WorldWideScience

Sample records for asphalt roofing shingles

  1. Asphalt Roofing Shingles Into Energy Project Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, Rex, PE

    2008-04-28

    Based on a widely cited September, 1999 report by the Vermont Agency of Natural Resources, nearly 11 million tons of asphalt roofing shingle wastes are produced in the United States each year. Recent data suggests that the total is made up of about 9.4 million tons from roofing tear-offs and about 1.6 million tons from manufacturing scrap. Developing beneficial uses for these materials would conserve natural resources, promote protection of the environment and strengthen the economy. This project explored the feasibility of using chipped asphalt shingle materials in cement manufacturing kilns and circulating fluidized bed (CFB) boilers. A method of enhancing the value of chipped shingle materials for use as fuel by removing certain fractions for use as substitute raw materials for the manufacture of new shingles was also explored. Procedures were developed to prevent asbestos containing materials from being processed at the chipping facilities, and the frequency of the occurrence of asbestos in residential roofing tear-off materials was evaluated. The economic feasibility of each potential use was evaluated based on experience gained during the project and on a review of the well established use of shingle materials in hot mix asphalt. This project demonstrated that chipped asphalt shingle materials can be suitable for use as fuel in circulating fluidized boilers and cement kilns. More experience would be necessary to determine the full benefits that could be derived and to discover long term effects, but no technical barriers to full scale commercial use of chipped asphalt shingle materials in these applications were discovered. While the technical feasibility of various options was demonstrated, only the use of asphalt shingle materials in hot mix asphalt applications is currently viable economically.

  2. A novel technique for the production of cool colored concrete tile and asphalt shingle roofing products

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul; Wood, Kurt; Skilton, Wayne; Petersheim, Jerry

    2009-11-20

    The widespread use of solar-reflective roofing materials can save energy, mitigate urban heat islands and slow global warming by cooling the roughly 20% of the urban surface that is roofed. In this study we created prototype solar-reflective nonwhite concrete tile and asphalt shingle roofing materials using a two-layer spray coating process intended to maximize both solar reflectance and factory-line throughput. Each layer is a thin, quick-drying, pigmented latex paint based on either acrylic or a poly(vinylidene fluoride)/acrylic blend. The first layer is a titanium dioxide rutile white basecoat that increases the solar reflectance of a gray-cement concrete tile from 0.18 to 0.79, and that of a shingle surfaced with bare granules from 0.06 to 0.62. The second layer is a 'cool' color topcoat with weak near-infrared (NIR) absorption and/or strong NIR backscattering. Each layer dries within seconds, potentially allowing a factory line to pass first under the white spray, then under the color spray. We combined a white basecoat with monocolor topcoats in various shades of red, brown, green and blue to prepare 24 cool color prototype tiles and 24 cool color prototypes shingles. The solar reflectances of the tiles ranged from 0.26 (dark brown; CIELAB lightness value L* = 29) to 0.57 (light green; L* = 76); those of the shingles ranged from 0.18 (dark brown; L* = 26) to 0.34 (light green; L* = 68). Over half of the tiles had a solar reflectance of at least 0.40, and over half of the shingles had a solar reflectance of at least 0.25.

  3. Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [Building Science Corporation, Westford, MA (United States); Lstiburek, Joseph W. [Building Science Corporation, Westford, MA (United States)

    2015-09-01

    Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a control vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. The Houston-area roof was an unvented attic insulated with spray-applied fiberglass. Most ridges and hips were built with a diffusion vent detail, capped with vapor permeable roof membrane. In contrast, the diffusion vent roofs had drier conditions at the roof peak in wintertime, but during the summer, RHs and MCs were higher than the unvented roof (albeit in the safe range).

  4. Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lstiburek, Joseph W. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Insulating roofs with dense-pack cellulose (instead of spray foam) has moisture risks, but is a lower cost approach. If moisture risks could be addressed, buildings could benefit from retrofit options, and the ability to bring HVAC systems within the conditioned space. Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a control vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. All roofs except the vented cathedral assembly experienced wood moisture contents and RH levels high enough to constitute failure. Disassembly at the end of the experiment showed that the unvented fiberglass roofs had wet sheathing and mold growth. In contrast, the cellulose roofs only had slight issues, such as rusted fasteners and sheathing grain raise. The Houston-area roof was an unvented attic insulated with spray-applied fiberglass. Most ridges and hips were built with a diffusion vent detail, capped with vapor permeable roof membrane. Some ridge sections were built as a conventional unvented roof, as a control. In the control unvented roofs, roof peak RHs reached high levels in the first winter; as exterior conditions warmed, RHs quickly fell. In contrast, the diffusion vent roofs had drier conditions at the roof peak in wintertime, but during the summer, RHs and MCs were higher than the unvented roof (albeit in the safe range).

  5. Technology Solutions Case Study: Field Testing an Unvented Roof with Asphalt Shingles in a Cold Climate

    Energy Technology Data Exchange (ETDEWEB)

    K. Ueno and J. Lstiburek

    2015-09-01

    Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a "control" vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. All roofs except the vented cathedral assembly experienced wood moisture contents and RH levels high enough to constitute failure. Disassembly at the end of the experiment showed that the unvented fiberglass roofs had wet sheathing and mold growth. In contrast, the cellulose roofs only had slight issues, such as rusted fasteners and sheathing grain raise.

  6. Building America Case Study: Field Testing an Unvented Roof with Asphalt Shingles in a Cold Climate, Boilingbrook, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    Insulating roofs with dense-pack cellulose (instead of spray foam) has moisture risks, but is a lower cost approach. If moisture risks could be addressed, buildings could benefit from retrofit options, and the ability to bring HVAC systems within the conditioned space. Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a 'control' vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. All roofs except the vented cathedral assembly experienced wood moisture contents and RH levels high enough to constitute failure. Disassembly at the end of the experiment showed that the unvented fiberglass roofs had wet sheathing and mold growth. In contrast, the cellulose roofs only had slight issues, such as rusted fasteners and sheathing grain raise. The Houston-area roof was an unvented attic insulated with spray-applied fiberglass. Most ridges and hips were built with a 'diffusion vent' detail, capped with vapor permeable roof membrane. Some ridge sections were built as a conventional unvented roof, as a control. In the control unvented roofs, roof peak RHs reached high levels in the first winter; as exterior conditions warmed, RHs quickly fell. In contrast, the diffusion vent roofs had drier conditions at the roof peak in wintertime, but during the summer, RHs and MCs were higher than the unvented roof (albeit in the safe range).

  7. Surface roughness effects on the solar reflectance of cool asphalt shingles

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Berdahl, Paul; Akbari, Hashem; Jacobs, Jeffry; Klink, Frank

    2008-02-17

    We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with small corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.

  8. Wood Shakes and Shingles for Roof Applications: Tips for Longer Life

    Science.gov (United States)

    Mark T. Knaebe

    2013-01-01

    Many wood shakes and shingles have been replaced by composition or asphalt-based shingles. Nevertheless, wood shakes and shingles are still widely used on commercial structures and residential houses.

  9. Investigation on the Effect of Recycled Asphalt Shingle (RAS in Portland Cement Mortar

    Directory of Open Access Journals (Sweden)

    Jinwoo An

    2016-04-01

    Full Text Available Tear-off roofing shingle, referred to as Reclaimed asphalt shingle (RAS, is the byproduct of construction demolition and it is a major solid waste stream in the U.S. Reuse of this byproduct in road construction sector can contribute to the success of materials sustainability as well as landfill conservation. Ground RAS has similar particle distribution as sand and its major component includes aggregate granules, fibers, and asphalt. To promote the beneficial utilization of RAS, this study evaluates the effect of RAS in cement mortar when used as replacement of sand. In addition, the study investigates how cellulose fibers from RAS behave under high alkaline environment during cement hydration process, which may significantly affect mortar’s strength performance. The laboratory study includes measurements of physical, mechanical, and durability behaviors of cement mortar containing RAS replacing sand up to 30%. It was found that the optimum mixture proportions are 5% and 10% for compressive strength and toughness, respectively.

  10. Two-year Wisconsin thermal loads for roof assemblies and wood, wood–plastic composite, and fiberglass shingles

    Science.gov (United States)

    Jerrold E. Winandy; Michael Grambsch; Cherilyn Hatfield

    2005-01-01

    Temperature histories for various types of roof shingles, wood roof sheathing, roof rafters, and non-ventilated attics are being monitored in outdoor attic structures using simulated North American light-framed construction. This report presents 2-year data histories for annual thermal loads for western redcedar, wood–thermoplastic composite, and fiberglass shingles...

  11. Analysis of three-year Wisconsin temperature histories for roof systems using wood, wood-thermoplastic composite, and fiberglass shingles

    Science.gov (United States)

    Jerrold E. Winandy; Cherilyn A. Hatfield

    2007-01-01

    Temperature histories for various types of roof shingles, wood roof sheathing, rafters, and nonventilated attics were monitored in outdoor attic structures using simulated North American light-framed construction. In this paper, 3-year thermal load histories for wood-based composite roof sheathing, wood rafters, and attics under western redcedar (WRC) shingles, wood-...

  12. Next-Generation Factory-Produced Cool Asphalt Shingles: Phase 1 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen M.; Chen, Sharon S.; Ban-Weiss, George A.; Gilbert, Haley E.; Berdahl, Paul H.; Rosado, Pablo J.; Destaillats, Hugo; Sleiman, Mohamad; Kirchstetter, Thomas W.

    2016-11-01

    As the least expensive category of high-slope roofing in the U.S., shingles are found on the roofs of about 80% of U.S. homes, and constitute about 80% (by product area) of this market. Shingles are also among the least reflective high-slope roofing products, with few cool options on the market. The widespread use of cool roofs in the two warmest U.S. climate zones could reduce annual residential cooling energy use in these zones by over 7%. This project targets the development of high-performance cool shingles with initial solar reflectance at least 0.40 and a cost premium not exceeding US$0.50/ft². Phase 1 of the current study explored three approaches to increasing shingle reflectance. Method A replaces dark bare granules by white bare granules to enhance the near-infrared reflectance attained with cool pigments. Method B applies a white basecoat and a cool-color topcoat to a shingle surfaced with dark bare granules. Method C applies a visually clear, NIR-reflecting surface treatment to a conventionally colored shingle. Method A was the most successful, but our investigation of Method B identified roller coating as a promising top-coating technique, and our study of Method C developed a novel approach based on a nanowire mesh. Method A yielded red, green, brown, and black faux shingles with solar reflectance up to 0.39 with volumetric coloration. Since the base material is white, these reflectances can readily be increased by using less pigment. The expected cost premium for Method A shingles is less than our target limit of $0.50/ft², and would represent less than a 10% increase in the installed cost of a shingle roof. Using inexpensive but cool (spectrally selective) iron oxide pigments to volumetrically color white limestone synthesized from sequestered carbon and seawater appears to offer high albedo at low cost. In Phase 2, we plan to refine the cool shingle prototypes, manufacture cool granules, and manufacture and market high-performance cool shingles.

  13. Recovery and reuse of asphalt roofing waste. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Desai, S.; Graziano, G.; Shepherd, P.

    1984-02-02

    Burning of asphalt roofing waste as a fuel and incorporating asphalt roofing waste in bituminous paving were identified as the two outstanding resource recovery concepts out of ten studied. Four additional concepts might be worth considering under different market or technical circumstances. Another four concepts were rated as worth no further consideration at this time. This study of the recovery of the resource represented in asphalt roofing waste has identified the sources and quantities of roofing waste. About six million cubic yards of scrap roofing are generated annually in the United States, about 94% from removal of old roofing at the job site and the remainder from roofing material production at factories. Waste disposal is a growing problem for manufacturers and contractors. Nearly all roofing waste is hauled to landfills at a considerable expense to roofing contractors and manufacturers. Recovery of the roofing waste resource should require only a modest economic incentive. The asphalt contained in roofing waste represents an energy resource of more than 7 x 10/sup 13/ Btu/year. Another 1 x 10/sup 13/ Btu/year may be contained in field-applied asphalt on commercial building roofs. The two concepts recommended by this study appear to offer the broadest applicability, the most favorable economics, and the highest potential for near-term implementation to reuse this resource.

  14. Shingles

    Science.gov (United States)

    ... Division of Neuroscience Director, NIH BRAIN Initiative® Health Scientist Administrator Channels Synapses Circuits Cluster Scientific Director, Division of Intramural Research Featured Director's Message menu search Enter Search Term Submit Search Shingles Information Page ...

