ingress is the main problem for existing structures in marine and de-icing salt

  5. Concrete Cracking Prediction Including the Filling Proportion of Strand Corrosion Products

    Science.gov (United States)

    Wang, Lei; Dai, Lizhao; Zhang, Xuhui; Zhang, Jianren

    2016-01-01

    The filling of strand corrosion products during concrete crack propagation is investigated experimentally in the present paper. The effects of stirrups on the filling of corrosion products and concrete cracking are clarified. A prediction model of crack width is developed incorporating the filling proportion of corrosion products and the twisting shape of the strand. Experimental data on cracking angle, crack width, and corrosion loss obtained from accelerated corrosion tests of concrete beams are presented. The proposed model is verified by experimental data. Results show that the filling extent of corrosion products varies with crack propagation. The rust filling extent increases with the propagating crack until a critical width. Beyond the critical width, the rust-filling extent remains stable. Using stirrups can decrease the critical crack width. Stirrups can restrict crack propagation and reduce the rust filling. The tangent of the cracking angle increases with increasing corrosion loss. The prediction of corrosion-induced crack is sensitive to the rust-filling extent. PMID:28772367

  6. Corrosion of steel tendons in concrete pressure vessels: review of recent literature and experimental investigations

    International Nuclear Information System (INIS)

    Griess, J.C.

    1978-01-01

    The fundamentals of localized corrosion are briefly discussed, and the literature concerning corrosion of carbon steel in aqueous environments, in particular the stress-corrosion cracking of carbon steels, is reviewed. The behavior of high strength steels in specific environments, including concrete and organic substances, is also summarized. The available information indicates that the corrosion of steels in correctly formulated concrete is minimal. Even appreciable concentrations of chloride, sulfate, sulfide, and nitrate salts can be tolerated in the concrete or grout without detrimental effects. Adherence to established standards in the preparation and application of grouts in tendon-bearing conduits should guarantee very long tendon lifetimes. Little is reported about the behavior of tendons in proprietary organic greases or waxes, but very good corrosion resistance is expected if the organic material remains intact. Stress-corrosion cracking tests performed with AISI 1080 steel tendon wires, using the constant-strain-rate method, produced results expected from data in the literature. Cracking was observed only in neutral or acid solutions containing hydrogen sulfide, in ammonium nitrate solutions, and possibly in a dilute solution of sodium bisulfite. General corrosion tests in water and in dilute solutions of sodium nitrate, chloride, or sulfate showed that oxygen was an important factor; corrosion was substantially greater when oxygen had free access to the solution than when access to oxygen was restricted. In the tests with oxygen the heaviest attack on the steel tendons was at the waterline of the solution

  7. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    Directory of Open Access Journals (Sweden)

    Xingjun Lv

    2011-11-01

    Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  8. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    Science.gov (United States)

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  9. Quality of concrete plant wastewater for reuse

    Directory of Open Access Journals (Sweden)

    H. M. Paula

    Full Text Available Efficient water use is one of the most important requirements of cleaner production, and the use of the wastewater from concrete production can be an important means to this end. However, there are no Brazilian studies on the quality of concrete plant wastewater and the activities in which such water can be used. This paper aims to evaluate the quality of concrete plant wastewater and to propose guidelines for its treatment for non-potable applications. Wastewater samples were collected from three points in the studied treatment system, and tests were later performed in the laboratory to evaluate the water quality. The results obtained were compared with the limit values for the quality parameters that have been used for the analysis of the non-potable water supply in Brazil. The results indicate a need to at least add coagulation and pH correction processes to the treatment system.

  10. Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

    Science.gov (United States)

    Tang, Fujian

    This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

  11. Ultrasonic Measurement of Corrosion Depth Development in Concrete Exposed to Acidic Environment

    Directory of Open Access Journals (Sweden)

    Fan Yingfang

    2012-01-01

    Full Text Available Corrosion depth of concrete can reflect the damage state of the load-carrying capacity and durability of the concrete structures servicing in severe environment. Ultrasonic technology was studied to evaluate the corrosion depth quantitatively. Three acidic environments with the pH level of 3.5, 2.5, and 1.5 were simulated by the mixture of sulfate and nitric acid solutions in the laboratory. 354 prism specimens with the dimension of 150 mm × 150 mm × 300 mm were prepared. The prepared specimens were first immersed in the acidic mixture for certain periods, followed by physical, mechanical, computerized tomography (CT and ultrasonic test. Damage depths of the concrete specimen under different corrosion states were obtained from both CT and ultrasonic test. Based on the ultrasonic test, a bilinear regression model is proposed to estimate the corrosion depth. It is shown that the results achieved by ultrasonic and CT test are in good agreement with each other. Relation between the corrosion depth of concrete specimen and the mechanical indices such as mass loss, compressive strength, and elastic modulus is discussed in detail. It can be drawn that the ultrasonic test is a reliable nondestructive way to measure the damage depth of concrete exposed to acidic environment.

  12. Bond-Slip Behavior of Basalt Fiber Reinforced Polymer Bar in Concrete Subjected to Simulated Marine Environment: Effects of BFRP Bar Size, Corrosion Age, and Concrete Strength

    OpenAIRE

    Yongmin Yang; Zhaoheng Li; Tongsheng Zhang; Jiangxiong Wei; Qijun Yu

    2017-01-01

    Basalt Fiber Reinforced Polymer (BFRP) bars have bright potential application in concrete structures subjected to marine environment due to their superior corrosion resistance. Available literatures mainly focused on the mechanical properties of BFRP concrete structures, while the bond-slip behavior of BFRP bars, which is a key factor influencing the safety and service life of ocean concrete structures, has not been clarified yet. In this paper, effects of BFRP bars size, corrosion age, and c...

  13. Virtual reality presentation for nondestructive evaluation of rebar corrosion in concrete based on IBEM

    International Nuclear Information System (INIS)

    Kyung, Je Woon; Leelarkiet, V.; Ohtsu, Masayasu; Yokata, Masaru

    2004-01-01

    In order to evaluate the corrosion of reinforcing steel-bars (rebar) in concrete, a nondestructive evaluation by the half-cell potential method is currently applied. In this study, potentials measured on a concrete surface are compensated into those on the concrete-rebar interface by the inverse boundary element method (IBEM). Because these potentials are obtained three-dimensionally (3-D), 3-D visualization is desirable. To this end, a visualization system has been developed by using VRML (Virtual Reality Modeling Language). As an application, results of a reinforced concrete (RC) slab with corroded rebars are visualized and discussed.

  14. Corrosion products of reinforcement in concrete in marine and industrial environments

    International Nuclear Information System (INIS)

    Vera, R.; Villarroel, M.; Carvajal, A.M.; Vera, E.; Ortiz, C.

    2009-01-01

    The corrosion products formed on embedded steel in concrete under simulated marine and industrial conditions and natural marine environment were studied. A 0.50 water/cement ratio concrete was used and 3.5% NaCl and 180 g L -1 of H 2 SO 4 with 70 ppm of chloride ions solutions were used to simulate the synthetic medium. The initial electrochemical variables of the steel and pH, chlorides and sulfates profiles were measured according to the concrete depth. The morphology of the corrosive attack was determined via scanning electron microscopy (SEM), and the composition of the corrosion products was determined using an X-ray analyzer and an X-ray diffractometer (XRD). The protective power of the corrosion products was evaluated through anodic polarization curves in a saturated Ca(OH) 2 solution. The results from XRD and SEM show that all the resulting corrosion products correspond to lepidocrocite, goethite and magnetite mixtures; moreover, akaganeite was also identified under natural and simulated marine environments. Siderite was only detected in samples exposed to a natural marine environment. Concerning the protective nature of the corrosion products, these show lower performance in a simulated industrial environment, where the corrosion rate of the steel is up to 1.48 μm year -1

  15. Corrosion products of reinforcement in concrete in marine and industrial environments

    Energy Technology Data Exchange (ETDEWEB)

    Vera, R. [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avenida Brasil 2950, Casilla 4059, Valparaiso (Chile)], E-mail: rvera@ucv.cl; Villarroel, M. [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avenida Brasil 2950, Casilla 4059, Valparaiso (Chile); Carvajal, A.M. [Facultad de Ingenieria, Escuela de Construccion Civil, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, Macul, Santiago (Chile); Vera, E.; Ortiz, C. [Universidad Pedagogica y Tecnologica de Colombia, Avenida Central Norte, Km 2, Tunja (Colombia)

    2009-03-15

    The corrosion products formed on embedded steel in concrete under simulated marine and industrial conditions and natural marine environment were studied. A 0.50 water/cement ratio concrete was used and 3.5% NaCl and 180 g L{sup -1} of H{sub 2}SO{sub 4} with 70 ppm of chloride ions solutions were used to simulate the synthetic medium. The initial electrochemical variables of the steel and pH, chlorides and sulfates profiles were measured according to the concrete depth. The morphology of the corrosive attack was determined via scanning electron microscopy (SEM), and the composition of the corrosion products was determined using an X-ray analyzer and an X-ray diffractometer (XRD). The protective power of the corrosion products was evaluated through anodic polarization curves in a saturated Ca(OH){sub 2} solution. The results from XRD and SEM show that all the resulting corrosion products correspond to lepidocrocite, goethite and magnetite mixtures; moreover, akaganeite was also identified under natural and simulated marine environments. Siderite was only detected in samples exposed to a natural marine environment. Concerning the protective nature of the corrosion products, these show lower performance in a simulated industrial environment, where the corrosion rate of the steel is up to 1.48 {mu}m year{sup -1}.

  16. An Experimental Study for Quantitative Estimation of Rebar Corrosion in Concrete Using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Md Istiaque Hasan

    2016-01-01

    Full Text Available Corrosion of steel rebar in reinforced concrete is one the most important durability issues in the service life of a structure. In this paper, an investigation is conducted to find out the relationship between the amount of reinforced concrete corrosion and GPR maximum positive amplitude. Accelerated corrosion was simulated in the lab by impressing direct current into steel rebar that was submerged in a 5% salt water solution. The amount of corrosion was varied in the rebars with different levels of mass loss ranging from 0% to 45%. The corroded rebars were then placed into three different oil emulsion tanks having different dielectric properties similar to concrete. The maximum amplitudes from the corroded bars were recorded. A linear relationship between the maximum positive amplitudes and the amount of corrosion in terms of percentage loss of area was observed. It was proposed that the relationship between the GPR maximum amplitude and the amount of corrosion can be used as a basis of a NDE technique of quantitative estimation of corrosion.

  17. Corrosion Behavior of Steel Reinforcement in Concrete with Recycled Aggregates, Fly Ash and Spent Cracking Catalyst

    Directory of Open Access Journals (Sweden)

    Hebé Gurdián

    2014-04-01

    Full Text Available The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by industrial by-products (15% of spent fluid catalytic cracking catalyst and 35% of fly ash and a 100% of natural coarse aggregate by recycled aggregate. The concretes prepared according to these considerations have been tested in terms of mechanical strengths and the protection offered against steel reinforcement corrosion under carbonation attack and chloride-contaminated environments. The proposed concrete combinations reduced the mechanical performance of concretes in terms of elastic modulus, compressive strength, and flexural strength. In addition, an increase in open porosity due to the presence of recycled aggregate was observed, which is coherent with the changes observed in mechanical tests. Regarding corrosion tests, no significant differences were observed in the case of the resistance of these types of concretes under a natural chloride attack. In the case of carbonation attack, although all concretes did not stand the highly aggressive conditions, those concretes with cement replacement behaved worse than Portland cement concretes.

  18. Corrosion Behavior of Steel Reinforcement in Concrete with Recycled Aggregates, Fly Ash and Spent Cracking Catalyst.

    Science.gov (United States)

    Gurdián, Hebé; García-Alcocel, Eva; Baeza-Brotons, Francisco; Garcés, Pedro; Zornoza, Emilio

    2014-04-21

    The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by industrial by-products (15% of spent fluid catalytic cracking catalyst and 35% of fly ash) and a 100% of natural coarse aggregate by recycled aggregate. The concretes prepared according to these considerations have been tested in terms of mechanical strengths and the protection offered against steel reinforcement corrosion under carbonation attack and chloride-contaminated environments. The proposed concrete combinations reduced the mechanical performance of concretes in terms of elastic modulus, compressive strength, and flexural strength. In addition, an increase in open porosity due to the presence of recycled aggregate was observed, which is coherent with the changes observed in mechanical tests. Regarding corrosion tests, no significant differences were observed in the case of the resistance of these types of concretes under a natural chloride attack. In the case of carbonation attack, although all concretes did not stand the highly aggressive conditions, those concretes with cement replacement behaved worse than Portland cement concretes.

  19. Concrete cover cracking with reinforcement corrosion of RC beam during chloride-induced corrosion process

    International Nuclear Information System (INIS)

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2010-01-01

    This paper deals with the evolution of the corrosion pattern based on two beams corroded by 14 years (beam B1CL1) and 23 years (beam B2CL1) of conservation in a chloride environment. The experimental results indicate that, at the cracking initiation stage and the first stage of cracking propagation, localized corrosion due to chloride ingress is the predominant corrosion pattern and pitting corrosion is the main factor that influences the cracking process. As corrosion cracking increases, general corrosion develops rapidly and gradually becomes predominant in the second stage of cracking propagation. A comparison between existing models and experimental results illustrates that, although Vidal et al.'s model can better predict the reinforcement corrosion of beam B1CL1 under localized corrosion, it cannot predict the corrosion of beam B2CL1 under general corrosion. Also, Rodriguez's model, derived from the general corrosion due to electrically accelerated corrosion experiments, cannot match natural chloride corrosion irrespective of whether corrosion is localized or general. Thus, for natural general corrosion in the second stage of cracking propagation, a new model based on the parameter of average steel cross-section loss is put forward to predict steel corrosion from corrosion cracking.

  20. CONCRETE STRUCTURES' QUALITY CONTROL IN PRACTICE

    OpenAIRE

    Dolaček-Alduk, Zlata; Blanda, Miroslav

    2011-01-01

    The Croatian civil engineering is characterized by a lack of systematic approach to planning, control and quality assurance in all phases of project realization. The results obtained in establishing the quality management system in some segments of civil engineering production represent initial trends in solving this problem. Benefits are of two types: the achievement of quality for the contractor and obtaining that quaity is being achieved for clients. Execution of concrete structures is a c...

  1. Quality control chart for crushed granite concrete

    Directory of Open Access Journals (Sweden)

    Ewa E. DESMOND

    2016-07-01

    Full Text Available A chart for assessing in-situ grade (strength of concrete, has been developed in this study. Four grades of concrete after the Nigerian General Specification for Roads and bridges (NGSRB-C20, C25, C30 and C35, is studied at different water-cement ratios for medium and high slump range. The concrete mixes are made from crushed granite rock as coarse aggregate with river sand as fine aggregate. Compression test on specimens are conducted at curing age of 1, 3, 7, 14, 21, 28 and 56 days. Results on concrete workability from slump values, and water-cement ratios revealed that specimens with lower water-cement ratio were less workable but had higher strength, compared to mixes with higher water cement ratio. A simple algorithm using nonlinear regression analysis performed on each experimental data set produced Strength-Age (S-A curves which were used to establish a quality control chart. The accuracy of these curves were evaluated by computing average absolute error (AAS, the error of estimate (EoE and the average absolute error of estimate (Abs EoE for each concrete mix. These were done based on the actual average experimental strengths to measure how close the predicted values are to the experimental data set. The absolute average error of estimate (Abs. EoE recorded was less than ±10% tolerance zone for concrete works.

  2. Development of an antimicrobial concrete to inhibiting corrosion; Konkurito wo fushoku kara gado suru kokin konkurito no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, Y.

    1999-11-10

    It has been clarified that the corrosion of concrete in sewage facilities is caused by the action of specific microorganism. The corrosion of concrete is caused by the complicate interaction of chemical substances and microorganisms existing in sewage water. As microorganisms related to this phenomenon, lead sulfate reductase and sulfur oxidase are well known. This paper introduces antimicrobials for concrete using zeolite as a main component and a concrete containing these antimicrobials, which were developed for killing or suppressing the generation of these microorganisms causing the corrosion of concrete. The sales results during 2 years since the start of the sales in May 1997 was 16 tons for antimicrobials including zeolite-supported silver - copper catalyst, and 8,138 tons for antimicrobial concrete. Sixty-eight companies have organized concrete workshop>, which will promote the popularization and technical guidance of antimicrobial concrete. (NEDO)

  3. Design and testing of corrosion damaged prestressed concrete joists: the Pescara Benchmark

    International Nuclear Information System (INIS)

    Di Evangelista, A; De Leonardis, A; Valente, C; Zuccarino, L

    2011-01-01

    An experimental campaign named the Pescara benchmark and devoted to study the dynamic behaviour of corroded p.c. joists has been conducted. The steel corrosion reduces the area of the reinforcement and causes cracking of concrete so that r/c members are subjected to loss of strength and stiffness. It is of interest to evaluate the corrosion level at which the damage can be detected through signal processing procedures and how close such level is to the r/c member safety limits. Joists of current industrial production having different steel to concrete ratios are tested in different laboratory conditions. Dynamic tests involve either free vibrations and forced vibrations due to a moving mass simulating actual traffic loads in railway bridges. The paper discusses the rationale of the tests including the set up of the artificial corrosion, the static characterization of the joist and the dynamic tests in the different stages of corrosion experienced.

  4. Ultrasonic assessment of service life of concrete structures subject to reinforcing steel corrosion

    Science.gov (United States)

    Udegbunam, Ogechukwu Christian

    Over half of the bridges in the United States were built before 1970. Such bridges and the network of roads that they carry include the Inter State system, which was built as part of the great public works program, following the end of the Second World War. During that era, the emphasis was on strength design and economical construction of new structures, and not much premium was placed on durability and maintainability concerns. Since the end of this construction boom in the early 1970s, the concern for the durability of transportation infrastructure has steadily gained prominence among those agencies that must secure, program and administer funds for maintaining highway networks. The objective of this research was to develop a nondestructive method of assessing the durability of concrete bridge decks susceptible to damage from corrosion of embedded reinforcing steel. This was accomplished by formulating a holistic approach that accounts for the major factors that influence corrosion based deterioration of reinforced concrete. In this approach, the assessment of the durability of concrete bridge decks is based on a model that estimates the time it takes for the cover concrete to fail a result of stresses caused by expansion of reinforcing steel bars, due to corrosion activities. This time to failure is comprised of two distinct periods that must be evaluated before the problem can be solved. The research consisted of an experimental program and an analytical study. In the experimental program concrete specimens were cast and tested to determine their diffusivity and mechanical properties. The diffusivity was used to evaluate the period it takes for corrosion of the reinforcing bars to commence. In the analytical study, the resistance of the concrete structure against the internal forces caused by corrosion was evaluated with the finite element techniques. This resistance was used to evaluate the period defining the failure of the cover concrete. These two periods

  5. Mathematical modeling for corrosion environment estimation based on concrete resistivity measurement directly above reinforcement

    International Nuclear Information System (INIS)

    Lim, Young-Chul; Lee, Han-Seung; Noguchi, Takafumi

    2009-01-01

    This study aims to formulate a resistivity model whereby the concrete resistivity expressing the environment of steel reinforcement can be directly estimated and evaluated based on measurement immediately above reinforcement as a method of evaluating corrosion deterioration in reinforced concrete structures. It also aims to provide a theoretical ground for the feasibility of durability evaluation by electric non-destructive techniques with no need for chipping of cover concrete. This Resistivity Estimation Model (REM), which is a mathematical model using the mirror method, combines conventional four-electrode measurement of resistivity with geometric parameters including cover depth, bar diameter, and electrode intervals. This model was verified by estimation using this model at areas directly above reinforcement and resistivity measurement at areas unaffected by reinforcement in regard to the assessment of the concrete resistivity. Both results strongly correlated, proving the validity of this model. It is expected to be applicable to laboratory study and field diagnosis regarding reinforcement corrosion. (author)

  6. The influence of main bar corrosion on bond strength in selfcompacting concrete

    Science.gov (United States)

    Ayop, S. S.; Emhemed, A. N. K.; Jamaluddin, N.; Sadikin, A.

    2017-11-01

    The experimental study was conducted to determine the influence of main bar corrosion on bond strength in self-compacting concrete (SCC). A total 16 tension pullout tests specimens reinforced with 10 mm and 14 mm diameter bar were used for the bond strength test. The properties of SCC were determined from the slump flow, T50cm, V-funnel and L box test. Reinforcing bars in the concrete were submitted to impressed current to accelerate the corrosion of the bar. It was found that the relationship between bond strength and concrete strength in un-corroded specimens differed from that of corroded specimens set in high-strength concrete because of brittleness in the corroded specimens, which caused a sudden loss of bond strength. The results revealed that specimens of un-corroded and corroded showed a higher percentage of bond strength degradation during the pullout tests.

  7. Experimental investigation of the relation between damage at the concrete-steel interface and initiation of reinforcement corrosion in plain and fibre reinforced concrete

    International Nuclear Information System (INIS)

    Michel, A.; Solgaard, A.O.S.; Pease, B.J.; Geiker, M.R.; Stang, H.; Olesen, J.F.

    2013-01-01

    Highlights: •Cracked plain and steel fibre reinforced concrete flexural beams were investigated. •“Instrumented rebars” provided location- and time-dependent corrosion measurements. •Interfacial condition can be used as a reliable indicator to quantify the risk of corrosion. •Simulated interfacial conditions are in very good agreement with all experimental observations. -- Abstract: Cracks in covering concrete are known to hasten initiation of steel corrosion in reinforced concrete structures. To minimise the impact of cracks on the deterioration of reinforced concrete structures, current approaches in (inter)national design codes often limit the concrete surface crack width. Recent investigations however, indicate that the concrete-reinforcement interfacial condition is a more fundamental criterion related to reinforcement corrosion. This work investigates the relation between macroscopic damage at the concrete-steel interface and corrosion initiation of reinforcement embedded in plain and fibre reinforced concrete. Comparisons of experimental and numerical results indicate a strong correlation between corrosion initiation and interfacial condition

  8. Assessment of permeation quality of concrete through mercury intrusion porosimetry

    International Nuclear Information System (INIS)

    Kumar, Rakesh; Bhattacharjee, B.

    2004-01-01

    Permeation quality of laboratory cast concrete beams was determined through initial surface absorption test (ISAT). The pore system characteristics of the same concrete beam specimens were determined through mercury intrusion porosimetry (MIP). Data so obtained on the measured initial surface absorption rate of water by concrete and characteristics of pore system of concrete estimated from porosimetry results were used to develop correlations between them. Through these correlations, potential of MIP in assessing the durability quality of concrete in actual structure is demonstrated

  9. The corrosion pattern of reinforcement and its influence on serviceability of reinforced concrete members in chloride environment

    International Nuclear Information System (INIS)

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2009-01-01

    This paper deals with two corroded reinforcement concrete beams, which have been stored under sustained load in a chloride environment for 14 and 23 years respectively. The evolution of corrosion pattern of reinforcement and its influence on serviceability are studied. In chloride-induced corrosion process, corrosion cracking affects significantly the corrosion pattern. During the corrosion cracking initiation period, only local pitting corrosion occurs. At early stage of cracking propagation, localized pitting corrosion is still predominant as cracks widths are very small and cracks are not interconnected, but a general corrosion slowly develops as the cracks widen. At late cracking stage, interconnected cracking with wide width develops along large parts of the beam leading to a general corrosion pattern. Macrocells and microcells concepts are used for the interpretation of the results. Mechanical experiments and corrosion simulation tests are performed to clarify the influence of this corrosion pattern evolution on the serviceability of the beams (deflection increase). Experimental results show that, when the corrosion is localized (early cracking stage), the steel-concrete bond loss is the main factor affecting the beams serviceability. The local cross-section loss resulting from pitting attack does not significantly influence the deflection of the beam. When corrosion is generalized (late cracking stage), as the steel-concrete bond is already lost, the generalized steel cross-section reduction becomes the main factor affecting the beams serviceability. But, at this stage, the deflection increase is slower due to the low general corrosion rate.

  10. Effect of supplementary cementing materials on the concrete corrosion control

    International Nuclear Information System (INIS)

    Mejia de Gutierrez, R.

    2003-01-01

    Failure of concrete after a period of years, less than the life expected for which it was designed, may be caused by the environment to which it has been exposed or by a variety of internal causes. The incorporation of supplementary materials has at the Portland cement the purpose of improving the concrete microstructure and also of influence the resistance of concrete to environmental attacks. Different mineral by-products as ground granulated blast furnaces slag (GGBS), silica fume (SF), meta kaolin (MK), fly ash (FA) and other products have been used as supplementary cementing materials. This paper is about the behavior of concrete in the presence of mineral additions. Compared to Portland cements, blended cements show lower heat of hydration, lower permeability, greater resistance to sulphates and sea water. These blended cements find the best application when requirements of durability are regarded as a priority specially on high performance concrete: (Author) 11 refs

  11. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

    Science.gov (United States)

    Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G.; Alver, Ninel

    2015-01-01

    Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods. PMID:26251904

  12. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

    Directory of Open Access Journals (Sweden)

    Ahmad Zaki

    2015-08-01

    Full Text Available Corrosion of reinforced concrete (RC structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods.

  13. Laboratory Assessment of Select Methods of Corrosion Control and Repair in Reinforced Concrete Bridges

    Directory of Open Access Journals (Sweden)

    Matthew D. Pritzl

    2014-01-01

    Full Text Available Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered mixed-in chlorides to represent chloride contamination due to deicing salts. All specimens were exposed to accelerated corrosion testing for three months, subjected to patch repairs with various treatments, and further subjected to additional three months of exposure to accelerated corrosion. The use of thermal sprayed zinc, galvanic embedded anodes, epoxy/polyurethane coating, acrylic coating, and an epoxy patch repair material was evaluated individually or in combination. The specimens were assessed with respect to corrosion currents (estimated mass loss, chloride ingress, surface rust staining, and corrosion of the reinforcing steel observed after dissection. Results indicated that when used in patch repair applications, the embedded galvanic anode with top surface coating, galvanic thermal sprayed zinc, and galvanic thermal sprayed zinc with surface coating were more effective in controlling corrosion than the other treatments tested.

  14. Methodology for assessing the probability of corrosion in concrete structures on the basis of half-cell potential and concrete resistivity measurements.

    Science.gov (United States)

    Sadowski, Lukasz

    2013-01-01

    In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential E corr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

  15. Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

    Directory of Open Access Journals (Sweden)

    Lukasz Sadowski

    2013-01-01

    Full Text Available In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm  ×  750 mm reinforced concrete slab specimens were investigated. Potential Ecorr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

  16. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    International Nuclear Information System (INIS)

    Montes-García, P; Jiménez-Quero, V; López-Calvo, H

    2015-01-01

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix

  17. Identification of controlling factors for the initiation of corrosion of fresh concrete sewers.

    Science.gov (United States)

    Jiang, Guangming; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2015-09-01

    The development of concrete corrosion in new sewer pipes undergoes an initiation process before reaching an active corrosion stage. This initiation period is assumed to last several months to years but the key factors affecting the process, and its duration, are not well understood. This study is therefore focused on this initial stage of the corrosion process and the effect of key environmental factors. Such knowledge is important for the effective management of corrosion in new sewers, as every year of life extension of such systems has a very high financial benefit. This long-term (4.5 year) study has been conducted in purpose-built corrosion chambers that closely simulated the sewer environment, but with control of three key environmental factors being hydrogen sulfide (H2S) gas phase concentration, relative humidity and air temperature. Fresh concrete coupons, cut from an industry-standard sewer pipe, were exposed to the corrosive conditions in the chambers, both in the gas phase and partially submerged in wastewater. A total of 36 exposure conditions were investigated to determine the controlling factors by regular retrieval of concrete coupons for detailed analysis of surface pH, sulfur compounds (elemental sulfur and sulfate) and concrete mass loss. Corrosion initiation times were thus determined for different exposure conditions. It was found that the corrosion initiation time of both gas-phase and partially-submerged coupons was positively correlated with the gas phase H2S concentration, but only at levels of 10 ppm or below, indicating that sulfide oxidation rate rather than the H2S concentration was the limiting factor during the initiation stage. Relative humidity also played a role for the corrosion initiation of the gas-phase coupons. However, the partially-submerged coupons were not affected by humidity as these coupons were in direct contact with the sewage and hence did have sufficient moisture to enable the microbial processes to proceed. The

  18. Modified Hydrotalcites as Smart Additives for Improved Corrosion Protection of Reinforced Concrete

    NARCIS (Netherlands)

    Yang, Z.

    2015-01-01

    Corrosion of reinforcing steel is a major culprit to durability and serviceability of concrete structures. This problem is highly relevant for civil engineering structures in the transport sector, such as bridges, tunnels, harbour quays and parking structures. The dominant aggressive external

  19. Corrosion monitoring for underground and submerged concrete structures - examples and interpretation issues

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.; Leegwater, G.

    2008-01-01

    Since about 1980 Corrosion Monitoring Systems have been used in many concrete structures in aggressive environmentworldwide. While these systemswork properly in aboveground environment, some questions have arisen for submerged conditions, e.g. the outer sides of tunnels, piers in seawater or

  20. Effect of corrosion on the fatigue service-life on steel and reinforced concrete beams

    NARCIS (Netherlands)

    Veerman, R.P.; van Breugel, K.; Koenders, E.A.B.

    2015-01-01

    Chloride-induced corrosion is a point of big concern in reinforced concrete (RC) structures. To monitor the actual health and to predict the remaining service-life of structures, it is important to understand the structural behaviour and the failure mechanism of structures exposed to chlorides under

  1. The Effect of Crack Width on Chloride-Induced Corrosion of Steel in Concrete

    Directory of Open Access Journals (Sweden)

    Weiwei Li

    2017-01-01

    Full Text Available When subjected to loading or thermal shrinkage, reinforced concrete structures usually behave in a cracking state, which raises the risk of bar corrosion from the working environment. The influence of cover cracking on chloride-induced corrosion was experimentally investigated through a 654-day laboratory test on cracked reinforced concrete specimens exposed to chloride solution. The concrete specimens have a dimension of 100 mm × 100 mm × 400 mm and a single prefabricated crack at the midspan. When the percentage concentration of chloride ion (0.6%, 1.2%, 2.1%, 3.0%, and 6.0% and crack width (uncracked, 0.2, 0.3, 0.4, and 0.5 mm are taken as variables, the experimental results showed that the corrosion rates for cracked specimens increased with increasing percentage concentration of chloride and increasing crack width. This study also showed the interrelationship between crack width and percentage concentration of chloride on the corrosion rate. In addition, an empirical model, incorporating the influence of the cover cracking and chloride concentration, was developed to predict the corrosion rate. This model allows the prediction of the maximum allowable wcr based on the given percentage concentration of chloride in the exposure condition.

  2. Long-term prediction of reinforced concrete structures - Use of thermodynamic data to assess steel corrosion in carbonated concrete

    Energy Technology Data Exchange (ETDEWEB)

    Huet, Bruno [Laboratoire d' Etude du Comportement des Betons et Argiles, DEN/DPC/SCCME/LECBA, Bat. 158, CEA Saclay, 91191 Gif sur Yvette cedex (France)]|[Laboratoire de Physico-Chimie Industrielle, LPCI, INSA de Lyon, Bat. Leonard de Vinci, 20 av. Albert Einstein, 69621 Villeurbanne cedex (France); L' Hostis, Valerie; Le Bescop, Patrick [Laboratoire d' Etude du Comportement des Betons et Argiles, DEN/DPC/SCCME/LECBA, Bat. 158, CEA Saclay, 91191 Gif sur Yvette cedex (France); Idrissi, Hassane [Laboratoire de Physico-Chimie Industrielle, LPCI, INSA de Lyon, Bat. Leonard de Vinci, 20 av. Albert Einstein, 69621 Villeurbanne cedex (France)

    2004-07-01

    In the context of the prediction of the long-term behaviour of reinforced concrete structures involved in the nuclear waste storage, the corrosion mechanisms of the steels have to be assessed and modelled. When nuclear wastes are embedded in reinforced concrete containers, the chemical environment of the reinforcement is progressively modified, due to the diffusion of the carbonation front inside the concrete matrix. This modification leads to the variation of the properties of the iron oxides formed at the steel/concrete interface, and the active corrosion can be initiated. In order to understand and modelled the mechanisms of steel corrosion in concrete, the equilibrium of two main systems must be separately described with the help of thermodynamic data issued from the literature: - The mineral phases, lime and calcium silicate hydrate (C-S-H), in equilibrium with the pore solution during the propagation of the carbonation front; - The iron oxides in equilibrium with the aqueous solution. For this purpose, the nature of aqueous species present in the pore solution was calculated in the whole range of pH encountered during the cement paste degradation by carbonation. As a matter of fact, as the pH decreases, calcium concentration decreases and silicates concentration increases due to the calcium carbonate formation and C-S-H dissolution. The pH of a carbonated concrete ranges between 8.3 and 10, depending on the partial pressure of carbon dioxide in the porosity and the conversion degree of carbonation. In this pH range, the iron oxides equilibria were analysed as a function of the redox potential and aqueous species (carbonates and sulphates present in the solution) present inside the solution. In a reductive solution and in presence of carbonates, the high solubility of iron oxides may prevent passivation or generate the dissolution of the passive film. Moreover, the relevance of thermodynamics calculations has been confirmed by corrosion tests of mild steel

  3. Long-term prediction of reinforced concrete structures - Use of thermodynamic data to assess steel corrosion in carbonated concrete

    International Nuclear Information System (INIS)

    Huet, Bruno; L'Hostis, Valerie; Le Bescop, Patrick; Idrissi, Hassane

    2004-01-01

    In the context of the prediction of the long-term behaviour of reinforced concrete structures involved in the nuclear waste storage, the corrosion mechanisms of the steels have to be assessed and modelled. When nuclear wastes are embedded in reinforced concrete containers, the chemical environment of the reinforcement is progressively modified, due to the diffusion of the carbonation front inside the concrete matrix. This modification leads to the variation of the properties of the iron oxides formed at the steel/concrete interface, and the active corrosion can be initiated. In order to understand and modelled the mechanisms of steel corrosion in concrete, the equilibrium of two main systems must be separately described with the help of thermodynamic data issued from the literature: - The mineral phases, lime and calcium silicate hydrate (C-S-H), in equilibrium with the pore solution during the propagation of the carbonation front; - The iron oxides in equilibrium with the aqueous solution. For this purpose, the nature of aqueous species present in the pore solution was calculated in the whole range of pH encountered during the cement paste degradation by carbonation. As a matter of fact, as the pH decreases, calcium concentration decreases and silicates concentration increases due to the calcium carbonate formation and C-S-H dissolution. The pH of a carbonated concrete ranges between 8.3 and 10, depending on the partial pressure of carbon dioxide in the porosity and the conversion degree of carbonation. In this pH range, the iron oxides equilibria were analysed as a function of the redox potential and aqueous species (carbonates and sulphates present in the solution) present inside the solution. In a reductive solution and in presence of carbonates, the high solubility of iron oxides may prevent passivation or generate the dissolution of the passive film. Moreover, the relevance of thermodynamics calculations has been confirmed by corrosion tests of mild steel

  4. Standard test method for initial screening of corrosion inhibiting admixtures for steel in concrete

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers a procedure for determining the effects of chemical admixtures on the corrosion of metals in concrete. This test method can be used to evaluate materials intended to inhibit chloride-induced corrosion of steel in concrete. It can also be used to evaluate the corrosivity of admixtures by themselves or in a chloride environment. This test is not applicable for emulsions. 1.2 &solely-SI-units; 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.

  5. Prediction of crack due to corrosion of reinforcing bar in low alkali concrete

    International Nuclear Information System (INIS)

    Takeda, Nobufumi; Iriya, Keishiro; Hitomi, Takashi; Konishi, Kazuhiro; Kurihara, Yuji

    2008-01-01

    Steel-reinforced low alkaline concrete containing pozzolan has been examined for application in high level radioactive waste disposal. Marine exposure examinations a period of six years were performed for concrete with 30% water-cement ratio, and the reduction in its compressive strength, the intrusion depth of chloride ions, and the corrosion of the reinforcing bar were investigated. On the basis of these results, the progress of corrosion of the reinforcing bar and the outbreak time of a corrosion crack in the reinforcing bar were predicted. The following results are obtained. 1) There was no decrease in the compressive strength of the test pieces during the marine exposure examinations. 2) There was little penetration of the chloride ions in comparison with ordinary Portland cement. 3) Although the corrosion of the reinforcing bar commenced at an early stage with a little quantity of chloride ion intrusion, the progress over the period of six years was extremely small. 4) The corrosion rate of the reinforcing bar in groundwater including sea water was estimated as 0.30-0.55 mg/(cm 2 ·year). In the case of a reinforcing bar with a thickness of 100 mm and diameter of 22 mm, the outbreak time of the reinforcing corrosion crack was predicted as 50-100 years after construction. (author)

  6. The efficiency of a corrosion inhibitor on steel in a simulated concrete environment

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, Nina; Kosec, Tadeja, E-mail: tadeja.kosec@zag.si; Legat, Andraž

    2016-12-01

    The aim of the present work was to characterize the efficiency of a corrosion inhibitor on steel in a simulated concrete pore solution. Laboratory measurements were performed at various chloride and inhibitor concentrations in order to simulate different applications of the inhibitor when used for the protection or rehabilitation of steel reinforcement in concrete. Two electrochemical techniques, i.e. potentiodynamic polarization scans and electrochemical impedance spectroscopy, were used for this study. The exposed surfaces of the steel specimens were subsequently investigated by Raman spectroscopy and scanning electron microscopy. It was found that the inhibitor can efficiently retard the corrosion of steel in a simulated concrete pore solution at concentrations of the inhibitor >2.0% and of chlorides <0.3% at a pH 10.5. On the other hand, when these conditions are not fulfilled, localized corrosion was observed. The results of the Raman and SEM/EDS analysis showed various morphologies of corrosion products and different types of corrosion attack depending on the pH of the pore solution, and the applied concentrations of the chlorides and the inhibitor. - Highlights: • Electrochemical studies performed at various Cl{sup −} and inhibitor concentrations. • Exposed steel surfaces investigated by Raman spectroscopy and SEM. • Cl{sup −}/inhibitor ratio is important parameter for the inhibitor's efficiency. • The corrosion can re-occur if the concentration of the inhibitor is reduced. • Different corrosion behaviour and oxides in the presence of inhibitor and/or Cl{sup −}.

  7. Sustainability assessment of concrete structure durability under reinforcement corrosion

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Michel, Alexander; Stang, Henrik

    In the present paper a parametric study is conducted based on an existing finite element based model. The influence of cover layer, reinforcement diameter and water-to-cement ratio is compared to a possible scatter in the results due to insufficient knowledge about the distribution of the corrosion...... current density along the circumference of the reinforcement. Simulations show that the scatter has a greater influence on the results than changing the parameters wherefore it is concluded that further investigation of the non-uniform deposition of corrosion products is essential to better understand...