  15. Shingles

    Science.gov (United States)

    ... they need to stay away from newborn babies, pregnant women, anyone with a weakened immune system, or anyone who is not vaccinated against chickenpox. So teens who get shingles may need to stay home ...

  16. Application of a bio-binder as a rejuvenator for wet processed asphalt shingles in pavement construction

    OpenAIRE

    OLDHAM, Daniel J.; Ellie H. Fini; Chailleux, Emmanuel

    2015-01-01

    This paper investigates the merits of application of bio-binder to enhance rheological properties of asphalt binder in the presence of wet processed recycled asphalt shingles (RAS). It will further examine the performance and workability of asphalt designed with and without a specified percentage of a bio-binder produced from swine manure and RAS. Bio-binder was introduced to liquid asphalt binder modified with four different percentages of RAS; the high and low temperature properties of each...

  17. Thermal load histories for North American roof assembles using various cladding materials including wood-thermoplastic composite shingles

    Science.gov (United States)

    J. E. Winandy

    2006-01-01

    Since 1991, thermal load histories for various roof cladding types have been monitored in outdoor attic structures that simulate classic North American light-framed construction. In this paper, the 2005 thermal loads for wood-based composite roof sheathing, wood rafters, and attics under wood-plastic composite shingles are compared to common North American roof...

  18. Integrating Recycled Glass Cullet in Asphalt Roof Shingles to Mitigate Heat Island Effect

    Science.gov (United States)

    2014-05-01

    then benefits to communities include reduced energy use, improved air quality, lower emissions, improved stormwater quantity and quality management ...found that for every dollar invested in the management of urban forestry, the benefits returned annually ranged from $1.37 to $3.09 (McPherson, et al...enhanced stormwater quantity and quality management , improved quality of life, and improved thermal comfort (U.S. Environmental Protection Agency

  19. The Effects of Infrared-Blocking Pigments and Deck Venting on Stone-Coated Metal Residential Roofs

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL

    2006-01-01

    Field data show that stone-coated metal shakes and S-mission tile, which exploit the use of infraredblocking color pigments (IrBCPs), along with underside venting reduce the heat flow penetrating the conditioned space of a residence by 70% compared with the amount of heat flow penetrating roofs with conventional asphalt shingles. Stone-coated metal roof products are typically placed on battens and counter-battens and nailed through the battens to the roof deck. The design provides venting on the underside of the metal roof that reduces the heat flow penetrating a home. The Metal Construction Association (MCA) and its affiliate members installed stone-coated metal roofs with shake and S-mission tile profiles and a painted metal shake roof on a fully instrumented attic test assembly at Oak Ridge National Laboratory (ORNL). Measurements of roof, deck, attic, and ceiling temperatures; heat flows; solar reflectance; thermal emittance; and ambient weather were recorded for each of the test roofs and also for an adjacent attic cavity covered with a conventional pigmented and direct nailed asphalt shingle roof. All attic assemblies had ridge and soffit venting; the ridge was open to the underside of the stone-coated metal roofs. A control assembly with a conventional asphalt shingle roof was used for comparing deck and ceiling heat transfer rates.

  20. List of Potentially Affected Sources for the Asphalt Processing and Roofing Manufacturing National Emission Standards for Hazardous Air Pollutants (NESHAP) November 2001

    Science.gov (United States)

    This is a November 2001 list of sources identified by EPA as potentially affected by the Asphalt Processing and Roofing Manufacturing National Emission Standards for Hazardous Air Pollutants (NESHAP).

  1. Asphalt cement poisoning

    Science.gov (United States)

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  2. Performance Evaluation of Advanced Retrofit Roof Technologies Using Field-Test Data Phase Three Final Report, Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Childs, Phillip W [ORNL; Atchley, Jerald Allen [ORNL

    2014-05-01

    This article presents various metal roof configurations that were tested at Oak Ridge National Laboratory in Tennessee, U.S.A. between 2009 and 2013, and describes their potential for reducing the attic-generated space conditioning loads. These roofs contained different combinations of phase change material, rigid insulation, low emittance surface and above-sheathing ventilation, with standing-seam metal panels on top. These roofs were designed to be installed on existing roofs decks, or on top of asphalt shingles for retrofit construction. All the tested roofs showed the potential for substantial energy savings compared to an asphalt shingle roof, which was used as a control for comparison. The roofs were constructed on a series of adjacent attics separated at the gables using thick foam insulation. The attics were built on top of a conditioned room. All attics were vented at the soffit and ridge. The test roofs and attics were instrumented with an array of thermocouples. Heat flux transducers were installed in the roof deck and attic floor (ceiling) to measure the heat flows through the roof and between the attic and conditioned space below. Temperature and heat flux data were collected during the heating, cooling and swing seasons over a 3 year period. Data from previous years of testing have been published. Here, data from the latest roof configurations being tested in year 3 of the project are presented. All test roofs were highly effective in reducing the heat flows through the roof and ceiling, and in reducing the diurnal attic temperature fluctuations.

  3. The effect of roofing material on the quality of harvested rainwater.

    Science.gov (United States)

    Mendez, Carolina B; Klenzendorf, J Brandon; Afshar, Brigit R; Simmons, Mark T; Barrett, Michael E; Kinney, Kerry A; Kirisits, Mary Jo

    2011-02-01

    Due to decreases in the availability and quality of traditional water resources, harvested rainwater is increasingly used for potable and non-potable purposes. In this study, we examined the effect of conventional roofing materials (i.e., asphalt fiberglass shingle, Galvalume(®) metal, and concrete tile) and alternative roofing materials (i.e., cool and green) on the quality of harvested rainwater. Results from pilot-scale and full-scale roofs demonstrated that rainwater harvested from any of these roofing materials would require treatment if the consumer wanted to meet United States Environmental Protection Agency primary and secondary drinking water standards or non-potable water reuse guidelines; at a minimum, first-flush diversion, filtration, and disinfection are recommended. Metal roofs are commonly recommended for rainwater harvesting applications, and this study showed that rainwater harvested from metal roofs tends to have lower concentrations of fecal indicator bacteria as compared to other roofing materials. However, concrete tile and cool roofs produced harvested rainwater quality similar to that from the metal roofs, indicating that these roofing materials also are suitable for rainwater harvesting applications. Although the shingle and green roofs produced water quality comparable in many respects to that from the other roofing materials, their dissolved organic carbon concentrations were very high (approximately one order of magnitude higher than what is typical for a finished drinking water in the United States), which might lead to high concentrations of disinfection byproducts after chlorination. Furthermore the concentrations of some metals (e.g., arsenic) in rainwater harvested from the green roof suggest that the quality of commercial growing media should be carefully examined if the harvested rainwater is being considered for domestic use. Hence, roofing material is an important consideration when designing a rainwater catchment. Copyright

  4. Shingles (For Parents)

    Science.gov (United States)

    ... lead to nerve-related problems such as facial paralysis, hearing problems, and problems with balance. In very rare cases, shingles can lead to encephalitis (inflammation of the brain). Diagnosis If you think your child might have shingles, call your doctor. If there's ...

  5. A review of changes in composition of hot mix asphalt in the United States.

    Science.gov (United States)

    Mundt, Diane J; Marano, Kristin M; Nunes, Anthony P; Adams, Robert C

    2009-11-01

    This review researched the materials, methods, and practices in the hot mix asphalt industry that might impact future exposure assessments and epidemiologic research on road paving workers. Since World War II, the U.S. interstate highway system, increased traffic volume, transportation speeds, and vehicle axle loads have necessitated an increase in demand for hot mix asphalt for road construction and maintenance, while requiring a consistent road paving product that meets state-specific physical performance specifications. We reviewed typical practices in hot mix asphalt paving in the United States to understand the extent to which materials are and have been added to hot mix asphalt to meet specifications and how changes in practices and technology could affect evaluation of worker exposures for future research. Historical documents were reviewed, and industry experts from 16 states were interviewed to obtain relevant information on industry practices. Participants from all states reported additive use, with most being less than 2% by weight. Crumb rubber and recycled asphalt pavement were added in concentrations approximately 10% per unit weight of the mix. The most frequently added materials included polymers and anti-stripping agents. Crumb rubber, sulfur, asbestos, roofing shingles, slag, or fly ash have been used in limited amounts for short periods of time or in limited geographic areas. No state reported using coal tar as an additive to hot mix asphalt or as a binder alternative in hot mix pavements for high-volume road construction. Coal tar may be present in recycled asphalt pavement from historical use, which would need to be considered in future exposure assessments of pavers. Changes in hot mix asphalt production and laydown emission control equipment have been universally implemented over time as the technology has become available to reduce potential worker exposures. This work is a companion review to a study undertaken in the petroleum refining

  6. Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

    Directory of Open Access Journals (Sweden)

    Aly Ahmed

    2009-01-01

    Full Text Available An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD, a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

  7. Roofing as a source of nonpoint water pollution.

    Science.gov (United States)

    Chang, Mingteh; McBroom, Matthew W; Scott Beasley, R

    2004-12-01

    Sixteen wooden structures with two roofs each were installed to study runoff quality for four commonly used roofing materials (wood shingle, composition shingle, painted aluminum, and galvanized iron) at Nacogdoches, Texas. Each roof, either facing NW or SE, was 1.22 m wide x 3.66 m long with a 25.8% roof slope. Thus, there were 32 alternatively arranged roofs, consisting of four roof types x two aspects x four replicates, in the study. Runoff from the roofs was collected through galvanized gutters, downspouts, and splitters. The roof runoff was compared to rainwater collected by a wet/dry acid rain collector for the concentrations of eight water quality variables, i.e. Cu(2+), Mn(2+), Pb(2+), Zn(2+), Mg(2+), Al(3+), EC and pH. Based on 31 storms collected between October 1997 and December 1998, the results showed: (1) concentrations of pH, Cu, and Zn in rainwater already exceed the EPA freshwater quality standards even without pollutant inputs from roofs, (2) Zn and Cu, the two most serious pollutants in roof runoff, exceeded the EPA national freshwater water quality standards in virtually 100% and more than 60% of the samples, respectively, (3) pH, EC, and Zn were the only three variables significantly affected by roofing materials, (4) differences in Zn concentrations were significant among all roof types and between all roof runoff and rainwater samples, (5) although there were no differences in Cu concentrations among all roof types and between roof runoff and rainwater, all means and medians of runoff and rainwater exceeded the national water quality standards, (6) water quality from wood shingles was the worst among the roof types studied, and (7) although SE is the most frequent and NW the least frequent direction for incoming storms, only EC, Mg, Mn, and Zn in wood shingle runoff from the SE were significantly higher than those from the NW; the two aspects affected no other elements in runoff from the other three roof types. Also, Zn concentrations from

  8. Fire resistant PV shingle assembly

    Science.gov (United States)

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  9. Herpes zoster (shingles) disseminated (image)

    Science.gov (United States)

    Herpes zoster (shingles) normally occurs in a limited area that follows a dermatome (see the "dermatome" picture). In individuals with damaged immune systems, herpes zoster may be widespread (disseminated), causing serious illness. ...

  10. Immunizations Part II: Shingles Vaccine

    Centers for Disease Control (CDC) Podcasts

    2008-09-24

    This podcast discusses older adults and shingles, as well as the importance of getting the shingles vaccine. It is primarily targeted to public health and aging services professionals.  Created: 9/24/2008 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP) and National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 9/24/2008.

  11. A Review of Methods for the Manufacture of Residential Roofing Materials

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Levinson, Ronnen; Berdahl, Paul

    2003-06-01

    Shingles, tiles, and metal products comprise over 80% (by roof area) of the California roofing market (54-58% fiberglass shingle, 8-10% concrete tile, 8-10% clay tile, 7% metal, 3% wood shake, and 3% slate). In climates with significant demand for cooling energy, increasing roof solar reflectance reduces energy consumption in mechanically cooled buildings, and improves occupant comfort in non-conditioned buildings. This report examines methods for manufacturing fiberglass shingles, concrete tiles, clay tiles, and metal roofing. The report also discusses innovative methods for increasing the solar reflectance of these roofing materials. We have focused on these four roofing products because they are typically colored with pigmented coatings or additives. A better understanding of the current practices for manufacturing colored roofing materials would allow us to develop cool colored materials creatively and more effectively.

  12. Sting of Shingles: Vaccine, Treatments Reduce Risks

    Science.gov (United States)

    ... of getting shingles.” Shingles is caused by the varicella-zoster virus—the same virus that causes chickenpox. Once you’ ... a blistery shingles rash to pass on the varicella-zoster virus to someone who’s never had chickenpox or a ...

  13. Investigation of Air Force Build-Up Roofing Tolerances.

    Science.gov (United States)

    1986-09-01

    outliers was not provided with sample test results. Ladislav Jerga , from Roof Systems Laboratory of Southfield Michigan, has conducted similar statistical...analysis on built-up roofing variances. Some of the research conducted by Ladislav Jerga has been made available (39). It is included herein for...More to Built-Up Roofing Asphalt Than Black and Sticky," Western Roofing, 4: 6-7 (February 1981). Jerga , Ladislav, Director. Personal Correspondence

  14. Shingles

    Science.gov (United States)

    ... had an allergic reaction to gelatin or the antibiotic neomycin.Has an allergy to any component of ... 2017October 2017Infants and Toddlersfamilydoctor.org editorial staffPrescription Drug Abuse in the ElderlyRead Article >>Prescription Drug Abuse in ...

  15. TASK 2.5.7 FIELD EXPERIMENTS TO EVALUATE COOL-COLORED ROOFING

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL; Cherry, Nigel J [ORNL; Allen, Richard Lowell [ORNL; Childs, Phillip W [ORNL; Atchley, Jerald Allen [ORNL; Ronnen, Levinson [Lawrence Berkeley National Laboratory (LBNL); Akbari, Hashem [Lawrence Berkeley National Laboratory (LBNL); Berhahl, Paul [Lawrence Berkeley National Laboratory (LBNL)

    2010-03-01

    Aesthetically pleasing dark roofs can be formulated to reflect like a highly reflective white roof in the near infrared portion of the solar spectrum. New paint pigments increase the near infrared reflectance of exterior finishes by minimizing the absorption of near-infrared radiation (NIR). The boost in the NIR reflectance drops the surface temperatures of roofs and walls, which in turn reduces cooling-energy use and provides savings for the homeowner and relief for the utilities. In moderate and hot climates, a roof surface with high solar reflectance and high thermal emittance was shown by Akbari et al. (2004) and by Parker and Sherwin (1998) to reduce the exterior temperature and produce savings in comfort cooling. The new cool color pigments can potentially reduce emissions of carbon dioxide, which in turn reduces metropolitan heat buildup and urban smog. The pigments can also help conserve water resources otherwise used to clean and process fuel consumed by fossil-fuel driven power plants. Cool roofs also result in a lower ambient temperature that further decreases the need for air conditioning, retards smog formation, and improves thermal comfort. Parker, Sonne and Sherwin (2002) demonstrated that white barrel and white flat tiles reduced cooling energy consumption by 22% of the base load used by an adjacent and identical home having direct nailed dark shingles. Part of the savings was due to the reflectance of the white tiles; however, another part was due to the mass of the tile and to the venting occurring within the double batten installation. With, Cherry and Haig (2009) have studied the influence of the thermal mass and batten space ventilation and have found that, referenced to an asphalt shingle system, it can be equivalent to an additional 28 points of solar reflectivity. The double batten arrangement has wooden counter battens laid vertically (soffit-to-ridge) against the roof deck, and then the conventional battens are laid horizontally across the

  16. Microstructural Analysis and Rheological Modeling of Asphalt Mixtures Containing Recycled Asphalt Materials

    Directory of Open Access Journals (Sweden)

    Augusto Cannone Falchetto

    2014-09-01

    Full Text Available The use of recycled materials in pavement construction has seen, over the years, a significant increase closely associated with substantial economic and environmental benefits. During the past decades, many transportation agencies have evaluated the effect of adding Reclaimed Asphalt Pavement (RAP, and, more recently, Recycled Asphalt Shingles (RAS on the performance of asphalt pavement, while limits were proposed on the amount of recycled materials which can be used. In this paper, the effect of adding RAP and RAS on the microstructural and low temperature properties of asphalt mixtures is investigated using digital image processing (DIP and modeling of rheological data obtained with the Bending Beam Rheometer (BBR. Detailed information on the internal microstructure of asphalt mixtures is acquired based on digital images of small beam specimens and numerical estimations of spatial correlation functions. It is found that RAP increases the autocorrelation length (ACL of the spatial distribution of aggregates, asphalt mastic and air voids phases, while an opposite trend is observed when RAS is included. Analogical and semi empirical models are used to back-calculate binder creep stiffness from mixture experimental data. Differences between back-calculated results and experimental data suggest limited or partial blending between new and aged binder.

  17. Prolong Your Roof's Performance: Roof Asset Management.

    Science.gov (United States)

    Teitsma, Jerry

    2001-01-01

    Discusses the roof asset management process for maintaining a roof system's integrity and value in a cost-effective manner. Included is a breakdown of roofing surface characteristics for multiply and single ply roofing systems. (GR)

  18. Condition Assessment Survey (CAS) Program. Deficiency standards and inspections methods manual: Volume 5, 0.05 Roofing

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    General information is presented for asset determinant factor/CAS repair codes/CAS cost factors; guide sheet tool & material listing; testing methods; inspection frequency; standard system design life tables; and system work breakdown structure. Deficiency standards and inspection methods are presented for built-up membrane; single- ply membrane; metal roofing systems; coated foam membrane; shingles; tiles; parapets; roof drainage system; roof specialties; and skylights.

  19. Green roofs

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-04-01

    Full Text Available of development on the quality of urban microclimates; Loss of valuable habitats for flora and fauna; Loss of porous land surfaces and its negative impact on storm water runoff; and The need for green space in urban environments Green roofs also present a... the simulation results predict an energy saving equal to 65-266 g C per m2 of green roof in electricity and in 65-266 g C per m2 in natural gas per annum. Extending the green roofs into an urban area may result in an additional 25 per cent energy saving arising...

  20. Green Roofs

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-08-01

    A New Technology Demonstration Publication Green roofs can improve the energy performance of federal buildings, help manage stormwater, reduce airborne emissions, and mitigate the effects of urban heat islands.

  1. Roof assembly

    CSIR Research Space (South Africa)

    De Villiers, A

    2010-01-01

    Full Text Available The objective of this chapter is to provide sustainability criteria for roof system design that can be used by planners, designers and developers as a planning, design and development guide for sustainable building projects....

  2. Development and testing of shingle-type solar cell modules. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, N.F.

    1979-02-28

    The design, development, fabrication and testing of a shingle-type terrestrial solar cell module which produces 98 watts/m/sup 2/ of exposed module area at 1 kW/m/sup 2/ insolation and 61/sup 0/C are reported. These modules make it possible to easily incorporate photovoltaic power generation into the sloping roofs of residential or commercial buildings by simply nailing the modules to the plywood roof sheathing. This design consists of nineteen series-connected 53 mm diameter solar cells arranged in a closely packaged hexagon configuration. These cells are individually bonded to the embossed surface of a 3 mm thick thermally tempered hexagon-shaped piece of ASG SUNADEX glass. Monsanto SAFLEX polyvinyl butyral is used as the laminating adhesive. RTVII functions as the encapsulant between the underside of the glass superstrate and a rear protective sheet of 0.8 mm thick TEXTOLITE. The semi-flexible portion of each shingle module is a composite laminate construction consisting of outer layers of B.F. Goodrich FLEXSEAL and an epichlorohydrin closed cell foam core. The module design has satisfactorily survived the JPL-defined qualification testing program which includes 50 thermal cycles between -40 and +90/sup 0/C, a seven-day temperature-humidity exposure test and a mechanical integrity test consisting of a bidirectional cyclic loading at 2390 Pa (50 lb/ft/sup 2/) which is intended to simulate loads due to a 45 m/s (100 mph) wind.

  3. Underwriters Laboratories Fire Tests of Sprayed Polyurethane Foam Applied Directly to Metal Roof Decks.

    Science.gov (United States)

    1983-12-01

    inch plain vegetable fiberboard attached by mechanical fasteners and with a built-up (tar or asphalt ) roof covering and gravel surface. When subjected...34in. - S74 * 5 7ft -6 CONSTRUCTION NO. 82 1. Foamed Platic* - Formed by simultaneous spraying of two liquid components isocyanate and resin...vegetable fiberboard attached by mechanical fasteners and with a built-up (tar or asphalt ) roof covering and gravel surface produced underdeck flame spread

  4. Soiling of building envelope surfaces and its effect on solar reflectance – Part III: Interlaboratory study of an accelerated aging method for roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Sleiman, M; Chen, S; Gilbert, HE; Kirchstetter, TW; Berdahl, P; Bibian, E; Bruckman, LS; Cremona, D; French, RH; Gordon, DA; Emiliani, M; Kable, J; Ma, L; Martarelli, M; Paolini, R; Prestia, M; Renowden, J; Marco Revel, G; Rosseler, O; Shiao, M; Terraneo, G; Yang, T; Yu, L; Zinzi, M; Akbari, H; Levinson, R; Destaillats, H

    2015-09-22

    A laboratory method to simulate natural exposure of roofing materials has been reported in a companion article. Here in the current article, we describe the results of an international, nine-participant interlaboratory study (ILS) conducted in accordance with ASTM Standard E691-09 to establish the precision and reproducibility of this protocol. The accelerated soiling and weathering method was applied four times by each laboratory to replicate coupons of 12 products representing a wide variety of roofing categories (single-ply membrane, factory-applied coating (on metal), bare metal, field-applied coating, asphalt shingle, modified-bitumen cap sheet, clay tile, and concrete tile). Participants reported initial and laboratory-aged values of solar reflectance and thermal emittance. Measured solar reflectances were consistent within and across eight of the nine participating laboratories. Measured thermal emittances reported by six participants exhibited comparable consistency. For solar reflectance, the accelerated aging method is both repeatable and reproducible within an acceptable range of standard deviations: the repeatability standard deviation sr ranged from 0.008 to 0.015 (relative standard deviation of 1.2–2.1%) and the reproducibility standard deviation sR ranged from 0.022 to 0.036 (relative standard deviation of 3.2–5.8%). The ILS confirmed that the accelerated aging method can be reproduced by multiple independent laboratories with acceptable precision. In conclusion, this study supports the adoption of the accelerated aging practice to speed the evaluation and performance rating of new cool roofing materials.

  5. Thermo-mechanical properties improvement of asphalt binder by using methylmethacrylate/ethylene glycol dimethacrylate

    OpenAIRE

    Ragab, A.A.; Reem K. Farag; Usama F. Kandil; El-Shafie, M.; A.M.M. Saleh; Ahmed F. El-Kafrawy

    2016-01-01

    Various polymer-modified asphalt compositions for paving and roofing applications are known since several years ago. The degree to which a polymer improves the asphalt’s properties depends on the compatibility of the polymer and the asphalt. Highly compatible polymers are more effective in providing property improvements. In this research, the influence of in situ polymerization of methylmethacrylate monomer with asphalt in presence of ethylene glycol dimethacrylate (EGDM) as a crosslinker on...

  6. Installation, care, and maintenance of wood shake and shingle siding

    Science.gov (United States)

    Jack Dwyer; Tony Bonura; Arnie Nebelsick; Sam Williams; Christopher G. Hunt

    2011-01-01

    This article gives general guidelines for selection, installation, finishing, and maintenance of wood shakes and shingles. The authors gathered information from a variety of sources: research publications on wood finishing, technical data sheets from paint manufacturers, installation instructions for shake and shingle siding, and interviews with experts having...

  7. Stopping Shingles (A Minute of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2018-01-25

    Shingles, also known as herpes zoster, is a disease characterized by a painful skin rash with blisters. This podcast discusses a new vaccine to prevent shingles.  Created: 1/25/2018 by MMWR.   Date Released: 1/25/2018.

  8. Indoor climate and moisture durability performances of houses with unvented attic roof constructions in a mixed-humid climate.