  8. Concrete Waste Recycling Process for High Quality Aggregate

    International Nuclear Information System (INIS)

    Ishikura, Takeshi; Fujii, Shin-ichi

    2008-01-01

    Large amount of concrete waste generates during nuclear power plant (NPP) dismantling. Non-contaminated concrete waste is assumed to be disposed in a landfill site, but that will not be the solution especially in the future, because of decreasing tendency of the site availability and natural resources. Concerning concrete recycling, demand for roadbeds and backfill tends to be less than the amount of dismantled concrete generated in a single rural site, and conventional recycled aggregate is limited of its use to non-structural concrete, because of its inferior quality to ordinary natural aggregate. Therefore, it is vital to develop high quality recycled aggregate for general uses of dismantled concrete. If recycled aggregate is available for high structural concrete, the dismantling concrete is recyclable as aggregate for industry including nuclear field. Authors developed techniques on high quality aggregate reclamation for large amount of concrete generated during NPP decommissioning. Concrete of NPP buildings has good features for recycling aggregate; large quantity of high quality aggregate from same origin, record keeping of the aggregate origin, and little impurities in dismantled concrete such as wood and plastics. The target of recycled aggregate in this development is to meet the quality criteria for NPP concrete as prescribed in JASS 5N 'Specification for Nuclear Power Facility Reinforced Concrete' and JASS 5 'Specification for Reinforced Concrete Work'. The target of recycled aggregate concrete is to be comparable performance with ordinary aggregate concrete. The high quality recycled aggregate production techniques are assumed to apply for recycling for large amount of non-contaminated concrete. These techniques can also be applied for slightly contaminated concrete dismantled from radiological control area (RCA), together with free release survey. In conclusion: a technology on dismantled concrete recycling for high quality aggregate was developed

  9. Investigation of Non-Uniform Rust Distribution and Its Effects on Corrosion Induced Cracking in Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Sutrisno Wahyuniarsih

    2017-01-01

    Full Text Available Uniform corrosion still widely used by a lot of researchers and engineers to analyze the corrosion induced cracking. However, in practice, corrosion process occurred non-uniformly. The part nearest to the exposed surface is more likely to have faster corrosion initiation compared with other regions. This research is mainly focused on investigating the effect of non-uniform rust distribution to cover cracking in reinforced concrete. An experimental test performed using accelerated corrosion test by using 5% NaCl solution and applied a constant electric current to the concrete samples. The rust distribution and measurement were observed by using a digital microscope. Based on the experimental result, it was found that the rust was distributed in a non-uniform pattern. As a result, the cracks also formed non-uniformly along the perimeter of steel bar. At the last part of this paper, a simulation result of concrete cracking induced by non-uniform corrosion is presented. The result compared with a simulation using uniform corrosion assumption to investigate the damage pattern of each model. The simulation result reveals stress evolution due to rust expansion which leads to concrete cracking. Furthermore, a comparison of stresses induced by non-uniform corrosion and uniform corrosion indicates that non-uniform corrosion could lead to earlier damage to the structure which is specified by the formation and propagation of the crack.

  10. Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

    OpenAIRE

    Sadowski, Lukasz

    2013-01-01

    In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpos...

  11. Electrochemical methods for the inspection of reinforcement corrosion in concrete structures - field experience

    International Nuclear Information System (INIS)

    Elsener, B.; Boehni, H.

    1992-01-01

    Maintenance and planning of the restoration work on reinforced concrete structures need a rapid, non-destructive inspection technique that detects corrosion at an early stage. In this paper the field experience with electrochemical techniques are reported. The results of potential surveys on bridge decks of the Swiss highways, realized with a new computer controlled eight-wheel measurement system, clearly show that a fixed potential value (as proposed in ASTM C 876-87) for the identification and location of active corrosion of steel in concrete does not exist. A statistical elaboration of the potential data allows to identify the potential value for corroding and passive rebar for each structure individually. A rapid new technique using galvanostatic pulse measurements was tested successfully on site. It gives clear, unambiguous results on the corrosion state of the rebars when half-cell potentials are uncertain. In addition, the ohmic resistance and the apparent polarization resistance are determined from the evaluation of the transients. From these values the concrete resistivity and the actual corrosion rate of the rebars may be estimated

  12. Corrosion of the reinforcing steel in the inhibited sawdust concrete construction

    International Nuclear Information System (INIS)

    Kobuliev, Z.V.

    2005-01-01

    In the article described the way of protection of the reinforcing steel in sawdust concrete construction by adding to inhibited sawdust concrete mixture containing nitrate-nitride calcium chloride (NNCC) and (NH 4 ) 2 Cr 2 O 7 , also NaNO 2 + NaNO 3 +NH 4 Cl and CaCl 2 +(NH 4 ) 2 +Cr 2 . There is determined, that the use of these additives increase strength properties of sawdust concrete at 28 day to 40-55% in comparison with sawdust concrete containing CaCl 2 , and decrease its corrosion-resistance activity, and provided reliability under condition of double excess of inhibitor ions (NO 2- , Cr 2 O 7- ) in comparison with ions (Cl-)

  13. Influence of chemical bonding of chlorides with aluminates in cement hidratation process on corrosion steel bars in concrete

    Directory of Open Access Journals (Sweden)

    Bikić Farzet H.

    2010-01-01

    Full Text Available The presence of chlorides in concrete is a permanent subject of research because they cause corrosion of steel bars. Chlorides added to the concrete during preparation, as accelerators of the bonding of cement minerals process, enter into reaction with aluminates, creating a phase known as chloroaluminate hydrates. In everyday conditions the product of chemical bonding between chlorides and aluminates is usually monochloridealuminate C3A·CaCl2·Hx, better known as Friedel's salt. In this paper, the influence of chemical bonding of chlorides with aluminates during the process of cement hydration on corrosion of steel bars in concrete was investigated. The process of chlorides bonding with aluminates yielding monochloride aluminate is monitored by XRD analyses. It was found that the amount of chlorides bonding with aluminates increases with an increase of temperature, and as a result, reduces the amount of 'free' chlorides in concrete. Potentiodynamic measurements have shown that increase in temperature of the heat treatment of working electrodes by chlorides leads to a reduction of steel bars corrosion as a result of either the increase of the monochloride-aluminate content or the decrease of free chlorides amount. Chlorides bound in chloroaluminate hydrates do not cause activation of steel bars corrosion in concrete. It was also proven that the increase of free chlorides concentration in the concrete leads to intensification of steel bars corrosion. This additionally approves that free chlorides are only the activators of process of steel bars corrosion in the concrete.

  14. Field Testing of High Current Electrokinetic Nanoparticle Treatment for Corrosion Mitigation in Reinforced Concrete

    Science.gov (United States)

    Cardenas, Henry; Alexander, Joshua; Kupwade-Patil, Kunal; Calle, Luz marina

    2010-01-01

    Electrokinetic Nanoparticle (EN) treatment was used as a rapid repair measure to mitigate chloride induced corrosion of reinforced concrete in the field. EN treatment uses an electric field to transport positively charged nanoparticles to the reinforcement through the concrete capillary pores. Cylindrical reinforced concrete specimens were batched with 4.5 wt % salt content (based on cement mass). Three distinct electrokinetic treatments were conducted using high current density (up to 5 A/m2) to form a chloride penetration barrier that was established in 5 days, as opposed to the traditional 6-8 weeks, generally required for electrochemical chloride extraction (ECE). These treatments included basic EN treatment, EN with additional calcium treatment, and basic ECE treatment. Field exposures were conducted at the NASA Beachside Corrosion Test Site, Kennedy Space Center, Florida, USA. The specimens were subjected to sea water immersion at the test site as a posttreatment exposure. Following a 30-day post-treatment exposure period, the specimens were subjected to indirect tensile testing to evaluate treatment impact. The EN treated specimens exhibited 60% and 30% increases in tensile strength as compared to the untreated controls and ECE treated specimens respectively. The surfaces of the reinforcement bars of the control specimens were 67% covered by corrosion products. In contrast, the EN treated specimens exhibited corrosion coverage of only 4%. Scanning electron microscopy (SEM) revealed a dense concrete microstructure adjacent to the bars of the treated specimens as compared to the control and ECE specimens. Energy dispersive spectroscopic (EDS) analysis of the polished EN treated specimens showed a reduction in chloride content by a factor of 20 adjacent to the bars. This study demonstrated that EN treatment was successful in forming a chloride penetration barrier rapidly. This work also showed that the chloride barrier was effective when samples were exposed to

  15. Modified corrosion protection coatings for Concrete tower of Transmission line

    Science.gov (United States)

    Guo, Kai; Jing, Xiangyang; Wang, Hongli; Yue, Zengwu; Wu, Yaping; Mi, Xuchun; Li, Xingeng; Chen, Suhong; Fan, Zhibin

    2017-12-01

    By adding nano SiO2 particles, an enhanced K-PRTV anti-pollution flashover coating had been prepared. Optical profile meter (GT-K), atomic force microscopy (AFM) and infrared spectrometer (FT-IR) characterization were carried out on the coating surface analysis. With the use of modified epoxy resin as the base material, the supplemented by phosphate as a corrosion stabilizer, to achieve a corrosion of steel and galvanized steel with rust coating. Paint with excellent adhesion, more than 10MPa (1), resistant to neutral salt spray 1000h does not appear rust point. At the same time coating a large amount of ultra-fine zinc powder can be added for the tower galvanized layer zinc repair function, while the paint in the zinc powder for the tower to provide sacrificial anode protection, to achieve self-repair function of the coating. Compared to the market with a significant reduction in the cost of rust paint, enhance the anti-corrosion properties.

  16. Evaluation of corrosion of prestressing steel in concrete using non-destructive techniques

    International Nuclear Information System (INIS)

    Ali, M.G.; Maddocks, A.R.

    2003-01-01

    Use of high strength steel in pre-stressed concrete structures has been in use in Australia for many decades. Highway bridges, among other structures, have extensively used pre-stress-ing and post-tensioning techniques. Although prestressing offers many competitive edges to it's traditional rival reinforced concrete, the consequence of damage to prestressing tendons could be catastrophic. Periodic visual inspections of prestressed concrete bridges throughout the world have demonstrated the growing problem of deterioration of prestressing steel as a result of corrosion. Early detection of damage to prestressing steel therefore is of paramount importance. Unfortunately no reliable and practical non-destructive evaluation technique has been available for assessing the condition of prestressing steel within concrete although a number of techniques appear promising. The following inspection methods have been highlighted in recent literature for their use as non-destructive inspection methods for prestressed concrete structures. In addition to the techniques discussed, a number of destructive, or invasive techniques also exist for determination of the corrosion status of prestressing tendons in prestressed structures. The following non-destructive techniques are discussed in some detail: Radiography; Computed Tomography; Surface Penetrating Radar; Impact Echo; Acoustic Emission Monitoring; Magnetic Field Disturbance Technique; Remnant Magnetism Method; Linear Polarisation Method; Electrical Resistance and Surface Potential Survey. The portability, limitations and use in Australia of these techniques are summarised in a table

  17. Transport and Corrosion Behavior of Cracked Reinforced Concrete

    DEFF Research Database (Denmark)

    Pease, Bradley Justin

    Reinforced concrete, due to its inherent versatility and durability as a building material, has been implemented for use in a multitude of structural applications which are exposed to widely varying environmental conditions. Often times these structures are designed for lengthy service lives....... The exposure conditions may vary from industrial products, chemicals, and gases, to annual variations in temperature, to chloride-rich environments such as marine structures and structures exposed to deicing salts. These chloride-rich environments are of central concern in Denmark and throughout the world....... In addition, cracks develop in concrete through various physical and chemical processes, which occur at varying periods of the lifetime of a structure, resulting in varying crack parameters (i.e. width, depth, and tortuosity). These cracks provide easy access of aggressive substances from the environment...

  18. Evaluation of anodes for galvanic cathodic prevention of steel corrosion in prestressed concrete piles in marine environments in Virginia.

    Science.gov (United States)

    1999-07-01

    Many of the major highway crossings over coastal waters in the Hampton area of Virginia are supported by prestressed concrete piles, some of which are showing signs of reinforcement corrosion. Grout jacketing alone is an inadequate protection against...

  19. Environmental variables evaluation on concrete structures corrosion for medium level activities repositories

    International Nuclear Information System (INIS)

    Requena, Carlos; Alvarez, Marta G.; Duffo, Gustavo S.

    2000-01-01

    The main purpose of this work was to evaluate the long term durability of reinforced concrete structures as medium-level waste container material. Electrochemical techniques have been used to evaluate the corrosion behaviour of steel rebars in several solutions simulating the liquid present in the pores of both alkaline and carbonated concrete in the presence of sulphate ions. Results shown that a decrease in p H has an adverse effect on the critical sulphate concentration. The inhibition effect of high carbonate/bicarbonate concentration is also shown. (author)

  20. Bond-Slip Behavior of Basalt Fiber Reinforced Polymer Bar in Concrete Subjected to Simulated Marine Environment: Effects of BFRP Bar Size, Corrosion Age, and Concrete Strength

    Directory of Open Access Journals (Sweden)

    Yongmin Yang

    2017-01-01

    Full Text Available Basalt Fiber Reinforced Polymer (BFRP bars have bright potential application in concrete structures subjected to marine environment due to their superior corrosion resistance. Available literatures mainly focused on the mechanical properties of BFRP concrete structures, while the bond-slip behavior of BFRP bars, which is a key factor influencing the safety and service life of ocean concrete structures, has not been clarified yet. In this paper, effects of BFRP bars size, corrosion age, and concrete strength on the bond-slip behavior of BFRP bars in concrete cured in artificial seawater were investigated, and then an improved Bertero, Popov, and Eligehausen (BPE model was employed to describe the bond-slip behavior of BFRP bars in concrete. The results indicated that the maximum bond stress and corresponding slip decreased gradually with the increase of corrosion age and size of BFRP bars, and ultimate slip also decreased sharply. The ascending segment of bond-slip curve tends to be more rigid and the descending segment tends to be softer after corrosion. A horizontal end in bond-slip curve indicates that the friction between BFRP bars and concrete decreased sharply.

  1. Effect of supplementary cementing materials on the concrete corrosion control

    Directory of Open Access Journals (Sweden)

    Mejía de Gutiérrez, R.

    2003-12-01

    Full Text Available Failure of concrete after a period of years, less than the life expected for which it was designed, may be caused by the environment to which it has been exposed or by a variety of internal causes. The incorporation of supplementary materials has at the Portland cement the purpose of improving the concrete microstructure and also of influence the resistance of concrete to environmental attacks. Different mineral by-products as ground granulated blast furnace slag (GGBS, silica fume (SF, metakaolin (MK, fly ash (FA and other products have been used as supplementary cementing materials. This paper is about the behavior of concrete in the presence of mineral additions. Compared to Portland cements, blended cements show lower heat of hydration, lower permeability, greater resistance to sulphates and sea water. These blended cements find the best application when requirements of durability are regarded as a priority specially on high performance concrete.

    La falla del concreto en un tiempo inferior a la vida útil para la cual se diseñó puede ser consecuencia del medio ambiente al cual ha estado expuesto o de algunas otras causas de tipo interno. La incorporación de materiales suplementarios al cemento Portland tiene el propósito de mejorar la microestructura del concreto y también de contribuir a la resistencia del concreto a los ataques del medio ambiente. Diferentes minerales y subproductos tales como escorias granuladas de alto horno, humo de sílice, metacaolín, ceniza volante y otros productos han sido usados como materiales suplementarios cementantes. Este documento presenta el comportamiento del hormigón en presencia de diferentes adiciones. Los cementos adicionados, comparados con los cementos Portland muestran bajos calores de hidratación, baja permeabilidad, mayor resistencia a sulfatos y a agua de mar. Estos cementos adicionados encuentran un campo de aplicación importante cuando los requerimientos de durabilidad son

  2. Analytical model of cracking due to rebar corrosion expansion in concrete considering the structure internal force

    Science.gov (United States)

    Lin, Xiangyue; Peng, Minli; Lei, Fengming; Tan, Jiangxian; Shi, Huacheng

    2017-12-01

    Based on the assumptions of uniform corrosion and linear elastic expansion, an analytical model of cracking due to rebar corrosion expansion in concrete was established, which is able to consider the structure internal force. And then, by means of the complex variable function theory and series expansion technology established by Muskhelishvili, the corresponding stress component functions of concrete around the reinforcement were obtained. Also, a comparative analysis was conducted between the numerical simulation model and present model in this paper. The results show that the calculation results of both methods were consistent with each other, and the numerical deviation was less than 10%, proving that the analytical model established in this paper is reliable.

  3. Corrosion-induced bond strength degradation in reinforced concrete-Analytical and empirical models

    International Nuclear Information System (INIS)

    Bhargava, Kapilesh; Ghosh, A.K.; Mori, Yasuhiro; Ramanujam, S.

    2007-01-01

    The present paper aims to investigate the relationship between the bond strength and the reinforcement corrosion in reinforced concrete (RC). Analytical and empirical models are proposed for the bond strength of corroded reinforcing bars. Analytical model proposed by Cairns.and Abdullah [Cairns, J., Abdullah, R.B., 1996. Bond strength of black and epoxy-coated reinforcement-a theoretical approach. ACI Mater. J. 93 (4), 362-369] for splitting bond failure and later modified by Coronelli [Coronelli, D. 2002. Corrosion cracking and bond strength modeling for corroded bars in reinforced concrete. ACI Struct. J. 99 (3), 267-276] to consider the corroded bars, has been adopted. Estimation of the various parameters in the earlier analytical model has been proposed by the present authors. These parameters include corrosion pressure due to expansive action of corrosion products, modeling of tensile behaviour of cracked concrete and adhesion and friction coefficient between the corroded bar and cracked concrete. Simple empirical models are also proposed to evaluate the reduction in bond strength as a function of reinforcement corrosion in RC specimens. These empirical models are proposed by considering a wide range of published experimental investigations related to the bond degradation in RC specimens due to reinforcement corrosion. It has been found that the proposed analytical and empirical bond models are capable of providing the estimates of predicted bond strength of corroded reinforcement that are in reasonably good agreement with the experimentally observed values and with those of the other reported published data on analytical and empirical predictions. An attempt has also been made to evaluate the flexural strength of RC beams with corroded reinforcement failing in bond. It has also been found that the analytical predictions for the flexural strength of RC beams based on the proposed bond degradation models are in agreement with those of the experimentally

  4. On the corrosion behaviour of phosphoric irons in simulated concrete pore solution

    International Nuclear Information System (INIS)

    Sahoo, Gadadhar; Balasubramaniam, R.

    2008-01-01

    The corrosion behaviour of three phosphoric irons P 1 (Fe-0.11P-0.028C), P 2 (Fe-0.32P-0.026C) and P 3 (Fe-0.49P-0.022C) has been studied in simulated concrete pore solution (saturated Ca(OH) 2 solution) containing different chloride concentration. This has been compared with that of two commercial concrete reinforcement steels, a low carbon steel TN (Fe-0.148C-0.542Mn-0.128Si) and a microalloyed corrosion resistant steel CS (Fe-0.151C-0.088P-0.197Si-0.149Cr-0.417Cu). The beneficial aspect of phosphoric irons was revealed from potentiodynamic polarization experiments. The pitting potentials and pitting nucleation resistances for phosphoric irons and CS were higher than that for TN. Electrochemical impedance spectroscopy (EIS) studies revealed thickening and growth of passive film as a function of time in case of phosphoric irons and CS in saturated Ca(OH) 2 pore solutions without chloride and in the same solution with 0.05% Cl - and 0.1% Cl - . In case of TN, breakdown of passive film resulted in active corrosion in simulated pore solution containing 0.1% Cl - . Linear polarization resistance measurements complemented EIS results. Visual observations indicated that phosphoric iron P 3 was immune to corrosion even after 125 days of immersion in saturated Ca(OH) 2 solution containing 5% NaCl. The good corrosion resistance of phosphoric irons in simulated concrete pore solution containing chloride ions has been related to the formation of phosphate, based on ultraviolet spectrophotometric analysis and Pourbaix diagram of phosphorus-water system

  5. Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications

    Directory of Open Access Journals (Sweden)

    Belarbi A.

    2018-01-01

    Full Text Available Advancement in material science has enabled the engineers to enhance the strength and long-term behavior of concrete structures. The conventional approach is to use steel for prestressed bridge girders. Despite having good ductility and strength, beams prestressed with steel are susceptible to corrosion when subjected to environmental exposure. The corrosion of the prestressing steel reduces load carrying capacity of the prestressed member and result in catastrophic failures. In the last decades, more durable composite materials such as Aramid Fiber Reinforced Polymer (AFRP, Glass Fiber Reinforced Polymer (GFRP and Carbon Fiber Reinforced Polymer (CFRP have been implemented in concrete structures as a solution to this problem. Among these materials, CFRP stands out as a primary prestressing reinforcement, which has the potential to replace steel and provide corrosion free prestressed bridge girders. Despite its promise, prestressing CFRP has not frequently been used for bridge construction worldwide. The major contributing factor to the lack of advancement of this promising technology in the United States (U.S. is the lack of comprehensive design specifications. Apart from a limited number of guides, manuals, and commentaries, there is currently no standard or comprehensive design guideline available to bridge engineers in the U.S. for the design of concrete structures prestressed with CFRP systems. The main goal is to develop design guidelines in AASHTO-LRFD format for concrete bridge girders with prestressing CFRP materials. The guidelines are intended to address the limitation in current AASHTO-LRFD Bridge Design Specifications which is applicable for prestressed bridge girders with steel strands. To accomplish this goal, some of the critical parameters that affect the design and long-term behavior of prestressed concrete bridge girders with prestressing CFRP systems are identified and included in the research work. This paper presents

  6. The influence of blast furnace slag, fly ash and silica fume on corrosion of reinforced concrete in marine environment

    NARCIS (Netherlands)

    Polder, R.B.

    1996-01-01

    Chloride penetration from sea water may cause corrosion of reinforcement in concrete structures. Adding reactive inorganic materials such as blast furnace slag, fly ash or silica fume to the cement matrix improves the resistance against chloride penetration as compared to Portland cement concrete. A

  7. Characterisation of chloride transport and reinforcement corrosion in concrete under cyclic wetting and drying by electrical resistivity

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.

    2002-01-01

    Concrete prisms were made with four cement types including cements with fly ash and/or blast furnace slag and three waterto- cement (w/c) ratios. Chloride penetration and corrosion of rebars were stimulated by subjecting prisms to cyclic loading with salt solution and drying. Concrete resistivity,

  8. Effect of Metakaolin and Slag blended Cement on Corrosion Behaviour of Concrete

    Science.gov (United States)

    Borade, Anita N.; Kondraivendhan, B.

    2017-06-01

    The present paper is aimed to investigate the influence of Metakaolin (MK) and Portland slag Cement (PSC) on corrosion behaviour of concrete. For this purpose, Ordinary Portland Cement (OPC) was replaced by 15% MK by weight and readymade available PSC were used. The standard concrete specimens were prepared for both compressive strength and half- cell potential measurement. For the aforesaid experiments, the specimens were cast with varying water to binder ratios (w/b) such as 0.45, 0.5 and 0.55 and exposed to 0%, 3%, 5% and 7.5% of sodium chloride (NaCl) solution. The specimens were tested at wide range of curing ages namely 7, 28, 56, 90 and 180 days. The effects of MK, w/b ratio, age, and NaCl exposure upon concrete were demonstrated in this investigation along with the comparison of results of both MK and PSC concrete were done. It was also observed that concrete with MK shows improved performance as compared to concrete with PSC.

  9. 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

  10. Influence of Simulated Acid Rain Corrosion on the Uniaxial Tensile Mechanical Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Ying-zi Zhang

    2012-01-01

    Full Text Available An experimental study on the uniaxial tensile property of concrete exposed to the acid rain environment was carried out. Acid rain with pH level of 1.0 was deposed by the mixture of sulfate and nitric acid solution in the laboratory. Dumbbell-shaped concrete specimens were immersed in the simulated acid rain completely. After being exposed to the deposed mixture for a certain period, uniaxial tensile test was performed on the concrete specimens. The results indicate that elastic modulus, tensile strength, and peak strain have a slight increase at the initial corrosion stage, and with the extension of corrosion process, elastic modulus and tensile strength decrease gradually, while the peak strain still increases. It is found that the compressive strength is more sensitive than the tensile strength in aggressive environment. Based on the experimental results, an equation was proposed to describe the ascending branch of the stress-strain curve of the concrete corroded by acid rain.

  11. Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

    Science.gov (United States)

    Haile, Tesfaalem; Nakhla, George

    2009-01-01

    The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

  12. Development and Evaluation of Cement-Based Materials for Repair of Corrosion-Damaged Reinforced Concrete Slabs

    OpenAIRE

    Liu, Rongtang; Olek, J.

    2001-01-01

    In this study, the results of an extensive laboratory investigation conducted to evaluate the properties of concrete mixes used as patching materials to repair reinforced concrete slabs damaged by corrosion are reported. Seven special concrete mixes containing various combinations of chemical or mineral admixtures were developed and used as a patching material to improve the durability of the repaired slabs. Physical and mechanical properties of these mixes, such as compressive strength, stat...

  13. The use of a Phosphate-Based Migrating Corrosion Inhibitor to Repair Reinforced Concrete Elements Contaminated by Chlorides

    Science.gov (United States)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The use of sodium monofluorophosphate (MFP) was experimented as migrator inhibiting treatment against corrosion of reinforced concrete elements induced by chlorides. The results show that sodium monofluorophosphate, applied by surface impregnation, is able to slow down reinforcement corrosion only for reinforcing steel bars with concrete cover not thicker than 1 cm. This limitation is most probably due to the difficulty, with the type of application adopted, in making MFP to reach concentrations high enough to inhibit the corrosive process at greater depths from the impregnation surface.

  14. Long Term Corrosion Experiment of Steel Rebar in Fly Ash-Based Geopolymer Concrete in NaCl Solution

    Directory of Open Access Journals (Sweden)

    Y. P. Asmara

    2016-01-01

    Full Text Available This research focuses on an experimental investigation to identify the effects of fly ash on the electrochemical process of concrete during the curing time. A rebar was analysed using potentiostat to measure the rest potential, polarization diagram, and corrosion rate. Water-to-cement ratio and amount of fly ash were varied. After being cured for 24 hours at a temperature of 65°C, the samples were immersed in 3.5% of NaCl solution for 365 days for electrochemical measurement. Measurements of the half-cell potential and corrosion current density indicated that the fly ash has significant effects on corrosion behaviour of concrete. Although fly ash tends to create passivity on anodic current, it increases corrosion rate. The corrosion potential of this concrete mixture decreases compared to concrete without fly ash. From the result, it can be summarized that concrete mixture with 70% of OPC (Ordinary Portland Cement and 30% fly ash has shown the best corrosion resistance.

  15. Evaluation of the reinforcing steel corrosion in concrete mixes that will be used for constructing mid activity disposal repositories

    International Nuclear Information System (INIS)

    Moreno, Manuel; Alvarez, Marta G.; Duffo, Gustavo S.

    2000-01-01

    This study presents an evaluation of the reinforcing steel bars (rebars) corrosion behavior embedded in high performance concrete's prepared with three different cement types (normal Portland, Sulfate resistant and with furnace slag). The results of the study will provide the basis to select the materials used for constructing the mid activity radioactive disposals containers. The effect of aggressive ions such as chlorides and sulfates, as well as concrete carbonation, on the rebar corrosion process is evaluated using concrete specimens containing rebar segments. The electrochemical parameters that characterize the rebar corrosion process (corrosion potential (E corr ), polarization resistance (Rp) and electrical resistivity of concrete (ρ)) where periodically monitored after a conditioning period of 100 days. The results show that under all exposure conditions evaluated the rebar segments in contact with the three concrete mixes achieve a passive state of corrosion. Due to the continuos curing process of concrete the values of ρ present an increasing trend within time, even in the specimens exposed to the immersed conditions. (author)

  16. Corrosion characteristics of a 4-year naturally corroded reinforced concrete beam with load-induced transverse cracks

    International Nuclear Information System (INIS)

    Fu, Chuanqing; Jin, Nanguo; Ye, Hailong; Jin, Xianyu; Dai, Wei

    2017-01-01

    Highlights: • A comprehensive study of corrosion characteristics of a naturally corroded RC beam. • New insights on the role of cracks in corrosion propagation of steel in concrete. • EMPA and 3D laser scanning provide quantitative analysis of corroded rebar. - Abstract: This work studies the corrosion characteristics of reinforcement in a 4-year naturally corroded concrete beam after accelerated chloride penetration. The results show that the presence of transverse cracks in the tension surface of reinforced concrete beam can globally exacerbate the loss of cross-sectional area of rebar. However, there is no strong correlation between the width of transverse cracks, with the width of longitudinal cracks and loss of cross-sectional area of corroded rebar at a specific location. The self-healing of cracks and sacrificing roles of stirrups at crack tips seem to reduce the impacts of cracks on the corrosion propagation.

  17. Corrosion Risk of Reinforced Concrete Structure Arising from Internal and External Chloride

    Directory of Open Access Journals (Sweden)

    M. J. Kim

    2018-01-01

    Full Text Available The corrosion risk of internal chloride and external chloride from three different exposure conditions was evaluated. The initiation of corrosion was detected by monitoring the galvanic current between cathode metal and embedded steel. The chloride threshold was determined by measuring the corrosion rate of steel by the polarization technique for internal chloride and the chloride profiling test for external chloride. As the result, the initiation of corrosion was accelerated with a cyclic wet/dry condition, compared to the totally wet condition. In addition, it was found that an increase of the drying ratio in the exposure condition resulted in an increase of corrosion rate after initiation. The threshold level of external chloride ranged from 0.2 to 0.3% weight by cement and internal chloride shows higher range, equated to 1.59–3.10%. Based on these data, the chloride penetration with exposure condition was predicted to determine the service life of reinforced concrete structure.

  18. Quality control of fireproof coatings for reinforced concrete structures

    Science.gov (United States)

    Gravit, Marina; Dmitriev, Ivan; Ishkov, Alexander

    2017-10-01

    The article analyzes methods of quality inspection of fireproof coatings (work flow, measuring, laboratory, etc.). In modern construction there is a problem of lack of distinct monitoring for the fire protection testing. There is a description of this testing for reinforced concrete structures. The article shows the results of calculation quality control of hatches as an example of fireproof coating for reinforced concrete structures.

  19. Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

    International Nuclear Information System (INIS)

    Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

    2016-01-01

    Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability. (paper)

  20. Corrosion of steel in concrete in cooling water walls. Report part 2 - Effects of the relative humidity on chlorine-initiated corrosion of the reinforcing steel; Korrosion paa staal i betong i kylvattenvaegar. Delrapport 2 - Relativa fuktighetens inverkan paa kloridinitierad armeringskorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Bertil; Ahlstroem, Johan; Sederholm, Bror; Nilsson, Lars-Olof; Lindmark, Sture

    2010-04-15

    Steel in concrete is protected against corrosion by the high pH value of the concrete. The passivity can however be broken if chloride ions penetrate into the concrete. It is presumed that a certain amount of chloride is needed to activate the steel. This value is called the threshold level. Even though many attempts have been performed no reliable value has been found. One of the reasons for this is probably that the threshold value is influenced by the humidity of the concrete. At very high humidity the transport of oxygen to the steel surface is slow and at low humidity the electrical resistance increases. The aim of this investigation has been to determine at what humidity the corrosion rate reaches its highest value. With this as a background new tests can be performed to predict the chloride threshold value. The results indicate that it most probably do exist a threshold value for each concrete quality. At chloride contents above the threshold value the steel looses its passivity. If severe corrosion takes place or not is however strongly dependent on the humidity of the concrete. In a close interval around 95 % relative humidity the steel is attacked by pitting corrosion when the threshold value is exceeded. At lower and higher humidity the passivity is incomplete and the corrosion rate in most cases marginal. Future investigations concerning chloride threshold values is recommended to be performed at a relative humidity of 95 % and by using reference samples according to proposed procedure.

  1. Concrete and corrosion monitoring during the 2nd supercontainer half-scale test

    International Nuclear Information System (INIS)

    Areias, L.; Troullinous, I.; Verstricht, J.; Iliopoulos, S.; Pyl, L.; Voet, E.; Van Ingelgem, Y.; Kursten, B.; Craeye, B.; Coppens, E.; Van Marcke, P.

    2015-01-01

    The Super-container (SC) is a reference design concept for the packaging of spent fuel (SF) and vitrified high-level radioactive waste (HLW). The SC conceptual design is based on a multiple barrier system consisting of an outer stainless steel envelope, a concrete buffer and a water-tight carbon steel overpack containing one or more waste canisters. The experimental test described in this paper uses a so called 'half-scale' model of the SC. A metal container containing an electrical heat source is used to simulate the heat-emitting waste of a real overpack. A total of 182 sensors have been installed to monitor the half-scale model. The majority of the sensors are embedded in the concrete materials, while a limited number of them are installed around the outside of the structure to measure the ambient temperature, relative humidity and air velocity. The instrumentation included the use of fibre optics to measure both distributed as well as semi-distributed temperature and strain in the three orthogonal directions, Digital Image Correlation (DIC) and Acoustic Emission (AE) to monitor microcrack initiation and evolution, and a new PermaZEN corrosion sensor to measure the active corrosion of the carbon steel overpack. The combined results of DIC and AE monitoring have enabled the detection and measurement of surface movement, captured the onset of micro crack formation and its propagation, and measured the displacement and strain fields at different levels across the height of the half-scale test as a function of time. In particular, the DIC measurements clearly identified the appearance of the first micro cracks formed on the concrete surface of the buffer with a crack width resolution of approximately 13 microns. The results of a laboratory test performed with the corrosion sensor show a rapid onset of corrosion at the beginning of the test followed by an equally rapid decrease in corrosion after only a few days of testing. The measured corrosion rates

  2. Advances in Chemical and Structural Characterization of Concretion with Implications for Modeling Marine Corrosion

    Science.gov (United States)

    Johnson, Donald L.; DeAngelis, Robert J.; Medlin, Dana J.; Carr, James D.; Conlin, David L.

    2014-05-01

    The Weins number model and concretion equivalent corrosion rate methodology were developed as potential minimum-impact, cost-effective techniques to determine corrosion damage on submerged steel structures. To apply the full potential of these technologies, a detailed chemical and structural characterization of the concretion (hard biofouling) that transforms into iron bearing minerals is required. The fractions of existing compounds and the quantitative chemistries are difficult to determine from x-ray diffraction. Environmental scanning electron microscopy was used to present chemical compositions by means of energy-dispersive spectroscopy (EDS). EDS demonstrates the chemical data in mapping format or in point or selected area chemistries. Selected-area EDS data collection at precise locations is presented in terms of atomic percent. The mechanism of formation and distribution of the iron-bearing mineral species at specific locations will be presented. Based on water retention measurements, porosity in terms of void volume varies from 15 v/o to 30 v/o (vol.%). The void path displayed by scanning electron microscopy imaging illustrates the tortuous path by which oxygen migrates in the water phase within the concretion from seaside to metalside.

  3. Selected durability studies of geopolymer concrete with respect to carbonation, elevated temperature, and microbial induced corrosion

    Science.gov (United States)

    Badar, Mohammad Sufian

    This thesis reports a comprehensive study related to the experimental evaluation of carbonation in reinforced geopolymer concrete, the evaluation of geopolymer concretes at elevated temperature, and the resistance of geopolymer concrete to microbial induced corrosion (MIC). Carbonation: Reinforced concretes, made of geopolymer, prepared from two class F fly ashes and one class C fly ash, were subjected to accelerated carbonation treatment for a period of 450 days. Electrochemical, microstructure and pore structure examinations were performed to evaluate the effect of corrosion caused due to carbonation. GPC specimens prepared from class F fly ash exhibited lower corrosion rates by a factor of 21, and higher pH values (pH>12) when compared with concrete specimens prepared from class C Fly ash (GPCMN). Microstructure and pore characterization of GPC prepared using class F fly ash revealed lower porosity by a factor of 2.5 as compared with thier counterparts made using GPC-MN. The superior performace of GPC prepared with the class F fly ash could be attributed to the dense pore structure and formation of the protective layer of calcium and sodium alumino silicate hydrates (C/N-A-S-H) geopolymeric gels around the steel reinforcement. Elevated Temperature: Geopolymers are an emerging class of cementitious binders which possess a potential for high temperature resistance that could possibly be utilized in applications such as nozzles, aspirators and refractory linings. This study reports on the results of an investigation into the performance of a fly ash based geopolymer binder in high temperature environments. Geopolymer concrete (GPC) was prepared using eleven types of fly ashes obtained from four countries. High content alumina and silica sand was used in the mix for preparing GPC. GPC was subjected to thermal shock tests following ASTM C 1100-88. The GPC samples prepared with tabular alumina were kept at 1093° C and immediately quenched in water. GPC specimens

  4. Influence of alkali, silicate, and sulfate content of carbonated concrete pore solution on mild steel corrosion behavior

    International Nuclear Information System (INIS)

    L'Hostis, V.; Huet, B.; Tricheux, L.; Idrissi, H.

    2010-01-01

    The increase in the rebar corrosion rate due to the concrete carbonation is the major cause of reinforced concrete degradation. The aim of this study was to investigate the corrosion behavior of mild steel rebars in simulated carbonated concrete solution. For this purpose, thermodynamic calculations, electrochemical techniques, gravimetric measurements, and surface analyses were used. Thermodynamic investigations of the nature of the interstitial solution provides an estimation of the influence of sulfate (SO 4 2- ) and alkali (Na + , K + ) content on carbonate alkalinity of the CO 2 /H 2 O open system (pCO 2 =0. 3 mbar). in this system, calcium-silicate hydrates (C-S-H) remain thermodynamically unstable and amorphous silica controls silicate aqueous content at 100 ppm. Electrochemical results highlight a decrease in the corrosion rate with increasing carbonate alkalinity and the introduction of silicate. The introduction of sulfate at fixed carbonate alkalinity shows a dual effect: at high carbonate alkalinity, the corrosion rate is increased whereas at low carbonate alkalinity, corrosion rate is decreased. Those results are supported by surface analysis. Authors conclude that silicate and sulfate release from cement hydrates and fixation of alkali on carbonated hydrates are key parameters to estimate mild steel corrosion in carbonated concrete. (authors)

  5. Response of reinforced concrete structures to macrocell corrosion of reinforcements. Part I: Before propagation of microcracks via an analytical approach

    International Nuclear Information System (INIS)

    Kiani, Keivan; Shodja, Hossein M.

    2011-01-01

    Highlights: ► Response of RC structures to macrocell corrosion of a rebar is studied analytically. ► The problem is solved prior to the onset of microcrack propagation. ► Suitable Love's potential functions are used to study the steel-rust-concrete media. ► The role of crucial factors on the time of onset of concrete cracking is examined. ► The effect of vital factors on the maximum radial stress of concrete is explored. - Abstract: Assessment of the macrocell corrosion which deteriorates reinforced concrete (RC) structures have attracted the attention of many researchers during recent years. In this type of rebar corrosion, the reduction in cross-section of the rebar is significantly accelerated due to the large ratio of the cathode's area to the anode's area. In order to examine the problem, an analytical solution is proposed for prediction of the response of the RC structure from the time of steel depassivation to the stage just prior to the onset of microcrack propagation. To this end, a circular cylindrical RC member under axisymmetric macrocell corrosion of the reinforcement is considered. Both cases of the symmetric and asymmetric rebar corrosion along the length of the anode zone are studied. According to the experimentally observed data, corrosion products are modeled as a thin layer with a nonlinear stress–strain relation. The exact expressions of the elastic fields associated with the steel, and concrete media are obtained using Love's potential function. By imposing the boundary conditions, the resulting set of nonlinear equations are solved in each time step by Newton's method. The effects of the key parameters which have dominating role in the time of the onset of concrete cracking and maximum radial stress field of the concrete have been examined.

  6. Pitting Corrosion Behaviour of New Corrosion-Resistant Reinforcement Bars in Chloride-Containing Concrete Pore Solution.

    Science.gov (United States)

    Jiang, Jin-Yang; Liu, Yao; Chu, Hong-Yan; Wang, Danqian; Ma, Han; Sun, Wei

    2017-08-04

    In this study, the pitting behaviour of a new corrosion-resistant alloy steel (CR) is compared to that of low-carbon steel (LC) in a simulated concrete pore solution with a chloride concentration of 5 mol/L. The electrochemical behaviour of the bars was characterised using linear polarisation resistance (LPR) and electrochemical impedance spectroscopy (EIS). The pitting profiles were detected by reflective digital holographic microscopy (DHM), scanning electron microscopy (SEM), and the chemical components produced in the pitting process were analysed by X-ray energy dispersive spectroscopy (EDS). The results show that the CR bars have a higher resistance to pitting corrosion than the LC bars. This is primarily because of the periodic occurrence of metastable pitting during pitting development. Compared to the pitting process in the LC bars, the pitting depth grows slowly in the CR bars, which greatly reduces the risk of pitting. The possible reason for this result is that the capability of the CR bars to heal the passivation film helps to restore the metastable pits to the passivation state.

  7. Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Hakan Yalciner

    2014-01-01

    Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

  8. A coupled carbonation-rust formation mechanical damage model for steel corrosion in reinforced concrete

    International Nuclear Information System (INIS)

    Nguyen, Huyen; Bary, B.; L'Hostis, Valerie; DeLarrard, T.

    2014-01-01

    This paper aims at presenting a strategy to simulate the corrosion of steel reinforcement due to carbonation of concrete in atmospheric environment. We propose a model coupling drying, carbonation, diffusion of oxygen, formation of rust and mechanics to describe these phenomena. The rust layer is assumed to be composed of two sub-layers with different elastic modulus. An unstable layer with a low modulus (from 0.1 to 5 GPa) is located next to the transformed medium, and another more stable one with a higher modulus (from 100 to 150 GPa) at the interface with steel reinforcement. This model is applied to a numerical meso-structure composed of 4 phases: mortar matrix, randomly distributed aggregates, steel rebar and rust layers to underline the effect of aggregates on damage initiation and corresponding crack pattern of concrete cover. (authors)

  9. Corrosion/94 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The approximately 500 papers from this conference are divided into the following sections: Rail transit systems--stray current corrosion problems and control; Total quality in the coatings industry; Deterioration mechanisms of alloys at high temperatures--prevention and remediation; Research needs and new developments in oxygen scavengers; Computers in corrosion control--knowledge based system; Corrosion and corrosivity sensors; Corrosion and corrosion control of steel reinforced concrete structures; Microbiologically influenced corrosion; Practical applications in mitigating CO 2 corrosion; Mineral scale deposit control in oilfield-related operations; Corrosion of materials in nuclear systems; Testing nonmetallics for life prediction; Refinery industry corrosion; Underground corrosion control; Mechanisms and applications of deposit and scale control additives; Corrosion in power transmission and distribution systems; Corrosion inhibitor testing and field application in oil and gas systems; Decontamination technology; Ozone in cooling water applications, testing, and mechanisms; Corrosion of water and sewage treatment, collection, and distribution systems; Environmental cracking of materials; Metallurgy of oil and gas field equipment; Corrosion measurement technology; Duplex stainless steels in the chemical process industries; Corrosion in the pulp and paper industry; Advances in cooling water treatment; Marine corrosion; Performance of materials in environments applicable to fossil energy systems; Environmental degradation of and methods of protection for military and aerospace materials; Rail equipment corrosion; Cathodic protection in natural waters; Characterization of air pollution control system environments; and Deposit-related problems in industrial boilers. Papers have been processed separately for inclusion on the data base

  10. Evaluation of the potential of additives as corrosion inhibitors of CA-50 carbon steel used as reinforcement in concretes

    International Nuclear Information System (INIS)

    Mennucci, Marina Martins

    2006-01-01

    In this work, various compounds were tested to evaluate their potential capability for their use as corrosion inhibitors of carbon steel reinforcement in concretes. The additives tested were sodium benzoate, polyethylene glycol, hexamethylenetetramine, benzotriazole and yttrium carbonate. Initially, exploratory tests were carried out to select the ones to be used as corrosion inhibitors, based on the inhibit ion efficiency determined from electrochemical tests, specifically polarization tests and electrochemical impedance spectroscopy. These tests were carried out in a solution composed of 0.01 N sodium hydroxide (NaOH) and 0.05 N potassium hydroxide (KOH) to simulate the composition of the solution inside the pores in concretes. The additive that presented the most promising potential to be used as corrosion inhibitor was benzotriazole (BTA). After the elimination of some compounds and selection of the additive with higher corrosion inhibit ion efficiency in the test medium, the effect of its concentration on the corrosion inhibition efficiency was evaluated. Sodium nitrite solutions with the same concentrations as those solutions with BTA were tested for comparison reasons. Sodium nitrite is a well established corrosion inhibitor for carbon steel reinforcement in concretes but it has been related to toxic effects. The BTA was associated to higher corrosion inhibition efficiencies than that of sodium nitrite in similar concentrations. A blackish adherent film was formed on the steel surface exposed to BTA solutions during long periods of immersion in the alkaline medium. The results suggest that BTA is a potential candidate for substitution of nitrites as corrosion inhibitor of reinforcements in concrete. (author)

  11. The effect of functionalized polycarboxylate structures as corrosion inhibitors in a simulated concrete pore solution

    Science.gov (United States)

    Fazayel, A. S.; Khorasani, M.; Sarabi, A. A.

    2018-05-01

    In this study, the effects of polycarboxylate derivatives with different comonomers and functional groups on the control or reduction of corrosion in steel specimens were evaluated through electrochemical impedance spectroscopy (EIS) and potentiodynamic analysis. A highly alkaline contaminated concrete pore solution (CPS) containing chlorides was used to simulate the pitting corrosion, and according to the results, the mechanism of inhibitive action was determined. Both the inhibition efficiency and pitting corrosion inhibition of methacrylate-copolymers were in the order of poly methacrylate-co acrylamide > poly methacrylate-co-2-acrylamido-2 methylpropane sulfonic acid > poly methacrylate-co-hydroxyethyl methacrylate. In addition, the corrosion potential of steel specimens in all studied concentrations of NaCl with different concentrations of polymethacrylate-co acrylamide (as the best inhibitor in this study) in saturated Ca(OH)2 solution showed almost an identical trend. Polymethacrylic acid-co-acrylamide showed a 92.35% inhibitor efficiency in the saturated Ca(OH)2 solution containing 1.8 wt.% chlorides and could effectively reduce the corrosion rate. Even at 3.5 wt.% of NaCl, this inhibitor could remarkably reduce the destructive effect of chloride ion attacks on the steel surface and passive film. The inhibition effect of these polymeric inhibitors seemed to be due to the formation of a barrier layer on the metal surface, approved by the well-known adsorption mechanism of organic molecules at the metal/solution interface. The results of SEM, EDS and AFM investigations were also in agreement with the outcomes of electrochemical studies.

  12. Concrete and steel construction quality control and assurance

    CERN Document Server

    El-Reedy, Mohamed A

    2014-01-01

    Starting with the receipt of materials and continuing all the way through to the final completion of the construction phase, Concrete and Steel Construction: Quality Control and Assurance examines all the quality control and assurance methods involving reinforced concrete and steel structures. This book explores the proper ways to achieve high-quality construction projects, and also provides a strong theoretical and practical background. It introduces information on quality techniques and quality management, and covers the principles of quality control. The book presents all of the quality control and assurance protocols and non-destructive test methods necessary for concrete and steel construction projects, including steel materials, welding and mixing, and testing. It covers welding terminology and procedures, and discusses welding standards and procedures during the fabrication process, as well as the welding codes. It also considers the total quality management system based on ISO 9001, and utilizes numer...

  13. Effect of steel surface conditions on reinforcing steel corrosion in concrete exposed to marine environments

    Directory of Open Access Journals (Sweden)

    Anzola, E.

    2005-09-01

    Full Text Available Laboratory methods and experimental tests were deployed in the present study to evaluate corrosion in reinforced concrete exposed to marine environments. Reinforcing steel exhibiting two different surface conditions prior to embedment in concrete were studied, one the one hand to assess the electrochemical behaviour of the bars during exposure of the concrete specimens to a simulated marine environment, and on the other to determine the strength of the steel/concrete bond. The reinforced concrete specimens prepared were adapted as required for electrochemical potential and corrosion rate testing. A total of 56 7x15-cm cylindrical specimens containing 3/8" steel rods anchored at a depth of 11.5 cm were made to evaluate the steel / concrete bond and exposed to a natural marine environment for 28 or 190 days prior to testing. All the specimens were made with ready-mixed concrete. It may be concluded from the results of the corrosion tests on reinforcing steel with different surface conditions that the oxide initially covering the bars was dissolved and the steel passivated by the alkalinity in the concrete. The chief finding of the bonding study was that the layer of oxide formed in pre-embedment steel deterioration contributed to establishing a better bond.

    En el contexto de esta investigación, se tomaron en consideración métodos y ensayos experimentales de laboratorio, que permiten hacer una evaluación de la corrosión del hormigón armado expuesto en ambientes marinos. Por una parte se evaluó el comportamiento electroquímico de dos condiciones de estados superficiales del acero embebido en el hormigón, exponiéndolo en un ambiente marino simulado y, por otra parte, se estudió la adherencia entre el acero y el hormigón, con los mismos estados superficiales usados para la evaluación electroquímica. Las probetas se fabricaron de hormigón con acero de refuerzo en su interior, adecuándolas para realizar los ensayos de potenciales

  14. The Effect of superficial cracks of the concrete on the behavior and corrosion rate of steel rebars in Persian Golf (Booshehr)

    International Nuclear Information System (INIS)

    Afshar, A.; Rajabi, A.

    2001-01-01

    The presence of superficial cracks in concrete increases the diffusion of destructive agents into concrete and the corrosion of rebars will take place. In the present work, the effects of cracks width on the behavior and corrosion rate of steel rebars in the concrete containing cements type I and II at Persian Gulf water have been studied. The results show that the corrosion rate of steel rebars in the concrete with cracks width less than 0.4 mm is negligible, but with increasing the cracks width to 0.7 mm, the corrosion rate increase rapidly. Also, the corrosion gate of gebars in the concrete containing cement type I is more than that of cement type II. The visual inspection of the surface area of gebars shows that the corroded area is 6-7 times of the crack width and length

  15. Green options for anti-corrosion of high strength concrete incorporating ternary pozzolan materials

    Directory of Open Access Journals (Sweden)

    Chen Yuan-Yuan

    2017-01-01

    Full Text Available This paper applied the densified mixture design algorithm(DMDA method by incorporating ternary pozzolans (fly ash, slag and silica fume; mix I and mix II to design high strength concrete (HSC mixtures with w/cm ratios from 0.24 to 0.30. Concrete without pozzolans was used as a control group (mix III, w/c from 0.24 to 0.30, and silica fume (5% was added as a substitute for part of the cement and set as mix IV. Experiments performed compressive strength, four-point resistance meter to measure the conductivity, and rapid chloride ion penetrability tests (ASTM C1202 were assessed the anti-corrosion. The life cycle inventory of LEED suggested by the PCA indicated the green options for cementitious materials. Results showed that mix I and II indicated cement used, CO2 reduction, raw materials and energy consumption all decreased more 50% than mix III, and mix IV was 5% less. The compressive strength and anti-corrosion levels showed that mix I and II were better than mix III and IV, and with ternary pozzolans could enhance the long-term durability (92 days due to a resistivity greater 20 KΩ-cm and a charge passed lower than 2000 Coulombs. HSC with an appropriate design could reduce the carbon footprint and improve the durability.

  16. Research on corrosion detection for steel reinforced concrete structures using the fiber optical white light interferometer sensing technique

    International Nuclear Information System (INIS)

    Zhao, Xuefeng; Cui, Yanjun; Kong, Xianglong; Wei, Heming; Zhang, Pinglei; Sun, Changsen

    2013-01-01

    In this paper, a novel kind of steel rebar corrosion monitoring technique for steel reinforced concrete structures is proposed, designed, and tested. The technique is based on the fiber optical white light interferometer (WLI) sensing technique. Firstly, a feasibility test was carried out using an equal-strength beam for comparison of strain sensing ability between the WLI and a fiber Bragg grating (FBG). The comparison results showed that the sensitivity of the WLI is sufficient for corrosion expansion strain monitoring. Then, two WLI corrosion sensors (WLI-CSs) were designed, fabricated, and embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion. Their performance was studied in an accelerated electrochemical corrosion test. Experimental results show that expansion strain along the fiber optical coil winding area can be detected and measured accurately by the proposed sensor. The advantages of the proposed monitoring technique allow for quantitative corrosion expansion monitoring to be executed in real time for reinforced concrete structures and with low cost. (paper)

  17. Quality control of recycled asphaltic concrete : final report.

    Science.gov (United States)

    1982-07-01

    This study examined the variations found in recycled asphaltic concrete mix based upon plant quality control data and verification testing. The data was collected from four recycled hot-mix projects constructed in 1981. All plant control and acceptan...

  18. Quality assurance program : bituminous concrete and central mix aggregates.

    Science.gov (United States)

    1980-01-01

    This report presents the results of a pilot quality assurance program initiated in the Richmond District in 1978. Under this program the producer's control tests are used for the acceptance of central mix aggregate and bituminous concrete and the Dep...

  19. Assessment of Quality of Asphalt Concrete used in Road ...

    African Journals Online (AJOL)

    OLUWASOGO

    subjected to bitumen extraction and sieve analysis, hot mix Marshall Stability and flow tests, penetration and ... asphalt concrete as well as other structures of the flexible pavement. ... High-quality road networks are very important to the.

  20. Study on improvement of durability for reinforced concrete by surface-painting migrating corrosion inhibitor and engineering application

    Science.gov (United States)

    Song, Ning; WANG, Zixiao; LIU, Zhiyong; Zhou, Jiyuan; Zheng, Duo

    2017-01-01

    The corrosion currents of steel bar in concrete with three W/B and four chloride contents after surface-painting two migrating corrosion inhibitors (PCI-2015 and MCI-A) 14d to 150d in atmospheric condition were measured. The results showed that the corrosion current density (I corr) of steel bar reduced to 0.1 μA.cm-2 from the initial highest 3.833 μA.cm-2 (W/B=0.65, NaCl-1%) after surface-painting PCI-2015 14 d, and the I corr was still lower than 0.1 μA.cm-2 until 150d. The compressive strength and chloride migration coefficient of concrete specimens were tested. The possible reasons of the mechanisms of durability improvement for reinforced concrete by applying PCI-2015 inhibitor were PCI-2015 may be reacted with calcium hydroxide in cement concrete and lots of inhibitor particles may be adsorbed on the active sites first and then a stable protective layer may be formed. The I corr of steel bars in a hydraulic aqueduct concrete structure after painting PCI-2015, MCI-A (the United States) and MCI-B (Europe) during 6 months was monitored by Gecor 8 tester. The results showed that the average values of I corr of steel bars after painting the PCI-2015 150d fulfilled the specification requirements in “Design code for concrete structure strengthening (E.3) ”(GB 50367-2013).

  1. On the corrosion of reinforcing steels in concrete in the presence of chlorides

    Directory of Open Access Journals (Sweden)

    R. Genin, Jean Marie

    1986-12-01

    Full Text Available The purpose of this study is to give a scientific justification to some empirical results, in steel corrosion field, from concrete containing chlorides. First, it appears that corrosion products on the steels, have different structures and natures in function of the chloride content would be inferior or superior to a characteristic value. Second, the penetration of the chlorides in the concrete can be described by a simple Fick's diffusion law in the most frecuent cases. When cement has a high proportion of tricalcium aluminates and the concrete a small porosity, Fick's law cannot be applied.

    Este estudio pretende dar a ciertos resultados empíricos, una justificación científica en el campo de la corrosión de los aceros, en un hormigón que contenga cloruros. En primer lugar, se pone de manifiesto que los productos de corrosión sobre los aceros tienen estructuras y naturalezas diferentes, en función de que el contenido de cloruro sea inferior o superior a un valor característico. En segundo lugar, se puede describir la penetración de los cloruros en el hormigón por una sencilla ley de difusión de Fick, en los casos más frecuentes. Cuando el cemento contiene una elevada proporción de aluminato tricálcico, y el hormigón poca porosidad, no se aplica la ley de Fick.

  2. Mechanical properties of layers of corrosion products at steel / concrete interface

    International Nuclear Information System (INIS)

    Dehoux, Anita

    2012-01-01

    To take account of the development of corrosion products layers in residual lifetime calculations of reinforced concrete structures requires a good knowledge of the mechanical properties of these products. Our study aims to determine the mechanical properties of layers of corrosion products. The approach consists of an identification of the microstructure properties complemented by homogenization calculations to calculate a mesoscopic behavior in linear elasticity of layers of corrosion products. The study includes a series of experimental campaigns at the microscopic scale. Vickers micro indentation tests analyzed by a Gaussian mixture model approach allowed the acquisition of hardness and elastic moduli at the microscale. An identification of the microstructure products is performed by Raman microspectrometry. The microstructure's characterization brings valuable information for homogenization calculations. The first approach has consisted of calculations of random media homogenization by self-consistent and generalized self-consistent schemes. In the second approach, effective modulus calculations were performed using numerical microstructures resulting from 2D images taken with an optical microscope. The corpus is composed of samples of different ages and origins, their microstructures were compared. (author) [fr

  3. Rebar corrosion due to carbonation in structural reinforced concretes for near-surface LLW repositories: A critical failure mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Torok, J

    1995-03-01

    The concrete roof of a near-surface radioactive waste repository is the principle protection against water infiltration and intrusion. The following potential roof failure mechanism is examined: carbon dioxide generated by the biodegradation of organic materials in the repository initiates corrosion of reinforcing steel embedded in the concrete roof. Because the bottom surface of the roof is mostly under tension, it is susceptible to cracking. The migration path for carbon dioxide is through cracks in the concrete between the bottom of the roof and the reinforcing bars. Carbonate corrosion of the reinforcing bars may result in concrete spalling, more extensive rebar corrosion and ultimately structural failure. Attention is brought to this failure mechanism because it has generally been overlooked in repository performance assessments. Literature relevant to the above failure is reviewed. Prerequisites for rebar corrosion are the presence of carbon dioxide and oxygen in the repository gas, high relative humidity and through-cracks in the concrete. High carbon dioxide concentrations and relative humidity are expected in the repository. The oxygen concentration in the repository is expected to be very low, and that is expected to minimize rebar corrosion rates. Cracks are likely to form in locations with high tensile stresses. Healing of the cracks could be a mitigating factor, but based on our analysis, it can not be relied on. To minimize the potential of this failure mechanism occurring with the Intrusion Resistant Underground Structure (IRUS), Canada`s proposed near-surface repository, carbon dioxide from the repository gas will be absorbed by the reactive, porous concrete placed between the waste and the roof. (author). 4 refs.

  4. Rebar corrosion due to carbonation in structural reinforced concretes for near-surface LLW repositories: A critical failure mechanism

    International Nuclear Information System (INIS)

    Torok, J.

    1995-03-01

    The concrete roof of a near-surface radioactive waste repository is the principle protection against water infiltration and intrusion. The following potential roof failure mechanism is examined: carbon dioxide generated by the biodegradation of organic materials in the repository initiates corrosion of reinforcing steel embedded in the concrete roof. Because the bottom surface of the roof is mostly under tension, it is susceptible to cracking. The migration path for carbon dioxide is through cracks in the concrete between the bottom of the roof and the reinforcing bars. Carbonate corrosion of the reinforcing bars may result in concrete spalling, more extensive rebar corrosion and ultimately structural failure. Attention is brought to this failure mechanism because it has generally been overlooked in repository performance assessments. Literature relevant to the above failure is reviewed. Prerequisites for rebar corrosion are the presence of carbon dioxide and oxygen in the repository gas, high relative humidity and through-cracks in the concrete. High carbon dioxide concentrations and relative humidity are expected in the repository. The oxygen concentration in the repository is expected to be very low, and that is expected to minimize rebar corrosion rates. Cracks are likely to form in locations with high tensile stresses. Healing of the cracks could be a mitigating factor, but based on our analysis, it can not be relied on. To minimize the potential of this failure mechanism occurring with the Intrusion Resistant Underground Structure (IRUS), Canada's proposed near-surface repository, carbon dioxide from the repository gas will be absorbed by the reactive, porous concrete placed between the waste and the roof. (author). 4 refs

  5. Management of corrosion control of reinforced concrete in the channel tunnel; Kaiyo tunnel no tekkin concrete no bosyoku kanri to unei

    Energy Technology Data Exchange (ETDEWEB)

    Poubaix, A. [Centre Belge d`Etude de La Corrosion, Bruxelles (Belgium); Cargo, S. [Eurotunnel Operation, Folkstone (United Kingdom)

    1994-12-15

    This paper reports, upon describing the summary of design and construction of Eurotunnel, the contents of the discussions carried out by the Brussels Corrosion Research Center, and their results. Circulating oxygen is supplied sufficiently, and the temperature and humidity are kept high in the tunnel in operation, whereas intermittent dryness may occur locally due to strong air circulation caused by a passing train. While corrosion may occur in any of the reinforcing bars, steel frames, or concrete, the basic corrosion mechanism includes pH decrease in concrete due to its carbonatization, cracking and damage in the concrete, and stray current effect. Detailed discussions were given on experiences of building offshore structures in every part of the world. A possibility of the tunnel getting corroded in 50 to 60 years due to de-passivation in reinforcing bars was indicated against the assumed usable life of 120 years. Therefore, cathodic protection and corrosion monitoring were studied, whereby a unique system was proposed to identify hazardous zones, grasp and analyze data concentratedly. 24 refs., 8 figs., 1 tab.

  6. Quality Control of Concrete Structure For APR1400 Construction

    International Nuclear Information System (INIS)

    Seo, Inseop; Song, Changhak; Kim, Duill

    2012-01-01

    Nuclear structure shall be constructed to protect internal facilities in the normal operation against external accidents such as the radiation shielding, earthquakes and to be leak-proof of radioactive substances to the external environment in case of loss of coolants. containment and auxiliary building of nuclear power plants are built in reinforced concrete structures to maintain these protection functions. Nuclear structures shall be designed to ensure soundness in operation since they are located on the waterfront where is easy do drain the cooling water and so deterioration and damage of concrete structures caused by seawater can occur. Durability is ensured for concrete structures of APR1400, a Korea standard NPP, in compliance with all safety requirements. In particular, owners perform quality control directly on the production and pouring of cast in place concrete for the concrete structure construction to make sure concrete structures established with quality homogeneity and durability. This report is to look into the quality control standard and management status of cast in place concrete for APR1400 construction

  7. Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures.

    Science.gov (United States)

    Angst, Ueli M; Boschmann, Carolina; Wagner, Matthias; Elsener, Bernhard

    2017-08-31

    The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory. Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged. The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established

  8. Effects of slag and fly ash on reinforcement corrosion in concrete in chloride environment. Research from the Netherlands

    NARCIS (Netherlands)

    Polder, R.B.

    2012-01-01

    A review is given of research on the durability performance of concrete made with blast furnace slag and fly ash related to chloride induced reinforcement corrosion, carried out in the Netherlands, where slag has been used in cement for almost a century. Results are presented from field studies on

  9. Effects of slag and fly ash on reinforcement corrosion in concrete in chloride environment : Research from the Netherlands

    NARCIS (Netherlands)

    Polder, R.B.

    2012-01-01

    A review is given of research on the durability performance of concrete made with blast furnace slag and fly ash related to chloride induced reinforcement corrosion, carried out in the Netherlands, where slag has been used in cement for almost a century. Results are presented from field studies on

  10. The influence of cracks on chloride-induced corrosion of reinforced concrete structures - development of the experimental set-up

    NARCIS (Netherlands)

    Blagojevic, A.; Koleva, D.A.; Walraven, J.C.

    2014-01-01

    Chloride-induced corrosion of steel reinforcement is one of the major threats to durability of reinforced concrete structures in aggressive environmental conditions. When the steel reinforcement starts to corrode, structures gradually lose integrity and service life is shortened. Cracks are

  11. Autogenous healing and reinforcement corrosion of water-penetrated separation cracks in reinforced concrete

    International Nuclear Information System (INIS)

    Ramm, W.; Biscoping, M.

    1998-01-01

    Depending on the crack width, the thickness of the structure, the water pressure, and the degree of acid of the water, long-term investigations have been performed over a period of 2 years with respect to the autogenous healing and reinforcement corrosion of water-penetrated separation cracks in reinforced concrete by the University of Kaiserslautern, supported by the Deutsche Forschungsgemeinschaft (DFG). For the waters penetrating the cracks deionised water (neutral, pH=7.0), and boric acid treated deionised water with a pH-value of 6.1 and 5.2 (weakly acid waters) were used. A complete autogenous healing could not be observed. The water penetrating the cracks could hardly be measured with a pH-value of 7.0 at the end of the test. While naturally at the beginning of the test, no influence of the water-chemical degree of the acids could be determined, the existing flow-through quantities towards the end of the test period depended clearly on the crack width and the pH-value. With an increasing crack width and an increasing acid-degree larger flow-through quantities were measured. Depending on the pH-value and the crack width it was determined whether and to which extent corrosion developed at the reinforcing steel bars crossing the cracks. With a crack width of 0.1 mm, corrosion was not to be observed in any case. For the test specimens with a crack width of 0.2 mm a start of the corrosion was found depending on the pH-value. With an increasing width of the crack, an increasing corrosion development is to be expected for test specimens penetrated by acid water. For a crack width of 0.4 mm and a pH-value of 5.2, the highest corrosion development was to be observed, however, there were weakenings of the cross section not worth being mentioned even after a 2-year test period. (orig.)

  12. Practical assessment of magnetic methods for corrosion detection in an adjacent precast, prestressed concrete box-beam bridge

    Science.gov (United States)

    Fernandes, Bertrand; Titus, Michael; Nims, Douglas Karl; Ghorbanpoor, Al; Devabhaktuni, Vijay Kumar

    2013-06-01

    Magnetic methods are progressing in the detection of corrosion in prestressing strands in adjacent precast, prestressed concrete box-beam bridges. This study is the first field trial of magnetic strand defect detection systems on an adjacent box-beam bridge. A bridge in Fayette County, Ohio, which was scheduled for demolition, was inspected. Damage to prestressed box-beams is often due to corrosion of the prestressing strands. The corroded strands show discontinuities and a reduced cross-sectional area. These changes, due to corrosion, are reflected in the magnetic signatures of the prestressing steel. Corrosion in the prestressing steel was detected using two magnetic methods, namely the 'magnetic flux leakage' (MFL) and the 'induced magnetic field'. The purpose of these tests was to demonstrate the ability of the magnetic methods to detect hidden corrosion in box-beams in the field and tackle the logistic problem of inspecting box-beams from the bottom. The inspections were validated by dissecting the bottom of the box-beams after the inspections. The results showed that the MFL method can detect hidden corrosion and strand breaks. Both magnetic field methods were also able to estimate corrosion by detecting the effective cross-sectional area of the strand in sections of the beams. Thus, it was shown that the magnetic methods can be used to predict hidden corrosion in prestressing strands of box-beams.

  13. Corrosion protection of the reinforcing steels in chloride-laden concrete environment through epoxy/polyaniline–camphorsulfonate nanocomposite coating

    International Nuclear Information System (INIS)

    Pour-Ali, Sadegh; Dehghanian, Changiz; Kosari, Ali

    2015-01-01

    Highlights: • Epoxy/polyaniline–camphorsulfonate nanocomposite coating well protects steel rebar. • Coating performance is evaluated by impedance measurements up to 1 year. • Ultimate bond strength between the coated rebars and concrete is measured. • Self-compacting concrete shows better anticorrosive property compared to normal one. - Abstract: In this study, an epoxy/polyaniline–camphorsulfonate nanocomposite (epoxy/PANI–CSA) is employed to protect reinforcing steels in chloride-laden concrete environment. The synthesized nanocomposite was characterized using Fourier transform infrared spectroscopy and transmission electron microscopy. Bare, epoxy-coated and epoxy/PANI–CSA nanocomposite-coated steel rebars were embedded in normal and self-compacting concretes. To evaluate their corrosion behaviors, open circuit potential and impedance measurements were performed for the duration of 1 year. Ultimate bond strength of concrete with the reinforcement bars were measured in corroded and uncorroded conditions. It was found that epoxy/PANI–CSA coating provides good corrosion resistance and durable bond strength with concrete for steel rebars

  14. Evaluation of the corrosion of reinforced concrete designed for low and medium activity level radioactive waste containers

    International Nuclear Information System (INIS)

    Duffo, G.S.; Arva, E.A; Schulz, F.M; Vasquez, D.R

    2010-01-01

    The National Atomic Energy Commission of Argentina (CNEA) is responsible for the design and construction of a monolithic repository for the final disposal of low and medium level radioactive wastes. In order to ensure the protection of people and the environment, the useful life of the repository should be 300 years and the conceptual design selected is based on the use of multiple, independent and redundant barriers. These barriers consist mainly of reinforced concrete. This work aims to establish a methodology to determine the concrete's useful life, evaluating parameters of interest using chemical and electrochemical techniques. For this purpose, reinforced concrete test pieces were made with two formulations - blast furnace cement (BFC) and with BFC plus silica fume admixture (BFC+SF)- and in each of the test pieces segments of reinforcement were included. The development over time of the corrosion potential and speed were evaluated, together with the resistivity of the concrete in the test pieces exposed to the laboratory environment, with an average relative humidity of 50%, a condition that favors the carbonation process. The diffusion coefficients of aggressive species, such as chloride and carbon dioxide, were also determined in test pieces made with the two formulations. In the test pieces exposed to the laboratory environment the reinforcements embedded in the BFC+SF concrete showed a lower corrosion speed compared to the BFC concrete. These results agree with the lower values for the speeds of carbonation and of chloride diffusion that show that the concrete with BFC+SF is more resistant to incoming aggressive species compared with the BFC. A container prototype for mid-level radioactive wastes was built and outfitted with instruments in order to monitor the development over time of the corrosion speed of the reinforcement rods by using corrosion sensors developed by the group. The prototype, exposed to atmospheric conditions, was manufactured with BFC

  15. A Galvanic Sensor for Monitoring the Corrosion Condition of the Concrete Reinforcing Steel: Relationship Between the Galvanic and the Corrosion Currents

    Directory of Open Access Journals (Sweden)

    Elsa Vaz Pereira

    2009-10-01

    Full Text Available This work reports a study carried out on the design and performance of galvanic and polarization resistance sensors to be embedded in concrete systems for permanent monitoring of the corrosion condition of reinforcing steel, aiming to establish a correlation between the galvanic currents, Igal, and the corrosion currents, Icorr, estimated from the polarization resistance, Rp. Sensors have been tested in saturated Ca(OH2 aqueous solutions, under a variety of conditions, simulating the most important parameters that can accelerate the corrosion of concrete reinforcing steel, such as carbonation, ingress of chloride ions, presence or absence of O2. For all the conditions, the influence of temperature (20 to 55 ºC has also been considered. From this study, it could be concluded that the galvanic currents are sensitive to the various parameters following a trend similar to that of the Rp values. A relationship between the galvanic and the corrosion current densities was obtained and the limiting values of the Igal, indicative of the state condition of the reinforcing steel for the designed sensor, were established.

  16. Corrosion Behavior of Carbon Steel in Concrete Material Composed of Tin Slag Waste in Aqueous Chloride Solution

    Science.gov (United States)

    Rustandi, Andi; Cahyadi, Agung; Taruli Siallagan, Sonia; Wafa' Nawawi, Fuad; Pratesa, Yudha

    2018-01-01

    Tin slag is a byproduct of tin ore smelting process which is rarely utilized. The main purpose of this work is to investigate the use of tin slag for concrete cement material application compared to the industrial Ordinary Portland Cement (OPC). Tin slag composition was characterized by XRD and XRF analysis. The characterization results showed the similar chemical composition of tin slag and OPC. It also revealed the semi crystalline structure of tin slag sample. Several electrochemical tests were performed to evaluate corrosion behavior of tin slag, OPC and various mixed composition of both materials and the addition of CaO. The corrosion behavior of OPC and tin slag were evaluated by using Cyclic Polarization, Electrochemical Impedance Spectroscopy (EIS) and Electrochemical Frequency Modulation (EFM) methods. Aqueous sodium chloride (NaCl) solution with 3.5% w.t concentration which similar to seawater was used as the electrolyte in this work. The steel specimen used as the reinforce bar (rebar) material of the concrete was carbon steel AISI 1045. The rebar was embedded in the concrete cement which composed of OPC and the various composition of tin slag including slag without addition of CaO and slag mixed with addition of 50 % CaO. The electrochemical tests results revealed that tin slag affected its corrosion behavior which becoming more active and increasing the corrosion rate as well as decreasing the electrochemical impedance.

  17. Quality control of concrete structures in nuclear power plant, (3)

    International Nuclear Information System (INIS)

    Takahashi, Hisao; Kawaguchi, Tohru; Oike, Takeshi; Morimoto, Shoichi; Takeshita, Shigetoshi.

    1979-01-01

    In general, concrete placed in the winter season has a tendency to have lower strength at the age of 4 weeks due to low curing temperature after placement. Therefore, under the Japanese code, the target mix Proportions in the winter season are modified adding an extra correction factor based on air temperature. Meanwhile, the quality control system for mass concrete to be placed in the winter system is indistinct at this stage. It is the aim of this report to present the results of investigations to clarify the following two subjects: (1) whether the correction factor due to temperature is needed or not for mass concrete in the winter season; (2) what kind of curing should be applied to control cylinders for estimating strength of mass concrete. (author)

  18. Studies on the corrosion resistance of reinforced steel in concrete with ground granulated blast-furnace slag--An overview.

    Science.gov (United States)

    Song, Ha-Won; Saraswathy, Velu

    2006-11-16

    The partial replacement of clinker, the main constituent of ordinary Portland cement by pozzolanic or latent hydraulic industrial by-products such as ground granulated blast furnace slag (GGBFS), effectively lowers the cost of cement by saving energy in the production process. It also reduces CO2 emissions from the cement plant and offers a low priced solution to the environmental problem of depositing industrial wastes. The utilization of GGBFS as partial replacement of Portland cement takes advantage of economic, technical and environmental benefits of this material. Recently offshore, coastal and marine concrete structures were constructed using GGBFS concrete because high volume of GGBFS can contribute to the reduction of chloride ingress. In this paper, the influence of using GGBFS in reinforced concrete structures from the durability aspects such as chloride ingress and corrosion resistance, long term durability, microstructure and porosity of GGBFS concrete has been reviewed and discussed.

  19. Corrosion of Steel in Concrete – Potential Monitoring and Electrochemical Impedance Spectroscopy during Corrosion Initiation and Propagation

    DEFF Research Database (Denmark)

    Küter, Andre; Mason, Thomas O.; Geiker, Mette Rica

    2005-01-01

    wires. The wires can act as both reference and counter electrode during EIS and, thus, no external electrode is required. The defined geometry solves reproducibility problems involved with application of an external reference electrode for EIS. Changes of the electromotive force (EMF) between rebar...... and titanium wires can be monitored immediately after preparation. The wire arrangement also allows investigation of local changes in the bulk mortar by EIS or by measuring the potential development of the titanium wires versus an external standard electrode. The specimen design was evaluated...... in an investigation on the effect of the steel quality and the steel surface properties on initiation and propagation of chloride-induced reinforcement corrosion. Besides untreated (as received) carbon rebars and stainless rebars, selected surface treatments and galvanization were investigated. The surface treatments...

  20. Quality of concrete in Temelin nuclear power plant construction

    International Nuclear Information System (INIS)

    Truhlar, K.

    1983-01-01

    The determination is described of cement strength prior to use and two methods are suggested: ultrasonic and point microscopic integration. The ultrasonic method uses test vessels of cement mortar on which measurements are made 24 hours after production. The second method was developed and is reckoned for independent use or in combination with ultrasonic. The said methods have been used in the cement works for cement quality control. They will also be used for controlling the quality of concrete mixes. Concrete compactness will be measured using a lysimetric densimeter or a tensimetric or dual-value probe. (E.S.)

  1. Non-destructive testing (NDT) of a segmental concrete bridge scheduled for demolition, with a focus on condition assessment and corrosion detection of internal tendons.

    Science.gov (United States)

    2017-05-01

    The service life and durability of prestressed concrete in bridges are vulnerable to corrosion damages due to many factors such as construction, material, and environment. To ensure public safety, it is important to inspect these structures and to de...

  2. Long term corrosion of iron in concrete and in atmospheric conditions: a contribution of archaeological analogues to mechanism comprehension

    International Nuclear Information System (INIS)

    Burger, E.; Demoulin, A.; Dillman, Ph.; Neff, D.; Berge, P.; Burger, E.; Perrin, St.; L'hostis, V.; Dillman, Ph.; Millard, A.

    2009-01-01

    Full text of publication follows: The prediction of iron (or low alloy steel) corrosion on very long term period is necessary in two different purposes: (i) the preservation and conservation of cultural heritage and (ii) the French storage and repository concept for the radioactive wastes. In order to determine the evolution of corrosion processes for very long period, mechanistic models have been developed. In these models that are based on a phenomenological approach to evaluate the average corrosion rates, two different environments are considered: concrete (steel reinforcements) and atmospheric. The study of archaeological analogues is a very pertinent tool for the validation of these models. First, physico-chemical analysis on old corrosion layers lead to a precise localisation and identification of the phases present in the corrosion system. Moreover, experimental reinduced corrosions of ancient samples under controlled parameters (temperature, relative humidity) bring new insight on the mechanisms involved. In particular, one crucial question related to the wet-dry cycle is the localisation of oxygen reduction sites in the rust layer. For this purpose, specific experiments have been set up to re-corrode the ancient samples in marked medium (using 18 O 2 ). Samples were exposed to cycling between high and low relative humidity, produced by saline saturated solutions. Then cross-sections of samples obtained were investigated by nuclear reaction analysis (NRA) 18 O(p,α) 15 N on the Pierre Sue Laboratory nuclear microprobe. In this presentation the 18 O distribution profiles are discussed and interpreted in order to bring new insight on corrosion mechanisms. A comparative interpretation is made for each medium (concrete and atmosphere)

  3. Radiographic testing in concrete structures

    International Nuclear Information System (INIS)

    Oliveira, D. de

    1987-01-01

    The radiographic testing done in concrete structures is used to analyse the homogeneity, position and corrosion of armatures and to detect discontinuity in the concrete such as: gaps, cracks and segregations. This work develops a Image quality Indicator (IQI) with an adequated sensibility to detect discontinuites based on BS4408 norm. (E.G.) [pt

  4. Safety-classified steel cylinder reinforced concrete pipelines: mechanism of corrosion, diagnosis and maintenance strategy

    International Nuclear Information System (INIS)

    Aimonino, J.; Jacq, S.