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-10-01

    A sealed or unvented attic is an energy-efficient envelope component that can reduce the amount of energy a house consumes for space conditioning if the air handler and/or ducts are located in the attic. The attic is typically sealed by using spray foam on the underside of the roof deck and covering the soffit, ridge and gable vents to minimize air leakage from the attic to the outside. This approach can save up to 10% in space-conditioning energy when ducts are located in the attic (DOE 2013). Past research done by ORNL and Florida Solar Energy Center suggests that in more hot, humid climates, an unvented attic could potentially create a more humid, uncomfortable living environment than a vented attic (Colon 2011, Boudreaux, Pallin et al. 2013). Research showed that controlling the higher indoor humidity could reduce the energy savings from the sealed, unvented attic, which in turn would decrease the energy savings payback. Research also showed that the roof assembly (5.5 inches of open-cell foam, 1inch of closed-cell foam, OSB, felt paper, and asphalt shingles) stored moisture, thus acting as a moisture buffer. During the fall and winter, the roof assembly stored moisture and during the spring and summer it released moisture. This phenomenon is not seen in a vented attic, in which the air exchange rate to the outside is greater and, in the winter, helps to dehumidify the attic air. It was also seen that in a vented attic, the direction of water vapor diffusion is on average from the attic to the interior of the house. Air leakage from the attic to the interior also occurs during more of the year in a house with an unvented attic than in one with a vented attic. These discoveries show that the moisture dynamics in a house with an unvented attic are much different from those in a house with a vented attic. This study reports on a series of computer model investigations completed to determine the key variables impacting indoor comfort and the durability of roof

  9. Weathering of Roofing Materials-An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Berdahl, Paul; Akbari, Hashem; Levinson, Ronnen; Miller, William A.

    2006-03-30

    An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freeze-thaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

  10. Stopping Shingles (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2018-01-25

    Shingles, also known as herpes zoster, is a disease characterized by a painful skin rash, with blisters usually occurring on one side of the body. Each year, approximately one million people in the U.S. get the disease. In this podcast, Dr. Mark Pallansch discusses a newly approved vaccine to prevent shingles.  Created: 1/25/2018 by MMWR.   Date Released: 1/25/2018.

  11. Asphaltic concrete pavement survey.

    Science.gov (United States)

    1963-04-01

    The ever increasing problem of wheel path rutting and excessive desification of asphaltic concrete pavement has been the subject of asphalt technology for quite sometime. It is known that the density of the pavement, which is significant for several ...

  12. Ecological Impacts of Replacing Traditional Roofs with Green Roofs in Two Urban Areas

    Directory of Open Access Journals (Sweden)

    Timothy Carter

    2008-01-01

    Full Text Available Urban land cover is dominated by impervious surface that degrades both terrestrial and aquatic ecosystems relative to predevelopment conditions. There are significant opportunities for designers of urban landscapes to use alternative land covers that have multiple functions, benefiting both human and nonhuman components of the urban ecosystem. Vegetated (green roofs are one form of alternative land cover that has shown the potential to provide a variety of ecological benefits in urban areas. We evaluated how stormwater retention, building energy and temperature, and rooftop habitat are influenced by the use of green roofs using test plots in Georgia and Massachusetts. Green roofs were shown to recreate part of the predevelopment hydrology through increasing interception, stormwater storage, evaporation, and transpiration on the rooftop and worked extremely well for small storm events. Temperature reductions were found on the green rooftop as compared to an asphalt surface, although other roof technologies that minimize temperatures, such as lighter colored membranes, provide similar benefits. Novel habitat was created on the rooftop, although the extent of this habitat was limited in part by plant survivability and the need for additional water inputs for diverse plant communities to survive. Despite the challenges, the green roof benefits reported here suggest that green roofs can be used effectively as a multifunctional land cover in urban areas.

  13. Roofing research: a bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.N.; Nichols, C.L.

    1981-04-01

    A listing, indexed by subject, primary author, and secondary authors, is presented of some 530 references in the literature related to roofing research - materials, construction, and in-service problems. Structural design of roofing systems is not covered.

  14. New roof element system

    DEFF Research Database (Denmark)

    Ditlev, Jesper; Rudbeck, Claus Christian

    1997-01-01

    The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs.......The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs....

  15. Renovation of Roof Structure

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    1997-01-01

    A 30 year old not-watertight roof based on wooden boards with roofing felt have been changed to a pitched structure with cementos plates. At the same time more thermal insulation has been placed.......A 30 year old not-watertight roof based on wooden boards with roofing felt have been changed to a pitched structure with cementos plates. At the same time more thermal insulation has been placed....

  16. A hybrid strategy in selecting diverse combinations of innovative sustainable materials for asphalt pavements

    Directory of Open Access Journals (Sweden)

    Baron Colbert

    2016-04-01

    Full Text Available This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction efficiencies, through measures such as construction warrantees and goals to reduce air pollution under the Kyoto Protocol, have increased the efforts to implement sustainable materials in roadways. The objective of this research is to develop a systematic approach toward selecting optimum combinations of sustainable materials for the construction of asphalt pavements. The selected materials, warm mix asphalt (WMA, recycled asphalt shingles (RAS, and reclaimed asphalt pavement (RAP were incorporated in this study. The results of this research are intended to serve as guidelines in the selection of the mixed sustainable materials for asphalt pavements. The approach developed from this project draws upon previous research efforts integrating graphical modeling with optimizing the amount of sustainable materials based on the performance. With regard to moisture susceptibility and rutting potential test results, as well as the MIM analysis based on a 95% confidence interval, the rutting performance and moisture susceptibility of asphalt mixtures are not significantly different regardless of the percentages of RAS, RAP, or WMA. The optimum mixture choices could be made by the plant emission rankings with consideration of the optimal WMA types, percentages of RAS/RAP, and WMA production temperatures. The WMA mixtures prepared with 75% RAP and Advera® WMA have produced the lowest CO2 emissions among the investigated mixture types.

  17. Evaluating Cool Impervious Surfaces: Application to an Energy-Efficient Residential Roof and to City Pavements

    Science.gov (United States)

    Rosado, Pablo Javier

    Summer urban heat island (UHI) refers to the phenomenon of having higher urban temperatures compared to the those in surrounding suburban and rural areas. Higher urban air temperatures lead to increased cooling demand, accelerates the formation of smog, and contributes to the generation of greenhouse gas emissions. Dark-colored impervious surfaces cover a significant fraction of an urban fabric, and as hot and dry surfaces, are a major contributor to the UHI effect. Adopting solar-reflective ("cool") roofs and cool pavements, and increasing the urban vegetation, are strategies proven to mitigate urban heat islands. These strategies often have an "indirect" effect (ambient cooling) and "direct" effect (change in solar energy flux entering the conditioned space) on the energy use of buildings. This work investigates some elements of the UHI mitigation strategies, specifically the annual direct effect of a cool roof, and the direct and indirect effects of cool pavements. The first topic researched in this paper consists in an experimental assessment of the direct effects from replacing a conventional dark roof with a highly energy-efficient cool roof. The study measures and calculates the annual benefits of the cool roof on the cooling and heating energy uses, and the associated emission reductions. The energy savings attributed to the cool roof are validated by measuring the difference between the homes in the heat loads that entered the conditioned space through the ceiling and HVAC ducts. Fractional annual cooling energy savings (26%) were 2.6 times the 10% daily cooling energy savings measured in a previous study that used a white coating to increase the albedo of an asphalt shingle roof by the same amount (0.44). The improved cooling energy savings (26% vs. 10%) may be attributed to the cool tile's above-sheathing ventilation, rather than to its high thermal mass. The roof also provided energy savings during the heating season, yielding fractional annual gas

  18. Asphalt in Pavement Maintenance.

    Science.gov (United States)

    Asphalt Inst., College Park, MD.

    Maintenance methods that can be used equally well in all regions of the country have been developed for the use of asphalt in pavement maintenance. Specific information covering methods, equipment and terminology that applies to the use of asphalt in the maintenance of all types of pavement structures, including shoulders, is provided. In many…

  19. POROUS ASPHALT???S CONTRIBUTION ON ROAD SAFETY AND ENVIRONMENT

    OpenAIRE

    Ali, Nur; Ramli, M. Isran; Hustim, Muralia

    2012-01-01

    The porous asphalt properties are different from dense asphalt concrete. Regarding the open structure of its gradation, the porous asphalt can reduce noise level from road traffic, drains water from the road surface, and the thermal conductivity. These behaviors lead to the porous asphalt contribution on road traffic safety and environment. This paper provides a comparison study regarding a literature review based on some developed countries??? experiences in using the porous asphalt related ...

  20. IMPROVED ROOF STABILIZATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Ebadian, Ph.D.

    1999-01-01

    Many U.S. Department of Energy (DOE) remediation sites have performed roof repair and roof replacement to stabilize facilities prior to performing deactivation and decommissioning (D&D) activities. This project will review the decision criteria used by these DOE sites, along with the type of repair system used for each different roof type. Based on this information, along with that compiled from roofing experts, a decision-making tool will be generated to aid in selecting the proper roof repair systems. Where appropriate, innovative technologies will be reviewed and applied to the decision-making tool to determine their applicability. Based on the results, applied research and development will be conducted to develop a method to repair these existing roofing systems, while providing protection for the D and D worker in a cost-efficient manner.

  1. Solution for Flat Roofs

    Directory of Open Access Journals (Sweden)

    Şt. Vasiliu

    2008-01-01

    Full Text Available Roofs are constructive subassemblies that are located at the top of buildings, which toghether with perimetral walls and some elements of the infrastructure belongs to the subsystem elements that close the building. An important share in the roofing is represented by the flat roofs. Flat roofs must meet the requirements of resistance to mechanical action, thermal insulation, acoustic and waterproof, fire resistance, durability and aesthetics. To meet these requirements is necessary an analysis of the component layers and materials properties that determine the durability of structural assembly.

  2. Paver Asphalt Distress Manual

    National Research Council Canada - National Science Library

    Shahin, M

    1997-01-01

    .... Army Construction Engineering Research Laboratories (USACERL) in June 1989. It comprises an illustrated asphalt pavement distress manual suitable for use by pavement inspection personnel in the field or in pavement inspection training courses...

  3. Latent Virus Reactivation in Astronauts and Shingles Patients

    Science.gov (United States)

    Mehta, Satish K.; Cohrs, Randall J.; Gilden, Donald H.; Tyring, Stephen K.; Castro, Victoria A.; Ott, C. Mark; Pierson, Duane L.

    2010-01-01

    Spaceflight is a uniquely stressful environment with astronauts experiencing a variety of stressors including: isolation and confinement, psychosocial, noise, sleep deprivation, anxiety, variable gravitational forces, and increased radiation. These stressors are manifested through the HPA and SAM axes resulting in increased stress hormones. Diminished T-lymphocyte functions lead to reactivation of latent herpesviruses in astronauts during spaceflight. Herpes simplex virus reactivated with symptoms during spaceflight whereas Epstein-Barr virus (EBV), cytomegalovirus (CMV), and varicella zoster virus (VZV) reactivate and are shed without symptoms. EBV and VZV are shed in saliva and CMV in the urine. The levels of EBV shed in astronauts increased 10-fold during the flight; CMV and VZV are not typically shed in low stressed individuals, but both were shed in astronauts during spaceflight. All herpes viruses were detected by polymerase chain reaction (PCR) assay. Culturing revealed that VZV shed in saliva was infectious virus. The PCR technology was extended to test saliva of 54 shingles patients. All shingles patients shed VZV in their saliva, and the levels followed the course of the disease. Viremia was also found to be common during shingles. The technology may be used before zoster lesions appear allowing for prevention of disease. The technology may be used for rapid detection of VZV in doctors offices. These studies demonstrated the value of applying technologies designed for astronauts to people on Earth.

  4. Collaborative active roof design

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.

    2008-01-01

    Roofs play an essential role in buildings. Their value and impact often significantly surpass the cost ratio they represent in the total investment cost of the building. Traditionally, roofs have a protecting function and their basic design has changed little over hundreds of years. Nowadays

  5. Modified Asphalt Binder with Natural Zeolite for Warm Mix Asphalt

    Directory of Open Access Journals (Sweden)

    Dubravský Marián

    2015-11-01

    Full Text Available In recent years, warm mix asphalt (WMA is becoming more and more used in the asphalt industry. WMA provide a whole range of benefits, whether economic, environmental and ecological. Lower energy consumption and less pollution is the most advantages of this asphalt mixture. The paper deals with the addition of natural zeolite into the sub base asphalt layers, which is the essential constituent in the construction of the road. Measurement is focused on basic physic – mechanical properties declared according to the catalog data sheets. The aim of this article is to demonstrate the ability of addition the natural zeolite into the all asphalt layers of asphalt pavement. All asphalt mixtures were compared with reference asphalt mixture, which was prepared in reference temperature.