    2015-01-01

    EDF operates 6 km of safety-classified steel cylinder reinforced concrete pipelines spread over 8 PWR nuclear reactors located on the sea coast. These pipelines, placed in galleries, convey approximately 3000 m 3 /h of sea water under a pressure of 4 bar. They have been in operation since the mid eighties or early nineties. Their service life is limited by different scenarios of corrosion by pitting due to the presence of chlorides from sea water. Pipelines are subjected to frequent visual checks that can lead to immediate temporary reinforcement and subsequent replacement. In addition, a diagnosis methodology was developed in order to better anticipate the maintenance operations and in order to assess the remaining service life of pipelines. This methodology combines autopsies of replaced pipes with periodic campaigns of exhaustive half-cell potential mapping. For exhaustive campaigns, the grid spacing was 30 cm x 30 cm, refined to 10 cm x 10 cm in singular zones, on the entire external concrete surface of pipelines, which represents around 6x10 5 measurement points for 6 km of pipelines. Robust specifications were drawn up for the measurement method and the interpretation of the results, initially based on RILEM and ASTM recommendations and then significantly reinforced based on operational feedback. These specifications ensure the implementation and the interpretation of half-cell potential mapping can be carried out on a very large scale and enable the comparison of results between successive campaigns. The diagnosis methodology was a decisive factor in the planning of a preventive maintenance strategy which would enable a pipeline service life of 60 years. (authors)

  5. Performance and working life of cathodic protection systems for concrete structures

    NARCIS (Netherlands)

    Polder, R.B.; Worm, D.; Courage, W.; Leegwater, G.

    2012-01-01

    Corrosion of reinforcing steel in concrete structures causes concrete cracking and steel diameter reduction, eventually resulting in loss of safety. Conventional repair means heavy, labour intensive and costly work and the required quality level is under economic pressure. Consequently, conventional

  6. Critical Quality Source Diagnosis for Dam Concrete Construction Based on Quality Gain-loss Function

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2014-06-01

    Full Text Available In dam concrete construction process, it not only has quality loss arising from quality fluctuation, but also gains quality compensation effect due to the mutual cooperation and adaptation coupling between working procedures (WPs. The calculation and transmission complexity of the quality loss and quality compensation affect the quality management of dam concrete construction. As the quality compensation effect existing in the production practice cannot be described by Taguchi quality loss function, the concept of quality gain-loss function was presented in this paper, which was based on endowing the constant term in the expansion of Taylor series with physical meaning—quality compensation. Based on quality gain-loss function theory, a new quality gain-loss transmission model of dam concrete construction based on GERT network was constructed and its effective algorithm was designed. WP quality gain-loss and its impact on the final product were reasonably measured, and the critical quality routes and critical quality WPs were detected and diagnosed in dam concrete construction network. Summer temperature-controlled concrete construction in the third phase of Three Gorges Project (TGP was taken as an example to carry out the study, and the calculation results showed the validity and practicability of the presented model and algorithm.

  7. Composition and Morphology of Product Layers in the Steel/Cement Paste Interface in Conditions of Corrosion and Cathodic Protection in Reinforced Concrete

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.; De Wit, J.H.W.; Fraaij, A.L.A.; Boshkov, N.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP). Of particular interest was to investigate if the introduced pulse CP (as

  8. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  9. Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica

    2012-01-01

    , are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two...... electrochemical techniques often used in instruments for on-site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long...... rate for actively corroding steel. For both techniques guidelines for polarisation times and currents are given for (on-site) non-destructive corrosion rate measurements on reinforcement steel in concrete....

  10. The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2016-09-01

    Full Text Available This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obtained from magnetic sensor-based measurement and numerical calculation, it is shown that the curves of tangential magnetic field at different lift-off height all intersect near the edge of the steel corrosion zone. The result indicates that the intersection of magnetic field curves can be used to detect and evaluate the range of the inner steel corrosion in engineering structures. The findings of this work propose a new and effective non-destructive test method for steel corrosion, and therefore enlarge the application of the micro-magnetic sensor.

  11. Effect of steel reinforcement with different degree of corrosion on degeneration of mechanical performance of reinforced concrete frame joints

    Directory of Open Access Journals (Sweden)

    Wu Xu

    2016-02-01

    Full Text Available Beam-column joints which shoulders high-level and vertical shearing effect that maintains balance of beam and column end is the major component influencing the performance of the whole framework. Post earthquake investigation suggests that collapse of frame structure is induced by failure of joints in most cases. Thus, beam-column joints must have strong bearing capacity and good ductility, and reinforced concrete structure just meets the above requirement. But corrosion caused by long time use of reinforced concrete framework will lead to degeneration of mechanical performance of joints. To find out the rule of effect of steel reinforcement with different corrosion rate on degeneration of bearing capacity of reinforced concrete framework joints, this study made a nonlinear numerical analysis on fifteen models without stirrup in the core area of reinforced concrete frame joints using displacement method considering axial load ratio of column end and constraint condition. This work aims to find out the key factor that influences mechanical performance of joints, thus to provide a basis for repair and reinforcement of degenerated framework joints.

  12. Production and quality control of concrete for the Rajasthan Atomic Power Station - [Part 2

    International Nuclear Information System (INIS)

    Singh Roy, P.K.; Sukhtankar, K.D.; Prasad, K.

    1975-01-01

    The following aspects of the production and quality control of concrete and concrete materials used in the construction of twin-reactor Rajasthan Atomic Power Station are discussed : (1) relationship between strength of cubes and cylinders made of concrete used for the prestressed dome (2) temperature control during pouring of concrete (3) thermal conductivity of heavy concrete (4) various types of grouting procedures used for different structures forming part of reactors (5) quality control of normal and heavy concrete and (6) leakage through form ties. Typical concrete mixes used for grouts are also given. (M.G.B.)

  13. Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

    Science.gov (United States)

    de Alcantara, Naasson P.; da Silva, Felipe M.; Guimarães, Mateus T.; Pereira, Matheus D.

    2015-01-01

    This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT) to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works. PMID:26712754

  14. Corrosion Assessment of Steel Bars Used in Reinforced Concrete Structures by Means of Eddy Current Testing

    Directory of Open Access Journals (Sweden)

    Naasson P. de Alcantara

    2015-12-01

    Full Text Available This paper presents a theoretical and experimental study on the use of Eddy Current Testing (ECT to evaluate corrosion processes in steel bars used in reinforced concrete structures. The paper presents the mathematical basis of the ECT sensor built by the authors; followed by a finite element analysis. The results obtained in the simulations are compared with those obtained in experimental tests performed by the authors. Effective resistances and inductances; voltage drops and phase angles of wound coil are calculated using both; simulated and experimental data; and demonstrate a strong correlation. The production of samples of corroded steel bars; by using an impressed current technique is also presented. The authors performed experimental tests in the laboratory using handmade sensors; and the corroded samples. In the tests four gauges; with five levels of loss-of-mass references for each one were used. The results are analyzed in the light of the loss-of-mass and show a strong linear behavior for the analyzed parameters. The conclusions emphasize the feasibility of the proposed technique and highlight opportunities for future works.

  15. Development of a new method of measurement of the polarization resistance to estimate the level of corrosion of the reinforced concrete of cooling towers

    International Nuclear Information System (INIS)

    Mitzithra, M.E.; Deby, F.; Laurens, S.; Balayssac, J.P.; Salin, J.

    2014-01-01

    This paper summarises the results obtained from the numerical simulations of an operative measurement mode of polarization resistance adapted for evaluating the corrosion of reinforced concrete on cooling towers. A simple operative measurement mode of R p is proposed, adapted for cooling towers submitted to corrosion due to carbonation. By means of numerical experimentations, abacuses and correction laws are built involving the different influencing parameters: steel reinforcement's concrete cover, concrete resistivity and current intensity injected from the counter electrode. Finally, a first application of the proposed procedure for calculating the real value of R p in laboratory conditions is presented. (authors)

  16. NANOMODIFIED CONCRETE

    Directory of Open Access Journals (Sweden)

    B. M. Khroustalev

    2015-01-01

    Full Text Available One of the main directions in construction material science is the development of  next generation concrete that is ultra-dense, high-strength, ultra-porous, high heat efficient, extra corrosion-resistant. Selection of such direction is caused by extreme operational impacts on the concrete, namely: continuously increasing load on the concrete and various dynamics of such loads; the necessity in operation of concrete products in a wide temperature range and their exposure to various chemical and physical effects.The next generation concrete represents high-tech concrete mixtures with additives that takes on and retain the required properties when hardening and being used under any operational conditions. A differential characteristic of the next generation concrete is its complexity that presumes usage of various mineral dispersed components, two- and three fractional fine and coarse aggregates, complex chemical additives, combinations of polymer and iron reinforcement.Design strength and performance properties level of the next generation concrete is achieved by high-quality selection of the composition, proper selection of manufacturing techniques, concrete curing, bringing the quality of concrete items to the required level of technical condition during the operational phase. However, directed formation of its structure is necessary in order to obtain high-tech concrete.Along with the traditional methods for regulation of the next generation concrete structure, modification of concrete while using silica nanoparticles is also considered as a perspective one because the concrete patterning occurs due to introduction of a binder in a mineral matrix. Due to this it is possible to obtain nano-modified materials with completely new properties.The main problem with the creation of nano-modified concrete is a uniform distribution of nano-materials in the volume of the cement matrix which is particularly important in the cases of adding a modifier in

  17. Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Linwen [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Université de Sherbrooke, Quebec (Canada); François, Raoul, E-mail: raoul.francois@insa-toulouse.fr [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Dang, Vu Hiep [Hanoi Architectural University, Faculty of Civil Engineering, Hanoi (Viet Nam); L' Hostis, Valérie [CEA Saclay, CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, Gif-sur-Yvette (France); Gagné, Richard [Université de Sherbrooke, Quebec (Canada)

    2015-01-15

    This paper deals with corrosion initiation and propagation in pre-cracked reinforced concrete beams under sustained loading during exposure to a chloride environment. Specimen beams that were cast in 2010 were compared to specimens cast in 1984. The only differences between the two sets of beams were the casting direction in relation to tensile reinforcement and the exposure conditions in the salt-fog chamber. The cracking maps, corrosion maps, chloride profiles, and cross-sectional loss of one group of two beams cast in 2010 were studied and their calculated corrosion rates were compared to that of beams cast in 1984 in order to investigate the factors influencing the natural corrosion process. Experimental results show that, after rapid initiation of corrosion at the crack tip, the corrosion process practically halted and the time elapsing before corrosion resumed depended on the exposure conditions and cover depth.

  18. A Navy User’s Guide for Quality Assurance of New Concrete Construction

    Science.gov (United States)

    2012-06-01

    allowable concrete drying shrinkage for marine concrete in the U.S. Navy is 0.05%. does not predict some concrete properties and degradation mechanisms...service life modeling. A concrete mixture that meets the service life requirements using STADIUM® but fails the shrinkage tests is not acceptable for...TECHNICAL REPORT TR-NAVFAC ESC-CI-1215 A NAVY USER’S GUIDE FOR QUALITY ASSURANCE OF NEW CONCRETE CONSTRUCTION

  19. The significance of curing in the future corrosion resistance of concrete structures

    Directory of Open Access Journals (Sweden)

    López, W.

    1991-09-01

    Full Text Available Steel in contact with fresh concrete is covered by a layer of passivating oxydes due to the alkaline nature of the pore solution. The presence of oxygen plays an important role in this passivation process as well as in the corrosión one when is developped due to the ingress of aggressives, such as, chloride ions. In the present paper, results are commented on the behaviour found when oxygen is limited due to the concrete curing conditions, in a completely saturated chamber. Surprisely, the results indicate that the oxygen availability during the curing has a marked influence on the future corrosion beabieviour This allows to deduce that the mechanisms involved are not so simple as was currently accepted and that new specific tests are needed to clarify the controversial points.

    Cuando el acero se pone en contacto con el hormigón fresco, debido a la naturaleza alcalina de éste, el acero se recubre de una capa de óxidos pasivantes, que lo mantienen constantemente protegido. En este proceso juega un papel preponderante la presencia del oxígeno, que resulta también esencial para el desarrollo de los procesos de corrosión, cuando hay agresivos presentes (por ejemplo los cloruros. En el presente trabajo se comentan resultados de los cambios que se aprecian, tanto en el proceso de pasivación como de corrosión, cuando el acceso de oxígeno se limita, circunstancia que se produce cuando el hormigón se cura en condiciones de saturación de agua. Los resultados muestran que la disponibilidad de oxígeno durante el curado tiene una marcada influencia en la resistencia futura a la corrosión lo, que indica que los mecanismos no son tan evidentes como se pensaba y se necesitarán ensayos futuros específicos para aclarar todos los aspectos que ahora aparecen como contradictorios

  20. Corrosion protection and steel-concrete bond improvement of prestressing strand.

    Science.gov (United States)

    2012-12-01

    Corrosion can lead to the premature deterioration and failure of transportation structures. In pre-stressed bridge structures corrosion is more severe, : leading to sudden failures when cracking is induced at pitting sites by tensile or compressive s...

  1. Durability of precast prestressed concrete piles in marine environment : reinforcement corrosion and mitigation - Part 1.

    Science.gov (United States)

    2011-06-01

    Research conducted in Part 1 has verified that precast prestressed concrete piles in : Georgias marine environment are deteriorating. The concrete is subjected to sulfate and : biological attack and the prestressed and nonprestressed reinforcement...

  2. Lean duplex stainless steels-The role of molybdenum in pitting corrosion of concrete reinforcement studied with industrial and laboratory castings

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, T.J. [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France); CRU Ugitech, Av Paul Girod 73400 Ugine (France); Chauveau, E.; Mantel, M. [CRU Ugitech, Av Paul Girod 73400 Ugine (France); Kinsman, N. [International Molybdenum Association, IMOA W4 4JE London (United Kingdom); Roche, V. [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France); Nogueira, R.P., E-mail: ricardo.nogueira@grenoble-inp.fr [LEPMI, UMR5279CNRS, Grenoble INP, Universite de Savoie, Universite Joseph Fourier, BP 75, 38402 St Martin d' Heres (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Mo influence on corrosion of DSS was studied with industrial and laboratory heats. Black-Right-Pointing-Pointer Beneficial effect of Mo was associated with ferrite corrosion resistance. Black-Right-Pointing-Pointer Mo-species in the alkaline solution did not improve pit resistance. Black-Right-Pointing-Pointer Mo role in DSS under alkaline conditions was ascribed to its presence in oxide film. - Abstract: The influence of Mo addition on pitting corrosion resistance of lean duplex stainless steels is not clearly understood in alkaline chloride conditions even if this element is widely recognized to increase corrosion resistance in acidic and neutral environments. This work aims to study the effect of Mo on pitting corrosion of lean duplex stainless steels in synthetic concrete pore solutions simulating degraded concrete. Results are discussed with respect to the influence of Mo on pitting potential for two industrial alloys in chloride rich and carbonated solution simulating concrete pore environments. To establish the real effect of Mo addition on lean duplex corrosion and passivation properties, two specific laboratory lean duplex alloys, for which the only difference is strictly the Mo content, are also studied. Mo presented a strong positive influence on the pitting corrosion resistance of industrial and laboratory lean duplex stainless steels in all studied chloride-rich solutions, but its effect is as less pronounced as the pH increases. In presence of Mo, pitting initiates and propagates preferentially in the austenitic phase at high temperature.

  3. Corrosion behaviour of reinforcements in a carbonaceous concrete: influence of the chemistry of the interstitial solution and of a transport barrier

    International Nuclear Information System (INIS)

    Huet, B.

    2005-10-01

    The phenomenon of steel reinforcements corrosion in a carbonaceous concrete is a many-sided process, little understood and of a great economical importance. The aim of this work is to identify, in condition of concrete carbonation, the corrosion mechanisms of reinforcements in order to anticipate the long term damage of the buildings. An analytical and experimental study has been carried out and has revealed two hypotheses. These ones consist to characterize the control of the corrosion velocity, either by the anodic reaction or by addition of an oxidant. The corrosion experiments in solution which represents the interstitial solution of a carbonaceous cement paste show that the evolution of the metal/medium interface is very sensitive to the species introduced in the medium during the carbonation process. The change of the ionic strength and of the sulfate and alkali metals concentrations are the main factors influencing the localization of the reactional areas, the nature of the phases formed at the interface as well as the corrosion velocities and their change with time. The evolution of the water saturation degree of the coating is the preponderant factor on the corrosion velocity. The analytical calculations and the experimental results show that for fixed hydrous conditions, the corrosion velocity in stationary conditions is negligible. The taking into account of transient conditions of transport as well as humidification and drying cycles is required for the long term anticipation of the damage of reinforced concrete buildings. (O.M.)

  4. Concrete

    DEFF Research Database (Denmark)

    2015-01-01

    Concrete is a component of coherent transition between a concrete base and a wooden construction. The structure is based on a quantity of investigations of the design possibilities that arise when combining digital fabrication tools and material capacities. Through tangible experiments the project...... specific for this to happen. And the knowledge and intention behind the drawing becomes specialised through the understanding of the fabrication processes and their affect on the materials.The structure Concrete is a result of a multi-angled kerf series in ash wood and a concrete base. The ash wood is cut...... using a 5-axis CNC router with a thin saw blade attached. The programming of the machining results in variations of kerfs that lets the ash wood twist into unique shapes.The shapes of the revolving ash ribbons continue into the concrete creating a cohesive shape. The form for the concrete itself is made...

  5. Influence of temporal resolution and processing of exposure data on modeling of chloride ingress and reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Flint, Madeleine; Michel, Alexander; Billington, Sarah L.

    2014-01-01

    a numerical heat and mass transport model that includes full coupling of heat, moisture and ion transport. Heat, moisture, and chloride concentration distributions were passed to a simplified reinforcement corrosion initiation and propagation model. The numerical study indicates that processing and temporal...... resolution of the exposure data has a considerable impact on long-term hygrothermal distribution, chloride ingress, and reinforcement section loss results. Use of time-averaged exposure data in the heat and mass transport model reduces the rate of chloride ingress in concrete and affects prediction...

  6. Long Term Corrosion Experiment of Steel Rebar in Fly Ash-Based Geopolymer Concrete in NaCl Solution

    OpenAIRE

    Asmara, Y. P.; Siregar, J. P.; Tezara, C.; Nurlisa, Wan; Jamiluddin, J.

    2016-01-01

    This research focuses on an experimental investigation to identify the effects of fly ash on the electrochemical process of concrete during the curing time. A rebar was analysed using potentiostat to measure the rest potential, polarization diagram, and corrosion rate. Water-to-cement ratio and amount of fly ash were varied. After being cured for 24 hours at a temperature of 65°C, the samples were immersed in 3.5% of NaCl solution for 365 days for electrochemical measurement. Measurements of ...

  7. Quality Assurance Review of SKB's Copper Corrosion Experiments

    International Nuclear Information System (INIS)

    Baldwin, Tamara D.; Hicks, Timothy W.

    2010-06-01

    SKB is preparing a license application for the construction of a final repository for spent nuclear fuel in Sweden. This application will be supported by the safety assessment SR-Site for the post-closure phase. The assessment of long-term safety is based on a broad range of experimental results from laboratory scale, intermediate scale and up to full scale experiments. It is essential that there is a satisfactory level of assurance that experiments have been carried out with sufficient quality, so that results can be considered to be reliable within the context of their use in safety assessment. The former named authority, SKI, has initiated a series of reviews of SKB's methods of quality assurance and their implementation. This quality assurance review is focused on the work of copper corrosion being conducted in at SKB's Hard Rock Laboratory (HRL) in Aespoe, LOT and Miniature canister (Minican) experiments. In order for the reviewers to get a broad understanding of the issue of copper corrosion both SKB reports as well as the viewpoint of MKG was collected prior to commencement of the actual review task. The purpose of this project is to assess SKB's quality assurance with the view of providing input for the preparation of the SR-Site safety assessment. This has been achieved by examination of the corrosion part of the LOT and Minican experiments using a check list, visits to the relevant facilities, and meetings with contractors and a few members of the SKB staff. The same approach for quality assurance reviews has been used earlier in similar review tasks. During the quality review of the selected projects, several QA- related issues of different degree of severity was noted by the reviewers. The most significant finding was that SKB has chosen to present only selected real-time corrosion monitoring data in TR-09-20. This was surprising and SSM expect that SKB will analyse the reason for this thoroughly. The reviewers also made other observations which can be

  8. Contribution to the study of corrosion in cementitious media for the phenomenological modelling of the long-term behaviour of reinforced concrete structures

    International Nuclear Information System (INIS)

    L'hostis, V.

    2010-12-01

    Many of the facilities and structures involved in the nuclear industry call for reinforced concrete (RC) in their construction. The corrosion of rebars is the main ageing pathology that those RC structures will meet during their service life (leading to concrete cracking and structural bearing capacity decrease). Concrete carbonation and chloride ingress in concrete are both at the origin of the active corrosion state. Passive corrosion has also to be considered in a context of very long lifetime (waste management). It is of primary importance to dispose of accurate and validated tools in order to predict where and how damages will appear. In 2002, the Commissariat a l Energie atomique decided to develop an intensive research programme dedicated to predicting the long-term behaviour of RC structures affected by steel corrosion (CIMETAL Project). This document aims at synthesize the main outputs coming from the project and exposes the scientific strategy was drawn and applied in order to predict the long-term behaviour of RCs that were mainly exposed to carbonation conditions. That strategy includes experiments for the characterisation of 'short-term' and 'long-term' corrosion layouts and processes, as well as modelling stages, with a view not only to predicting the behaviour of RC, but also to pointing out phenomena that are further verified experimentally. (author)

  9. Characterisation of the steel concrete interface submitted to chloride-induced corrosion

    International Nuclear Information System (INIS)

    L'Hostis, V.; Amblard, E.; Guillot, W.; Paris, C.; Bellot-Gurlet, L.

    2013-01-01

    This paper deals with the characterisation by means of electrochemical, gravimetric and analytical methods of chloride-induced-corrosion behaviour of steel coupons embedded in chloride-containing-cement pastes. Corrosion rates were estimated from electrochemical measurements as well as gravimetric ones. They vary from 2.6 to 5.7μm/year for 5 and 10 g/L chloride-containing cement pastes. Analytical characterisations (including optical and electron microscopy and Raman micro-spectroscopy) showed that corrosion patterns are not depending on the chloride content of the cement paste (5 and 10 g/L chloride in the interstitial solution). A localised corrosion pattern composed of pits growing inside the metallic substratum, a corrosion products layer (CPL) and a transformed medium (TM) was pointed out. CPL can be divided into two sub-layers (CPL1 and CPL2), characterised by the presence or absence of calcium coming from the cement matrix. (authors)

  10. The effect of fly ashes in the corrosion and durability in concretes; Efecto de las Cenizas Volantes en la Durabilidad y en la Corrosion en Armaduras del Hormigon

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    From the beginning of this century, fly ashes have been the object of a variety of studies and research-looking for different ways of application. The construction industry reuses the highest volume of the fly ash actually produced. Researches carried out on the behaviour of hydraulic blended materials mixed with fly ash have supported the progressive use of these by-products, and simultaneously have opened new ways of application. Spanish fly ash producers together with research centers, as IETcc, have been involved in investigations since 70`s. The last important research carried out has been the one dealing with the durability of concrete made with fly ash and its interaction with the corrosion of reinforcements. In this work five fly ashes of silicon-aluminous type were mixed with portland cement containing low alkali and aluminates in order to enhance the effect of those components from the fly ash. The main goal was to study the degradation mechanisms of concretes made with fly ashes, substituting partially the cement (15 and 35%) in several aggressive media: containing sulfates, chlorides or sea water. The effect to these aggressive media on the durability has also been considered regarding reinforcements. Different type of tests were carried out in laboratory and under natural exposure. In the case of laboratory studies the objectives were: 1) to stablish the mechanisms of hardening. The effect of fly ashes in pozolanic reaction and in the microstructure of the material. 2) Resistance of the addition of fly ashes against chloride and sulfates. Definition of the deterioration mechanisms. 3) Effect of fly ashes on the corrosion of reinforcements. Influence on the passivation process. Resistance against carbonation and chloride attack. (Author)

  11. Cymbopogon citratus and NaNO2 Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

    Directory of Open Access Journals (Sweden)

    Joshua Olusegun Okeniyi

    2018-01-01

    Full Text Available This paper studies behaviours of Cymbopogon citratus leaf-extract and NaNO2, used as equal-mass admixture models, in 3.5% NaCl-immersed steel-reinforced concrete by nondestructive electrochemical methods and by compressive-strength improvement/reduction effects. Corrosion-rate, corrosion-current, and corrosion-potential constitute electrochemical test-techniques while compressive-strength effect investigations followed ASTM C29 and ASTM C33, in experiments using positive-controls for the electrochemical and compressive-strength studies. Analyses of the different electrochemical test-results mostly portrayed agreements on reinforcing-steel anticorrosion effects by the concentrations of natural plant and of chemical admixtures in the saline/marine simulating-environment and in the distilled H2O (electrochemical positive control of steel-reinforced concrete immersions. These indicated that little amount (0.0833% cement for concrete-mixing of Cymbopogon citratus leaf-extract was required for optimal inhibition efficiency, η = 99.35%, on reinforcing-steel corrosion, in the study. Results of compressive-strength change factor also indicated that the 0.0833% Cymbopogon citratus concentration outperformed NaNO2 admixture concentrations also in compressive-strength improvement effects on the NaCl-immersed steel-reinforced concrete. These established implications, from the study, on the suitability of the eco-friendly Cymbopogon citratus leaf-extract for replacing the also highly effective NaNO2 inhibitor of steel-in-concrete corrosion in concrete designed for the saline/marine service-environment.

  12. Multi-physics and multi-scale deterioration modelling of reinforced concrete part I: Coupling transport and corrosion at the material scale

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2015-01-01

    is fully coupled, i.e. information, such as temperature and moisture distribution, phase assemblage, corrosion current density, damage state of concrete cover, etc., are continuously exchanged between the models. Although not explicitly outlined in this paper, such an analysis may be further integrated...... models are sketched to describe (i) transport of heat and matter in porous media as well as phase assemblage in hardened Portland cement, (ii) corrosion of reinforcement, and (iii) material performance including corrosion-induced damages on the meso and macro scale. The presented modelling framework...

  13. Concrete

    OpenAIRE

    Kruse Aagaard, Anders

    2015-01-01

    Concrete is a component of coherent transition between a concrete base and a wooden construction. The structure is based on a quantity of investigations of the design possibilities that arise when combining digital fabrication tools and material capacities.Through tangible experiments the project discusses materiality and digitally controlled fabrications tools as direct expansions of the architect’s digital drawing and workflow. The project sees this expansion as an opportunity to connect th...

  14. Study of waterline corrosion on the carbon steel liner cast in concrete at the condensation pool. I. Literature review II. Study of the risk for waterline corrosion on the steel liner cast in concrete at the cylinder wall at Barsebaeck 1

    International Nuclear Information System (INIS)

    Sederholm, Bror; Kalinowski, Mariusz; Eistrat, Kaija

    2009-02-01

    The reactor containment in Swedish BWR-type nuclear power plants consists of an inner cylinder-shaped container of stainless steel, with an outer liner of carbon steel about 300 mm from the stainless steel container, both cast in concrete. If water leaks from the inner stainless steel container into the concrete, the risk of corrosion on the carbon steel liner may be increased by the presence of a waterline, and voids in the concrete at the metal surface. The first part of the report is a survey of published information regarding waterline corrosion and the effect of wholly or partly liquid-filled voids at a steel surface cast in concrete. The second part is a report on the investigations of the corrosion status of the steel liner on the inside of the reactor containment at the Barsebaeckverket 1 plant and of the laboratory investigations of the concrete samples that were taken from the reactor containment wall. The waterline corrosion effect is caused by local differences in environmental factors at the water/air border, primarily the supply of oxygen (air), which allows corrosion cells similar to galvanic cells to be set up. On a vertical, partly immersed steel structure the corrosion rate largely varies with the supply of oxygen, with the highest corrosion rate at or immediately above the waterline, where the supply of both oxygen (air) and electrolyte is good. The relative corrosion rates around the waterline may be modified by the action of various concentration cells. Waterline effects due to aeration cells or other concentration cells have been shown to increase the risk for corrosion damage locally, even when the overall corrosion rate does not increase, since corrosion is concentrated to a smaller area and may have a more localised character. Waterline conditions can also develop at a cast-in metal surface inside partly water-filled voids in the concrete. Voids as such at a concrete/metal interface, leaving metal without adhering concrete, have also been

  15. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. I : Application of Electrochemical Techniques

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Van Westing, E.

    2007-01-01

    The electrochemical behavior of steel reinforcement in conditions of corrosion and cathodic protection was studied, using electrochemical impedance spectroscopy (EIS) and compared to reference (noncorroding) conditions. Polarization resistance (PR) method and potentiodynamic polarization (PDP) were

  16. Standard test method for determining effects of chemical admixtures on corrosion of embedded steel reinforcement in concrete exposed to chloride environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers a procedure for determining the effects of chemical admixtures on the corrosion of metals in concrete. This test method can be used to evaluate materials intended to inhibit chloride-induced corrosion of steel in concrete. It can also be used to evaluate the corrosivity of admixtures in a chloride environment. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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.

  17. The quality control for biological-shield heavy concrete construction of nuclear power project

    International Nuclear Information System (INIS)

    Sun Hongjun; Ma Xinchao

    2012-01-01

    The paper introduces the function and characteristics of biological protective heavy-concrete, and its main application scope and role in Fangjiashan nuclear power project. From the aspects of raw material selection, mixing ratio test, heavy concrete production, the paper discusses the main control points of heavy concrete construction process, points out the basic characteristics of heavy concrete construction, and put forward measures to prevent density non-uniformity during heavy concrete construction and to control slump during transportation. Results prove that reasonable construction process control can assure the engineering quality. (authors)

  18. Finite element model for expansive stress due to corrosion of reinforced concrete structures; Analisis con elemento finito de los esfuerzos expansivos por corrosion en las estructuras de concreto reforzado

    Energy Technology Data Exchange (ETDEWEB)

    Castorena Gonzalez, J.H.; Calderon Guillen, J.A. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: kstor28@yahoo.com.mx; cajoel_99@yahoo.com; Almeraya Calderon, F.; Gaona Tiburcio, C. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: facundo.almeraya@cimav.edu.mx; citlalli.gaona@cimav.edu.mx; Almaral Sanchez, J.L. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: jalmaral@gmail.com; Martinez Villafane, A. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: martinez.villafane@cimav.edu.mx

    2011-01-15

    The corrosion in the reinforcement steel is a problem that diminishes the useful life of reinforced concrete structures, reside committing its structural security. In the available models to estimate the mechanical effect of the corrosion, it is assumed that the corroded steel, through the oxides that grow to its surroundings, exercises a pressure on the surrounding concrete supposing a problem of plane stress or plane strain. In this work, the problem is modeled with three-dimensional finite element starting from an experiment on a subjected cylinder to accelerated corrosion, with strain gage to measure the pressure indirectly in the interface steel-concrete. From the results obtained it can be concluded that the effect of the length of corroded steel, anodic length, has a significant effect on the magnitude of the pressure in the interface steel-concrete, fact that can be used to improve the existing models. [Spanish] La corrosion en el acero de refuerzo es un problema que disminuye la vida util en las estructuras de concreto reforzado, ademas de comprometer su seguridad estructural. En los modelos disponibles para estimar el efecto mecanico de la corrosion, se supone que el acero corroido, a traves de los oxidos que crecen a su alrededor, ejercen una presion sobre el concreto circundante suponiendo un problema de esfuerzos o deformaciones planas, En el presente trabajo, se modela el problema con elemento finito tridimensional a partir de un experimento sobre un cilindro de concreto reforzado sometido a corrosion acelerada, instrumentado para medir indirectamente la presion en la interfase acero-concreto. De los resultados obtenidos se concluye que el efecto de la longitud de acero corroido, longitud anodica, tiene un efecto significativo sobre la magnitud de la presion en la interfase acero-concreto, hecho que puede ser utilizado para mejorar los modelos existentes.

  19. Radiometric assessment of quality of concrete mix with respect to hardened concrete strength

    International Nuclear Information System (INIS)

    Czechowski, J.

    1983-01-01

    The experiments have confirmed the relationship between the intensity of backscattered gamma radiation and the density of fresh concrete, and also between the flow of backscattered fast neutrons and the water content. From the said two parameters it is possible to derive the compression strength of concrete over the determined period of mix hardening, e.g., after 28 days. For a certain composition of concrete it is possible to derive empirical relations between the intensity of backscattered gamma radiation and neutrons and concrete strength after hardening and to construct suitable nomograms. (Ha)

  20. 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.

  1. Manufacture and quality control of concrete for Ikata Nuclear Power Station, Shikoku Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Tada, Akiomi; Kitada, Takao

    1989-01-01

    Ikata Nuclear Power Station, only one nuclear power station in Shikoku, is located at the root of Sada Peninsula on Seto Inland sea side. At present, No.1 and No.2 plants of 566 MW each are in commercial operation, and on the east side, No.3 plant is under construction. No.3 plant is a PWR type plant of 890 MWe output, and the start of commercial operation is scheduled in March, 1995. In the construction of No.3 plant, the concrete used for civil engineering and building works is about 430,000 m 3 , and for the improvement of the quality control of concrete, the pursuit of economic efficiency, the fostering of concrete technology of employee and the coprosperity with local industries, the facilities for manufacturing concrete were constructed within the premise of the power station. The amount of use of concrete and respective materials classified by respective fiscal years, and the amount of manufacture of concrete that determines the scale of the concrete plant are shown. As to the construction of the concrete plant, the foundation work was started in March, 1987, and the machine foundation and building works were started in May, 1987. The acceptance was completed on August 17, 1987. The facilities of manufacturing concrete, the manufacture of concrete, and the quality control of materials and concrete are reported. (author)

  2. On the use of ground penetrating radar to detect rebar corrosion in concrete structures

    Science.gov (United States)

    Eisenmann, David; Margetan, Frank J.; Ellis, Shelby

    2018-04-01

    Two new studies are summarized in this paper. In the first, we compare recent GPR measurements on the same bridge to those obtained in 2012. The newer measurements use both the 1.6 GHz antenna used in the earlier work and an alternative higher frequency antenna (2.6 GHz). We discuss similarities and differences between the old and new results at 1.6 GHz, and also summarize the effect of the frequency change on the newer measurements. Many factors can contribute to the strength of the GPR echo seen from a given rebar, including the rebar's length, its distance from and tilt angle relative to the antenna, and the location and size of the metal-loss region. In the second section of the paper we discuss new laboratory measurements to systematically investigate these geometric effects. In 2016 we studied such effects using a simplified measurement setup where only an air layer separated the antenna from the rebar. Here we discuss similar measurements simulating rebar embedded in concrete. For our concrete "phantom" we use a layer of moist sand in between two parallel concrete blocks. When the moisture content is properly chosen, the EM properties of sand are similar to those of cured concrete. The block/sand/block sandwich then serves as a concrete-like medium in which a rebar can be inserted and readily repositioned. Results of GPR measurements using this new sandwich approach are reported and compared with those of the earlier "air layer only" measurements.

  3. Resistance of Alkali-Activated Slag Concrete to Chloride-Induced Corrosion

    Directory of Open Access Journals (Sweden)

    Joon Woo Park

    2015-01-01

    Full Text Available The corrosion resistance of steel in alkali-activated slag (AAS mortar was evaluated by a monitoring of the galvanic current and half-cell potential with time against a chloride-contaminated environment. For chloride transport, rapid chloride penetration test was performed, and chloride binding capacity of AAS was evaluated at a given chloride. The mortar/paste specimens were manufactured with ground granulated blast-furnace slag, instead of Portland cement, and alkali activators were added in mixing water, including Ca(OH2, KOH and NaOH, to activate hydration process. As a result, it was found that the corrosion behavior was strongly dependent on the type of alkali activator: the AAS containing the Ca(OH2 activator was the most passive in monitoring of the galvanic corrosion and half-cell potential, while KOH, and NaOH activators indicated a similar level of corrosion to Portland cement mortar (control. Despite a lower binding of chloride ions in the paste, the AAS had quite a higher resistance to chloride transport in rapid chloride penetration, presumably due to the lower level of capillary pores, which was ensured by the pore distribution of AAS mortar in mercury intrusion porosimetry.

  4. Detection of the corrosion in reinforced concrete with GPR: the case study of the Park Guell

    Science.gov (United States)

    Sossa, Viviana; Perez-Gracia, Vega; Gonzalez-Drigo, Ramon; Caselles, Oriol; Clapes, Jaume

    2017-04-01

    Detection of corrosion is important in cultural heritage assessment. Many structures contain metallic targets embedded in masonry or mortar, and corrosion cab cause important damage. However, detection using non-destructive methods is difficult and highly localized, providing in most cases incomplete results. In order to obtain a more extended analysis, GPR was applied and evaluated to detect damage as consequence of corrosion. This technique is a non-destructive method that covers a large area of study while other methods are constrained to a small areas or specific points. Therefore, some controlled laboratory tests were designed to determine possible differences in radargrams obtained in the case of corroded and non-corroded targets. These analysis allowed to observe that the corrosion seems to increase the attenuation of the radar signal, being difficult to detect targets near the damaged bars. The results were applied to study the mosaic roofs in the Park Guell, in Barcelona. This park is one of the most important Modernista (Art Noveau) complex in Barcelona. It is characterized by structures with roofs and banks with tessellation. Some of these structures are most likely supported by metal elements, and seepage cause important damage observed over the tessellation. The objective of the study was to define the possible existence of those metallic targets, determining their location. And, in the case of existence of metallic elements, defining which are the zones more affected by corrosion. The results demonstrates the existence of metallic supports in many parts, as well as some defined areas that could be damaged. Acknowledgement: This work has been partially funded by the Spanish Government and by the European Commission with FEDER funds, through the research projects CGL2011-23621 and CGL2015-65913-P. The study is also a contribution to the EU funded COST Action TU1208, "Civil Engineering Applications of Ground Penetrating Radar", to the working group 2.2.