  6. Modified Asphalt Binder with Natural Zeolite for Warm Mix Asphalt

    Science.gov (United States)

    Dubravský, Marián; Mandula, Ján

    2015-11-01

    In recent years, warm mix asphalt (WMA) is becoming more and more used in the asphalt industry. WMA provide a whole range of benefits, whether economic, environmental and ecological. Lower energy consumption and less pollution is the most advantages of this asphalt mixture. The paper deals with the addition of natural zeolite into the sub base asphalt layers, which is the essential constituent in the construction of the road. Measurement is focused on basic physic - mechanical properties declared according to the catalog data sheets. The aim of this article is to demonstrate the ability of addition the natural zeolite into the all asphalt layers of asphalt pavement. All asphalt mixtures were compared with reference asphalt mixture, which was prepared in reference temperature.

  7. Volumetric characteristics and compactability of asphalt rubber mixtures with organic warm mix asphalt additives

    National Research Council Canada - National Science Library

    A M Rodríguez-Alloza; J Gallego

    2017-01-01

    Warm Mix Asphalt (WMA) refers to technologies that reduce manufacturing and compaction temperatures of asphalt mixtures allowing lower energy consumption and reducing greenhouse gas emissions from asphalt plants...

  8. Modified Asphalt Binder with Natural Zeolite for Warm Mix Asphalt

    OpenAIRE

    Dubravský Marián; Mandula Ján

    2015-01-01

    In recent years, warm mix asphalt (WMA) is becoming more and more used in the asphalt industry. WMA provide a whole range of benefits, whether economic, environmental and ecological. Lower energy consumption and less pollution is the most advantages of this asphalt mixture. The paper deals with the addition of natural zeolite into the sub base asphalt layers, which is the essential constituent in the construction of the road. Measurement is focused on basic physic – mechanical properties decl...

  9. Norwegian Pitched Roof Defects

    Directory of Open Access Journals (Sweden)

    Lars Gullbrekken

    2016-06-01

    Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

  10. Improved roof stabilization technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ebadian, M.A.

    1998-01-01

    Decontamination and decommissioning (D and D) activities require that personnel have access to all areas of structures, some of which are more than 40 years old. In many cases, these structures have remained in a standby condition for up to 10 years; few preventative maintenance activities have been performed on them because of lack of funding or a defined future plan of action. This situation has led to deteriorated building conditions, resulting in potential personnel safety hazards. In addition, leaky roofs allow water to enter the buildings, which can cause the spread of contamination and increase building deterioration, worsening the already unsafe working conditions. To ensure worker safety and facilitate building dismantlement, the assessment of roof stabilization techniques applicable to US Department of Energy (DOE) structures has become an important issue. During Fiscal year 1997 (FY97), a comprehensive reliability-based model for the structural stabilization analysis of roof system in complex structures was developed. The model consists of three major components: a material testing method, a deterministic structural computer model, and a reliability-based optimization, and probabilistic analyses of roof structures can be implemented. Given site-specific needs, this model recommends the most appropriate roof stabilization system. This model will give not only an accurate evaluation of the existing roof system in complex structures, but it will also be a reliable method to aid the decision-making process. This final report includes in its appendix a Users` Manual for the Program of Deterministic and Reliability Analysis of Roof Structures.

  11. Roof bolting equipment & technology

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2009-04-15

    Technology provides an evaluator path to improvement for roof bolting machines. Bucyrus offers three different roof bolts models for various mining conditions. The LRB-15 AR is a single-arm boiler recommended for ranges of 32 inches and above; the dual-arm RB2-52A for ranges of 42 inches and above; and the dual-arm RB2-88A for ranges of 54 inches and above. Design features are discussed in the article. Developments in roof bolting technology by Joy Mining Machinery are reported. 4 photos.

  12. Adaptable typologies for active roofs

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.; Zeiler, W.

    2006-01-01

    The main objective of this part of the 6th framework Pan-European EUR-ACTIVE ROOF-er project is to improve the interaction between design participants of dynamic adaptable Active Roofs in product development and Active Roofs from an architects/ customers perspective. Improvements in Active Roof

  13. Construction of Experimental Roofing.

    Science.gov (United States)

    1981-11-01

    Workmen shall wear clean, soft-soled sneaker -type shoes . 2.4 Preparation For Reroofing: (E) 2.4.1 Removal: Debris from existing roof shall be removed...Workmen shall wear clean, soft-soled sneaker - type shoes . d. Preparation for Reroofing: (1) Removal: Debris from existing roof shall be removed using a...Preparation; Surfaces shall be dry and free of loose coatings or other contaminants. Workmen shall wear clean, soft-soled sneaker -type shoes . 2.4

  14. Laboratory evaluation of selected tar sand asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Button, J.W.; Epps, J.A.; Gallaway, B.M.

    1980-12-01

    Three tar sand asphalts of similar grades prepared from one syncrude by three different refining methods were characterized by tests commonly used to specify paving asphalts together with certain special tests. Asphalt-aggregate mixtures were prepared using these asphalts and tested in the laboratory to determine strength stiffness stability, tensile properties, temperature effects and water susceptibility. Comparison of the tar sand asphalt properties to conventional petroleum asphalt properties reveal no striking differences.

  15. A review of asphalt and asphalt mixture aging

    Directory of Open Access Journals (Sweden)

    Wilmar Darío Fernández-Gómez

    2013-01-01

    Full Text Available This paper presents an extensive review of the pertinent literature regarding asphalt and asphalt mixture Aging. Aging affects flexible pavement performance and is produced by intrinsic and extrinsic variables as well as exposure time. Intrinsic variables include asphalt and aggregate properties, a mixture’s asphalt content, binder film thickness and air void content; extrinsic variables are associated with production (short-term aging and exposure to environmental field conditions (long-term aging. Taken together, both variables demonstrate that aging results from three distinct mechanisms: volatilisation, oxidation and steric hardening. Temperature, pressure and photo degradation treatments are used to simulate aging in the laboratory and empirical and semi-empirical models are created to represent and study aging. Aging increases asphalt complex modulus and decreases the phase angle. Mixtures become stiffer while fatigue life becomes reduced. Carbonyl and sulfoxide group formation in asphalt are often studied as such chemical changes show oxidation in aged asphalts. The prevailing models used to predict asphalt aging are discussed, though more comprehensive research into asphalt aging is still needed.

  16. A review of asphalt and asphalt mixture aging

    Directory of Open Access Journals (Sweden)

    Wilmar Darío Fernández-Gómez

    2012-09-01

    Full Text Available This paper presents an extensive review of the pertinent literature regarding asphalt and asphalt mixture Aging. Aging affects flexible pavement performance and is produced by intrinsic and extrinsic variables as well as exposure time. Intrinsic variables include asphalt and aggregate properties, a mixture’s asphalt content, binder film thickness and air void content; extrinsic variables are associated with production (short-term aging and exposure to environmental field conditions (long-term aging. Taken together, both variables demonstrate that aging results from three distinct mechanisms: volatilisation, oxidation and steric hardening. Temperature, pressure and photo degradation treatments are used to simulate aging in the laboratory and empirical and semi-empirical models are created to represent and study aging. Aging increases asphalt complex modulus and decreases the phase angle. Mixtures become stiffer while fatigue life becomes reduced. Carbonyl and sulfoxide group formation in asphalt are often studied as such chemical changes show oxidation in aged asphalts. The prevailing models used to predict asphalt aging are discussed, though more comprehensive research into asphalt aging is still needed.

  17. Evolution of Flat Roofs

    Directory of Open Access Journals (Sweden)

    Şt. Vasiliu

    2009-01-01

    Full Text Available Roofs are constructive subassembles that are located at the top of buildings, which toghether with perimetral walls and some elements of the infrastructure belongs to the subsystem elements that close the building. Roofs must meet resistance requirements to mechanical action, thermal insulating, waterproofing and acoustic, fire resistance, durability, economy and aesthetics. The man saw the need to build roofs from the oldest ancient times. Even if the design of buildings has an empirical character, are known and are preserved until today constructions that are made in antiquity, by the Egyptians, Greeks and Romans with architectural achievements, worthy of admiration and in present time. General composition of civil construction has been influenced throughout the evolution of construction history by the level of production forces and properties of building materials available in every historical epoch. For over five millennia, building materials were stone, wood and ceramic products (concrete was used by theRomans only as filling material.

  18. Roof-integrated photovoltaic modules with integrated inverters and hybrid usage on the roof of a farmhouse; PV-Dachintegration von Solarmodulen mit integriertem Inverter und Hybridnutzung am Schindeldach des Bauernhauses 'Zaugg'

    Energy Technology Data Exchange (ETDEWEB)

    Eckmanns, A.; Stucki, B.

    2000-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) describes a solar system that features photovoltaic shingles used instead of conventional tiles, use of the heat generated under the roof for hay ventilation / drying and module-integrated micro-inverters. The report discusses the findings of the project, which was started to gain practical experience with such a hybrid electrical-thermal system. Beside the monitored electrical power output the results include an appraisal of the effects of the air temperature under the shingles on inverter operation as well as the thermal output power of the system, which exceeded expectations, and the thermal energy yield, which was below expectations due to the limited operation period of the hay drying system.

  19. Acoustic Properties of Absorbent Asphalts

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-08-01

    Road traffic is one of the greater cause of noise pollution in urban centers; a prolonged exposure to this source of noise disturbs populations subjected to it. In this paper is reported a study on the absorbent coefficients of asphalt. The acoustic measurements are carried out with a impedance tube (tube of Kundt). The sample are measured in three conditions: with dry material (traditional), “wet” asphalt and “dirty” asphalt.

  20. Thermo-mechanical properties improvement of asphalt binder by using methylmethacrylate/ethylene glycol dimethacrylate

    Directory of Open Access Journals (Sweden)

    A.A. Ragab

    2016-09-01

    Full Text Available Various polymer-modified asphalt compositions for paving and roofing applications are known since several years ago. The degree to which a polymer improves the asphalt’s properties depends on the compatibility of the polymer and the asphalt. Highly compatible polymers are more effective in providing property improvements. In this research, the influence of in situ polymerization of methylmethacrylate monomer with asphalt in presence of ethylene glycol dimethacrylate (EGDM as a crosslinker on the rheological and thermal properties of asphalt binder of type penetration grade 60/70 was studied. To achieve this aim, MMA/EGDM(MC in different ratios as 5, 10 and 15% (w/w were used to modify the thermo-mechanical properties of asphalt via forming chemical bond, and the changing in mechanical and thermal properties, of the mixes as well as the storage stability were studied. Also, the morphology (SEM, thermal characterization (TGA, dynamic mechanical analysis (DMA, bending and rheological tests were detected. The obtained experimental results revealed that the addition of MC causes both the rheological and thermal properties of the binder to improve and the prepared PMAs has high temperature susceptibility and low curing time. The improvement in the properties of the virgin asphalt will be effective in using this soft type in coating applications instead of highly expensive oxidized one.

  1. Dead sea asphalts: historical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A.

    1978-05-01

    Asphalts are present in the Dead Sea basin in three forms: (1) huge blocks, up to 100 tons in weight, composed of extremely pure (>99.99%) solid asphalt occasionally found floating on the lake, (2) veins, seepages, and cavity and fissure fillings in Lower Cretaceous to Holocene rocks, and (3) ozocerite veins on the eastern shore of the lake. Dead Sea asphalts probably have been documented over a longer period of time than any other hydrocarbon deposit--from antiquity to the 19th century. Major uses of asphalt from the Dead Sea have been as an ingredient in the embalming process, for medicinal purposes, for fumigation, and for agriculture. The first known war for control of a hydrocarbon deposit was in the Dead Sea area in 312 B.C. between the Seleucid Syrians and the Nabatean Arabs who lived around the lake. Surface manifestations of asphalt are linked closely to tectonic activity. In the lake itself, the asphalt is associated with diapirs During certain historic periods, tectonic and diapiric activity caused frequent liberation to the Dead Sea surface of semiliquid asphalt associated with large amounts of hydrogen sulfide gas. When the tectonic activity was attenuated, as in the 19th and 20th centuries, the rate of asphalt seepage to the bottom sediments of the Dead Sea was much slower and the asphalt solidified on the lake bottom. The release of asphalt to the surface became much more sporadic, and may have resulted in part from earthquakes. Thus, future asphalt prospecting in the Dead Sea area should be conducted along the boundaries of diapirs or their associated faults.

  2. Polyurethane synthesis reactions in asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Bukowski, A.; Gretkiewicz, J.

    1982-04-01

    A series of asphalt-polyurethane composites was prepared by means of polyurethane synthesis in asphalt and carried out in melt. The applied materials were asphalts of differentiated group components content, polyester polyols of chain structure from linear to strongly branched, 2,4-tolylene diisocyanate, 4,4-methylenebis(phenyl isocyanate), and tinorganic catalyst. The asphalt components react with isocyanates to a minimal degree. The influence of the applied substrates, temperature, and polyurethane content in the system on the basic kinetic relations characterizing the process is presented. Polyurethane synthesis in asphalts does not differ in a fundamental way from the obtaining of polyurethanes, especially when their content in the composition is significant, 20 wt% and more.

  3. 40 CFR 60.472 - Standards for particulate matter.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... Processing and Asphalt Roofing Manufacture § 60.472 Standards for particulate matter. (a) On and after the...) Particulate matter in excess of: (i) 0.04 kg/Mg (0.08 lb/ton) of asphalt shingle or mineral-surfaced roll...

  4. Mechanical Properties of Warm Mix Asphalt Prepared Using Foamed Asphalt Binders : Executive Summary Report

    Science.gov (United States)

    2011-03-01

    Hot mix asphalt (HMA) is a mixture containing aggregates and asphalt binders prepared at specified : proportions. The aggregates and asphalt binder proportions are determined through a mix design : procedure such as the Marshall Mix Design or the Sup...

  5. Induction Healing of Porous Asphalt Concrete

    OpenAIRE

    Liu, Q.

    2012-01-01

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the surface layer, is the main damage mechanism of porous asphalt surface wearing courses. In this research, an induction healing approach (namely, activating the healing process of asphalt concrete through ...

  6. Steep-Slope Assembly Testing of Clay and Concrete Tile With and Without Cool Pigmented Colors

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL

    2005-11-01

    Cool color pigments and sub-tile venting of clay and concrete tile roofs significantly impact the heat flow crossing the roof deck of a steep-slope roof. Field measures for the tile roofs revealed a 70% drop in the peak heat flow crossing the deck as compared to a direct-nailed asphalt shingle roof. The Tile Roofing Institute (TRI) and its affiliate members are keenly interested in documenting the magnitude of the drop for obtaining solar reflectance credits with state and federal "cool roof" building efficiency standards. Tile roofs are direct-nailed or are attached to a deck with batten or batten and counter-batten construction. S-Misson clay and concrete tile roofs, a medium-profile concrete tile roof, and a flat slate tile roof were installed on fully nstrumented attic test assemblies. Temperature measures of the roof, deck, attic, and ceiling, heat flows, solar reflectance, thermal emittance, and the ambient weather were recorded for each of the tile roofs and also on an adjacent attic cavity covered with a conventional pigmented and directnailed asphalt shingle roof. ORNL measured the tile's underside temperature and the bulk air temperature and heat flows just underneath the tile for batten and counter-batten tile systems and compared the results to the conventional asphalt shingle.

  7. Alabama warm mix asphalt field study : final report.

    Science.gov (United States)

    2010-05-01

    The Alabama Department of Transportation hosted a warm mix asphalt field demonstration in August 2007. The warm mix asphalt technology demonstrated was Evotherm Dispersed Asphalt Technology. The WMA and hot mix asphalt produced for the demonstration ...

  8. Effect of oxidation and extent of oxidation on biologically active PACs in asphalt products.

    Science.gov (United States)

    Trumbore, David; Osborn, Linda; Blackburn, Gary; Niebo, Ron; Kriech, Anthony; Maxim, L Daniel

    2011-10-01

    Recent studies have reported divergent results in rodent cancer assays using fume condensates from a variety of asphalt products. This paper presents results of a study investigating the role of oxidation, or extent of oxidation, on these findings. Five straight run asphalts, made from widely used crude oils, were used as inputs to both production scale and laboratory oxidation units and processed to a range of softening points used in common roofing products. For each of the five asphalts studied, the oxidation reaction significantly decreased measures of polycyclic aromatic compounds (PACs) that have been linked, previously and in analyses included in this study, to tumor induction in rodent bioassays. Mutagenicity index determined by the modified Ames assay was reduced between 41% and 50% from the input asphalt to the final oxidized product. A fluorescence method tuned to a subset of PAC compounds that have been associated with carcinogenic behavior in mouse bioassays was reduced between 39% and 71%. The decrease was largest in the first quarter of the oxidation reaction. These findings indicate that oxidation, by itself, was not a likely factor in the tumor induction seen in the previous studies. Rather, other factors such as the conditions of fume generation and crude source (coupled with possible differences in distillation endpoints) were more likely to have determined the outcomes. Analyses of previously published data, presented in this paper, suggest that the modified Ames and fluorescence assays are valuable screening tools for use in future health-related asphalt research.

  9. Premature asphalt concrete pavement cracking.

    Science.gov (United States)

    2015-06-01

    Recently, the Oregon Department of Transportation (ODOT) has identified hot mix asphalt concrete : (HMAC) pavements that have displayed top-down cracking within three years of construction. The objective of : the study was to evaluate the top-down cr...

  10. Predictors of shingles reports at diagnosis of common variable immunodeficiency and selective immunoglobulin G subclass deficiency in 212 Alabama adults

    Directory of Open Access Journals (Sweden)

    James C. Barton

    2012-07-01

    Full Text Available We sought to determine predictors of shingles reports in adults with common variable immunodeficiency or immunoglobulin (Ig G subclass deficiency (CVID/IgGSD. We tabulated observations at diagnosis of CVID/IgGSD in 212 white adult index patients (165 women, 47 men who responded to a question about having had shingles. None had been vaccinated for herpes zoster. We analyzed age, sex, and shingles reports; blood levels of CD19+, CD4+, CD8+, and CD56+ mononuclear cells; serum levels of IgG subclasses, IgA, and IgM; and positivity for human leukocyte antigen (HLA-A and -B haplotypes. Cell counts and immunoglobulin levels were normalized with loge (ln transformation for analyses. Thirty-one patients (14.6% reported shingles; 11 reported recurrent or disseminated shingles. Patients with shingles reports had greater mean age at diagnosis of CVID/IgGSD [54±13 (standard deviation years vs. 47±12 years; P=0.0130] and a greater prevalence of HLA-A*01, B*08 positivity (35.5% vs. 17.7%; P=0.0227. In a 13-factor logistic regression model, there was a positive association of age with shingles reports [P=0.0151; odds ratio (1.05, 95% confidence interval 1.01, 1.08]. HLA-A*01, B*08 positivity was also positively associated with shingles reports [P=0.0480; odds ratio 2.61 (1.00, 6.81]. During a mean followup interval of 7.5 years after CVID/IgGSD diagnosis, the prevalence of recurrent shingles was almost five-fold greater in patients with previous shingles reports. In conclusion, in white adults at CVID/IgGSD diagnosis, age at diagnosis and positivity for HLA-A*01, B*08 have significant positive associations with reports of previous shingles.

  11. Zoster vaccine live for the prevention of shingles in the elderly patient

    Directory of Open Access Journals (Sweden)

    Jamie Zussman

    2008-06-01

    Full Text Available Jamie Zussman, Lorraine YoungDepartment of Medicine, Dermatology Division, David Geffen School of Medicine at the University of California, Los Angeles, CaliforniaAbstract: Shingles, also known as herpes zoster, is a common disease in the elderly population that is caused by reactivation of latent varicella zoster virus. Its manifestations and complications can lead to significant short- and long-term morbidity. In 2006, the United States Food and Drug Administration approved Zoster Vaccine Live (Zostavax® for the prevention of herpes zoster in immunocompetent adults age 60 and over. The approval was based on the results of a large, multi-center clinical trial, the Shingles Prevention Study. This study showed that vaccination significantly decreased shingles incidence, burden of illness due to disease, and the development of, and severity of postherpetic neuralgia. This review offers an overview of varicella zoster virus infection and complications, a summary of the Shingles Prevention Study, and a critical analysis designed to aid the practicing physician who has questions about vaccine administration.Keywords: zoster vaccine, shingles, herpes zoster, postherpetic neuralgia, zostavax

  12. Unified Facilities Criteria (UFC) Design Guide. Army Reserve Facilities

    Science.gov (United States)

    2010-02-01

    membrane roofing will be used for low-slope roofs. 3-5.1.5 Preferred interior...be separated by rated construction Wet location light fixtures \\2\\ Contactor /2/ to shut down power to equipment under hood – coordinate with fire... membrane roofing systems (EPDM and Mod-Bit), and fiberglass-based asphalt shingle roof systems./2/ Other systems may be acceptable with Using

  13. PERFORMANCE EVALUATION OF A SUSTAINABLE AND ENERGY EFFICIENT RE-ROOFING TECHNOLOGY USING FIELD-TEST DATA

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Miller, William A [ORNL; Childs, Phillip W [ORNL; Kosny, Jan [ORNL; Kriner, Scott [Metal Construction Association, Glenview, IL

    2011-01-01

    Three test attics were constructed to evaluate a new sustainable method of re-roofing utilizing photo-voltaic (PV) laminates, metal roofing panels, and PCM heat sink in the Envelope Systems Research Apparatus (ESRA) facility in the ORNL campus. Figure 1 is a picture of the three attic roofs located adjacent to each other. The leftmost roof is the conventional shingle roof, followed by the metal panel roof incorporating the cool-roof coating, and third from left is the roof with the PCM. On the PCM roof, the PV panels are seen as well; they're labelled from left-to-right as panels 5, 6 and 7. The metal panel roof consists of three metal panels with the cool-roof coating; in further discussion this is referred to as the infrared reflective (IRR) metal roof. The IRR metal panels reflect the incoming solar radiation and then quickly re-emit the remaining absorbed portion, thereby reducing the solar heat gain of the attic. Surface reflectance of the panels were measured using a Solar Spectrum Reflectometer. In the 0.35-2.0 {mu}m wavelength interval, which accounts for more than 94% of the solar energy, the IRR panels have an average reflectance of 0.303. In the infrared portion of the spectrum, the IRR panel reflectance is 0.633. The PCM roof consists of a layer of macro-encapsulated bio-based PCM at the bottom, followed by a 2-cm thick layer of dense fiberglass insulation with a reflective surface on top, and metal panels with pre-installed PV laminates on top. The PCM has a melting point of 29 C (84.2 F) and total enthalpy between 180 and 190 J/g. The PCM was macro-packaged in between two layers of heavy-duty plastic foil forming arrays of PCM cells. Two air cavities, between PCM cells and above the fiberglass insulation, helped the over-the-deck natural air ventilation. It is anticipated that during summer, this extra ventilation will help in reducing the attic-generated cooling loads. The extra ventilation, in conjunction with the PCM heat sink, are used to

  14. Green roofs: potential at LANL

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Elena M [Los Alamos National Laboratory

    2009-01-01

    Green roofs, roof systems that support vegetation, are rapidly becoming one of the most popular sustainable methods to combat urban environmental problems in North America. An extensive list of literature has been published in the past three decades recording the ecological benefits of green roofs; and now those benefits have been measured in enumerated data as a means to analyze the costs and returns of green roof technology. Most recently several studies have made substantial progress quantifying the monetary savings associated with storm water mitigation, the lessoning of the Urban Heat Island, and reduction of building cooling demands due to the implementation of green roof systems. Like any natural vegetation, a green roof is capable of absorbing the precipitation that falls on it. This capability has shown to significantly decrease the amount of storm water runoff produced by buildings as well as slow the rate at which runoff is dispensed. As a result of this reduction in volume and velocity, storm drains and sewage systems are relieved of any excess stress they might experience in a storm. For many municipalities and private building owners, any increase in storm water mitigation can result in major tax incentives and revenue that does not have to be spent on extra water treatments. Along with absorption of water, vegetation on green roofs is also capable of transpiration, the process by which moisture is evaporated into the air to cool ambient temperatures. This natural process aims to minimize the Urban Heat Island Effect, a phenomenon brought on by the dark and paved surfaces that increases air temperatures in urban cores. As the sun distributes solar radiation over a city's area, dark surfaces such as bitumen rooftops absorb solar rays and their heat. That heat is later released during the evening hours and the ambient temperatures do not cool as they normally would, creating an island of constant heat. Such excessively high temperatures induce heat

  15. Constructing better roads with asphalt rubber

    Directory of Open Access Journals (Sweden)

    Pais Jorge C.

    2015-12-01

    Full Text Available Brazilians mixtures containing asphalt rubber were evaluated by mechanical laboratory tests. A conventional mixture with asphalt CAP-50/70 was produced as a mixture control. With the aim of compare the Brazilians mixtures performance, a Portuguese asphalt rubber mixture was tested as well. The testing set involved the determination of the mechanical properties, fatigue and permanent deformation, of asphalt rubber produced by wet process through two different systems: continuous blend and terminal blend. The asphalt rubber morphology was evaluated in order to determine the compatibility of the systems. The asphalt rubber mixtures exhibit good resistance to permanent deformation and prolonged fatigue life in relation to mixture control. Therefore it is concluded that the application of asphalt rubber alters the characteristics of asphalt mixture in a very beneficial way.