  5. Quality evaluation tests for pervious concrete pavements’ placement

    Directory of Open Access Journals (Sweden)

    Milena Rangelov

    2017-05-01

    Full Text Available Pervious concrete pavements are gaining popularity for stormwater management. Therefore, there is an impending need for the development of quality control and acceptance specifications. In this study, the necessary initial steps are taken towards this goal. The procedures to conduct fresh and hardened density/porosity (φ and 28-day compressive strength (f′c were evaluated. The proper methodology for casting specimens in the field was identified by examining the agreement between the fresh (D and hardened density (ρ. The effect of cylindrical size, and curing methods as combinations of air and moist curing during the four-week period on f′c was studied.Both cylinder sizes demonstrated comparable values of hardened porosity (φ = 16 percent and hardened density (D = 2.11 kg/m3, as well as strong linear φ–D correlations (R2 range 0.60–0.90. The values of D agree well with those of the fresh density (two percent or less difference, which confirmed the suitability of the implemented casting and compaction procedure. Small cylinders presented higher 28-day f′c than large cylinders by 7.7 to 19 percent, depending on the curing category. The two-week air followed by two-week moist curing (2A2 M method yielded the highest 28-day f′c for both specimen sizes, however, longer periods of moist curing did not result in higher strengths. Cylinders from 1A3M, which were exposed to the longest moist curing, demonstrate the lowest f′c. Thermogravimetric analysis (TGA confirmed the trends seen in 28-day f′c and proved (that longer moist curing resulted in the loss of C–S–H and Ca(OH2. Keywords: Pervious concrete, Porosity, Density, Compressive strength, Curing

  6. Quality control of concrete structures in nuclear power plant, (4)

    International Nuclear Information System (INIS)

    Takahashi, Hisao; Kawaguchi, Tohru; Oike, Takeshi; Morimoto, Shoichi; Takeshita, Shigetoshi.

    1979-01-01

    This report describes the result of an investigation to clarify the effect of concrete temperature as mixed in the summer season on the strength gain characteristics of mass concrete such as used in construction of nuclear power plants. It is pointed out that the low strength gain of control cylinders in summer is caused by two main factors, viz., the absence of water modification in the mix design according to concrete temperature as mixed and high curing temperature after placing up to mold removal rather than concrete temperature itself as mixed. On the other hand, it has been clarified that high strength gain in mass concrete can be realized by lowering concrete temperature as mixed so as to lower the subsequent curing temperature at early age. Furthermore, it is explained that the larger the size of the member is, the more effect can be expected from lowering concrete temperature. The effect of concrete temperature as mixed on high strength concrete to be used in PCCV is discussed in the Appendix. (author)

  7. Measurement and Improvement the Quality of the Compressive Strength of Product Concrete

    Directory of Open Access Journals (Sweden)

    Zohair Hassan Abdullah

    2018-01-01

    Full Text Available The research dealt with studying path technology to manufacture of concrete cubes according to specification design of Iraq to the degree of concrete C20 No. 52 of 1984, and in which sample was cubic shape and the dimensions (150 × 150 × 150 mm for each dimensions and the proportion of mixing of the concrete is (1:2:4 using in the casting floor. For concrete resistance required that achieve the degree of confidence of 100%, were examined compressive strength 40 samples of concrete cubes of age 28 days in the Labs section of Civil Department – Technical Institute of Babylon, all made from the same mixing concrete. Where, these samples classified within the acceptable tests were adopted in the implementation of investment projects in the construction sector. The research aims first, to measure the compressive strength of concrete cubes because the decrease or increase the compressive strength from specification design contributes to the failure of investment projects in the construction sector therefore, test was classified units that produced within damaged units. Second, to study an improvement the quality of compressive strength of concrete cubes. Results show that the proportion of damaged cubes are 0.00685, compressive strength was achieve confidence level 99.5% and producing of concrete cubes within the acceptable level of quality (3 Sigma. The quality of compressive strength was improved to good level use advanced sigma  levels. DOI: http://dx.doi.org/10.25130/tjes.24.2017.20

  8. Structural performance evaluation on aging underground reinforced concrete structures. Part 6. An estimation method of threshold value in performance verification taking reinforcing steel corrosion

    International Nuclear Information System (INIS)

    Matsuo, Toyofumi; Matsumura, Takuro; Miyagawa, Yoshinori

    2009-01-01

    This paper discusses applicability of material degradation model due to reinforcing steel corrosion for RC box-culverts with corroded reinforcement and an estimation method for threshold value in performance verification reflecting reinforcing steel corrosion. First, in FEM analyses, loss of reinforcement section area and initial tension strain arising from reinforcing steel corrosion, and deteriorated bond characteristics between reinforcement and concrete were considered. The full-scale loading tests using corroded RC box-culverts were numerically analyzed. As a result, the analyzed crack patterns and load-strain relationships were in close agreement with the experimental results within the maximum corrosion ratio 15% of primary reinforcement. Then, we showed that this modeling could estimate the load carrying capacity of corroded RC box-culverts. Second, a parametric study was carried out for corroded RC box culverts with various sizes, reinforcement ratios and levels of steel corrosion, etc. Furthermore, as an application of analytical results and various experimental investigations, we suggested allowable degradation ratios for a modification of the threshold value, which corresponds to the chloride induced deterioration progress that is widely accepted in maintenance practice for civil engineering reinforced concrete structures. Finally, based on these findings, we developed two estimation methods for threshold value in performance verification: 1) a structural analysis method using nonlinear FEM included modeling of material degradation, 2) a practical method using a threshold value, which is determined by structural analyses of RC box-culverts in sound condition, is multiplied by the allowable degradation ratio. (author)

  9. Aggregates for quality concrete from debris using optimised crushing

    NARCIS (Netherlands)

    van de Wouw, P.M.F.; Florea, M.V.A.; Buyle, G.; Brouwers, H.J.H.

    2015-01-01

    Worldwide, natural disasters and conflicts result in damaged or collapsed buildings requesting clearing of debris and reconstruction. The on‐site recycling of concrete waste into new structural concrete reduces the utilization of raw materials, decreases transport and production energy cost, and

  10. Quality assurance and supervision of mass concrete construction under EPC mode

    International Nuclear Information System (INIS)

    Peng Hong

    2013-01-01

    Taking one typical general contraction project-Hainan Changjiang nuclear power project as an example, this paper introduces the mass concrete construction of nuclear island foundation of Unit 1 in its installation phase, elaborates how to conduct quality assurance and supervision for concrete production, construction, supervision and management, detects relevant weak points of quality and management in the mass concrete construction through quality assurance supervision, puts forward management requirements for the supervising organizations, accumulates useful experience on how to promote contractors to implement the contract in line with national laws, regulations and to improve the management in equipment installation, commissioning and acceptance. (authors)

  11. Deterioration of Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Chloride ingress is a common cause of deterioration of reinforced concrete bridges. Concrete may be exposed to chloride by seawater or de-icing salts. The chloride initiates corrosion of the reinforcement, which through expansion disrupts the concrete. In addition, the corrosion reduces the cross...

  12. Innovative process routes for a high-quality concrete recycling.

    Science.gov (United States)

    Menard, Y; Bru, K; Touze, S; Lemoign, A; Poirier, J E; Ruffie, G; Bonnaudin, F; Von Der Weid, F

    2013-06-01

    This study presents alternative methods for the processing of concrete waste. The mechanical stresses needed for the embrittlement of the mortar matrix and further selective crushing of concrete were generated by either electric impulses or microwaves heating. Tests were carried out on lab-made concrete samples representative of concrete waste from concrete mixer trucks and on concrete waste collected on a French demolition site. The results obtained so far show that both techniques can be used to weaken concrete samples and to enhance aggregate selective liberation (that is the production of cement paste-free aggregates) during crushing and grinding. Electric pulses treatment seems to appear more efficient, more robust and less energy consuming (1-3 kWh t(-1)) than microwave treatment (10-40 kWh t(-1)) but it can only be applied on samples in water leading to a major drawback for recycling aggregates or cement paste in the cement production process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Quality control of concretes for conditioning of spent radioactive sources

    International Nuclear Information System (INIS)

    Gonzalez N, M.

    2015-01-01

    The spent sealed radioactive sources are considered as a specific type of radioactive wastes and should be properly stored to ensure their integrity and prevent or limit the release of radionuclides in the geosphere. For this, these sources can be put up in concrete matrices. This research presents the evaluation and characterization of five concretes prepared with 4 brands of commercial cements: CPC Extra RS, CPC 30R Impercem of Cemex, Cruz Azul CPC 30R and CPC 30R of Apasco; three sizes of coarse aggregate (<30 mm, 29-11 mm and <10 mm) and fine aggregate (0.0797 mm) used as matrices for conditioning of spent sealed radioactive sources, in order to verify if these specific concretes accredit the standard NOM-019-Nucl-1995. After hardening for 28 days the concrete specimens were subjected to the tests: compressive strength; thermal cycles, irradiation, leaching and permeability, later to be characterized by: 1) X-ray diffraction in order to meet their crystalline phases; 2) scanning electron microscopy, to determine changes in morphology; 3) infrared spectroscopy, to determine the structural changes of concrete from its functional groups; 4) Raman spectroscopy to determine their structural changes and 5) Moessbauer spectroscopy, which determines changes in the oxidation state of iron in the concrete. According to the results and the changes presented by each concrete after applying the tests set by NOM-019-Nucl-1995, is concluded that the concrete made with cement Cemex brand (CPC 30-RS Extra), gravel of particle size 11-29 mm and sieved sand (0.0797 mm) can be used as matrices of spent sealed sources conditioning. Is remarkable a morphological and structural change of the concrete due to gamma irradiation and heat treatment. (Author)

  14. Corrosion of steel in concrete in cooling water walls. Report part 1 - Literature survey; Korrosion paa staal i betong i kylvattenvaegar. Delrapport 1 - Litteraturgranskning

    Energy Technology Data Exchange (ETDEWEB)

    Lindmark, Sture; Sederholm, Bror

    2010-09-15

    The aim of the present literature study has been to collect knowledge about reported concentrations of chloride concentrations in concrete exposed to brackish water and also to get an overview of whether a critical threshold chloride concentration for chloride induced corrosion on steel embedded in concrete has been reported and/or accepted. Only five known reports present chloride concentrations in concrete that has been exposed to brackish water. All three refer to the Baltic sea or the Gulf of Bothnia. Reported chloride concentrations in the concrete is considerably higher (more than a factor of ten) than what would have been expected if the chloride had been present in the concrete only as sea water in the pore system. One reason why high chloride concentrations occur in certain zones of the concrete may be that in these zones, evaporation and capillary suction of salt water may occur alternately. Another reason is that chloride ions are physically and/or chemically bound to the cement paste structure. Chloride binding is reported to be dependent on pH value in the pore solution. In line with this, another report suggests that the pH value of the outer chloride solution (the exposure solution) may be affected by the test sample when tests are carried out in small beakers, like in the laboratory. The author of that report says this might be a reason why critical chloride concentrations with respect to steel corrosion measured in the laboratory and in the field will deviate. As for reported threshold levels, many different values have been reported, differing by more than a factor 100, irrespective of the way of reporting (chloride by cement weight, chloride to hydroxide ratio, chloride to pore solution volume, etc). Some authors claim that in fact no one, single critical chloride concentration exists, but that it will depend on several other factors such as humidity, oxygen availability, pH etc. Furthermore, there are different opinions on whether bound

  15. Production and quality control of concrete for the Rajasthan Atomic Power Station - [Part 1

    International Nuclear Information System (INIS)

    Singha Roy, P.K.; Sukhtankar, K.D.; Prasad, K.

    1975-01-01

    The production and quality control of concrete and concrete materials for the construction of the twin-reactor Rajasthan Atomic Power Station with its 400 MW net capacity posed many challenges since many of the requirements for the properties of concrete were new and were being laid down for the first time in India. Some of the conditions for the concrete included leak-tightness against gas pressure, total absence of shrinkage in the containment even when the ambient temperature during concreting was as high as 45degC, placing concrete at a temperature as low as 8degC, the use of non-shrink and high strength grout, absolute impermeability against water, high density for radiation shielding, controlled modulus of elasticity for large machine foundations, high strength with high slump for the prestressed concrete dome, etc. Though the total quantity of concrete was not very much compared with a large river valley or steel plant project, (e.g., about 1.2 X 10 6 m 3 for a 2-million tonne steel plant) it was quite significant, being about 70,000 m 3 of normal density and 2,100 m 3 of high density concrete. The production of these quantities entailed intensive material study and investigation, development of new mixes with additives not tried out before in the country, and design and quality control techniques which were unique in many respects. The paper deals with the production and quality control of concrete, including grouts used in the projects, but the actual concreting and construction operations are not discussed. (author)

  16. Using biological and physico-chemical test methods to assess the role of concrete mixture design in resistance to microbially induced corrosion

    Science.gov (United States)

    House, Mitchell Wayne

    Concrete is the most widely used material for construction of wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated portland cement make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multi-stage degradation process known as microbially induced corrosion, or MIC. MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur oxidizing bacteria Thiobacillus that resides on concrete surfaces above the waterline. Sulfuric acid then attacks the cement paste portion of the concrete matrix through decalcification of calcium hydroxide and calcium silica hydrate coupled with the formation of expansive corrosion products. The attack proceeds inward resulting in reduced service life and potential failure of the concrete structure. There are several challenges associated with assessing a concrete's susceptibility to MIC. First, no standard laboratory tests exist to assess concrete resistance to MIC. Straightforward reproduction of MIC in the laboratory is complicated by the use of microorganisms and hydrogen sulfide gas. Physico-chemical tests simulating MIC by immersing concrete specimens in sulfuric acid offer a convenient alternative, but do not accurately capture the damage mechanisms associated with biological corrosion. Comparison of results between research studies is difficult due to discrepancies that can arise in experimental methods even if current ASTM standards are followed. This thesis presents two experimental methods to evaluate concrete resistance to MIC: one biological and one physico-chemical. Efforts are made to address the critical aspects of each testing method currently absent in the literature. The first method presented is a new test

  17. Estimation of Corrosion-Free Life for Concrete Containing Ground Granulated Blast-Furnace Slag under a Chloride-Bearing Environment

    Directory of Open Access Journals (Sweden)

    Sung In Hong

    2017-01-01

    Full Text Available The rate of chloride transport by diffusion in concrete containing ground granulated blast-furnace slag (GGBS was mathematically estimated to predict the corrosion-free service life of concrete structures exposed to seawater environment. As a factor to corrosiveness of steel embedment, replacement ratio of GGBS was selected, accounting for 25 and 50% to total binder. As a result, it was found that an increase in the GGBS content resulted in an increase in the chloride binding capacity, which would give rise to a lower chloride diffusion rate, thereby reducing the risk of chloride-induced corrosion. When it comes to the sensitivity of parameters to service life, the effective diffusivity showed a marginal influence on serviceability, irrespective of GGBS contents while surface chloride content and critical threshold concentration revealed more crucial factors to long term chloride diffusion. As the GGBS replacement increased, the variation in service life has become less influential with changing parameters. Substantially, GGBS concrete at high replacement ratio enhanced the service life due to a combination of dense pore structure and enhanced chloride binding capacity.

  18. Quality evaluation of concrete under compacting by vibration using resistance of electro current

    International Nuclear Information System (INIS)

    Nozaki, Yoshisugu

    2006-01-01

    Quality of concrete in structures is affected not only quality of materials; i.e. fresh concrete delivered to site but also placing and compaction works. Factors related to the latter are not studied minutely, and the works in site are judged and controlled by skilled person under his experience, and these process are said to the neck in QC and rationalization in construction site. The study to develop the evaluation system of fresh concrete quality is described in the paper, In the experiment, electrode was attached to formwork and resistance of electro current was recorded while vibrating. It can recognized that resistance is closely related to internal quality of concrete, so the resistance may be the effective index to know optimum compaction time in placing work.

  19. Evaluation of resistivity meters for concrete quality assurance.

    Science.gov (United States)

    2015-06-01

    This research evaluated a series of MoDOT concrete mixtures to verify existing relationships between surface resistivity (SR), rapid : chloride permeability (RCP), chloride ion diffusion, and the AASHTO penetrability classes. The research also perfor...

  20. Numerical simulation of the detection of crack in reinforced concrete structures of NPP due to expansion of reinforcing corrosive products using Impact-Echo method

    Directory of Open Access Journals (Sweden)

    Morávka Š.

    2008-12-01

    Full Text Available Nuclear energy boom is starting nowadays. But also current nuclear power plants (NPP are duty to certify their security for regular renewal of their operating licenses. NPP security can be significantly affected by defects of large amount of ageing reinforced concrete structures. Advanced Impact-Echo method seams to be very hopeful to cooperate at performing in-service inspections such structures. Just these in-service inspections are included in the first priority group of specific technical issues according to the recommendations of OECD-Nuclear Energy Agency, Commission on Safety of Nuclear Installation in the field of ageing management.This paper continues of extensive project dealing with Impact-Echo method application. It will present method description and main results of numerical modeling of detection and localization of crack caused by corrosive product expansion. Steel reinforcing rods are subjected to corrosion due to diffusion of corrosive agents from structure surface. Corrosive products have up to 7-times larger volume than pure steel. Raised strain can cad lead up to concrete failure and crack development. We investigate whether it is possible to detect these growing cracks by Impact-Echo method in time.Experimental verification of our numerical predictions is prepared on Civil Faculty in Brno.

  1. Passive behaviour of alloy corrosion-resistant steel Cr10Mo1 in simulating concrete pore solutions with different pH

    International Nuclear Information System (INIS)

    Ai, Zhiyong; Jiang, Jinyang; Sun, Wei; Song, Dan; Ma, Han; Zhang, Jianchun; Wang, Danqian

    2016-01-01

    Highlights: • A new alloy corrosion-resistant steel Cr10Mo1 is developed for reinforcing rebar of concrete in severe environments. • The effects of pH on the passive behaviour of Cr10Mo1 steel compared with plain carbon steel were studied systematically by electrochemical techniques and surface analysis. • The mechanism for self-reinforcing passivity against carbonation of the corrosion-resistant steel is revealed. - Abstract: The passive behaviour of new alloy corrosion-resistant steel Cr10Mo1 and plain carbon steel (as a comparison) in simulating concrete pore solutions of different pH (ranging from 13.5 to 9.0) under open circuit potential conditions, was evaluated by various electrochemical techniques: potentiodynamic polarization, capacitance measurements and electrochemical impedance spectroscopy. The chemical composition and structure of passive films were investigated by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The electrochemical responses of passive films show that Cr10Mo1 steel has an increasing passivity with pH decreasing while carbon steel dose conversely, revealing carbonation does no negative effect on passivation of the corrosion-resistant steel. SIMS reveals that the passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer mainly consisting of Fe oxides and hydroxides, and an inner layer enriched in Cr species, while only a Fe-concentrated layer for carbon steel. According to the XPS analysis results, as the pH decreases, more stable and protective Cr oxides are enriched in the film on Cr10Mo1 steel while Fe oxides gradually decompose. Higher content of Cr oxides in the film layer provides Cr10Mo1 corrosion-resistant steel more excellent passivity at lower pH.

  2. Passive behaviour of alloy corrosion-resistant steel Cr10Mo1 in simulating concrete pore solutions with different pH

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Zhiyong, E-mail: 230139452@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Jiang, Jinyang, E-mail: jiangjinyang16@163.com [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Sun, Wei, E-mail: sunwei@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Song, Dan, E-mail: songdancharls@hhu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); College of Mechanics and Materials, Hohai University, Nanjing 210098, Jiangsu (China); Ma, Han, E-mail: mahan-iris@shasteel.cn [Research Institute of Jiangsu Shasteel Iron and Steel, Zhangjiagang 215625, Jiangsu (China); Zhang, Jianchun, E-mail: Zhangjc-iris@shasteel.cn [Research Institute of Jiangsu Shasteel Iron and Steel, Zhangjiagang 215625, Jiangsu (China); Wang, Danqian, E-mail: wonderbaba@126.com [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China)

    2016-12-15

    Highlights: • A new alloy corrosion-resistant steel Cr10Mo1 is developed for reinforcing rebar of concrete in severe environments. • The effects of pH on the passive behaviour of Cr10Mo1 steel compared with plain carbon steel were studied systematically by electrochemical techniques and surface analysis. • The mechanism for self-reinforcing passivity against carbonation of the corrosion-resistant steel is revealed. - Abstract: The passive behaviour of new alloy corrosion-resistant steel Cr10Mo1 and plain carbon steel (as a comparison) in simulating concrete pore solutions of different pH (ranging from 13.5 to 9.0) under open circuit potential conditions, was evaluated by various electrochemical techniques: potentiodynamic polarization, capacitance measurements and electrochemical impedance spectroscopy. The chemical composition and structure of passive films were investigated by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The electrochemical responses of passive films show that Cr10Mo1 steel has an increasing passivity with pH decreasing while carbon steel dose conversely, revealing carbonation does no negative effect on passivation of the corrosion-resistant steel. SIMS reveals that the passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer mainly consisting of Fe oxides and hydroxides, and an inner layer enriched in Cr species, while only a Fe-concentrated layer for carbon steel. According to the XPS analysis results, as the pH decreases, more stable and protective Cr oxides are enriched in the film on Cr10Mo1 steel while Fe oxides gradually decompose. Higher content of Cr oxides in the film layer provides Cr10Mo1 corrosion-resistant steel more excellent passivity at lower pH.

  3. Implications of groundwater quality to corrosion problem and urban ...

    African Journals Online (AJOL)

    Bheema

    Surface and groundwater chemistry being an important factor in urban ... a network of pipes, conduits, metallic rods, reinforced concrete footings and other ... the WNW running fault belts (Wukro, Mekelle, Chelekot and Felega Mariam) and Rift.

  4. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    International Nuclear Information System (INIS)

    Simescu, Florica; Idrissi, Hassane

    2008-01-01

    We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 . After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  5. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    Directory of Open Access Journals (Sweden)

    Florica Simescu and Hassane Idrissi

    2008-01-01

    Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO46(OH2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  6. Progress of admixtures and quality of concrete. 2. ; Approaches to ultra-high-strength concrete. Konwa zairyo no shinpo to concrete no hinshitsu. 2. ; Chokokyodo concrete eno approach

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, T. (Shimizu Construction Co. Ltd., Tokyo (Japan)); Abe, M. (Building Research Institute, Tsukuba (Japan))

    1994-02-15

    Ultra-high-strength concrete of 600 kgf/cm[sup 2] or more is reviewed. MDF (macro defect free) cement, spheroidal cement and mechanically stabilized cement have been developed for ultra-high-strength concrete, however, in general, DSP (densified system containing homogeneously arranged ultra-fine particles) technique is now usual in which a water-cement ratio is reduced by use of advanced air entraining and water reducing agents and cured concrete is densified by use of ultra-fine particles as admixture. Four kinds of substances such as naphthalene system and polycarboxylic acid system are used as air entraining and water reducing agents, and silica fume is used as ultra-fine particle admixture which can be effectively replaced with blast furnace slag or fly ash. Various use examples of ultra-high-strength concrete such as an ocean platform are found in the world, however, only some examples such as a PC truss bridge and the main tower of a PC cable stayed bridge in Japan. 22 refs., 10 figs., 2 tabs.

  7. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  8. Study of recycled concrete aggregate quality and its relationship with recycled concrete compressive strength using database analysis

    Directory of Open Access Journals (Sweden)

    González-Taboada, I.

    2016-09-01

    Full Text Available This work studies the physical and mechanical properties of recycled concrete aggregate (recycled aggregate from concrete waste and their influence in structural recycled concrete compressive strength. For said purpose, a database has been developed with the experimental results of 152 works selected from over 250 international references. The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption. Moreover, the study analyses how the recycled aggregate (both percentage and quality and the mixing procedure (pre-soaking or adding extra water influence the recycled concrete strength of different categories (high or low water to cement ratios. When recycled aggregate absorption is low (under 5%, pre-soaking or adding extra water to avoid loss in workability will negatively affect concrete strength (due to the bleeding effect, whereas with high water absorption this does not occur and both of the aforementioned correcting methods can be accurately employed.El estudio analiza las propiedades físico-mecánicas de los áridos reciclados de hormigón (procedentes de residuos de hormigón y su influencia en la resistencia a compresión del hormigón reciclado estructural. Para ello se ha desarrollado una base de datos con resultados de 152 trabajos seleccionados a partir de más de 250 referencias internacionales. Los resultados del tratamiento de la base indican que densidad y absorción son las propiedades más sensibles a la calidad del árido reciclado. Además, este estudio analiza cómo el árido reciclado (porcentaje y calidad y el procedimiento de mezcla (presaturación o adición de agua extra influyen en la resistencia del hormigón reciclado de diferentes categorías (alta o baja relación agua-cemento. Cuando la absorción es baja (inferior al 5% presaturar o añadir agua para evitar pérdidas de trabajabilidad afectan negativamente a la resistencia (debido al bleeding

  9. HIGH-QUALITY SELF-COMPACTING CONCRETE WITH COAL BURNING WASTE

    Directory of Open Access Journals (Sweden)

    Voronin Viktor Valerianovich

    2018-01-01

    Full Text Available Subject: nowadays self-compacting concretes (SCC, the use of which requires no additional compaction, have become widespread for use in densely-reinforced structures and hard-to-reach places. In self-compacting concretes, finely-ground admixtures-microfillers are widely used for controlling technological properties. Their introduction into the concrete mix allows us to obtain more dense structure of concrete. The influence of micro-fillers on water consumption and plasticity of concrete mix, on kinetics of strength gain rate, heat release and corrosion resistance is also noticeable. Research objectives: the work focuses on the development of composition of self-compacting concrete with assigned properties with the use of fly ash based on coal burning waste, optimized with the help of experimental design method in order to clarify the influence of ash and cement quantity, sand size on strength properties. Materials and methods: pure Portland cement CEM I 42.5 N was used as a binder. Crushed granite of fraction 5…20 mm was used as coarse aggregate, coarse quartz sand with the fineness modulus of 2.6 and fine sand with the fineness modulus of 1.4 were used as fillers. A superplasticizer BASF-Master Glenium 115 was used as a plasticizing admixture. The fly ash from Cherepetskaya thermal power plant was used as a filler. The study of strength and technological properties of self-compacting concrete was performed by using standard methods. Results: we obtained three-factor quadratic dependence of strength properties on the content of ash, cement and fraction of fine filler in the mix of fine fillers. Conclusions: introduction of micro-filler admixture based on the fly ash allowed us to obtain a concrete mix with high mobility, fluidity and self-compaction property. The obtained concrete has high strength characteristics, delayed strength gain rate due to replacement of part of the binder with ash. Introduction of the fly ash increases degree of

  10. THE CORROSION CONTROL-WATER QUALITY SPIDER WEB

    Science.gov (United States)

    This presentation provides an overview of new research results and emerging research needs with respect to both corrosion control issues, (lead, copper, iron) and to issues of inorganic contaminants that can form or accumulate in distribution system, water, pipe scales and distri...

  11. The influence of form release agent application to the quality of concrete surfaces

    International Nuclear Information System (INIS)

    Klovas, A; Daukšys, M

    2013-01-01

    The main aim of this article was to obtain concrete surface quality changes by the usage of different form release agent application. Secondly, to determine blemishes of concrete surfaces and divide them according to combined method provided by two documents and by using computer program: CIB Report No. 24 T olerances on blemishes of concrete , GOST 13015.0–83 and I mageJ . Two different concrete compositions were made: BA1 (low fluidity, vibration is needed) and BA8 (high fluidity, vibration is not needed). Three castings with each formwork were conducted. Water emulsion based form release agent was used. Different applications (normal and excessive) of form release agent were used on the formwork

  12. Corrosion behaviour of steel rebars embedded in a concrete designed for the construction of an intermediate-level radioactive waste disposal facility

    Directory of Open Access Journals (Sweden)

    Schulz F.M.

    2013-07-01

    Full Text Available The National Atomic Energy Commission of the Argentine Republic is developing a nuclear waste disposal management programme that contemplates the design and construction of a facility for the final disposal of intermediate-level radioactive wastes. The repository is based on the use of multiple, independent and redundant barriers. The major components are made in reinforced concrete so, the durability of these structures is an important aspect for the facility integrity. This work presents an investigation performed on an instrumented reinforced concrete prototype specifically designed for this purpose, to study the behaviour of an intermediate level radioactive waste disposal facility from the rebar corrosion point of view. The information obtained will be used for the final design of the facility in order to guarantee a service life more or equal than the foreseen durability for this type of facilities.

  13. Microstructural evaluation of the lacquered layer quality after corrosion load

    Directory of Open Access Journals (Sweden)

    Jaroslava Svobodova

    2015-03-01

    Full Text Available Surface pre-treatment is one of the most important steps before applying the final surface treatment. These pre-treatments, like phosphating, alkaline degreasing, pickling in acids, is used to remove impurities from the surface of the base material and to create appropri-ate conditions for adhesion of the final coating (metal coatings, organic coatings. Currently are on the rise surface treatments technologies, which are based on nanotechnology. It's a new generation of chemical products for the chemical surface preparation. This paper deals with the evaluation of microstructure of painted sheet metal after corrosion load with salt spray in the corrosion chamber. Metal sheets used for the experiment have been produced from low-carbon non alloy steel. For pre-treatment of the sheet metal was used alkaline degreasing (CC, iron phosphating (Feph and nanotechnology based product Alfipas (Zr in combinations: group A - CC + Zr, group B - Feph + Zr and group C - CC + Feph + Zr. The aim of this paper is to analyze the behavior of painted sheet metal after corrosion load and evaluate the effect of pretreatment to resistance of painted surface layer.

  14. Influence of recycled aggregate quality and proportioning criteria on recycled concrete properties.

    Science.gov (United States)

    López-Gayarre, F; Serna, P; Domingo-Cabo, A; Serrano-López, M A; López-Colina, C

    2009-12-01

    This paper presents the results of experimental research using concrete produced by substituting part of the natural coarse aggregates with recycled aggregates from concrete demolition. The influence of the quality of the recycled aggregate (amount of declassified and source of aggregate), the percentage of replacement on the targeted quality of the concrete to be produced (strength and workability) has been evaluated. The granular structure of concrete and replacement criteria were analyzed in this study, factors which have not been analyzed in other studies. The following properties of recycled concretes were analyzed: density, absorption, compressive strength, elastic modulus, amount of occluded air, penetration of water under pressure and splitting tensile strength. A simplified test program was designed to control the costs of the testing while still producing sufficient data to develop reliable conclusions in order to make the number of tests viable whilst guaranteeing the reliability of the conclusions. Several factors were analyzed including the type of aggregate, the percentage of replacement, the type of sieve curve, the declassified content, the strength of concrete and workability of concrete and the replacement criteria. The type of aggregate and the percentage of replacement were the only factors that showed a clear influence on most of the properties. Compressive strength is clearly affected by the quality of recycled aggregates. If the water-cement ratio is kept constant and the loss of workability due to the effect of using recycled aggregate is compensated for with additives, the percentage of replacement of the recycled aggregate will not affect the compressive strength. The elastic modulus is affected by the percentage of replacement. If the percentage of replacement does not exceed 50%, the elastic modulus will only change slightly.

  15. Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Sun, H. Y.; Yuan, Z. Y.; Yang, Z.; Shan, G. L. [Nanjing Hydraulic Research Institute, Nanjing (China); Shen, M. X. [Hehai University, Nanjing (China)

    2017-06-15

    Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weather ability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

  16. Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

    International Nuclear Information System (INIS)

    Sun, H. Y.; Yuan, Z. Y.; Yang, Z.; Shan, G. L.; Shen, M. X.

    2017-01-01

    Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weather ability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

  17. Evaluation of the potential of additives as corrosion inhibitors of CA-50 carbon steel used as reinforcement in concretes; Avaliacao da potencialidade de aditivos como inibidores de corrosao do aco carbono CA-50 usado como armadura de estruturas de concreto

    Energy Technology Data Exchange (ETDEWEB)

    Mennucci, Marina Martins

    2006-07-01

    In this work, various compounds were tested to evaluate their potential capability for their use as corrosion inhibitors of carbon steel reinforcement in concretes. The additives tested were sodium benzoate, polyethylene glycol, hexamethylenetetramine, benzotriazole and yttrium carbonate. Initially, exploratory tests were carried out to select the ones to be used as corrosion inhibitors, based on the inhibit ion efficiency determined from electrochemical tests, specifically polarization tests and electrochemical impedance spectroscopy. These tests were carried out in a solution composed of 0.01 N sodium hydroxide (NaOH) and 0.05 N potassium hydroxide (KOH) to simulate the composition of the solution inside the pores in concretes. The additive that presented the most promising potential to be used as corrosion inhibitor was benzotriazole (BTA). After the elimination of some compounds and selection of the additive with higher corrosion inhibit ion efficiency in the test medium, the effect of its concentration on the corrosion inhibition efficiency was evaluated. Sodium nitrite solutions with the same concentrations as those solutions with BTA were tested for comparison reasons. Sodium nitrite is a well established corrosion inhibitor for carbon steel reinforcement in concretes but it has been related to toxic effects. The BTA was associated to higher corrosion inhibition efficiencies than that of sodium nitrite in similar concentrations. A blackish adherent film was formed on the steel surface exposed to BTA solutions during long periods of immersion in the alkaline medium. The results suggest that BTA is a potential candidate for substitution of nitrites as corrosion inhibitor of reinforcements in concrete. (author)

  18. Corrosion/95 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The papers in this conference represent the latest technological advances in corrosion control and prevention. The following subject areas are covered: cathodic protection in natural waters; materials for fossil fuel combustion and conversion systems; modern problems in atmospheric corrosion; innovative ideas for controlling the decaying infrastructure; deposits and their effects on corrosion in industry; volatile high temperature and non aqueous corrosion inhibitors; corrosion of light-weight and precoated metals for automotive application; refining industry corrosion; corrosion in pulp and paper industry; arctic/cold weather corrosion; materials selection for waste incinerators and associated equipment; corrosion measurement technology; environmental cracking of materials; advancing technology in the coating industry; corrosion in gas treating; green inhibition; recent advances in corrosion control of rail equipment; velocity effects and erosion corrosion in oil and gas production; marine corrosion; corrosion of materials in nuclear systems; underground corrosion control; corrosion in potable and industrial water systems in buildings and its impact on environmental compliance; deposit related boiler tube failures; boiler systems monitoring and control; recent developments and experiences in reactive metals; microbiologically influenced corrosion; corrosion and corrosion control for steel reinforced concrete; international symposium on the use of 12 and 13 Cr stainless steels in oil and gas production environments; subsea corrosion /erosion monitoring in production facilities; fiberglass reinforced pipe and tubulars in oilfield service; corrosion control technology in power transmission and distribution; mechanisms and methods of scale and deposit control; closing the loop -- results oriented cooling system monitoring and control; and minimization of aqueous discharge

  19. Development of ultrasonic testing technique with a large transducer to inspect the containment vessel plates embedded in concrete for corrosion on nuclear power plant (2)

    International Nuclear Information System (INIS)

    Ishida, Hitoshi

    2005-01-01

    The containment vessel plates embedded in concrete on Pressurized Water Reactors are inaccessible to inspect directly. Therefore, it is advisable to prepare inspection technology to detect existence and a location of corrosion on the embedded plates indirectly. The purpose of this study is establishment of ultrasonic testing technique to be able to inspect the containment vessel plates embedded in concrete widely from the accessible point. Experiments to detect artificial hollows simulating corrosion and stud bolts which hold the mold of concrete on a surface of a carbon steel plate mock-up covered with concrete were carried out with newly made low frequency (0.3MHz and 0.5MHz) 90 degrees refraction angle shear horizontal (SH) wave transducers combined with three active elements, which were equivalent to a 120 mm width element. As the results: (1) The echoes from the artificial hollows with a depth of 19 mm and 9.5mm at a distance of 1.5 m and the stud bolts with a diameter of 8mm at a distance of 0.7 - 1.7m could be discriminated clearly. (2) The multiple echoes bouncing three times between the front side and the back side of the plate, which was equivalent to a distance of about 12m, could be discriminated. (3) A divergence angle and a -6dB divergence angle of the large element (combined three elements) transducer were about 7 degrees and about 3 degrees. (4) The echoes from the hollows with a depth of 9.5m could be detected at a distance of 3.6 m with a reflection at the side wall of the mock-up. (5) It was estimated that the maximum distance of detection of the echo from the stud bolt with a diameter of 8mm was about 2.9 ∼ 3.6 m. Therefore we evaluate that the large element transducer can propagate the SH wave to about a half of a distance to the bottom of the embedded containment vessel and it is possible to detect the defects such as corrosion to a distance of 3.6 m. (author)

  20. The Passive Film Growth Mechanism of New Corrosion-Resistant Steel Rebar in Simulated Concrete Pore Solution: Nanometer Structure and Electrochemical Study.

    Science.gov (United States)

    Jiang, Jin-Yang; Wang, Danqian; Chu, Hong-Yan; Ma, Han; Liu, Yao; Gao, Yun; Shi, Jinjie; Sun, Wei

    2017-04-14

    An elaborative study was carried out on the growth mechanism and properties of the passive film for a new kind of alloyed corrosion-resistant steel (CR steel). The passive film naturally formed in simulated concrete pore solutions (pH = 13.3). The corrosion resistance was evaluated by various methods including open circuit potential (OCP), linear polarization resistance (LPR) measurements, and electrochemical impedance spectroscopy (EIS). Meanwhile, the 2205 duplex stainless steel (SS steel) was evaluated for comparison. Moreover, the passive film with CR steel was studied by means of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Atomic Force Microscope (AFM), and the Mott‑Schottky approach. The results showed that the excellent passivity of CR steel could be detected in a high alkaline environment. The grain boundaries between the fine passive film particles lead to increasing Cr oxide content in the later passivation stage. The filling of cation vacancies in the later passivation stage as well as the orderly crystalized inner layer contributed to the excellent corrosion resistance of CR steel. A passive film growth model for CR steel was proposed.

  1. The nature of rusts and corrosion characteristics of low alloy and plain carbon steels in three kinds of concrete pore solution with salinity and different pH

    International Nuclear Information System (INIS)

    Singh, J.K.; Singh, D.D.N.

    2012-01-01

    Highlights: ► LAS rebars corrode 2–3 times slower than PCS in concrete pore solution and mortars. ► Raman and XRD studies show that goethite and maghemite phases of rusts formed on LAS. ► On PCS unstable phases of lepidocrocite and akaganite are formed. ► EIS confirms more stable rust on LAS than on PCS. ► A model is proposed to explain formation of passive film on surface of steels. - Abstract: Correlation of corrosion characteristics and nature of rusts on low alloy (LA) and plain carbon (PC) steels exposed in simulated concrete pore solution of different pH is studied. Rusts formed under wet/dry conditions are examined by Raman spectroscopy and X-ray diffraction. LA rust is more adherent compared to PC as confirmed by measurement of weight in gain and electrochemical studies. EIS results show improvement in protective properties of steels with passage of time. Both steels are found prone to pitting attack in chloride contaminated pore solution. Rebars embedded in concrete exhibit same trend as recorded in solution exposure tests.

  2. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  3. Investigation of the resistance of several new metallic reinforcing bars to chloride-induced corrosion in concrete.

    Science.gov (United States)

    2003-01-01

    The Virginia Department of Transportation recently initiated a search for metallic reinforcing bars that are not only more durable and corrosion resistant than the epoxy-coated bars currently used, but also economical. In the last few years, several ...

  4. Modeling reinforced concrete durability : [summary].

    Science.gov (United States)

    2014-06-01

    Many Florida bridges are built of steel-reinforced concrete. Floridas humid and marine : environments subject steel in these structures : to corrosion once water and salt penetrate the : concrete and contact the steel. Corroded steel : takes up mo...