  16. A review of warm mix asphalt.

    Science.gov (United States)

    2008-12-01

    Warm Mix Asphalt (WMA) technology, recently developed in Europe, is gaining strong interest in the US. By : lowering the viscosity of asphalt binder and/or increasing the workability of mixture using minimal heat, WMA : technology allows the mixing, ...

  17. Controlling conductivity of asphalt concrete with graphite.

    Science.gov (United States)

    2014-08-01

    Electrically conductive asphalt concrete has a huge potential for various multifunctional applications such as : self-healing, self-sensing, and deicing. In order to utilize the full spectrum of applications of electrically conductive : asphalt compo...

  18. Induction Healing of Porous Asphalt Concrete

    NARCIS (Netherlands)

    Liu, Q.

    2012-01-01

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the

  19. Induction Healing of Porous Asphalt Concrete

    NARCIS (Netherlands)

    Schlangen, E.; Liu, Q.

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the

  20. Evaluation of recycled asphaltic concrete : final report.

    Science.gov (United States)

    1977-01-01

    This report describes a project in which approximately 6,200 tons (5,630 Mg) of asphaltic concrete were recycled through a conventional asphalt batch plant. During the construction of the project, a buildup of asphalt-coated fines occurred in the dry...

  1. [PAH exposure in asphalt workers].

    Science.gov (United States)

    Garattini, Siria; Sarnico, Michela; Benvenuti, Alessandra; Barbieri, P G

    2010-01-01

    There has been interest in evaluating the potential carcinogenicity of bitumen fumes in asphalt workers since the 1960's. The IARC classified air-refined bitumens as possible human carcinogens, while coal-tar fumes were classified as known carcinogens. Occupational/environmental PAH exposure can be measured by several urinary markers. Urinary 1-OHP has become the most commonly used biological marker of PAH exposure in asphalt workers. The aim of this study was to assess asphalt workers' exposure levels by monitoring 1-OHP urinary excretion and compare this data with those of non-occupationally exposed subjects. We investigated three groups of asphalt workers: 100 in summer 2007, 29 in winter 2007, and 148 during summer 2008 and compared 1-OHP urinary concentrations using Kruskall-Wallis test. Median 1-OHP urinary concentrations during the three biomonitoring sampling periods were 0.65, 0.17 and 0.53 microg/g creatinine respectively. There was a significant difference in 1-OHP values between the three groups (p < 0.001). our study showed that PAH exposure of asphalt workers' is higher than that observed in the general population and in workers in urban areas. Our results suggest that PAH exposure in the three groups studied is not sufficiently kept under control by the use of personal protective equipment and that biomonitoring is useful in evaluating PAH exposure and for risk assessment. Regulations need to be enforced for workers exposed to cancer risk, such as the register of workers exposed to carcinogens.

  2. 30 CFR 75.204 - Roof bolting.

    Science.gov (United States)

    2010-07-01

    ... accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the.... (4) In each roof bolting cycle, the actual torque or tension of the first tensioned roof bolt... during each roof bolting cycle shall be tested during or immediately after the first row of bolts has...

  3. Green roofs and rooftop gardens

    National Research Council Canada - National Science Library

    Hanson, Beth; Schmidt, Sarah

    2012-01-01

    .... The editors have included profiles of a wide range of green roofs in New York City, including a rooftop farm in Queens, a high school classroom in the Bronx, and Brooklyn Botanic Garden's Visitor Center...

  4. ENERGY STAR Certified Roof Products

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.3 ENERGY STAR Program Requirements for Roof Products that are effective as of July 1,...

  5. Asphalt Mixture for the First Asphalt Concrete Directly Fastened Track in Korea

    Directory of Open Access Journals (Sweden)

    Seong-Hyeok Lee

    2015-01-01

    Full Text Available The research has been initiated to develop the asphalt mixtures which are suitable for the surface of asphalt concrete directly fastened track (ADFT system and evaluate the performance of the asphalt mixture. Three aggregate gradations which are upper (finer, medium, and below (coarser. The nominal maximum aggregate size of asphalt mixture was 10 mm. Asphalt mixture design was conducted at 3 percent air voids using Marshall mix design method. To make impermeable asphalt mixture surface, the laboratory permeability test was conducted for asphalt mixtures of three different aggregate gradations using asphalt mixture permeability tester. Moisture susceptibility test was conducted based on AASHTO T 283. The stripping percentage of asphalt mixtures was measured using a digital camera and analyzed based on image analysis techniques. Based on the limited research results, the finer aggregate gradation is the most suitable for asphalt mixture for ADFT system with the high TSR value and the low stripping percentage and permeable coefficient. Flow number and beam fatigue tests for finer aggregate asphalt mixture were conducted to characterize the performance of asphalt mixtures containing two modified asphalt binders: STE-10 which is styrene-butadiene-styrene (SBS polymer and ARMA which is Crum rubber modified asphalt. The performance tests indicate that the STE-10 shows the higher rutting life and fatigue life.

  6. Hydrological Performance of Green Roofs

    OpenAIRE

    Poorova, Zuzana; Vranayova, Zuzana

    2015-01-01

    There should be a balance between artificial environment and natural environment. As forests, fields, gardens and urban lands are being replaced with bituminous, concrete and unnatural surfaces, necessity of recovering green and blue spaces and natural areas is becoming more and more critical. Green roof is a tool in strategy of making more pervious areas and beating more impervious areas. Green roof is lately becoming part of urban storm water management. Considering this fact, new construct...

  7. Prevalence of shingles and its association with PTSD among HIV-infected women in Rwanda.

    Science.gov (United States)

    Sinayobye, Jean d'Amour; Hoover, Donald R; Shi, Qiuhu; Mutimura, Eugene; Cohen, Hillel W; Anastos, Kathryn

    2015-03-06

    To examine the prevalence of reported shingles in the last 6 months and its association with post-traumatic stress disorder (PTSD), depression and severity of HIV disease in Rwandan women with HIV. This cross-sectional study was conducted as part of the Rwanda Women's Interassociation Study and Assessment (RWISA), an observational cohort study designed to assess the impact of HIV and residual factors from experiencing rape in the 1994 genocide in Rwandan women. Participants were recruited through grassroots women's associations of people living with HIV infection and clinical care sites for HIV infection. Most participants (58.5%, n=405/692) had PTSD. This cross-sectional analysis was conducted in 710 HIV-infected women enrolled in RWISA. Inclusion criteria were: age >15 years, informed consent, HIV test, ability to complete the interview in the local language, travel to and from the research site and participate in a baseline outpatient visit, and being naive to antiretroviral therapy at enrolment. The outcome of interest was self-reported shingles in the past 6 months. The exposure was PTSD defined using the cross-culturally validated Harvard Trauma Questionnaire. Overall prevalence of reported shingles in the past 6 months was 12.5% (n=89/710). There was an inverse relationship between shingles prevalence and immunological status: 7.6%, 12.3% and 16.7% of women with CD4 >350, 200-350 and <200 cells/µL, respectively, reported singles (p=0.01). In multivariate analysis, PTSD (aOR 1.7; 95% CI 1.02 to 2.89) and low CD4 (aOR 2.4; 95% CI 1.23 to 4.81) were independently associated with reported shingles in the past 6 months. Our study found a significant independent relationship between PTSD and reported shingles, suggesting that PTSD may be associated with immune compromise that can result in herpes zoster reactivation. Further study is needed. It also confirmed previous findings of a strong relationship between shingles and greater immunosuppression in

  8. Analysis of the dispersion of air pollutants from a factory Asphalt in Nuevo Vallarta, Nay., Mex

    Science.gov (United States)

    Carrillo-Gonzalez, F. M.; Gaitán-Rodríguez, M.; Cornejo-López, V. M.; Morales-Hernández, J. C.

    2013-12-01

    An asphalt factory has operated intermittently near the urban area of Nuevo Vallarta on Banderas Bay, Nayarit, Mex. This factory has emissions that can affect the health of people living in the colonies nearest are Valle Dorado and San Vicente. The dispersion of emissions depends on the wind (sea breeze-land breeze) and the roof of the inversion, these phenomena determined by the density and temperature of the lower layers of the atmosphere. Asphalts are dark colored binder materials, formed by a complex non-volatile hydrocarbon chains and high molecular weight. Asphalts are produced from petroleum, but by a process of evaporation of the volatiles, leaving the asphalt alone. Therefore, the material emitted by the fireplace are mainly low molecular weight hydrocarbons known as polycyclic aromatic hydrocarbons (PAHs). The Emergency Response Guide 2008 developed by various agencies in Canada, U.S. and Mexico mentions that the hydrocarbon gas can have health effects. Animal studies have shown that PAHs can cause harmful effects to the skin, body fluids and some PAHs are carcinogenic. An analysis of the wind field, monthly and seasonal averages for the years 2010 and 2011, recorded in AWS administered by the CEMCO and other stations located near the study area.

  9. Effect of using of reclaimed asphalt and/or lower temperature asphalt on the availability of the road network

    NARCIS (Netherlands)

    Nicholls, C.; Wayman, M.; Mollenhauer, K.; McNally, C.; Tabakovic, A.; Varveri, A.; Cassidy, S.; Shahmohammadi, R.; Taylor, R.

    2015-01-01

    The use of reclaimed asphalt, secondary component materials and/or additives and lower temperature asphalt are being increasingly used in order to improve the sustainability of asphalt production. The use of reclaimed asphalt reduces the need for virgin materials whilst lower temperature asphalts

  10. Development of test method for evaluating root resistance of pavement used for roof garden caused by thickening growth of root

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Saori; Tanaka, Kyoji [Tokyo Institute of Technology, Tokyo, (Japan)

    2010-07-01

    The growth of roots of plants can damage roof garden components, such as pavements. This paper developed a test method for evaluating the resistance of pavement used in roof gardens to damage from a thickening growth of roots. The study assessed the behaviour of plant roots and evaluated the force of root growth subjected to hypertrophy. A system to measure the enlargement force of roots was designed and used for measurements over a period of 8 months on a cherry blossom of 21 years growth. The enlargement force was approximately 440 N/cm. A mechanical simulated root was designed and used to carry out experimental tests on asphalt pavements. The tests results demonstrated the viability of simulated root for evaluation of root resistances in pavements and various components of roof gardens.

  11. Permanent deformation of asphalt mixes

    NARCIS (Netherlands)

    Molenaar, A.A.A.; Van de Ven, M.F.C.; Muraya, P.M.

    This dissertation describes the results of a research that was conducted on the permanent deformation of asphalt mixtures. Central to this research was the separate characterization of the contribution of the aggregate skeleton and the bituminous mortar towards resistance to permanent deformation.

  12. Permanent deformation of asphalt mixes

    NARCIS (Netherlands)

    Muraya, P.M.

    2007-01-01

    This dissertation describes the results of a research that was conducted on the permanent deformation of asphalt mixtures. Central to this research was the separate characterization of the contribution of the aggregate skeleton and the bituminous mortar towards resistance to permanent deformation.

  13. Design and evaluation of foamed asphalt base materials : [research summary].

    Science.gov (United States)

    2013-05-01

    Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), : recycled concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt : binder to produce a partially stabilized base material. Although widely used, most :...

  14. Best practices for full-depth reclamation using asphalt emulsions.

    Science.gov (United States)

    2015-07-01

    Full depth reclamation of asphalt pavements using asphalt emulsions (AEFDR) is a process that recycles and rejuvenates the existing : asphalt pavement surface, base, and, sometimes, the subgrade, providing an improved underlying structure for the new...