  5. The concept of floating electrode for contact-less electrochemical measurements: Application to reinforcing steel-bar corrosion in concrete

    International Nuclear Information System (INIS)

    Keddam, M.; Novoa, X.R.; Vivier, V.

    2009-01-01

    The concept of floating electrode is introduced for defining the common electrochemical behaviour of any non-connected, electronically conducting, body immersed in an electrolytic medium. The emphasis is put on both its own polarisation features and its influence on the d.c. and a.c. current and potential across the cell, hence the feasibility, among others, of contact-less electrochemical measurements on floating electrodes. Application to reinforcing steel bars in concrete is investigated by numerical computation of the a.c. current and potential fields in a broad range of concrete resistivity, interfacial resistance and capacitance. Impedance defined in a 4-electrode configuration, when rationalised against the concrete resistivity, is shown to provide, within a realistic range of parameters, a practical mean to access the properties of the bar-concrete interface.

  6. Using a centrifuge for quality control of pre-wetted lightweight aggregate in internally cured concrete

    Science.gov (United States)

    Miller, Albert E.

    Early age shrinkage of cementitious systems can result in an increased potential for cracking which can lead to a reduction in service life. Early age shrinkage cracking can be particularly problematic for high strength concretes, which are often specified due to their high strength and low permeability. However, these high strength concretes frequently exhibit a reduction in the internal relative humidity (RH) due to the hydration reaction (chemical shrinkage) and self-desiccation which results in a bulk shrinkage, termed autogenous shrinkage, which is substantial at early ages. Due to the low permeability of these concretes, standard external curing is not always efficient in addressing this reduction in internal RH since the penetration of water can be limited. Internal curing has been developed to reduce autogenous shrinkage. Internally cured mixtures use internal reservoirs filled with fluid (generally water) that release this fluid at appropriate times to counteract the effects of self-desiccation thereby maintaining a high internal RH. Internally cured concrete is frequently produced in North America using pre-wetted lightweight aggregate. One important aspect associated with preparing quality internally cured concrete is being able to determine the absorbed moisture and surface moisture associated with the lightweight aggregate which enables aggregate moisture corrections to be made for the concrete mixture. This thesis represents work performed to develop a test method using a centrifuge to determine the moisture state of pre-wetted fine lightweight aggregate. The results of the test method are then used in a series of worksheets that were developed to assist field technicians when performing the tests and applying the results to a mixture design. Additionally, research was performed on superabsorbent polymers to assess their ability to be used as an internal curing reservoir.

  7. Phyllanthus muellerianus and C6H15NO3 synergistic effects on 0.5 M H2SO4-immersed steel-reinforced concrete: Implication for clean corrosion-protection of wind energy structures in industrial environment

    Science.gov (United States)

    Okeniyi, Joshua Olusegun; Omotosho, Olugbenga Adeshola; Popoola, Abimbola Patricia Idowu; Loto, Cleophas Akintoye

    2016-07-01

    This paper investigates Phyllanthus muellerianus leaf-extract and C6H15NO3 (triethanolamine: TEA) synergistic effects on reinforcing-steel corrosion-inhibition and the compressive-strength of steel-reinforced concrete immersed in 0.5 M H2SO4. This is to assess suitability of the synergistic admixture usage for wind-energy steel-reinforced concrete structures designed for industrial environments. Steel-reinforced concrete specimens were admixed with individual and synergistic designs of Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures and immersed in the 0.5 M H2SO4. Electrochemical monitoring of corrosion potential, as per ASTM C876-91 R99, and corrosion current were obtained and statistically analysed, as per ASTM G16-95 R04, for modelling noise resistance. Post-immersion compressive-strength testing then followed, as per ASTM C39/C39M-03, for detailing the admixture effect on load-bearing strength of the steel-reinforced concrete specimens. Results showed that while individual Phyllanthus muellerianus leaf-extract concentrations exhibited better inhibition-efficiency performance than C6H15NO3, synergistic additions of C6H15NO3 to Phyllanthus muellerianus leaf-extract improved steel-rebar corrosion-inhibition. Thus, 6 g Phyllanthus muellerianus + 2 g C6H15NO3 synergistically improved inhibition-efficiency to η = 84.17%, from η = 55.28% by the optimal chemical or from η = 74.72% by the optimal plant-extract admixtures. The study also established that improved compressive strength of steel-reinforced concrete with acceptable inhibition of the steel-rebar corrosion could be attained through optimal combination of the Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures.

  8. Hybrid Coatings Enriched with Tetraethoxysilane for Corrosion Mitigation of Hot-Dip Galvanized Steel in Chloride Contaminated Simulated Concrete Pore Solutions

    Science.gov (United States)

    Figueira, Rita B.; Callone, Emanuela; Silva, Carlos J. R.; Pereira, Elsa V.; Dirè, Sandra

    2017-01-01

    Hybrid sol-gel coatings, named U(X):TEOS, based on ureasilicate matrices (U(X)) enriched with tetraethoxysilane (TEOS), were synthesized. The influence of TEOS addition was studied on both the structure of the hybrid sol-gel films as well as on the electrochemical properties. The effect of TEOS on the structure of the hybrid sol-gel films was investigated by solid state Nuclear Magnetic Resonance. The dielectric properties of the different materials were investigated by electrochemical impedance spectroscopy. The corrosion behavior of the hybrid coatings on HDGS was studied in chloride-contaminated simulated concrete pore solutions (SCPS) by polarization resistance measurements. The roughness of the HDGS coated with hybrids was also characterized by atomic force microscopy. The structural characterization of the hybrid materials proved the effective reaction between Jeffamine® and 3-isocyanate propyltriethoxysilane (ICPTES) and indicated that the addition of TEOS does not seem to affect the organic structure or to increase the degree of condensation of the hybrid materials. Despite the apparent lack of influence on the hybrids architecture, the polarization resistance measurements confirmed that TEOS addition improves the corrosion resistance of the hybrid coatings (U(X):TEOS) in chloride-contaminated SCPS when compared to samples prepared without any TEOS (U(X)). This behavior could be related to the decrease in roughness of the hybrid coatings (due TEOS addition) and to the different metal coating interaction resulting from the increase of the inorganic component in the hybrid matrix. PMID:28772667

  9. Corrosion of circulating water pipings in thermal and nuclear power stations and corrosion prevention measures

    International Nuclear Information System (INIS)

    Hachiya, Minoru

    1982-01-01

    In the age of energy conservation at present, the power generation facilities have been examined from the viewpoint of performance, endurance and economy, and in particular, the prevention of the loss due to the corrosion of various facilities is one of most important problems. Since circulating water pipings are in contact with sea water and soil, the peculiar corrosion phenomena are brought about on their external and internal surfaces. Namely, the pitting corrosion due to the environment of soil quality difference, the defects of coating and the contact with reinforcing bars in concrete occurs on the external surface, and the overall corrosion due to the increase of flow velocity and the pitting corrosion due to the defects of coating, the contact with different kinds of metals and the gap in corrosion-resistant steel occur on the internal surface. As the measures for corrosion prevention, corrosion-preventive coating and electric corrosion prevention are applied. The principle, the potential and current density, the system, the design procedure and the examples of application of electric corrosion prevention are described. (Kako, I.)

  10. A software prototype for assessing the reliability of a concrete bridge superstructure subjected to chloride-induced reinforcement corrosion

    DEFF Research Database (Denmark)

    Schneider, Ronald; Thöns, Sebastian; Fischer, Johannes

    2014-01-01

    state of the box girder and a structural model for evaluating the overall system reliability. The condition model is based on a dynamic Bayesian network (DBN) model which considers the spatial variation of the corrosion process. Inspection data are included in the calculation of the system reliability...

  11. Benefits of measuring half-cell potentials and rebar corrosion rates in condition surveys of concrete bridge decks.

    Science.gov (United States)

    1992-01-01

    The practice of conducting a half-cell potential survey during the assessment of the condition of a concrete deck was reexamined with the objective of eliminating some of the doubts concerning its benefits. It was found that the survey grid size of 4...

  12. Corrosion rate of rebars from linear polarization resistance and destructive analysis in blended cement concrete after chloride loading

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.; Bertolini, L.; Guerriere, M.

    2002-01-01

    Concrete specimens with various binders including Portland cement, fly ash, blast furnace slag and composite cement and three water-to-cement ratios were subjected to cyclic wetting with salt solution and drying. Specimens contained six mild steel bars at two cover depths and two activated titanium

  13. Concrete under severe conditions. Environment and loading

    International Nuclear Information System (INIS)

    2007-01-01

    The objective of the CONSEC Conferences is to focus on concrete infrastructures, either subjected to severe environment or severe loading, or any combination of severe conditions. Experience from the performance of existing concrete structures, and especially under severe environmental conditions, severe accidental loading or extended lifespan, has demonstrated the need for better integration of structural and durability design, new design concepts including reliability-based durability design, performance-based material requirements, structural robustness, and an improved basis for documentation of obtained construction quality and durability properties during concrete construction. An improved basis for operation and preventive maintenance of concrete structures including repairs and retrofitting is also very important. Premature corrosion of reinforcing steel, inadequate structural design for seismic or blast loading, are examples of reduced service life of concrete structures that not only represent technical and economical problems, but also a huge waste of natural resources and hence also, an environmental and ecological problem. Experience of structures effectively submitted to severe conditions represents a unique benchmark for quantifying the actual safety and durability margin of concrete structures. In fact for several reasons, most concrete design codes, job specifications and other requirements for concrete structures have frequently shown to yield insufficient and unsatisfactory results and ability to solve the above problems, as well as issues raised by specific very long-term or very severe requirements for nuclear and industrial waste management, or civil works of strategic relevance. Recently available high to ultra-high performance concrete may find rational and valuable application in such cases. It is very important, therefore, to bring people with different professional backgrounds together to exchange experience and develop multi

  14. The Grey Relational Analysis of Quality Investigation of Concrete Containing Solar PV Cells

    Directory of Open Access Journals (Sweden)

    Hsu Hui-Mi

    2015-01-01

    Full Text Available The construction industry through the use of less polluting green energy technology is already imminent and more had to do, and continue to improve as the development of green energy. Concrete is the most common-used construction material in the modern world. Traditional concrete is a composite, which is made of aggregate, Portland cement and water. Production of Portland cement consumes large amount of energy and releases lots of carbon dioxide, nevertheless, the developing of sustainable society means more urgent and important to search for new cementitious materials to replace Portland cement in future constructions. The research employs Taguchi method and Grey Relational Analysis (GRA to invetigate the performance of alkali activated silica fume concrete in which amorphous silicon solar cells are ground and added into the mixture in three-phase analysis. Firstly, this study used Taguchi’s orthogonal array to evaluate the influence of the control factors and identify the important factors influencing quality characteristics. Secondly, all normalizing experiment variables ranked the grey relational grades of multi-quality characteristics. Finally, this study integrated the Taguchi method and the equal weights by using GRA to establish both equal and entropy weight-based grey relational values.

  15. Modeling reinforced concrete durability.

    Science.gov (United States)

    2014-06-01

    This project developed a next-generation modeling approach for projecting the extent of : reinforced concrete corrosion-related damage, customized for new and existing Florida Department of : Transportation bridges and suitable for adapting to broade...

  16. Corrosion/96 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO 2 corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base

  17. DEPENDENCIES TO DETERMINE THE MEASURE OF DAMAGE AND CALCULATION OF RESIDUAL LIFE OF REINFORCED CONCRETE SUPERSTRUCTURE, EXPOSED TO SALT CORROSION

    OpenAIRE

    SAATOVA NODIRA ZIYAYEVNA

    2016-01-01

    In this paper we consider the current method of determining the measure of damage of concrete and reinforcement. The proposed dependence measures of damage, convenient for use in predicting the life of structures superstructures.The practical method of calculation determination of residual resource of the exploited superstructures developed. The main source of data for calculating the residual life are the parameters defined by the technical diagnosis.

  18. Characteristics of iron corrosion scales and water quality variations in drinking water distribution systems of different pipe materials.

    Science.gov (United States)

    Li, Manjie; Liu, Zhaowei; Chen, Yongcan; Hai, Yang

    2016-12-01

    Interaction between old, corroded iron pipe surfaces and bulk water is crucial to the water quality protection in drinking water distribution systems (WDS). Iron released from corrosion products will deteriorate water quality and lead to red water. This study attempted to understand the effects of pipe materials on corrosion scale characteristics and water quality variations in WDS. A more than 20-year-old hybrid pipe section assembled of unlined cast iron pipe (UCIP) and galvanized iron pipe (GIP) was selected to investigate physico-chemical characteristics of corrosion scales and their effects on water quality variations. Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Inductively Coupled Plasma (ICP) and X-ray Diffraction (XRD) were used to analyze micromorphology and chemical composition of corrosion scales. In bench testing, water quality parameters, such as pH, dissolved oxygen (DO), oxidation reduction potential (ORP), alkalinity, conductivity, turbidity, color, Fe 2+ , Fe 3+ and Zn 2+ , were determined. Scale analysis and bench-scale testing results demonstrated a significant effect of pipe materials on scale characteristics and thereby water quality variations in WDS. Characteristics of corrosion scales sampled from different pipe segments show obvious differences, both in physical and chemical aspects. Corrosion scales were found highly amorphous. Thanks to the protection of zinc coatings, GIP system was identified as the best water quality stability, in spite of high zinc release potential. It is deduced that the complicated composition of corrosion scales and structural break by the weld result in the diminished water quality stability in HP system. Measurement results showed that iron is released mainly in ferric particulate form. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Corrosion of Steel in Concrete – Specimen Design for Investigation of Interface and Bulk Conversions during Curing and Exposure

    DEFF Research Database (Denmark)

    Küter, Andre; Møller, Per; Geiker, Mette Rica

    2005-01-01

    A reinforced mortar specimen that allows electromotive force (EMF) measurements and electrochemical impedance spectroscopy (EIS) was designed and tested. The specimen consists of a mortar cylinder with a central rebar and a concentric arrangement of embedded electrode wires. The wires can act...... as both reference and counter electrode during EIS and the arrangement allows investigation of local changes in the bulk mortar by measuring the EMF of each wire versus an external standard electrode. The state of corrosion of the rebar can be investigated by EIS and EMF. EIS can be performed before...

  20. Drinking water quality assessment and corrosion mitigation in the hospital water supply system of Chacas Village (Peru

    Directory of Open Access Journals (Sweden)

    Riccardo Bigoni

    2014-07-01

    Full Text Available Rural hospitals in developing countries often lack appropriate water treatments to assure their water needs. In these facilities, due to water different uses and its use with medical equipment, water quality problems can cause very hazardous situations. In particular, corrosion of water distribution systems is a common issue that can cause unwanted changes in water quality and failures of the distribution system’s pipes. These considerations suggest that a complete monitoring program and water treatments to control and guarantee the water quality would be required in each health-care facility. This study assessed the quality of the water at the rural hospital of Chacas (Peru as measured via specific physical-chemical and microbiological parameters. The results show that the chemical and microbiological qualities of the water generally worsen from catchment to the hospital’s taps. Moreover, this work investigated the effects of a dolomite limestone filter installed to adjust the quality of the water distributed at the hospital and thereby mitigate the water’s corrosiveness. Corrosion indices were calculated to provide useful information on the water’s corrosiveness and positive results were obtained in reducing corrosiveness after the installation of the dolomite filter.

  1. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  2. Durable concrete for a waste repository - Measurement of ionic ingress

    International Nuclear Information System (INIS)

    Feldman, R.F.; Beaudoin, J.J.; Philipose, K.E.

    1990-01-01

    A waste repository for the below ground disposal of low level radioactive waste is planned at Chalk River Nuclear Laboratories. It relies greatly on the durability of concrete for the required 500 year service life. A research program to design durable concrete and predict its service life is in progress. The degradation of the concrete depends to a large extent on the rate of ingress of corrosive agents. Penetration of chloride and sulfate ions are particularly relevant. Twenty mix formulations were developed to create various types and qualities of concrete, and to study their behavior in different site environmental conditions. A total of 1,000 concrete specimens are being exposed at 20C and 45C to 25 different combinations of the corrosive agents including CO 2 . Procedures to measure the ionic profiles and to determine the factors controlling diffusion of the ions in the various concretes have been developed. Results of selected concrete systems exposed to chloride and sulfate solutions for 1 year are presented and discussed in terms of pore structure and permeability parameters of the concrete

  3. Evaluation of bridge deck with shrinkage-compensating concrete.

    Science.gov (United States)

    2016-04-01

    Concrete bridge decks are susceptible to premature cracking and to corrosion of reinforcing steel. Low-permeability : concrete does not always ensure durability if the concrete has excessive cracks that facilitate the intrusion of aggressive solution...

  4. Stray current vs anodic polarization in reinforced mortar: a comparative study on steel corrosion behaviour in both regimes

    NARCIS (Netherlands)

    Chen, Zhipei; Koleva, D.A.; van Breugel, K.

    2015-01-01

    Stray current arising from direct current electrified traction systems and then circulat-ing in reinforced concrete structures may initiate corrosion or even accelerate existing corrosion processes on embedded reinforcement. Therefore, stray-current induced corrosion of nearby reinforced concrete

  5. Degradation of Waterfront Reinforced Concrete Structures

    African Journals Online (AJOL)

    Key words: Degradation, reinforced concrete, Dar es Salaam port. Abstract—One of the ... especially corrosion of the reinforcement. ... Corrosion of steel reinforcement contributes .... cracks along the line of reinforcement bars and most of the ...

  6. Surface Chloride Levels in Colorado Structural Concrete

    Science.gov (United States)

    2018-01-01

    This project focused on the chloride-induced corrosion of reinforcing steel in structural concrete. The primary goal of this project is to analyze the surface chloride concentration level of the concrete bridge decks throughout Colorado. The study in...

  7. Prompt gamma-ray analysis of steel slag in concrete

    International Nuclear Information System (INIS)

    Naqvi, Akhtar Abbas; Garwan, Muhammad Ahmad; Nagadi, Mahmoud Mohammad; Rehman, Khateeb-ur; Raashid, Mohammad; Masalehuddin Mohiuddin, Mohammad; Al-Amoudi, Omar Saeed Baghabra

    2009-01-01

    Blast furnace slag (BFS) is added to Portland cement concrete to increase its durability, particularly its corrosion resistance. Monitoring the concentration of BFS in concrete for quality control purposes is desired. In this study, the concentration of BFS in concrete was measured by utilizing an accelerator-based prompt gamma-ray neutron activation analysis (PGNAA) setup. The optimum size of the BFS cement concrete specimen that produces the maximum intensity of gamma rays at the detector location was calculated through Monte Carlo simulations. The simulation results were experimentally validated through the gamma-ray yield measurement from BFS cement concrete specimens having different radii. The concentration of BFS in the cement concrete specimens was assessed through calcium and silicon gamma-ray yield measurement from cement concrete specimens containing 5 to 80 wt% BFS. The yield of calcium gamma rays decreases with increasing BFS concentration in concrete while the yield of silicon gamma rays increases with increasing BFS concentration in concrete. The calcium-to-silicon gamma-ray yield ratio has an inverse relation with BFS concentration in concrete. (author)

  8. Quality control of concrete in construction of No.2 and No.5 plants in Kashiwazaki Kariwa Nuclear Power Station, Tokyo Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Yamashita, Toshio; Nukui, Yasushi; Nojiri, Takaharu.

    1990-01-01

    The construction site and its weather condition are outlined. In the Nuclear Power Station, No.1 plant and No.5 plant with 1100 MWe output each have been already in operation, and No.2 plant with 1100 MWe output is about to start the operation. In this report, the quality control of about 700,000 m 3 of concrete used for No.2 and No.5 plants construction from October, 1983 to November, 1989 is described. The features of the concrete used are shown. The facilities for producing the concrete, which were set up in the construction site, the mixing of the concrete and the quality control are reported. The system for carrying out the quality control of materials and concrete is shown with a flowchart. The material testing on cement, aggregate, water quality, fly ash and chemical additives was carried out. The slump, air quantity, temperature, strength and specific gravity of concrete were tested. (K.I.)

  9. Quality Assurance Review of SKB's Copper Corrosion Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Tamara D.; Hicks, Timothy W. (Galson Sciencies LTD. 5 Grosvenor House, Melton Road, Oakham (United Kingdom))

    2010-06-15

    SKB is preparing a license application for the construction of a final repository for spent nuclear fuel in Sweden. This application will be supported by the safety assessment SR-Site for the post-closure phase. The assessment of long-term safety is based on a broad range of experimental results from laboratory scale, intermediate scale and up to full scale experiments. It is essential that there is a satisfactory level of assurance that experiments have been carried out with sufficient quality, so that results can be considered to be reliable within the context of their use in safety assessment. The former named authority, SKI, has initiated a series of reviews of SKB's methods of quality assurance and their implementation. This quality assurance review is focused on the work of copper corrosion being conducted in at SKB's Hard Rock Laboratory (HRL) in Aespoe, LOT and Miniature canister (Minican) experiments. In order for the reviewers to get a broad understanding of the issue of copper corrosion both SKB reports as well as the viewpoint of MKG was collected prior to commencement of the actual review task. The purpose of this project is to assess SKB's quality assurance with the view of providing input for the preparation of the SR-Site safety assessment. This has been achieved by examination of the corrosion part of the LOT and Minican experiments using a check list, visits to the relevant facilities, and meetings with contractors and a few members of the SKB staff. The same approach for quality assurance reviews has been used earlier in similar review tasks. During the quality review of the selected projects, several QA- related issues of different degree of severity was noted by the reviewers. The most significant finding was that SKB has chosen to present only selected real-time corrosion monitoring data in TR-09-20. This was surprising and SSM expect that SKB will analyse the reason for this thoroughly. The reviewers also made other

  10. Corrosion behavior of reinforcing steel in concrete for nuclear facilities exposed in high chloride and low pH environment

    International Nuclear Information System (INIS)

    Nishimura, Toshiyasu; Raman, Vedarajan

    2010-01-01

    The Cl ion concentration and pH were monitored by inserting micro-electrodes into artificial pores in the mortar which was exposed in 0.5 mol/l chloride solution (pH 4.0). At the same time, the electrochemical behavior of the reinforcing steel was investigated by EIS. The Cl ion concentration in the mortar was obtained using Ag/AgCl micro-electrodes, showing that this behavior is generally controlled by diffusion. When the diffusion equation was used in this work, the diffusion coefficient (D c ) showed a high value of D c = 9.5 x 10 -5 mm 2 /s. Similarly, the pH in the mortar was obtained using W/WO x micro-electrodes. With a 10 mm cover thickness, pH continued to decrease to pH 8.0, which was considered by penetration of H + ions from the surface. Based on the results of monitoring with the micro-electrodes, solutions simulating those in the pores in mortar were prepared and used in EIS measurements. The charge transfer resistance R ct in the simulated solutions showed good correspondence with the impedance Z (Z 1mHz -Z sol ) in the actual mortar. This is attributed to the fact that the corrosion of reinforcing steel was controlled by the solution conditions (mainly Cl concentration and pH) in the pores in mortar.

  11. Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

    Science.gov (United States)

    Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

    2017-06-01

    Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

  12. Influence of metakaolin on chemical resistance of concrete

    International Nuclear Information System (INIS)

    Mlinárik, L; Kopecskó, K

    2013-01-01

    Nowadays the most suitable and widely used construction material is concrete. We could develop concrete for every request in connection with the properties of fresh concrete and the quality of hardened concrete, too. The demand is rising in application of special concretes, like high performance and ultra high performance concretes (HPC, UHPC). These are usable in extreme natural circumstances or in very corrosive surroundings (for example: sewage farm, sewer, cooling tower, biogas factories). The pH value of the commercial sewage is between 7–8, but this value is often around 4 or less. The concrete pipes, which transport the sewage, are under corrosion, because above the liquid level sulphuric acid occurs due to microbes. Acidic surroundings could start the corrosion of concrete. When the pH value reduces, the influence of the acids will increase. The most significant influence has the sulphuric acid. The pH value of sulphuric acid is about 1, or less. Earlier in the cooling towers of coal thermal power stations used special coating on the concrete wall. Recently application of high performance concrete without polymeric coating is more general. Cementitious supplementary materials are widely used to protect the concrete from these corrosive surroundings. Usually used cementitious supplementary materials are ground granulated blastfurnace slag (GGBS), flying ash (FA) or silica fume (SF). In the last years there has been a growing interest in the application of metakaolin. Metakaolin is made by heat treatment, calcinations of a natural clay mineral, kaolinite. In our present research the chemical resistance of mortars in different corrosive surroundings (pH=1 sulphuric acid; pH=3 acetic acid) and the chloride ion migration were studied on series of mortar samples using rapid chloride migration test. Cement paste and mortar samples were made with 17% metakaolin replacement or without metakaolin. The following cements were used: CEM II/A-S 42.5 N, CEM I 42.5 N

  13. Effect of temperature on structural quality of the cement paste and high-strength concrete with silica fume

    International Nuclear Information System (INIS)

    Janotka, Ivan; Nuernbergerova, Terezia

    2005-01-01

    Experimental investigation conducted to study the thermo-mechanical properties of concrete at Temelin (Czech Republic), Mochovce (Slovakia), and Penly (France) nuclear power plants reveals structural integrity degradation between 100 and 200 deg C due to both a loss of water bound in hydrated cement minerals and subsequently air void formation. Test results indicate changes in strength, average pore radius and calculated permeability coefficients for Mochovce specimens exposed to temperatures up to 400 deg C. It demonstrates that the permeability coefficient measured on the basis of pore sizes using mercury intrusion porosimetry is suitable technique for the evaluation of concrete quality. It confirms that strength and permeability coefficient are equivalent structural quality variables of concrete. At 400 deg C gel-like hydration products are decomposed, at 600 deg C Ca(OH) 2 is dehydroxylated, and CaCO 3 dissociation to CaO and CO 2 accompanied with the re-crystallisation of non-binding phases from hydrated cement under re-combustion are dominant processes between 600 and 800 deg C. This stage of concrete is characterised by the collapse of its structural integrity, revealing residual compressive strength. This paper reports high-strength concrete behaviour subjected to temperatures up to 200 deg C. In accordance with previous results, research studies of structure-property relation show the changes in strength, dynamic modulus of elasticity, strain-stress behaviour, and shrinkage-induced deformations influenced by a hydrate phase decomposition. Volume reduction of the hydrate phase due to the loss of bound water mass is the cause of air void formation, and pore structure coarsening. The main attention is herein devoted to the evaluation of utility property decrease of high-strength concrete and microstructure degradation of the cement paste with the same composition than that in concrete when attacked by elevated temperatures

  14. Modelling of the Deterioration of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Stochastic modelling of the deterioration of reinforced concrete structures is addressed in this paper on basis of a detailed modelling of corrosion initiation and corrosion cracking. It is proposed that modelling of the deterioration of concrete should be based on a sound understanding...... of the physical and chemical properties of the concrete. The relationship between rebar corrosion and crack width is investigated. A new service life definition based on evolution of the corrosion crack width is proposed....

  15. Concrete aggregate durability study.

    Science.gov (United States)

    2009-06-01

    There are many factors that affect the durability of Portland cement concrete (PCC), including the mix design and the : materials used, the quality of construction, and the environment. Durability is not an intrinsic property of the concrete, but : i...

  16. Using half-cell potential measurement to access the severity of corrosion in reinforced concrete structures in Gentilly-2 reactor building

    International Nuclear Information System (INIS)

    Picard, S.; Kadoum, N.; Poirier, F.

    2009-01-01

    The half-cell potential technique has been used to assess the corrosion in the reactor's building ring beam of the Gentilly-2 nuclear power plant. It is a non-destructive technique based on the ASTM C 876 Standard. Corrosion is the result of a difference of potential between anodic and cathodic zones within the re-bars network and these potential differences are measured in the half-cell potential technique. Time exposure is the leading factor and we recommend the installation of permanent electrodes of reference in strategic areas. The results show a low corrosion activity level on 98% of the investigated surface and no severe corrosion potential reading has been registered. Furthermore the exercise shows that the repair technique has no influence on the corrosion activity of the steel network. Since most of the readings are located in the low corrosion activity level (from 0 to -100 mV), it illustrates that there is heterogeneity of the corrosion activity within the ring beam. We recommend a system to monitor the evolution of the corrosion phenomena in real time. The installation of reference electrodes positioned in some ring beam strategic areas is a simple and accurate way of monitoring the corrosion activity of the steel in the structure. In the case where an evolution in higher level is noted in the corrosion activity, it would be possible to act and prevent any further degradation of the structure

  17. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  18. HIGH-QUALITY ORNAMENTAL FINE CONCRETES MODIFIED BY NANOPARTICLES OF TITANIUM DIOXIDE

    Directory of Open Access Journals (Sweden)

    Bazhenov Yuriy Mikhaylovich

    2012-10-01

    Full Text Available Ultrasonic method of generation of a stable suspension of nano-particles of titanium dioxide and the strengthening properties of the ornamental fine concrete that contains cement binders with a nano-dispersed additive constitute the subject of the research covered by the authors. Nanoparticles react with the basic chemical elements that compose the concrete and act as crystallization centres. Therefore, the concrete porosity is reduced, while physical and technology-related properties of the ornamental fine concrete are improved. The authors have proven that the application of the nano-dispersed additive that contains titanium dioxide influences the processes of the structure formation in respect of fine ornamental concretes and improves the strength, as well as the water and cold resistance of fine concretes. The improvement is attributed to the dense concrete structure and strong adhesion between cement grains and between the cement and the aggregate. This conclusion is based on the data obtained through the employment of an electronic microscope used to identify the porosity of fine concretes.

  19. Quality control of concrete at the stage of designing its composition and technology

    Energy Technology Data Exchange (ETDEWEB)

    Kudyakov, A., E-mail: kudyakow@mail.tomsknet.ru; Prischepa, I., E-mail: ingaprishepa@mail.ru; Kiselev, D.; Prischepa, B. [Tomsk State University of Architecture and Building, 2 Solyanaya sq., Tomsk, 634003 (Russian Federation)

    2016-01-15

    The results of tests on samples of foam concrete with a hardening accelerator are presented. As the setting and hardening accelerators the following chemical additives were used: Universal-P-2 and Asilin 12. All additives were added into the insulating foam concrete mix of brand D 400 in the amount of 0.5% to 1% of cement weight. By using of additives in foam concrete technology – hardening accelerators Asilin 12 and Universal P2 in the amount of 0.5 % - and 1.0% by weight of cement foam concrete structure formation is accelerated and increases strength by 60%. For the industrial preparation of foam concrete mix technological regulations are worked out, in which it is recommended to use additives – hardening accelerators Asilin 12 in the amount of 0.5% and Universal P2 - 1% of cement weight.

  20. Quality control of concrete at the stage of designing its composition and technology

    Science.gov (United States)

    Kudyakov, A.; Prischepa, I.; Kiselev, D.; Prischepa, B.

    2016-01-01

    The results of tests on samples of foam concrete with a hardening accelerator are presented. As the setting and hardening accelerators the following chemical additives were used: Universal-P-2 and Asilin 12. All additives were added into the insulating foam concrete mix of brand D 400 in the amount of 0.5% to 1% of cement weight. By using of additives in foam concrete technology - hardening accelerators Asilin 12 and Universal P2 in the amount of 0.5 % - and 1.0% by weight of cement foam concrete structure formation is accelerated and increases strength by 60%. For the industrial preparation of foam concrete mix technological regulations are worked out, in which it is recommended to use additives - hardening accelerators Asilin 12 in the amount of 0.5% and Universal P2 - 1% of cement weight.

  1. Quality control of concrete at the stage of designing its composition and technology

    International Nuclear Information System (INIS)

    Kudyakov, A.; Prischepa, I.; Kiselev, D.; Prischepa, B.

    2016-01-01

    The results of tests on samples of foam concrete with a hardening accelerator are presented. As the setting and hardening accelerators the following chemical additives were used: Universal-P-2 and Asilin 12. All additives were added into the insulating foam concrete mix of brand D 400 in the amount of 0.5% to 1% of cement weight. By using of additives in foam concrete technology – hardening accelerators Asilin 12 and Universal P2 in the amount of 0.5 % - and 1.0% by weight of cement foam concrete structure formation is accelerated and increases strength by 60%. For the industrial preparation of foam concrete mix technological regulations are worked out, in which it is recommended to use additives – hardening accelerators Asilin 12 in the amount of 0.5% and Universal P2 - 1% of cement weight

  2. Factors Affecting the Quality of Concrete Containing Solar PV Cells through Taguchi Method

    Directory of Open Access Journals (Sweden)

    Cheng An

    2015-01-01

    Full Text Available In order to comply with the implementation of sustainable development, the construction industry through the use of less polluting green energy technology is already imminent and more had to do. Production of Portland cement consumes large amount of energy and releases lots of carbon dioxide, nevertheless, the developing of sustainable society means more urgent and important to search for new cementitious materials to replace Portland cement in future constructions. The research employs Taguchi method to identify the key factors influencing the performance of alkali activated silica fume concrete in which amorphous silicon solar cells are ground and added into the mixture. Taguchi method has made valuable contributions to statistics and engineering. It provides techniques for investigating variation in experiments, system, parameter and tolerance design, all of which have been influential in improving manufactured quality. The conclusions were made thru ANOVA and F-test based on the statistical analyses. Next, we expect the inconsistence observed in the study to be further resolved by Grey Relational Analysis which is a normalization evaluation technique to solve the complicated multi-performance characteristics optimization effectively.

  3. Thirty Years Researches on Development for Sustainable Concrete Technology

    Directory of Open Access Journals (Sweden)

    Sim Jongsung

    2017-01-01

    Full Text Available The enormous amount of concrete production has a serious impact on energy, resources, environment and ecosystem. Therefore, the issue of development of sustainable concrete technology with little impact on the environment is becoming a major issue. In this paper, researches related with sustainable development of concrete are presented in last three decades. FRP has high corrosion resistance and lightweight, thus it can be potential solution for sustainable development of concrete structures as strengthening material or reinforcement instead of steel. Researches and techniques are presented on performance of concrete beam with FRP rebar and enhancing performance of existing concrete structure using FRP strengthening methods. The application of recycled concrete aggregate (RCA has sometimes been limited in the practice and remained in the low-valued purposes only such as road base materials. In past 10 years, a great improvement in the recycling technique to produce RCA of which quality is close to natural aggregate, hence the applicability and evaluation of RCA are presented in this paper. This paper includes experimental studies for application of waste glass which could decrease CO2 emission from cement producing. The achievements of these studies are presented in this paper to contribute for sustainable development of concrete infrastructures.

  4. Special protective concretes

    International Nuclear Information System (INIS)

    Bouniol, P.

    2001-01-01

    Concrete is the most convenient material when large-scale radiation protection is needed. Thus, special concretes for nuclear purposes are used in various facilities like reactors, reprocessing centers, storage sites, accelerators, hospitals with nuclear medicine equipment, food ionization centers etc.. The recent advances made in civil engineering for the improvement of concrete durability and compactness are for a large part transposable to protection concretes. This article presents the basic knowledge about protection concretes with the associated typological and technological aspects. A large part is devoted to the intrinsic properties of concretes and to their behaviour in irradiation and temperature conditions: 1 - definition and field of application of special protective concretes; 2 - evolution of concepts and technologies (durability of structures, techniques of formulation, new additives, market evolution); 3 - design of protective structures (preliminary study, radiation characteristics, thermal constraints, damping and dimensioning, mechanical criteria); 4 - formulation of special concretes (general principles, granulates, hydraulic binders, pulverulent additives, water/cement ratio, reference composition of some special concretes); 5 - properties of special concretes (damping and thermo-mechanical properties); 6 - induced-irradiation and temperature phenomena (activation, radiolysis, mineralogical transformations, drying, shrinking, creep, corrosion of reinforcement). (J.S.)

  5. THE INFLUENCE OF PRODUCT QUALITY , PRICE PERCEPTION AND BRAND IMAGE ON SATISFACTION AND CUSTOMER LOYALTY HOLCIM CONCRETE READYMIX IN JAKARTA

    OpenAIRE

    Sita Budiastari

    2016-01-01

    The purpose of this research is to find a picture of the effect of product quality , price perception and brand image on satisfaction and customer loyalty ready mix concrete in Jakarta . This research is a quantitative study with descriptive and causal methods undertaken at Holcim Beton in 2013 with a sample of 100 customers in Jakarta and its surrounding the industrial and commercial segments project . Data collection by questionnaire respondents and analyzed using path analysis with SPSS ve...

  6. Combined Non-destructive Testing (NDT) methods for evaluating concrete quality

    International Nuclear Information System (INIS)

    Mohamad Pauzi Ismail; Noor Azreen Masenwat; Suhairy Sani; Nasharuddin Isa; Mohamad Haniza Mahmud

    2014-01-01

    This paper described the results of combining Non-destructive measurements on concrete. Local crushed granite and hematite were used as coarse aggregates; mining sand and river sand were used as fine aggregates to produce various density and strength of concrete. Concrete samples (150 mm cubes and interlocked blocks) were prepared by changing mix ratio, water to cement ratio (w/c) and types of aggregates. Density, rebound number(N) and ultrasonic pulse velocity (UPV) of the samples were taken before compressed to failure. The measurement results are explained and discussed. (author)

  7. Fatigue Model for the Structural Integrity Evaluation Applied to a Wind Turbine Concrete Shaft, Considering Corrosion and Freeze and Thaw Degradation

    DEFF Research Database (Denmark)

    Saucedo-Mora, Luis; Thöns, Sebastian

    2017-01-01

    Fatigue is one of the principal damage mechanisms in a slender concrete structure under cyclic loads. And needs to be calculated locally through all the structure, considering the lading conditions and the particularities of concrete. The model presented here is capable to account for the fatigue...

  8. Lunar concrete for construction

    Science.gov (United States)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  9. How Concrete Is Concrete?

    Science.gov (United States)

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  10. Corrosion and chemical resistant masonry materials handbook

    National Research Council Canada - National Science Library

    Sheppard, Walter Lee

    1986-01-01

    ... and other equipment. But few other than chemists and chemical engineers identify "corrosion" as chemical degradation or destruction of a material, and therefore, something that can happen to nonmetals (concrete, plastics, brick, timber, etc.) as well as to nletals. The National Association of Corrosion Engineers so defined "corrosion" over thirty years ago but this f...

  11. Acoustic Emission Analysis of Prestressed Concrete Structures

    Science.gov (United States)

    Elfergani, H. A.; Pullin, R.; Holford, K. M.

    2011-07-01

    Corrosion is a substantial problem in numerous structures and in particular corrosion is very serious in reinforced and prestressed concrete and must, in certain applications, be given special consideration because failure may result in loss of life and high financial cost. Furthermore corrosion cannot only be considered a long term problem with many studies reporting failure of bridges and concrete pipes due to corrosion within a short period after they were constructed. The concrete pipes which transport water are examples of structures that have suffered from corrosion; for example, the pipes of The Great Man-Made River Project of Libya. Five pipe failures due to corrosion have occurred since their installation. The main reason for the damage is corrosion of prestressed wires in the pipes due to the attack of chloride ions from the surrounding soil. Detection of the corrosion in initial stages has been very important to avoid other failures and the interruption of water flow. Even though most non-destructive methods which are used in the project are able to detect wire breaks, they cannot detect the presence of corrosion. Hence in areas where no excavation has been completed, areas of serious damage can go undetected. Therefore, the major problem which faces engineers is to find the best way to detect the corrosion and prevent the pipes from deteriorating. This paper reports on the use of the Acoustic Emission (AE) technique to detect the early stages of corrosion prior to deterioration of concrete structures.

  12. Acoustic Emission Analysis of Prestressed Concrete Structures

    International Nuclear Information System (INIS)

    Elfergani, H A; Pullin, R; Holford, K M

    2011-01-01

    Corrosion is a substantial problem in numerous structures and in particular corrosion is very serious in reinforced and prestressed concrete and must, in certain applications, be given special consideration because failure may result in loss of life and high financial cost. Furthermore corrosion cannot only be considered a long term problem with many studies reporting failure of bridges and concrete pipes due to corrosion within a short period after they were constructed. The concrete pipes which transport water are examples of structures that have suffered from corrosion; for example, the pipes of The Great Man-Made River Project of Libya. Five pipe failures due to corrosion have occurred since their installation. The main reason for the damage is corrosion of prestressed wires in the pipes due to the attack of chloride ions from the surrounding soil. Detection of the corrosion in initial stages has been very important to avoid other failures and the interruption of water flow. Even though most non-destructive methods which are used in the project are able to detect wire breaks, they cannot detect the presence of corrosion. Hence in areas where no excavation has been completed, areas of serious damage can go undetected. Therefore, the major problem which faces engineers is to find the best way to detect the corrosion and prevent the pipes from deteriorating. This paper reports on the use of the Acoustic Emission (AE) technique to detect the early stages of corrosion prior to deterioration of concrete structures.

  13. Comparative analysis of structural concrete quality assurance practices on nine nuclear power plant construction projects. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Willenbrock, J.H.; Thomas, H.R. Jr.; Burati, J.L. Jr.

    1978-06-01

    The basic objective of this research effort was to perform a comparative analysis of the Quality Assurance practices related to the structural concrete phase on nine nuclear power plant projects which are (or have been) under construction in the United States in the past ten years. This analysis identified the response of each Quality Assurance program to the applicable criteria of 10 CFR Part 50, Appendix B as well as to the pertinent regulatory requirements and industry standards. The major emphasis was placed on the construction aspects of the structural concrete phase of each project. The engineering and design aspects were examined whenever they interfaced with the construction aspects. For those aspects of the Quality Assurance system which can be considered managerial in nature (i.e., organizational relationships, types of Quality Assurance programs, corrective action procedures, etc.) an attempt has been made to present the alternative approaches that were identified. For those aspects of the Quality Assurance system which are technical in nature (i.e., the frequency of testing for slump, compressive strength, etc.) an attempt has been made to present a comparative analysis between projects and in relation to the recommended or mandated practices presented in the appropriate industry codes and standards.

  14. Comparative analysis of structural concrete quality assurance practices on nine nuclear power plant construction projects. Final report

    International Nuclear Information System (INIS)

    Willenbrock, J.H.; Thomas, H.R. Jr.; Burati, J.L. Jr.

    1978-06-01

    The basic objective of this research effort was to perform a comparative analysis of the Quality Assurance practices related to the structural concrete phase on nine nuclear power plant projects which are (or have been) under construction in the United States in the past ten years. This analysis identified the response of each Quality Assurance program to the applicable criteria of 10 CFR Part 50, Appendix B as well as to the pertinent regulatory requirements and industry standards. The major emphasis was placed on the construction aspects of the structural concrete phase of each project. The engineering and design aspects were examined whenever they interfaced with the construction aspects. For those aspects of the Quality Assurance system which can be considered managerial in nature (i.e., organizational relationships, types of Quality Assurance programs, corrective action procedures, etc.) an attempt has been made to present the alternative approaches that were identified. For those aspects of the Quality Assurance system which are technical in nature (i.e., the frequency of testing for slump, compressive strength, etc.) an attempt has been made to present a comparative analysis between projects and in relation to the recommended or mandated practices presented in the appropriate industry codes and standards

  15. Galvanic Corrosion of Lead by Iron (Oxyhydr)Oxides: Potential Impacts on Drinking Water Quality.

    Science.gov (United States)

    Trueman, Benjamin F; Sweet, Gregory A; Harding, Matthew D; Estabrook, Hayden; Bishop, D Paul; Gagnon, Graham A

    2017-06-20

    Lead exposure via drinking water remains a significant public health risk; this study explored the potential effects of upstream iron corrosion on lead mobility in water distribution systems. Specifically, galvanic corrosion of lead by iron (oxyhydr)oxides was investigated. Coupling an iron mineral cathode with metallic lead in a galvanic cell increased lead release by 531 μg L -1 on average-a 9-fold increase over uniform corrosion in the absence of iron. Cathodes were composed of spark plasma sintered Fe 3 O 4 or α-Fe 2 O 3 or field-extracted Fe 3 O 4 and α-FeOOH. Orthophosphate immobilized oxidized lead as insoluble hydroxypyromorphite, while humic acid enhanced lead mobility. Addition of a humic isolate increased lead release due to uniform corrosion by 81 μg L -1 and-upon coupling lead to a mineral cathode-release due to galvanic corrosion by 990 μg L -1 . Elevated lead in the presence of humic acid appeared to be driven by complexation, with 208 Pb and UV 254 size-exclusion chromatograms exhibiting strong correlation under these conditions (R 2 average = 0.87). A significant iron corrosion effect was consistent with field data: lead levels after lead service line replacement were greater by factors of 2.3-4.7 at sites supplied by unlined cast iron distribution mains compared with the alternative, lined ductile iron.

  16. Experimental validation of optimum resistance moment of concrete ...

    African Journals Online (AJOL)

    Experimental validation of optimum resistance moment of concrete slabs reinforced ... other solutions to combat corrosion problems in steel reinforced concrete. ... Eight specimens of two-way spanning slabs reinforced with CFRP bars were ...

  17. Events as Power Source: Wireless Sustainable Corrosion Monitoring

    OpenAIRE

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-01-01

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is ...

  18. Multi-physical and multi-scale deterioration modelling of reinforced concrete part II: Coupling corrosion and damage at the structural scale

    DEFF Research Database (Denmark)

    Lepech, Michael; Rao, Anirudh; Kiremidjian, Anne

    2015-01-01

    Deterioration of reinforced concrete infrastructure such as bridges, tunnels, and buildings represents one of the major challenges currently facing developed countries. This deterioration leads to economic costs for maintenance and replacement, environmental impacts such increased global warming...... potential as a result of cement production and traffic emissions, and social costs related to traffic congestion and human health concerns. While engineering tools and methods for structural modelling and design of new reinforced concrete infrastructure are mature, the methods and tools for modelling...

  19. Corrosion performance of epoxy-coated reinforcement in aggressive environments

    Science.gov (United States)

    Vaca Cortes, Enrique

    The objective of this research was to investigate the integrity and corrosion performance of epoxy-coated reinforcement in aggressive environments. A series of experimental studies were conducted: (a) hot water immersion and knife adhesion testing for assessment of coating adhesion; (b) materials and procedures for repairing coating damage; (c) degree of mechanical damage caused during concrete placement when using metal head and rubber head vibrators; (d) accelerated corrosion of coated bars embedded in macrocell and beam specimens placed in a corrosive environment for more than four years. The effects of coating condition and amount of damage, repaired vs. unrepaired damage, bar fabrication, and concrete cracking were studied. Regardless of coating condition, the performance of epoxy-coated bars was better than that of uncoated bars. Unlike black bars, coated bars did not exhibit deep pitting or substantial loss of cross section at crack locations. Damage to epoxy coating was the most significant factor affecting corrosion performance. Bars with coating in good condition, without any visible damage, performed best. The greater the size and frequency of damage, the more severe and extensive the amount of corrosion. The performance of bars that were fabricated or bent after coating was worse than that of coated straight bars. Mixing coated and uncoated bars in the same concrete member led to undesirable performance. Patching damaged coating reduced but did not prevent corrosion, particularly at bar ends. The most important factor in coating repair was the type and properties of the patching material. Surface preparation prior to coating had little effect. The absence of cracks in the concrete delayed, but did not prevent the onset of corrosion of coated bars. During consolidation of concrete, rubber head vibrators caused less damage to epoxy-coated reinforcement than did comparable metal heads. Hot water and adhesion tests were useful and practical for evaluating

  20. Probability density fittings of corrosion test-data: Implications on ...

    Indian Academy of Sciences (India)

    Steel-reinforced concrete; probability distribution functions; corrosion ... to be present in the corrosive system at a suitable concentration (Holoway et al 2004; Söylev & ..... voltage, equivalent to voltage drop, across a resistor divided by the ...

  1. Corrosion and corrosion control

    International Nuclear Information System (INIS)

    Khanna, A.S.; Totlani, M.K.

    1995-01-01

    Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

  2. Dictionary corrosion and corrosion control

    International Nuclear Information System (INIS)

    1985-01-01

    This dictionary has 13000 entries in both languages. Keywords and extensive accompanying information simplify the choice of word for the user. The following topics are covered: Theoretical principles of corrosion; Corrosion of the metals and alloys most frequently used in engineering. Types of corrosion - (chemical-, electro-chemical, biological corrosion); forms of corrosion (superficial, pitting, selective, intercrystalline and stress corrosion; vibrational corrosion cracking); erosion and cavitation. Methods of corrosion control (material selection, temporary corrosion protection media, paint and plastics coatings, electro-chemical coatings, corrosion prevention by treatment of the corrosive media); Corrosion testing methods. (orig./HP) [de

  3. Numerical Study of Corrosion Crack Opening

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Frandsen, Henrik Lund; Svensson, Staffan

    2008-01-01

    is proportional. More recently, the constant of proportionality, the so-called crack-corrosion index, has been studied further with respect to its dependence on the diameter of the reinforcement and the concrete cover. In the present paper the above-mentioned work is presented and extended with more realistic 3D......-models of the cracked concrete beam. The crack-corrosion index is evaluated for a variation of different parameters, i.e. bar diameter, concrete cover, crack length and type of corrosion product. This paper is an extended version of a paper by Thoft-Christensen et al. (2005) presented at the IFIP WG 7.5 Conference...... for the corrosion crack opening. Experiments and theoretical analysis by a numerical method, FEM, support that the relation between the reduction of the reinforcement bar diameter due to corrosion and the corresponding increase in crack width for a given time interval, measured on the surface of a concrete specimen...

  4. Quality control analysis : part IV : field simulation of asphaltic concrete specifications.

    Science.gov (United States)

    1969-02-01

    The report present some of the major findings, from a simulated study of statistical specifications, on three asphaltic concrete projects representing a total of approximately 30, 000 tons of hot mix. The major emphasis of the study has been on the a...

  5. Assessment of sand quality on concrete performance : examination of acidic and sulfate/sulfide-bearing sands.

    Science.gov (United States)

    2014-12-01

    The purpose of this research is to examine how the presence of sulfide- and sulfate-containing : minerals in acidic aggregates may affect the properties of mortar and concrete. Analyses were : performed to compare two sands from a deposit in the Geor...

  6. Effect of fly ash on the strength of porous concrete using recycled coarse aggregate to replace low-quality natural coarse aggregate

    Science.gov (United States)

    Arifi, Eva; Cahya, Evi Nur; Christin Remayanti, N.

    2017-09-01

    The performance of porous concrete made of recycled coarse aggregate was investigated. Fly ash was used as cement partial replacement. In this study, the strength of recycled aggregate was coMPared to low quality natural coarse aggregate which has high water absorption. Compression strength and tensile splitting strength test were conducted to evaluate the performance of porous concrete using fly ash as cement replacement. Results have shown that the utilization of recycled coarse aggregate up to 75% to replace low quality natural coarse aggregate with high water absorption increases compressive strength and splitting tensile strength of porous concrete. Using fly ash up to 25% as cement replacement improves compressive strength and splitting tensile strength of porous concrete.

  7. Water quality analysis and its relation to the scaling and corrosion tendency in an open water cooling system

    International Nuclear Information System (INIS)

    Zaini Hamzah; Halimah Abdul Ghani; Masitah Alias

    2008-01-01

    The problem of scaling and corrosion are common phenomena in a water cooling system especially the open cooling system. This study was carried out in Temenggor dam with an objective to check the water quality at the intake and tailrace of the hydro power plant. In-situ measurement and laboratory analysis on the water samples were carried out. Seven parameters were measured in-situ for example temperature, pH, specific conductivity, dissolved oxygen (DO), total dissolved solid (TDS), turbidity, and chlorine concentration. The water samples were collected using water sampler at three locations near the intake area at surface, and at the interval of one meter up to three meter depth. Two locations at the tailrace also were collected in the same pattern. These samples were brought back to the laboratory in UiTM, Shah Alam for further analysis. Laboratory analysis includes alkalinity, Ca 2+ , Mg 2+ and Fe 2+ concentrations, and total suspended solid (TSS). From the results, the LSI, RSI and PSI were calculated to predict the scaling and corrosion tendency. The index shows strong tendency for corrosion to take place in the cooling system as the related factors supported it. (author)

  8. Partnering with a local concrete block manufacturing plant to improve quality of construction materials in Haiti’s Central Plateau

    Directory of Open Access Journals (Sweden)

    Aaron Gordon

    2016-09-01

    Full Text Available This paper presents a successful ongoing partnership between Clemson Engineers for Developing Countries (CEDC and a concrete masonry unit (CMU manufacturing plant in rural Haiti. The infrastructure destruction and resulting loss of life of the 2010 earthquake in Haiti highlighted the need for improved building materials and codes. This partnership has helped to improve the strength of CMUs in the plant, both creating a safer local built environment and expanding the economic opportunities for this plant. Using samples of aggregate and cement from the site in Haiti, students in Clemson performed experiments to optimise the CMU mix design and made other suggestions to improve efficiency and quality of their product. Consistency continues to be a challenge for the CMU plant, and this paper also describes proposed procedures to help the plant implement quality control and quality assurance plans.

  9. Anchorage in concrete construction

    CERN Document Server

    Eligehausen, Rolf; Silva, John F

    2013-01-01

    A comprehensive treatment of current fastening technology using inserts (anchor channels, headed stud), anchors (metal expansion anchor, undercut anchor, bonded anchor, concrete screw and plastic anchor) as well as power actuated fasteners in concrete. It describes in detail the fastening elements as well as their effects and load-bearing capacities in cracked and non-cracked concrete. It further focuses on corrosion behaviour, fire resistance and characteristics with earthquakes and shocks. It finishes off with the design of fastenings according to the European Technical Approval Guideline (ETAG 001), the Final Draft of the CEN Technical Specification 'Design of fastenings for use in concrete' and the American Standards ACI 318-05, Appendix D and ACI 349-01, Appendix B.

  10. Passivation Characteristics of Alloy Corrosion-Resistant Steel Cr10Mo1 in Simulating Concrete Pore Solutions: Combination Effects of pH and Chloride.

    Science.gov (United States)

    Ai, Zhiyong; Sun, Wei; Jiang, Jinyang; Song, Dan; Ma, Han; Zhang, Jianchun; Wang, Danqian

    2016-09-01

    The electrochemical behaviour for passivation of new alloy corrosion-resistant steel Cr10Mo1 immersed in alkaline solutions with different pH values (13.3, 12.0, 10.5, and 9.0) and chloride contents (0.2 M and 1.0 M), was investigated by various electrochemical techniques: linear polarization resistance, electrochemical impedance spectroscopy and capacitance measurements. The chemical composition and structure of passive films were determined by XPS. The morphological features and surface composition of the immersed steel were evaluated by SEM together with EDS chemical analysis. The results evidence that pH plays an important role in the passivation of the corrosion-resistant steel and the effect is highly dependent upon the chloride contents. In solutions with low chloride (0.2 M), the corrosion-resistant steel has notably enhanced passivity with pH falling from 13.3 to 9.0, but does conversely when in presence of high chloride (1.0 M). The passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer enriched in Fe oxides and hydroxides, and an inner layer, rich in Cr species. The film composition varies with pH values and chloride contents. As the pH drops, more Cr oxides are enriched in the film while Fe oxides gradually decompose. Increasing chloride promotes Cr oxides and Fe oxides to transform into their hydroxides with little protection, and this is more significant at lower pH (10.5 and 9.0). These changes annotate passivation characteristics of the corrosion-resistant steel in the solutions of different electrolyte.

  11. Innovative process routes for a high-quality concrete recycling in the aggregates and cement industries

    OpenAIRE

    Bru , Kathy; Menard , Yannick; Touzé , Solène; Le Moign , Alain; Poirier , Jean Eric; Ruffié , Gilles; Bonnaudin , Fabrice; Von Der Weid , Frédéric

    2011-01-01

    International audience; Hardened concrete is a composite material that contains two main phases: the matrix (hardened cement paste, 20 %) and aggregates (gravels and sand, 80 %). The liberation and the recycling of these constituents can provide an answer to i) the exploration of new aggregates supply sources imposed by the depletion of natural deposit and the faced difficulties when trying to open new quarries and ii) the reduction of CO2 emissions in the clinker manufacturing process throug...

  12. The metal and concrete cask for SNF and its radiation protection quality control

    International Nuclear Information System (INIS)

    Shchigolev, N.D.; Golubev, O.M.

    2005-01-01

    The transportation and packing module on the basis of metal and concrete cask for the long-term storage and shipment of the spent nuclear fuel is developed in compliance with the requirements of the national standards and IAEA recommendations. Such wares designed for the NPP and submarine reactors fuel may be remade also for the research ones. A procedure and remote device for the radiation protection control of this cask equally its integrity checks after dynamic testing also is described. (author)

  13. Evaluation of the bactericidal characteristics of nano-copper oxide or functionalized zeolite coating for bio-corrosion control in concrete sewer pipes

    International Nuclear Information System (INIS)

    Haile, T.; Nakhla, G.; Allouche, E.; Vaidya, S.

    2010-01-01

    The bactericidal characteristics of nano-copper oxide or functionalized zeolite coated concrete pipes against Acidithiobacillus thiooxidans were studied by measuring the temporal variation of bacterial dry cell weight measurement, cellular Adenosine Triphosphate production, as well as oxygen uptake rate of the aforementioned bacterium. Uncorroded (UC), severely corroded (SC), and moderately corroded (MC) concrete pipes were electrochemically coated with a nano-copper oxide, while another uncorroded concrete pipe was used to apply functionalized zeolite coating (Z2). Specimens were characterized by field emission-scanning electron microscopy, and optical microscopy. Oxygen uptake rate of the bacterium was the highest in UC followed by the MC. Oxygen uptake rate and cellular Adenosine Triphosphate decreased progressively in Z2 and SC throughout the duration of the experiment due to decline in live bacterial cell. The maximum bacterial specific growth rate was 1.1 x 10 -2 day -1 for both UC and MC, with a decay rates varying from 1.4 x 10 -2 to 2.6 x 10 -2 day -1 . The minimum concentration limits for the inhibition of the bacterium in the nano-copper oxide coated concrete pipes ranged from 2.3 mg to 2.6 mg Cu per mg dry cell weight.

  14. Optimum concrete compression strength using bio-enzyme

    OpenAIRE

    Bagio Tony Hartono; Basoeki Makno; Tistogondo Julistyana; Pradana Sofyan Ali

    2017-01-01

    To make concrete with high compressive strength and has a certain concrete specifications other than the main concrete materials are also needed concrete mix quality control and other added material is also in line with the current technology of concrete mix that produces concrete with specific characteristics. Addition of bio enzyme on five concrete mixture that will be compared with normal concrete in order to know the optimum level bio-enzyme in concrete to increase the strength of the con...

  15. TRANSPARENT CONCRETE

    OpenAIRE

    Sandeep Sharma*, Dr. O.P. Reddy

    2017-01-01

    Transparent concrete is the new type of concrete introduced in todays world which carries special property of light transmitting due to presence of light Optical fibres. Which is also known as translucent concrete or light transmitting concrete, it is achieved by replacing coarse aggregates with transparent alternate materials (Optical fibres). The binding material in transparent concrete may be able to transmit light by using clear resins the concrete mix. The concrete used in industry in pr...

  16. Construction of the Kashiwazaki-Kariwa Nuclear Power Plant. Preparation and quality control of concrete for RCCV of the No. 6/7 machines

    International Nuclear Information System (INIS)

    Morishita, Hideki; Tsuchiya, Yoshimasa; Eguchi, Kiyoshi; Hosaka, Hiroshi

    1998-01-01

    In construction engineering of the Kashiwazaki-Kariwa Nuclear Power Plant, about 3,400 km 3 of concrete was used for whole machines from No. 1 to No. 7. For the Nos. 6 and 7 plants (K-6/7), the improved boiling-water reactor (ABWR) was adopted first in the world, a reinforced concrete reactor vessel (RCCV) was used in alternative with the conventional steel one. The RCCV is composed of a cylindrical shell, a planar top-slab and a mat, which are required to have functions such as shielding pressure resistance and seismic resistance. Each of every portions has a large section and is required to deal for mass concrete. As the K-6/7 have a lot of steel reinforcements for their mass concrete is necessary to pay careful attention to their fillings on a standpoint of their operations, high performance AE dewatering agent concrete with high fluidity was used. When the AE dewatering agent concrete was designed to prepare, various fundamental experiments were conducted to confirm their superior performance. As result, the concrete with high quality in material property could be processed. (G.K.)

  17. STRENGTH AND DURABILITY STUDIES ON SODIUM NITRITE INHIBITOR IN ORDINARY AND HIGH PERFORMANCE CONCRETE

    OpenAIRE

    Madhavan, V.; Jeyasehar, C. Antony

    2013-01-01

    Deterioration of concrete occurs due to physical actions, chemical reactions and electro chemical reactions at steel / concrete interface causing reinforcement corrosion. Among these, reinforcement corrosion is one of the most important causes of deterioration. Reinforcement corrosion induced by chlorides is one of the most frequent causes of corrosion of steel and 40 percent of steel corrodes due to chloride attack. To delay the corrosion process many techniques such as increasing the concre...

  18. Optimizing the use of natural gravel Brantas river as normal concrete mixed with quality fc = 19.3 Mpa

    Science.gov (United States)

    Limantara, A. D.; Widodo, A.; Winarto, S.; Krisnawati, L. D.; Mudjanarko, S. W.

    2018-04-01

    The use of natural gravel (rivers) as concrete mixtures is rarely encountered after days of demands for a higher strength of concrete. Moreover, today people have found High-Performance Concrete which, when viewed from the rough aggregate consisted mostly of broken stone, although the fine grain material still used natural sand. Is it possible that a mixture of concrete using natural gravel as a coarse aggregate is capable of producing concrete with compressive strength equivalent to a concrete mixture using crushed stone? To obtain information on this, a series of tests on concrete mixes with crude aggregates of Kalitelu Crusher, Gondang, Tulungagung and natural stone (river gravel) from the Brantas River, Ngujang, Tulungagung in the Materials Testing Laboratory Tugu Dam Construction Project, Kab. Trenggalek. From concrete strength test results using coarse material obtained value 19.47 Mpa, while the compressive strength of concrete with a mixture of crushed stone obtained the value of 21.12 Mpa.

  19. How PE tape performs under concrete coating

    International Nuclear Information System (INIS)

    Dritt, H.J.

    1984-01-01

    The program objectives were to evaluate the performance of polyethylene tape plant coating and fusion bonded epoxy powder systems with particular respect to the following: 1. Concrete coating application procedures; 2. The shear resistance during laying and retrieving operations of the coating at the various interfaces (a) Pipe and anti-corrosion coating; (b) Anti-corrosion coating and outerwrap; (c) Overlap areas of the anti-corrosion and outerwrap layers; (d) Between concrete and the various corrosion coatings during laying and retrieving operations. 3. Resistance to damage of the coating as a consequence of cracking or slippage of the concrete weight coating. 4. Ability of various coatings to withstand the damage during concrete application by both impact and compression methods; 5. Evaluation of tape and shrink sleeve joint coatings at the cut-back area as well as performance of tape under hot asphalt coating

  20. Concrete laying laboratory

    International Nuclear Information System (INIS)

    Bastlova, K.

    1986-01-01

    The task of the concrete laying laboratory established within a special department for quality control and assurance at the Dukovany nuclear power plant, is to check the composition of concrete mixes produced by the central concrete production plant on the site, and the shipment, laying and processing of concrete. The composition is given of special barite and serpentinite concretes designed for biological shields. The system of checks and of filing the results is briefly described. Esperience is summed up from the operation of the concrete laying laboratory, and conclusions are formulated which should be observed on similar large construction sites. They include the precise definition of the designer's requirements for the quality of concrete, the surface finish of concrete surfaces, the method of concreting specific structures around bushings, increased density reinforcements and various technological elements, and requirements for shipment to poorly accessible or remote places. As for the equipment of the laboratory, it should be completed with an instrument for the analysis of fresh concrete mixes, a large capacity drying kiln, etc. (Z.M.)

  1. How Concrete is Concrete

    OpenAIRE

    Koeno Gravemeijer

    2010-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two diff...

  2. Sustainability and durability analysis of reinforced concrete structures

    Science.gov (United States)

    Horáková, A.; Broukalová, I.; Kohoutková, A.; Vašková, J.

    2017-09-01

    The article describes an assessment of reinforced concrete structures in terms of durability and sustainable development. There is a short summary of findings from the literature on evaluation methods for environmental impacts and also about corrosive influences acting on the reinforced concrete structure, about factors influencing the durability of these structures and mathematical models describing the corrosion impacts. Variant design of reinforced concrete structure and assessment of these variants in terms of durability and sustainability was performed. The analysed structure was a concrete ceiling structure of a parking house for cars. The variants differ in strength class of concrete and thickness of concrete slab. It was found that in terms of durability and sustainable development it is significantly preferable to use higher class of concrete. There are significant differences in results of concrete structures durability for different mathematical models of corrosive influences.

  3. Advances in Modeling Concrete Service Life : Proceedings of 4th International RILEM PhD Workshop

    CERN Document Server

    Gulikers, Joost

    2012-01-01

    In this book, a critical analysis is made on service life models related to reinforcement corrosion. The contributors are on the frontier of knowledge in the field of durability of reinforced concrete. Topics covered in the book include: causes and mechanisms of deterioration, transport mechanisms in concrete, numerical modeling of concrete behavior, durability modeling and prediction, reliability approach to structural design for durability, structural behavior following degradation of concrete structures, deterioration and repair of concrete structures, and corrosion measurement techniques.

  4. Estimation of the Service Lifetime of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper estimation of the service lifetime of concrete bridges is discussed. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling of the corrosion process is an important aspect of the estimation of the service lifetime. In this paper...

  5. Marine Water Effect on Compressive Strength of Concrete: A Case ...

    African Journals Online (AJOL)

    However, in the case of reinforced concrete, it is recommended that reinforcement be prevented from corrosion by using stainless steels where available and corrosion inhibitors. However, long-term effect of seawater concentration on properties of concrete such as creep and durability were not investigated in this work.

  6. How Concrete is Concrete

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2010-07-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics

  7. Cathodic protection of reinforced concrete structures in the Netherlands - Experience and developments: Cathodic protection of concrete - 10 years experience

    NARCIS (Netherlands)

    Polder, R.B.

    1998-01-01

    Cathodic protection (CP) of reinforcing steel in concrete structures has been used successfully for over 20 years. CP is able to stop corrosion in a reliable and economical way where chloride contamination has caused reinforcement corrosion and subsequent concrete damage. To new structures where

  8. SIMULATION MODELS OF RESISTANCE TO CONCRETE MOVEMENT IN THE CONCRETE CONVEYING PIPE OF THE AUTOCONCRETE PUMP

    OpenAIRE

    Anofriev, P. G.

    2015-01-01

    Purpose. In modern construction the placing of concrete is often performed using distribution equipment of concrete pumps. Increase of productivity and quality of this construction work requires improvement of both concrete pumps and their tooling. The concrete pumps tooling consists of standardized concrete conveying pipes and connector bends radius of up to 2 m. A promising direction of tooling improvement is the reduce of resistance to movement of the concrete in the concrete conveying pip...

  9. Monitoring corrosion rates and localised corrosion in low conductivity water

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

    Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised...... corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement techniques (high-sensitive electrical resistance, weight loss) have been applied in operating plants. Changes in the corrosion processes are best monitored in non-aggressive, low conductivity media...

  10. Impact of hydrated cement paste quality and entrained air-void system on the durability of concrete.

    Science.gov (United States)

    2011-06-30

    This study is designed to examine whether traditional limits used to describe the air-void system still : apply to concrete prepared with new admixtures and materials. For this research, the concrete mixtures : prepared were characterized with tradit...

  11. Modelación con elementos finitos del agrietamiento en el hormigón por corrosión localizada en la armadura Finite element modeling of cracking in concrete due to localized corrosion in the reinforcement

    Directory of Open Access Journals (Sweden)

    J Castorena

    2007-04-01

    Full Text Available En base a estudios con elemento finito, en el presente trabajo se obtiene un modelo capaz de predecir la cantidad de acero corroído (rcrit en la armadura necesaria para que aparezca la primera grieta visible en la superficie del recubrimiento del hormigón. Para el análisis con elemento finito se utiliza el software ANSYS, el cual dispone del elemento SOLID65, con el que es posible modelar el hormigón simple, ya que tiene la capacidad de sufrir aplastamiento en compresión y agrietarse a tracción. El caso de la capa de óxido es modelado mediante elementos de contacto CONTA174, y la armadura con SOLID65, pero sin las opciones de aplastamiento y agrietamiento. El modelo obtenido está en función del recubrimiento libre, diámetro del refuerzo, tipo de hormigón y la longitud corroída, denominada ésta longitud anódica. Los resultados muestran la gran influencia que tiene la corrosión localizada (longitud anódica pequeña-longitud catódica grande sobre el cálculo de rcrit, y que dicho efecto sólo es posible analizarlo de manera tridimensional. Así mismo, se muestra la eficiencia de utilizar los elementos de contacto CONTA174 para representar el crecimiento de óxidos. El modelo obtenido explica en un 92% el fenómeno y se compara con resultados experimentales encontrados en la literaturaBased on studies with finite element method, a model able to predict the quantity of steel corrosion (rcrit necessary for the first visible crack appearance in the surface of the concrete cover was obtained. For the finite element analysis the software ANSYS was used, which has the element SOLID65, with which is possible to model plain concrete, since has the capacity to show crushing in compression and to cracking in tension. The case of the oxide layer is modeled by means of contact elements CONTA174 and the steel with SOLID65, but without the crushing and cracking options. The obtained model is in function of the free cover, diameter of the

  12. Biodecontamination of concrete

    International Nuclear Information System (INIS)

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-01-01

    A novel technology for biologically decontaminating concrete is being jointly developed by scientists at the Idaho National Engineering Laboratory (INEL) and British Nuclear Fuels plc (BNFL). The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of concrete. Most radionuclide contamination of concrete is fixed in the outer few mm of the concrete surface. By capturing and controlling this natural process, a biological method of removing the surface of concrete to depths up to several mm is being developed. Three types of bacteria are known to be important in MID of concrete: nitrifying bacteria that produce nitric acid, sulfur oxidizing bacteria that produce sulfuric acid, and certain heterotrophic bacteria that produce organic acids. An investigation of natural environments demonstrated with scanning electron microscopy the presence of bacteria on concrete surfaces of a variety of structures, such as bridges and dams, where corrosion is evident. Enumeration of sulfur oxidizing and nitrifying bacteria revealed their presence and activity on structures to varying degrees in different environments. Under ideal conditions, Thiobacillus thiooxidans, a sulfur oxidizing bacteria, attached to and colonized the surface of concrete specimens. Over 1mm depth of material from a 10 cm x 10 cm square surface was removed in 68 days in the Thiobacillus treated specimen compared to a sterile control. Laboratory and field demonstrations are currently being conducted using experimental chambers designed to be mounted directly to concrete surfaces where radionuclide contamination exists. Data is being obtained in order to determine actual rates of surface removal and limitations to the system. This information will be used to develop a full scale decontamination technology

  13. Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic tile and green roofs in Chongqing, China.

    Science.gov (United States)

    Zhang, Qianqian; Wang, Xiaoke; Hou, Peiqiang; Wan, Wuxing; Li, Ruida; Ren, Yufen; Ouyang, Zhiyun

    2014-01-01

    There is an urgent requirement to examine the quality of harvested rainwater for potable and non-potable purposes, based on the type of roofing material. In this study, we examined the effect on the quality of harvested rainwater of conventional roofing materials (concrete, asphalt and ceramic tile roofs) compared with alternative roofing materials (green roof). The results showed that the ceramic tile roof was the most suitable for rainwater-harvesting applications because of the lower concentrations of leachable pollutants. However, in this study, the green roof was not suitable for rainwater harvesting applications. In addition, seasonal trends in water quality parameters showed that pollutants in roof runoff in summer and autumn were lower than those in winter and spring. This study revealed that the quality of harvested rainwater was significantly affected by the roofing material; therefore, local government and urban planners should develop stricter testing programs and produce more weathering resistant roofing materials to allow the harvesting of rainwater for domestic and public uses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. The use of electrochemical measurement techniques towards quality control and optimisation of corrosion properties of thermal spray coatings

    NARCIS (Netherlands)

    Vreijling, M.P.W.; Hofman, R.; Westing, E.P.M. van; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    Metal spray coatings are ever more recognised as a possible superior means of corrosion protection in many environments. Extended service life combined with little or no maintenance provides interesting opportunities for both environmentalists and corrosion engineers. Although many successful

  15. Electrochemical Corrosion Behavior of Carbon Steel and Hot Dip Galvanized Steel in Simulated Concrete Solution with Different pH Values

    Directory of Open Access Journals (Sweden)

    Wanchen XIE

    2017-08-01

    Full Text Available Hot dip galvanizing technology is now widely used as a method of protection for steel rebars. The corrosion behaviors of Q235 carbon steel and hot galvanized steel in a Ca(OH2 solution with a pH from 10 to 13 was investigated by electrode potential and polarization curves testing. The results indicated that carbon steel and hot galvanized steel were all passivated in a strong alkaline solution. The electrode potential of hot dip galvanized steel was lower than that of carbon steel; thus, hot dip galvanized steel can provide very good anodic protection for carbon steel. However, when the pH value reached 12.5, a polarity reversal occurred under the condition of a certain potential. Hot dip galvanized coating became a cathode, and the corrosion of carbon steel accelerated. The electrochemical behaviors and passivation abilities of hot dip galvanized steel and carbon steel were affected by pH. The higher the pH value was, the more easily they were passivated.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16675

  16. Laboratory study of reinforcement protection with corrosion inhibitors

    International Nuclear Information System (INIS)

    Stefanescu, D.; Mihalache, M.; Mogosan, S.

    2013-01-01

    Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that degradation of the reinforced concrete structures caused by the corrosion of the reinforcing steel represents more than 80% of all damages in the world. Much effort has been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages in new structures. Migrating Corrosion Inhibitor technology was developed to protect the embedded steel rebar/concrete structure. These inhibitors can be incorporated as an admixture or can be surface impregnated on existing concrete structures. The effectiveness of two inhibitors (ethanolamine and diethanolamine) mixed in the reinforced concrete was evaluated by gravimetric measurements. The corrosion behavior of the steel rebar and the inhibiting effects of the amino alcohol chemistry in an aggressive environment were monitored using electrochemical measurements and scanning electron microscopy (SEM) investigations. (authors)

  17. Quality assurance requirements for installation, inspection, and testing of structural concrete and structural steel during the construction phase of nuclear power plants

    International Nuclear Information System (INIS)

    1975-04-01

    This guide describes a method acceptable to the NRC staff for complying with the Commission's regulations with regard to quality assurance requirements for installation, inspection, and testing of structural concrete and structural steel during the construction phase of nuclear power plants. This guide applies to all types of nuclear power plants. (U.S.)

  18. Supplementary quality assurance requirements for installation, inspection, and testing of structural concrete and structural steel during the construction phase of nuclear power plants

    International Nuclear Information System (INIS)

    Anon.

    1974-01-01

    This standard sets forth the supplementary quality assurance requirements for installation, inspection, and testing of structural concrete and structural steel for nuclear power plant construction. The requirements may also be extended to other appropriate parts of nuclear power plants when specified in contract documents. This standard is intended to be used in conjunction with ANSI N45.2

  19. THE INFLUENCE OF PRODUCT QUALITY , PRICE PERCEPTION AND BRAND IMAGE ON SATISFACTION AND CUSTOMER LOYALTY HOLCIM CONCRETE READYMIX IN JAKARTA

    Directory of Open Access Journals (Sweden)

    Sita Budiastari

    2016-09-01

    Full Text Available The purpose of this research is to find a picture of the effect of product quality , price perception and brand image on satisfaction and customer loyalty ready mix concrete in Jakarta . This research is a quantitative study with descriptive and causal methods undertaken at Holcim Beton in 2013 with a sample of 100 customers in Jakarta and its surrounding the industrial and commercial segments project . Data collection by questionnaire respondents and analyzed using path analysis with SPSS version 20.0. The results of the study concluded that ( 1 product quality does not effect to customer satisfaction ( 2 Perception price positive and significant effect on customer satisfaction, ( 3 Brand Image does not have an influence on customer satisfaction, ( 4 all independent variables , quality of products , Perception price and a positive brand image and significant consequences for the dependent variable Customer satisfaction, with the value of determination of 50%, while 50% are influenced by other variables ( 5 Product Quality and significant effect on customer loyalty through customer satisfaction, ( 6 Perceived Price does not effect on loyalty through customer satisfaction, ( 7 brand image have effect and siginikan loyalty through customer satisfaction, ( 8 Dependent variable of product quality , price perception and brand image together and significant effect on customer loyalty through customer satisfaction, with value of determination of 77.4 %, and 22.6 % are influenced by other factors. The findings recommend that Holcim aims to improve product quality , perceived price and brand image to increase loyalty through customer satisfaction . It is also recommended to Holcim for increase of services and information to customers in order for increase customer satisfaction and loyalty.

  20. The Effects of Corrosive Chemicals on Corrosion Rate of Steel Reinforcement Bars: II. Swamp Sludges

    Directory of Open Access Journals (Sweden)

    Henki Ashadi

    2010-10-01

    Full Text Available A polluted environment will influence the building age. The objective of this research was to find out the influence of corrosive chemicals within the sludge swamp area with the corrosion rate of steel concrete. Corrosion in steel concrete usually occur in acid area which contain of SO42-, Cl- and NO3-. The research treatment used by emerging ST 37 andST 60 within 60 days in 'polluted' sludge swamp area. Three variation of 'polluted' swamp sludge were made by increasing the concentration a corrosive unsure up to 1X, 5X and 10X. The corrosion rate measured by using an Immersion Method. The result of Immersion test showed that sulphate had a greatest influence to corrosion rate of ST 37 and ST 60 and followed by chloride and nitrate. Corrosion rate value for ST 37 was 17.58 mpy and for ST 60 was 12.47 mpy.

  1. Recycled Concrete as Aggregate for Structural Concrete Production

    Directory of Open Access Journals (Sweden)

    Mirjana Malešev

    2010-04-01

    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  2. Durability of precast prestressed concrete piles in marine environment, part 2. Volume 1 : concrete.

    Science.gov (United States)

    2012-06-01

    The overall purpose of this research was to determine methods which may be applied : economically to mitigate corrosion of reinforcement in precast prestressed concrete piles in : Georgias marine environments. The research was divided into two par...

  3. Impacts of water quality on the corrosion of cast iron pipes for water distribution and proposed source water switch strategy.

    Science.gov (United States)

    Hu, Jun; Dong, Huiyu; Xu, Qiang; Ling, Wencui; Qu, Jiuhui; Qiang, Zhimin

    2018-02-01

    Switch of source water may induce "red water" episodes. This study investigated the impacts of water quality on iron release, dissolved oxygen consumption (ΔDO), corrosion scale evolution and bacterial community succession in cast iron pipes used for drinking water distribution at pilot scale, and proposed a source water switch strategy accordingly. Three sets of old cast iron pipe section (named BP, SP and GP) were excavated on site and assembled in a test base, which had historically transported blended water, surface water and groundwater, respectively. Results indicate that an increasing Cl - or SO 4 2- concentration accelerated iron release, but alkalinity and calcium hardness exhibited an opposite tendency. Disinfectant shift from free chlorine to monochloramine slightly inhibited iron release, while the impact of peroxymonosulfate depended on the source water historically transported in the test pipes. The ΔDO was highly consistent with iron release in all three pipe systems. The mass ratio of magnetite to goethite in the corrosion scales of SP was higher than those of BP and GP and kept almost unchanged over the whole operation period. Siderite and calcite formation confirmed that an increasing alkalinity and hardness inhibited iron release. Iron-reducing bacteria decreased in the BP but increased in the SP and GP; meanwhile, sulfur-oxidizing, sulfate-reducing and iron oxidizing bacteria increased in all three pipe systems. To avoid the occurrence of "red water", a source water switch strategy was proposed based on the difference between local and foreign water qualities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Corrosion studies on PREPP waste form

    International Nuclear Information System (INIS)

    Welch, J.M.; Neilson, R.M. Jr.

    1984-05-01

    Deformation or Failure Test and Accelerated Corrosion Test procedures were conducted to investigate the effect of formulation variables on the corrosion of oversize waste in Process Experimental Pilot Plant (PREPP) concrete waste forms. The Deformation or Failure Test did not indicate substantial waste form swelling from corrosion. The presence or absence of corrosion inhibitor was the most significant factor relative to measured half-cell potentials identified in the Accelerated Corrosion Test. However, corrosion inhibitor was determined to be only marginally beneficial. While this study produced no evidence that corrosion is of sufficient magnitude to produce serious degradation of PREPP waste forms, the need for corrosion rate testing is suggested. 11 references, 4 figures, 8 tables

  5. CONCRETE MIX DESIGN FOR STRUCTURES SUBJECTED TO EXPOSURE CLASS XC1 DEPENDING ON CONCRETE COVER

    Directory of Open Access Journals (Sweden)

    O. Yu. Cherniakevich

    2016-01-01

    Full Text Available The reinforced steel corrosion which is the most important problem of reinforced concrete structures durability is generally stipulated for carbonization of concrete surrounding it. Concrete cover calculation at the design stage is predicated one because of the differences in manufacturing conditions and use of constructions. The applying of the probabilistic approaches to the carbonation process modeling allows to get predicated grade of the depth of carbonization of concrete and, thus, to settle minimum concrete cover thickness for a given projected service life of a construction. The procedures for concrete mix design for different strength classes of concrete are described in the article. Current recommendations on assignment of concrete strength class as well as concrete cover are presented. The European Standard EN 206:2013 defines the content requirements for the concrete structures operated in the exposure class XC1, including the minimum values of water-cement ratio, minimum cement content, and minimum strength class of concrete. Since the standard does not include any basis or explanations of the requirements, we made an effort to develop a scientific justification for the mentioned requirements. We developed the probabilistic models for the process of carbonation of concrete based on the concrete mix which was designed using the software VTK-Korroziya. The reinforced concrete structures with concrete cover 20–35 mm operated in the most unfavorable conditions within the exposure class XC1 were analyzed. The corresponding probabilistic calculations of the depth of carbonated concrete are described in the article. 

  6. ADVANCEMENTS IN CONCRETE TECHNOLOGY

    OpenAIRE

    Shri Purvansh B. Shah; Shri Prakash D. Gohil; Shri Hiren J. Chavda; Shri Tejas D. Khediya

    2015-01-01

    Developing and maintaining world’s infrastructure to meet the future needs of industrialized and developing countries is necessary to economically grow and improve the quality of life. The quality and performance of concrete plays a key role for most of infrastructure including commercial, industrial, residential and military structures, dams, power plants. Concrete is the single largest manufactured material in the world and accounts for more than 6 billion metric tons of materials annual...

  7. How Concrete is Concrete?

    Directory of Open Access Journals (Sweden)

    Koeno Gravemeijer

    2011-01-01

    Full Text Available If we want to make something concrete in mathematics education, we are inclined introduce, what we call, ‘manipulatives’, in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own, abstract, knowledge; in the latter, we try to find an example that the others will be familiar with. This article first looks at the tension between these two different ways of making things concrete. Next another role of manipulatives, will be discussed, namely that of means for scaffolding and communication. In this role, manipulatives may function as means of support in a process that aims at helping students to build on their own thinking while constructing more sophisticated mathematics.Key words:  Conceret Learning Materials, School Math, Common Sense, Scaffolding, Communication DOI: http://dx.doi.org/10.22342/jme.2.1.780.1-14

  8. Mortar fights acid corrosion

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-14

    The burning of coal or oil to produce heat required to operate a power boiler also generates a severe corrosion problem within the interior of the duct and stacks used to emit the flue gas into the atmosphere. How can concrete and steel be protected from the effects of acid attack, when the acids are carried in a gas form, or come into direct contact with the steel or concrete from spillage or immersion conditions. Industry in North America has found that the solution to this problem is to build an outside concrete column, in this case of Portland cement, and inside that column, build a totally independent brick liner bonded with Sauereisen mortar.

  9. Corrosion cracking

    International Nuclear Information System (INIS)

    Goel, V.S.

    1985-01-01

    This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600

  10. Usage of Crushed Concrete Fines in Decorative Concrete

    Science.gov (United States)

    Pilipenko, Anton; Bazhenova, Sofia

    2017-10-01

    The article is devoted to the questions of usage of crushed concrete fines from concrete scrap for the production of high-quality decorative composite materials based on mixed binder. The main problem in the application of crushed concrete in the manufacture of decorative concrete products is extremely low decorative properties of crushed concrete fines itself, as well as concrete products based on them. However, crushed concrete fines could have a positive impact on the structure of the concrete matrix and could improve the environmental and economic characteristics of the concrete products. Dust fraction of crushed concrete fines contains non-hydrated cement grains, which can be opened in screening process due to the low strength of the contact zone between the hydrated and non-hydrated cement. In addition, the screening process could increase activity of the crushed concrete fines, so it can be used as a fine aggregate and filler for concrete mixes. Previous studies have shown that the effect of the usage of the crushed concrete fines is small and does not allow to obtain concrete products with high strength. However, it is possible to improve the efficiency of the crushed concrete fines as a filler due to the complex of measures prior to mixing. Such measures may include a preliminary mechanochemical activation of the binder (cement binder, iron oxide pigment, silica fume and crushed concrete fines), as well as the usage of polycarboxylate superplasticizers. The development of specific surface area of activated crushed concrete fines ensures strong adhesion between grains of binder and filler during the formation of cement stone matrix. The particle size distribution of the crushed concrete fines could achieve the densest structure of cement stone matrix and improve its resistance to environmental effects. The authors examined the mechanisms of structure of concrete products with crushed concrete fines as a filler. The results of studies of the properties of

  11. Comparative analysis of structural concrete Quality Assurance practices on nine nuclear and three fossil fuel power plant construction projects. Final summary report

    International Nuclear Information System (INIS)

    Willenbrock, J.H.; Thomas, H.R. Jr.; Burati, J.J. Jr.

    1978-12-01

    A summary of two reports, COO/4120-1 and COO/4120-2, is given. A comparative analysis was made of the Quality Assurance practices related to the structural concrete phase on nine nuclear and three fossil fuel power plant projects which are (or have been) under construction in the United States in the past ten years. For the nuclear projects the analysis identified the response of each Quality Assurance program to the applicable criteria of 10 CFR Part 50, Appendix B as well as to the pertinent regulatory requirements and industry standards. For the fossil projects the analysis identified the response of each Quality Assurance program to criteria similar to those which were applicable in the nuclear situation. The major emphasis was placed on the construction aspects of the structural concrete phase of each project. The engineering and design aspects were examined whenever they interfaced with the construction aspects

  12. EUROCORR 2007 - The European corrosion congress - Progress by corrosion control. Book of Abstracts

    International Nuclear Information System (INIS)

    2007-01-01

    This book of abstracts contains lectures, workshops and posters which were held on the European Corrosion Congress 2007 in Freiburg (Germany). The main topics of the sessions and posters are: 1. Corrosion and scale inhibition; 2. Corrosion by hot gases and combustion products; 3. Nuclear corrosion; 4. Environment sensitive fracture; 5. Surface Science; 6. Physico-chemical methods of corrosion testing; 7. Marine corrosion; 8. Microbial corrosion; 9. Corrosion of steel in concrete; 10. Corrosion in oil and gas production; 11. Coatings; 12. Corrosion in the refinery industry; 13. Cathodic protection; 14. Automotive Corrosion; 15. Corrosion of polymer materials. The main topics of the workshops are: 1. High temperature corrosion in the chemical, refinery and petrochemical industries; 2. Bio-Tribocorrosion; 3. Stress corrosion cracking in nuclear power plants; 4. Corrosion monitoring in nuclear systems; 5. Cathodic protection for marine and offshore environments; 6. Self-healing properties of new surface treatments; 7. Bio-Tribocorrosion - Cost 533/Eureka-ENIWEP-Meeting; 8. Drinking water systems; 9. Heat exchangers for seawater cooling

  13. Impact of water quality change on corrosion scales in full and partially replaced lead service lines

    Science.gov (United States)

    BackgroundChanges in water qualities have been associated with an increase in lead release from full and partial lead service lines (LSLs), such as the cases of Washington D.C. or more recently of Flint (Mi). Water qualities affect the mineralogy of the scales. Furthermore, follo...

  14. Measurement of reinforcement corrosion in marine structures

    International Nuclear Information System (INIS)

    Mohammad Ismail; Nordin Yahaya

    1999-01-01

    The marine environment is known to be aggressive. Structures constructed on this belt need to undergo periodic assessment in order to ensure no defects or signs of deterioration had occurred. One of the most common deterioration that occurs on marine structures is corrosion of the reinforcement. Corrosion is an electrochemical process. The product of corrosion can increase the reinforcement volume, hence causing cracking on concrete cover. If no action is taken, delamination and spalling of concrete will follow and this will affect the structures integrity. It is therefore important to know the state of the structures condition by monitoring them periodically. NDT techniques that can detect the occurrence of corrosion of reinforcement in concrete uses half cell and resistivity meter. The method of application and interpretation of results are discussed. (author)

  15. Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability

    Directory of Open Access Journals (Sweden)

    A. Saand

    2017-12-01

    Full Text Available Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.

  16. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS

    International Nuclear Information System (INIS)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-01-01

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits

  17. A review on carbonation study in concrete

    Science.gov (United States)

    Venkat Rao, N.; Meena, T.

    2017-11-01

    In this paper the authors have reviewed the carbonation studies which are a vital durability property of concrete. One of the major causes for deterioration and destruction of concrete is carbonation. The mechanism of carbonation involves the penetration carbon dioxide (CO2) into the concrete porous system to form an environment by reducing the pH around the reinforcement and initiation of the corrosion process. The paper also endeavours to focus and elucidate the gravity of importance, the process and chemistry of carbonate and how the various parameters like water/cement ratio, curing, depth of concrete cones, admixtures, grade of concrete, strength of concrete, porosity and permeability effect carbonation in concrete. The role of Supplementary Cementitious Materials (SCMs) like Ground granulated Blast Furnace Slag (GGBS) and Silica Fume (SF) has also been reviewed along with the influence of depth of carbonation.

  18. Self-compacting concrete (SCC)

    DEFF Research Database (Denmark)

    Geiker, Mette Rica

    2008-01-01

    In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...

  19. Pervious Concrete

    OpenAIRE

    Torsvik, Øyvind André Hoff

    2012-01-01

    Pervious concrete is a material with a high degree of permeability but generally low strength. The material is primarily used for paving applications but has shown promise in many other areas of usage. This thesis investigates the properties of pervious concrete using normal Norwegian aggregates and practices. An overview of important factors when it comes to designing and producing pervious concrete is the result of this investigation. Several experiments have been performed in the concrete ...

  20. Reinforcement Corrosion: Numerical Simulation and Service Life Prediction

    DEFF Research Database (Denmark)

    Michel, Alexander

    defects and b) define the end of service life once reinforcement corrosion is initiated neglecting corrosion processes during the propagation stage. The goal of this work was to develop a framework for the service life prediction of reinforced concrete covering initiation and propagation of chloride......Modelling of deterioration processes in concrete structures plays an increasing role in the design of reinforced concrete structures. Large sums are spent every year to ensure the durability of concrete structures, especially towards reinforcement corrosion. Improved durability provides increased...... structural reliability, economical improvements in form of less need for maintenance and repair as well as increased sustainability due to an increased energy and resource efficiency. Several service life prediction models dealing with reinforcement corrosion in concrete structurescan be found...

  1. Ultrasonic guided wave for monitoring corrosion of steel bar

    Science.gov (United States)

    Liu, Xi; Qin, Lei; Huang, Bosheng

    2018-01-01

    Steel corrosion of reinforced concrete structures has become a serious problem all over the word. In this paper, the work aims at monitoring steel corrosion using ultrasonic guided wave (UGW). Ultrasonic guided wave monitoring is a dynamic and non-destructive testing technology. The advantages of ultrasonic guided wave monitoring for reinforcement corrosion are real-time, online and continuous. In addition, it can judge the different stages of steel bar corrosion, which achieved non-destructive detection.

  2. Corrosion engineering

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, M.G.

    1986-01-01

    This book emphasizes the engineering approach to handling corrosion. It presents corrosion data by corrosives or environments rather than by materials. It discusses the corrosion engineering of noble metals, ''exotic'' metals, non-metallics, coatings, mechanical properties, and corrosion testing, as well as modern concepts. New sections have been added on fracture mechanics, laser alloying, nuclear waste isolation, solar energy, geothermal energy, and the Statue of Liberty. Special isocorrosion charts, developed by the author, are introduced as a quick way to look at candidates for a particular corrosive.

  3. Structural Precast Concrete Handbook

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly.......Structural concept for precast concrete systems. Design og precast reinforced concrete components. Design of precast concrete connections. Illustrations on design of precast concrete buildings. Precast concrete assembly....

  4. Effect of Surface Pretreatment on Quality and Electrochemical Corrosion Properties of Manganese Phosphate on S355J2 HSLA Steel

    Czech Academy of Sciences Publication Activity Database

    Pastorek, F.; Borko, K.; Fintová, Stanislava; Kajánek, D.; Hadzima, B.

    2016-01-01

    Roč. 6, č. 4 (2016), s. 1-9 ISSN 2079-6412 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : corrosion * steel * sandblasting * manganese phosphate Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 2.175, year: 2016 http://www.mdpi.com/2079-6412/6/4/46

  5. Corrosion and alteration of materials from the nuclear industry

    International Nuclear Information System (INIS)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Feron, D.; Guerin, Y.; Latge, C.; Limoge, Y.; Madic, C.; Santarini, G.; Seiler, J.M.; Vernaz, E.; Richet, C.

    2010-01-01

    , testing means, experimental techniques, internal corrosion of zircaloy sheath - the iodine effect, stress corrosion of nickel alloys - hydrogen influence, stress corrosion of stainless steels; C - wear corrosion: a coupled phenomenon, research in the framework of service life extension of the French electronuclear park; 3 - Corrosion in future reactors: A - corrosion in gas reactors: corrosion by helium impurities, oxidation resistance of silicon carbide, corrosion of graphite and carbon-carbon composites; B - corrosion in liquid metal reactors: sodium FBRs, lead and lead alloys reactors; C- corrosion in molten salt reactors: corrosion of Hastelloy N-type nickel alloys by molten fluorides, mass transfer in aniso-thermal fluoride systems, tellurium embrittlement, electrochemical study of pure metals corrosion in molten fluorides; 4 - Materials corrosion and alteration in the back-end of the fuel cycle: A - corrosion in concentrated nitric environment: materials behaviour, self-catalytic mechanism of nitric acid reduction; B - corrosion in unsaturated aqueous environment: metallic corrosion in unsaturated environment - application to the storage of waste containers, bitumens alteration, reinforced concrete behaviour and iron framework corrosion, concrete behaviour in severe thermal environment; C - Corrosion in saturated aqueous environment: metals corrosion in clayey environment, long-term behaviour of glasses, ceramics alteration, underwater concrete durability, clays transformation; D - materials biodegradation: microorganisms and nuclear wastes, biodegradation of bitumen, concretes and steels; 5 - Conclusion, glossary

  6. Concrete = aggregate, cement, water?

    International Nuclear Information System (INIS)

    Jelinek, J.

    1990-01-01

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  7. Corrosion '98: 53. annual conference and exposition, proceedings

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    This conference was divided into the following sections: Corrosion in Gas Treating; Problems and Solutions in Commercial Building Water Systems; Green Corrosion/Scale Inhibitors; Atmospheric Corrosion; AIRPOL Update/98; Rubber Lining--Answers to Many Problems; Interference Problems; Environmental Assisted Cracking: Fundamental Research and Industrial Applications; Corrosion in Nuclear Systems; New Developments in Scale and Deposit Control; Corrosion and Corrosion Protection in the Transportation Industries; What's All the Noise About--Electrochemical That Is; Refining Industry Corrosion; Corrosion Problems in Military Hardware: Case Histories, Fixes and Lessons Learned; Cathodic Protection Test Methods and Instrumentation for Underground and On-grade Pipelines and Tanks; Recent Developments in Volatile Corrosion Inhibitors; Corrosion in Supercritical Fluids; Microbiologically Influenced Corrosion; Advances in Understanding and Controlling CO 2 Corrosion; Managing Corrosion with Plastics; Material Developments for Use in Exploration and Production Environments; Corrosion in Cold Regions; The Effect of Downsizing and Outsourcing on Cooling System Monitoring and Control Practices; New Developments in Mechanical and Chemical Industrial Cleaning; Mineral Scale Deposit Control in Oilfield Related Operations; Biocides in Cooling Water; Corrosion and Corrosion Control of Reinforced Concrete Structures; Materials Performance for Fossil Energy Conversion Systems; Marine corrosion; Thermal Spray--Coating and Corrosion Control; Flow Effects on Corrosion in Oil and Gas Production; Corrosion Measurement Technologies; Internal Pipeline Monitoring--Corrosion Monitoring, Intelligent Pigging and Leak Detection; Cathodic Protection in Natural Waters; Corrosion in Radioactive Liquid Waste Systems; On-line Hydrogen Permeation Monitoring Equipment and Techniques, State of the Art; Water Reuse and Recovery; Performance of Materials in High Temperature Environments; Advances in Motor

  8. Corrosion in power industry

    International Nuclear Information System (INIS)

    Ventakeshwarlu, K.S.

    1979-01-01

    A brief account of the problem areas encountered as a result of corrosion in the electrical power industry including nuclear power industry is given and some of the measures contemplated and/or implemented to control corrosion are outlined. The corrosion problems in the steam generators and cladding tubes of the nuclear power plant have an added dimension of radioactivation which leads to contamination and radiation field. Importance of monitoring water quality and controlling water chemistry by addition of chemicals is emphasised. (M.G.B.)

  9. Corrosion and alteration of materials from the nuclear industry; La Corrosion et l'alteration des materiaux du nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Feron, D.; Guerin, Y.; Latge, C.; Limoge, Y.; Madic, C.; Santarini, G.; Seiler, J.M.; Vernaz, E.; Richet, C.

    2010-07-01

    , testing means, experimental techniques, internal corrosion of zircaloy sheath - the iodine effect, stress corrosion of nickel alloys - hydrogen influence, stress corrosion of stainless steels; C - wear corrosion: a coupled phenomenon, research in the framework of service life extension of the French electronuclear park; 3 - Corrosion in future reactors: A - corrosion in gas reactors: corrosion by helium impurities, oxidation resistance of silicon carbide, corrosion of graphite and carbon-carbon composites; B - corrosion in liquid metal reactors: sodium FBRs, lead and lead alloys reactors; C- corrosion in molten salt reactors: corrosion of Hastelloy N-type nickel alloys by molten fluorides, mass transfer in aniso-thermal fluoride systems, tellurium embrittlement, electrochemical study of pure metals corrosion in molten fluorides; 4 - Materials corrosion and alteration in the back-end of the fuel cycle: A - corrosion in concentrated nitric environment: materials behaviour, self-catalytic mechanism of nitric acid reduction; B - corrosion in unsaturated aqueous environment: metallic corrosion in unsaturated environment - application to the storage of waste containers, bitumens alteration, reinforced concrete behaviour and iron framework corrosion, concrete behaviour in severe thermal environment; C - Corrosion in saturated aqueous environment: metals corrosion in clayey environment, long-term behaviour of glasses, ceramics alteration, underwater concrete durability, clays transformation; D - materials biodegradation: microorganisms and nuclear wastes, biodegradation of bitumen, concretes and steels; 5 - Conclusion, glossary

  10. Glazed Concrete

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    Why glazed concrete? Concrete hardens and finds its strength at room temperature whereas clay products must first be fired before they achieve this strength. They are stronger and three times as durable as clay products, which is a weighty reason for choosing concrete.5 Another reason, which....... If this succeeds, it will be possible to manufacture thin, large-scale glazed concrete panels comparable in size to concrete sandwich construction and larger which, with or without back-casting, can work as load-bearing construction elements....

  11. Assessing Level and Effectiveness of Corrosion Education in the UAE

    Directory of Open Access Journals (Sweden)

    Hwee Ling Lim

    2012-01-01

    Full Text Available The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates had insufficient knowledge of corrosion engineering and superficial understanding of corrosion in real-life design contexts. The effectiveness of corrosion education is determined by both competence in corrosion knowledge/skills and availability of resources (faculty and research. Though most departments would not hire new corrosion-specialist faculty, department research efforts and industry partnerships in corrosion research were present. The paper concluded with recommendations for improving knowledge and skills of future engineers in corrosion and enhancing corrosion instruction to better meet industry needs.

  12. Concrete density estimation by rebound hammer method

    International Nuclear Information System (INIS)

    Ismail, Mohamad Pauzi bin; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

    2016-01-01

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite

  13. Concrete Hinges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2014-01-01

    In the first part of the 20th century concrete hinges developed by Freyssinet and Mesnager were widely tested and implemented in concrete structures. The concrete hinges were used a great deal in closed-spandrel arch bridges. Since such a bridge type has not been competitive for the past 40 years......, the research in concrete hinges has not evolved significantly in that period. But introducing a new state-of-the-art concrete arch bridge solution (Pearl-Chain arches invented at the Technical University of Denmark) creates a necessity of a concrete hinge research based on modern standards. Back when research...... in concrete hinges was more common different designs were proposed for the geometry and reinforcement. Previous research focused on fatigue, multi-axial stresses around the hinge throat, and the relation between rotation- and moment. But many different test-setups were proposed by different researchers...

  14. Concrete structures

    CERN Document Server

    Setareh, Mehdi

    2017-01-01

    This revised, fully updated second edition covers the analysis, design, and construction of reinforced concrete structures from a real-world perspective. It examines different reinforced concrete elements such as slabs, beams, columns, foundations, basement and retaining walls and pre-stressed concrete incorporating the most up-to-date edition of the American Concrete Institute Code (ACI 318-14) requirements for the design of concrete structures. It includes a chapter on metric system in reinforced concrete design and construction. A new chapter on the design of formworks has been added which is of great value to students in the construction engineering programs along with practicing engineers and architects. This second edition also includes a new appendix with color images illustrating various concrete construction practices, and well-designed buildings. The ACI 318-14 constitutes the most extensive reorganization of the code in the past 40 years. References to the various sections of the ACI 318-14 are pro...

  15. Concrete sample point: 304 Concretion Facility

    International Nuclear Information System (INIS)

    Rollison, M.D.

    1995-01-01

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis

  16. Key quality aspects for a new metallic composite pipe: corrosion testing, welding, weld inspection and manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Conder, Robert J.; Felton, Peter [Xodus Group Ltd., Aberdeen (United Kingdom); Smith, Richard [Shell Global Solutions Inc., Houston, TX (United States); Burke, Raymond [Pipestream Inc., Houston, TX (United States); Dikstra, Frits; Deleye, Xavier [Applus RTD Ltd., Rotterdam (Netherlands)

    2010-07-01

    XPipeTM is a new metallic composite pipe. This paper discusses three aspects of this new technology. The first subject is determination of the probability of hydrogen embrittlement by the XPipeTM manufacturing method. Two materials were analyzed in three tests: slow strain rate test, constant load test and notched tensile test. The results showed that the high strength steels used do not appear to be susceptible to hydrogen embrittlement. The second subject of this article is weld inspection. A non-destructive testing method of girth welds is developed to allow inspection of the thin-walled austenitic liner pipe. The results demonstrated that the welds can be inspected using the creeping wave technique. The third subject is quality control systems using the SCADA system, which maintains traceability of the materials and monitors and records all parameters during the production process. This system appears to be efficient in ensuring that the product pipe meets recognized quality standards.

  17. Numerical assessment of non-uniform corrosion scenarios of rebar ...

    Indian Academy of Sciences (India)

    The total service life of reinforced concrete (RC) components subject to ... of chloride diffusion coefficient on the material parameters of concrete, internal ... resistivity, concrete quality, cover depth, temperature, humidity and chloride content.

  18. Events as Power Source: Wireless Sustainable Corrosion Monitoring

    Directory of Open Access Journals (Sweden)

    Guodong Sun

    2013-12-01

    Full Text Available This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source, which monitors the corrosion events in reinforced concrete (RC structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

  19. Events as power source: wireless sustainable corrosion monitoring.

    Science.gov (United States)

    Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

    2013-12-17

    This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf) energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

  20. Probabilistic design of fibre concrete structures

    Science.gov (United States)

    Pukl, R.; Novák, D.; Sajdlová, T.; Lehký, D.; Červenka, J.; Červenka, V.

    2017-09-01

    Advanced computer simulation is recently well-established methodology for evaluation of resistance of concrete engineering structures. The nonlinear finite element analysis enables to realistically predict structural damage, peak load, failure, post-peak response, development of cracks in concrete, yielding of reinforcement, concrete crushing or shear failure. The nonlinear material models can cover various types of concrete and reinforced concrete: ordinary concrete, plain or reinforced, without or with prestressing, fibre concrete, (ultra) high performance concrete, lightweight concrete, etc. Advanced material models taking into account fibre concrete properties such as shape of tensile softening branch, high toughness and ductility are described in the paper. Since the variability of the fibre concrete material properties is rather high, the probabilistic analysis seems to be the most appropriate format for structural design and evaluation of structural performance, reliability and safety. The presented combination of the nonlinear analysis with advanced probabilistic methods allows evaluation of structural safety characterized by failure probability or by reliability index respectively. Authors offer a methodology and computer tools for realistic safety assessment of concrete structures; the utilized approach is based on randomization of the nonlinear finite element analysis of the structural model. Uncertainty of the material properties or their randomness obtained from material tests are accounted in the random distribution. Furthermore, degradation of the reinforced concrete materials such as carbonation of concrete, corrosion of reinforcement, etc. can be accounted in order to analyze life-cycle structural performance and to enable prediction of the structural reliability and safety in time development. The results can serve as a rational basis for design of fibre concrete engineering structures based on advanced nonlinear computer analysis. The presented

  1. Study on Corrosion-induced Crack Initiation and Propagation of Sustaining Loaded RCbeams

    Science.gov (United States)

    Zhong, X. P.; Li, Y.; Yuan, C. B.; Yang, Z.; Chen, Y.

    2018-05-01

    For 13 pieces of reinforced concrete beams with HRB500 steel bars under long-term sustained loads, at time of corrosion-induced initial crack of concrete, and corrosion-induced crack widths of 0.3mm and 1mm, corrosion of steel bars and time-varying behavior of corrosion-induced crack width were studied by the ECWD (Electro-osmosis - constant Current – Wet and Dry cycles) accelerated corrosion method. The results show that when cover thickness was between 30 and 50mm,corrosion rates of steel bars were between 0.8% and 1.7% at time of corrosion-induced crack, and decreased with increasing concrete cover thickness; when corrosion-induced crack width was 0.3mm, the corrosion rate decreased with increasing steel bar diameter, and increased with increasing cover thickness; its corrosion rate varied between 0.98% and 4.54%; when corrosion-induced crack width reached 1mm, corrosion rate of steel bars was between 4% and 4.5%; when corrosion rate of steel bars was within 5%, the maximum and average corrosion-induced crack and corrosion rate of steel bars had a good linear relationship. The calculation model predicting the maximum and average width of corrosion-induced crack is given in this paper.

  2. Effect of chloride-based deicers on reinforced concrete structures.

    Science.gov (United States)

    2012-07-01

    We conducted an extensive literature review and performed laboratory tests to assess the effect of chloride-based deicers on the rebars and dowel bars in concrete and to determine whether or not deicer corrosion inhibitors help preserve the transport...

  3. Durability performance of submerged concrete structures - phase 2.

    Science.gov (United States)

    2015-09-01

    This project determined that severe corrosion of steel can occur in the submerged : portions of reinforced concrete structures in marine environments. Field studies of decommissioned : pilings from Florida bridges revealed multiple instances of stron...

  4. Concrete Fibrations

    OpenAIRE

    Pagnan, Ruggero

    2017-01-01

    As far as we know, no notion of concrete fibration is available. We provide one such notion in adherence to the foundational attitude that characterizes the adoption of the fibrational perspective in approaching fundamental subjects in category theory and discuss it in connection with the notion of concrete category and the notions of locally small and small fibrations. We also discuss the appropriateness of our notion of concrete fibration for fibrations of small maps, which is relevant to a...

  5. Reviewing the Carbonation Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    S P Singh

    2016-07-01

    Full Text Available The paper reviews the studies on one of the important durability properties of concrete i.e. Carbonation. One of the main causes of deterioration of concrete is carbonation, which occurs when carbon dioxide (CO2 penetrates the concrete’s porous system to create an environment with lower pH around the reinforcement in which corrosion can proceed. Carbonation is a major cause of degradation of concrete structures leading to expensive maintenance and conservation operations. Herein, the importance, process and effect of various parameters such as water/cement ratio, water/binder ratio, curing conditions, concrete cover, super plasticizers, type of aggregates, grade of concrete, porosity, contaminants, compaction, gas permeability, supplementary cementitious materials (SCMs/ admixtures on the carbonation of concrete has been reviewed. Various methods for estimating the carbonation depth are also reported briefly

  6. High resolution estimates of the corrosion risk for cultural heritage in Italy

    International Nuclear Information System (INIS)

    De Marco, Alessandra; Screpanti, Augusto; Mircea, Mihaela; Piersanti, Antonio; Proietti, Chiara; Fornasier, M. Francesca

    2017-01-01

    Air pollution plays a pivotal role in the deterioration of many materials used in buildings and cultural monuments causing an inestimable damage. This study aims to estimate the impacts of air pollution (SO 2 , HNO 3 , O 3 , PM 10 ) and meteorological conditions (temperature, precipitation, relative humidity) on limestone, copper and bronze based on high resolution air quality data-base produced with AMS-MINNI modelling system over the Italian territory over the time period 2003–2010. A comparison between high resolution data (AMS-MINNI grid, 4 × 4 km) and low resolution data (EMEP grid, 50 × 50 km) has been performed. Our results pointed out that the corrosion levels for limestone, copper and bronze are decreased in Italy from 2003 to 2010 in relation to decrease of pollutant concentrations. However, some problem related to air pollution persists especially in Northern and Southern Italy. In particular, PM 10 and HNO 3 are considered the main responsible for limestone corrosion. Moreover, the high resolution data (AMS-MINNI) allowed the identification of risk areas that are not visible with the low resolution data (EMEP modelling system) in all considered years and, especially, in the limestone case. Consequently, high resolution air quality simulations are suitable to provide concrete benefits in providing information for national effective policy against corrosion risk for cultural heritage, also in the context of climate changes that are affecting strongly Mediterranean basin. - Highlights: • Air pollution plays a pivotal role in the deterioration of cultural materials. • Limestone, copper and bronze corrosion levels decreased in Italy from 2003 to 2010. • PM 10 is considered the main responsible for limestone corrosion in Northern Italy. • HNO3 is considered the main responsible for limestone corrosion in all analyzed years. • High-resolution data are particularly useful to define area at risk for corrosion. - Importance of the high

  7. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion......Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  8. Use of alternative waste materials in producing ultra-high performance concrete

    Directory of Open Access Journals (Sweden)

    Ahmad Shamsad

    2017-01-01

    Full Text Available In a corrosive environment similar to that of the Arabian Gulf, use of high-performance concrete is one of the options to ensure a target service life of concrete structures. However, in absence of good quality coarse aggregates, it is a challenging task to produce high-performance concrete. Recently, the possibility of producing ultra-high-performance concrete (UHPC has been widely reported in the literature. UHPC is produced without coarse aggregates at very low water to cementitious materials ratio, high amounts of cement, mineral admixtures, and superplasticizer along with fine quartz sand as aggregate, quartz powder as micro-filler, a nd steel fibres for fracture toughness. In the present work, an effort was made to utilize local waste materials as alternative mineral admixtures and local dune sand as aggregate in producing different UHPC mixtures without addition of quartz powder. The mechanical properties, shrinkage, and durability characteristics of the UHPC mixtures were studied. Test results indicate that it is possible to produce UHPC mixtures using alternative waste materials, which would have targeted flow, strength, toughness, and resistance against reinforcement corrosion. The information presented in the paper would help in optimum selection of a mixture of UHPC considering the availability of local materials, exposure conditions and structural requirements.

  9. Assessing Level and Effectiveness of Corrosion Education in the UAE

    OpenAIRE

    Lim, Hwee Ling

    2012-01-01

    The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates...

  10. Flexural reinforced concrete member with FRP reinforcement

    OpenAIRE

    Putzolu, Mariana

    2017-01-01

    One of the most problematic point in construction is the durability of the concrete especially related to corrosion of the steel reinforcement. Due to this problem the construction sector, introduced the use of Fiber Reinforced Polymer, the main fibers used in construction are Glass, Carbon and Aramid. In this study, the author aim to analyse the flexural behaviour of concrete beams reinforced with FRP. This aim is achieved by the analysis of specimens reinforced with GFRP bars, with theoreti...

  11. Quality evaluation of carbonaceous industrial by-products and its effect on properties of autoclave aerated concrete

    Science.gov (United States)

    Fomina, E. V.; Lesovik, V. S.; Fomin, A. E.; Kozhukhova, N. I.; Lebedev, M. S.

    2018-03-01

    Argillite is a carbonaceous industrial by-product that is a potential source in environmentally friendly and source-saving construction industry. In this research, chemical and mineral composition as well as particle size distribution of argillite were studied and used to develop autoclave aerated concrete as partial substitute of quartz sand. Effect of the argillite as a mineral admixture in autoclave aerated concrete was investigated in terms of compressive and tensile strength, density, heat conductivity etc. The obtained results demonstrated an efficiency of argillite as an energy-saving material in autoclave construction composites.

  12. Effectiveness of resins/exudates of trees in corrosion prevention of ...

    African Journals Online (AJOL)

    Corrosion of steel reinforcement is one of the important factors that are responsible for the short service life of reinforced concrete members, in marine structures like bridges, piers and jetties. This study, investigated the effectiveness of resin/exuda tes in corrosion prevention of reinforcement in reinforced concrete cubes.

  13. Accelerated cyclic corrosion tests

    Directory of Open Access Journals (Sweden)

    Prošek T.

    2016-06-01

    Full Text Available Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

  14. Assessment of the Reliability Profiles for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper calculation of reliability profiles is discussed. ULS as well as SLS limit states are formulated. Corrosion due to chloride penetration is the considered deterioration mechanism. Three models for corrosion are formulated. A definition of service lifetime for concrete bridges...

  15. Seismic evaluation and retrofit of deteriorated concrete bridge components.

    Science.gov (United States)

    2013-06-01

    Corrosion of steel bars in reinforced concrete structures is a major durability problem for bridges constructed in the New York State : (NYS). The heavy use of deicing salt compounds this problem. Corrosion of steel bars results in loss of steel cros...

  16. Self-compacting concrete mixtures for road BUILDING

    Directory of Open Access Journals (Sweden)

    Tran Tuan My

    2012-10-01

    Therefore, effective concrete road pavements require self-compacting though non-segregating concrete mixtures to comply with the pre-set values of their properties, namely, bending and compressive strength, corrosion resistance, freeze resistance, etc. Acting in cooperation with Department of Technology of Binders and Concretes of MSUCE, NIIMosstroy developed and examined a self-compacting cast concrete mixture designated for durable monolithic road pavements. The composition in question was generated by adding a multi-component modifier into the mix. The modifier was composed of a hyperplasticiser, active (structureless fine and crystalline silica, and a concrete hardening control agent.

  17. Survey of Experience Using Reinforced Concrete in Floating Marine Structures.

    Science.gov (United States)

    1983-01-01

    analyzed in several steps. The load history can be simulated by .. using load increments and independent load vectors . 4.31 NTH is not only active in...NILSEN, N., " FEILD TEST OF REINFORCEMENT CORROSION IN CONCRETE", PERFORMANCE OF CONCRETE IN MARINE ENVIRONMENT, ACI SPECIAL PUBLICATION SP-65, 1980. 136

  18. Bacteria-based self-healing concrete : An introduction

    NARCIS (Netherlands)

    Mors, R.M.; Jonkers, H.M.

    2012-01-01

    Crack formation in concrete is common, but a typical phenomenon related to durability. Percolation of cracks may lead to leakage problems or ingress of deleterious materials, causing deterioration of the concrete matrix or corrosion of embedded steel reinforcement. Durability can be enhanced by

  19. Early stage beneficial effects of cathodic protection in concrete structures

    NARCIS (Netherlands)

    Polder, R.B.; Peelen, W.H.A.; Neeft, E.A.C.; Stoop, B.T.J.

    2010-01-01

    Over the last 25 years, cathodic protection (CP) of reinforced concrete structures suffering from chloride induced reinforcement corrosion has shown to be successful and durable. CP current causes steel polarisation, electrochemical reactions and ion transport in the concrete. CP systems are

  20. Service Life and Maintenance Modelling of Reinforced Concrete Bridge Decks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Recent research in the area of assessment and maintenance of reinforced concrete bridge decks is presented in this paper. Three definitions of service lifetime are introduced and the difficult problem of assessing the service life is discussed. A stochastic modelling of corrosion and corrosion...... cracking is introduced and the site dependency of corrosion is stressed. Finally, a recently developed optimal repair strategy for bridges is briefly explained....