  15. Environmentally Friendly Cleaners for Removing Tar and Asphalt from Tactical and Transportation Vehicles

    Science.gov (United States)

    2011-05-01

    Asphalt: A brownish- black solid or semisolid mixture of bitumens obtained from native deposits or as a petroleum byproduct, used in paving, roofing...Elemental analysis of select bitumen (Holleran et al. 2005) Weight percent otherwise as mentioned* Element Mexican Arkansas Boscan (Venezuela...California Carbon (C) 83.77 85.78 82.9 86.77 Hydrogen H) 9.91 10.19 10.45 10.94 Nitrogen (N) 0.28 0.26 0.78 1.10 Sulfur (S) 5.25 3.41 5.43 0.99 Oxygen (O

  16. Mechanical characterization of porous asphalt mixes modi-fying the asphalt with fatty acid amides -FAA-

    Directory of Open Access Journals (Sweden)

    Vanessa Senior Arrieta

    2017-01-01

    Full Text Available Porous asphalt mixes (PAM, form a special road surface for asphalt pavement structures, have a special particle size distribution that lets infiltrate to the runoff storm water through of it because of its voids content about 20 %. Many researchers conducted studies and have concluded that the use of modified asphalts is completely necessary to design PAM. Organic and chemical additives and special procedures as foamed asphalt have enhanced the performance of PAM, during their service life. This paper is focused on the mechanical characterization of PAM and how the asphalt modified with fatty acid amides, influenced on their behavior and performance. Based on an experimental methodology with laboratory tests aimed at establishing a comparison between porous asphalt mixes, using for its design and production a penetration 60-70 pure asphalt and another one asphalt modified with fatty acid amides.

  17. Traditional ecological knowledge (TEK) at Shingle Point, YT: observations on changes in the environment and fish populations

    National Research Council Canada - National Science Library

    Brewster, J.D; Neumann, D; Ostertag, S.K; Loseto, L.L

    2016-01-01

    .... Shingle Point, YT is a traditional and modern day fishing and hunting community for Western Arctic indigenous people and is part of a marine protected area and the Inuvialuit Settlement Region (ISR...

  18. Risk of Shingles in Adults with Primary Sjogren's Syndrome and Treatments: A Nationwide Population-Based Cohort Study.

    Directory of Open Access Journals (Sweden)

    Jen-Yin Chen

    Full Text Available Primary Sjögren's syndrome (pSS is associated with immunological dysfunctions--a well-known risk factor of shingles. This study aimed to examine the incidence and risk of shingles in adults with pSS and pharmacological treatments.This retrospective population-based cohort study was conducted using National Health Insurance claims data. Using propensity scores, 4,287 pSS adult patients and 25,722-matched cohorts by age, gender, selected comorbidities and Charlson comorbidity index scores were identified. Kaplan-Meier analysis and Cox regression were conducted to compare the differences in developing shingles. In pSS, oral and eye dryness are treated with substitute agents. Extraglandular features are often treated with pharmacological drugs including steroids and immunosuppressants. pSS patients were grouped as follows: no pharmacological drugs, steroids alone; immunosuppressants alone; combined therapies.During the follow-up, 463 adults with pSS (10.80% and 1,345 control cohorts (5.23% developed shingles. The cumulative incidence of shingles in pSS patients (18.74/1,000 patient-years was significantly higher than controls (8.55/1,000 patient-years. The adjusted hazard ratio (HR of shingles was 1.69 (95% confidence interval (CI 1.50-1.90. In age-subgroup analyses, incidences of shingles in pSS increased with age and peaked in pSS patients aged ≧60; however, adjusted HRs decreased with age. Compared to control cohorts with no drugs, adjusted HRs for shingles in pSS patients were ranked from high to low as: combined therapies (4.14; 95% CI 3.14-5.45 > immunosuppressants alone (3.24; 95% CI 2.36-4.45 > steroids alone (2.54; 95% CI 2.16-2.97 > no pharmacological drugs (2.06; 95% CI 1.76-2.41. Rates of shingles-associated hospitalization and postherpetic neuralgia were 5.62% and 24.41%, both of which were significantly higher than those (2.60%; 13.01% in the control cohorts.Adults with pSS were at greater risk for shingles than control cohorts

  19. Advanced Energy Efficient Roof System

    Energy Technology Data Exchange (ETDEWEB)

    Jane Davidson

    2008-09-30

    Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The

  20. Mechanical Properties of Warm Mix Asphalt Prepared Using Foamed Asphalt Binders

    Science.gov (United States)

    2011-03-01

    Warm mix asphalt (WMA) is a name given to a group of technologies that have the common purpose of reducing the viscosity : of the asphalt binders. This reduction in viscosity offers the advantage of producing asphalt-aggregate mixtures at lower mixin...

  1. Operational properties of nanomodified stone mastic asphalt

    OpenAIRE

    Inozemtsev Sergey Sergeevich; Korolev Evgeniy Valer’evich

    2015-01-01

    In order to prolong the lifetime and to improve the quality of pavements made of asphalt concrete it is necessary to apply innovative solutions in the process of design of such building materials. In order to solve the problem of low durability of asphalt concrete a modifier was proposed, which consists of diatomite, iron hydroxide sol (III) and silica sol. Application of the diatomite with nanoscale layer of nanomodifier allows getting a stone mastic asphalt, which has high values of physica...

  2. Development of a Long-Life-Cycle, Highly Water-Resistant Solar Reflective Retrofit Roof Coating

    Energy Technology Data Exchange (ETDEWEB)

    Polyzos, Georgios [ORNL; Hunter, Scott Robert [ORNL; Sharma, Jaswinder K [ORNL; Cheng, Mengdawn [ORNL; Chen, Sharon S [Lawrence Berkeley National Laboratory (LBNL); Demarest, Victoria [Dow Chemical Company; Fabiny, William [Dow Chemical Company; Destaillats, Hugo [Lawrence Berkeley National Laboratory (LBNL); Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

    2016-03-04

    Highly water-resistant and solar-reflective coatings for low-slope roofs are potentially among the most economical retrofit approaches to thermal management of the building envelope. Therefore, they represent a key building technology research program within the Department of Energy. Research efforts in industry and the Department of Energy are currently under way to increase long-term solar reflectance on a number of fronts. These include new polymer coatings technologies to provide longer-lasting solar reflectivity and improved test methodologies to predict long-term soiling and microbial performance. The focus on long-term improvements in soiling and microbial resistance for maximum reflectance does not address the single most important factor impacting the long-term sustainability of low-slope roof coatings: excellent water resistance. The hydrophobic character of asphaltic roof products makes them uniquely suitable for water resistance, but their low albedo and poor exterior durability are disadvantages. A reflective coating that maintains very high water resistance with increased long-term resistance to soiling and microbial activity would provide additional energy savings and extend roof service life.

  3. Performance Characteristics of Silane Silica Modified Asphalt

    Directory of Open Access Journals (Sweden)

    Xuedong Guo

    2016-01-01

    Full Text Available At present there are many kinds of fillers and modifier used for modified asphalt, but the effect of modifier differs in thousands of ways; most of them can increase the high temperature performance of asphalt, but the modified effect of low-temperature crack resistance, water stability, and antifatigue performance is different. Aiming at the subsistent problems, this paper innovatively puts forward the idea of taking the silane silica (nanosilica modified with silane coupling agent as filler to develop one kind of modified asphalt concrete which has excellent comprehensive performance based on the idea of enhance the whole performance of asphalt concrete and interface consolidation strength between aggregate and asphalt at the same time. The best mixing amount of silane silica and the production process of modified asphalt were conducted by contrasting the test date as penetration, viscosity, and softening point; the aging of asphalt and modified asphalt was analyzed by TG test, the superiority of silane silica modified asphalt is more clearly understandable by chemical analysis results. Meanwhile it is proved that silane silica has positive effect to improve the mixture of high and low temperature performance, water stability, and aging resistance through a series of road performance tests.

  4. Aging of Rejuvenated Asphalt Binders

    Directory of Open Access Journals (Sweden)

    Mojtaba Mohammadafzali

    2017-01-01

    Full Text Available An important concern that limits the RAP content in asphalt mixtures is the fact that the aged binder that is present in the RAP can cause premature cracking. Rejuvenators are frequently added to high RAP mixtures to enhance the properties of the binder. There is no existing method to predict the longevity of a rejuvenated asphalt. This study investigated the aging of rejuvenated binders and compared their durability with that of virgin asphalt. Various samples with different types and proportions of RAP, virgin binder, and rejuvenator were aged by RTFO and three cycles of PAV. DSR and BBR tests were conducted to examine the high-temperature and low-temperature rheological properties of binders. Results indicated that the type and dosage of the rejuvenator have a great influence on the aging rate and durability of the binder. Some rejuvenators make the binder age slower, while others accelerate aging. These observations confirm the importance of evaluating the long-term aging of recycled binders. For this purpose, critical PAV time was proposed as a measure of binder’s longevity.

  5. Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2005-10-01

    Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on this information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. For the prediction of roof geology and stability condition in real time, a micro processor was used and a program developed to monitor and record the drilling parameters of roof bolter. These parameters include feed pressure, feed flow (penetration rate), rotation pressure, rotation rate, vacuum pressure, oil temperature of hydraulic circuit, and signals for controlling machine. From the results of a series of laboratory and underground tests so far, feed pressure is found to be a good indicator for identifying the voids/fractures and estimating the roof rock strength. The method for determining quantitatively the location and the size of void/fracture and estimating the roof rock strength from the drilling parameters of roof bolter was developed. Also, a set of computational rules has been developed for in-mine roof using measured roof drilling parameters and implemented in MRGIS (Mine Roof Geology Information System), a software package developed to allow mine engineers to make use of the large amount of roof drilling parameters for predicting roof geology properties automatically. For the development of roof bolting criteria, finite element models were developed for tensioned and fully grouted bolting

  6. Sustainable asphalt pavement: Application of slaughterhouse waste oil and fly ash in asphalt binder

    Science.gov (United States)

    Sanchez Ramos, Jorge Luis

    Increasing energy costs, lack of sufficient natural resources and the overwhelming demand for petroleum has stimulated the development of alternative binders to modify or replace petroleum-based asphalt binders. In the United States, the petroleum-based asphalt binder is mainly used to produce the Hot Mix Asphalt (HMA). There are approximately 4000 asphalt plants that make 500 million tons of asphalt binder valued at roughly 3 billion/year. The instability of the world's oil market has pushed oil prices to more than 80 per barrel in 2012, which increased the cost of asphalt binder up to $570 per ton. Therefore, there is a timely need to find alternative sustainable resources to the asphalt binder. This paper investigates the possibility of the partial replacement of the asphalt binder with slaughterhouse waste and/or fly ash. In order to achieve this objective, the asphalt binder is mixed with different percentages of waste oil and/or fly ash. In order to investigate the effect of these additives to the performance of the asphalt binder, a complete performance grade test performed on multiple samples. The results of the performance grade tests are compared with a control sample to observe how the addition of the waste oil and/or fly ash affects the sample. Considering the increasing cost and demand of asphalt, the use of slaughterhouse waste oil and/or fly ash as a partial replacement may result in environmental and monetary improvements in the transportation sector.

  7. PREDICTING THERMAL PERFORMANCE OF ROOFING SYSTEMS IN SURABAYA

    Directory of Open Access Journals (Sweden)

    MINTOROGO Danny Santoso

    2015-07-01

    Full Text Available Traditional roofing systems in the developing country likes Indonesia are still be dominated by the 30o, 45o, and more pitched angle roofs; the roofing cover materials are widely used to traditional clay roof tiles, then modern concrete roof tiles, and ceramic roof tiles. In the 90’s decay, shop houses are prosperous built with flat concrete roofs dominant. Green roofs and roof ponds are almost rarely built to meet the sustainable environmental issues. Some tested various roof systems in Surabaya were carried out to observe the roof thermal performances. Mathematical equation model from three references are also performed in order to compare with the real project tested. Calculated with equation (Kabre et al., the 30o pitched concrete-roof-tile, 30o clay-roof-tile, 45o pitched concrete-roof-tile are the worst thermal heat flux coming to room respectively. In contrast, the bare soil concrete roof and roof pond system are the least heat flux streamed onto room. Based on predicted calculation without insulation and cross-ventilation attic space, the roof pond and bare soil concrete roof (greenery roof are the appropriate roof systems for the Surabaya’s climate; meanwhile the most un-recommended roof is pitched 30o or 45o angle with concrete-roof tiles roofing systems.

  8. Generating realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2011-01-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs, and show a connection with the straight skeleton of P. We show that the maximum possible number of distinct realistic roofs over P is ( ⌊(n-4)/4⌋ (n-4)/2) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n 4) preprocessing time. We also present an O(n 5)-time algorithm for computing a realistic roof with minimum height or volume. © 2011 Springer-Verlag.

  9. Pelletized Asphalt for Airfield Damage Repair

    Science.gov (United States)

    2009-08-01

    14, 2008. Gulf Asphalt Contractor (GAC), Panama City, FL, provided all labor , material (with the exception of pelletized asphalt) and equipment for...produced. Benefits include: reduced transportation, traffic disruption, operating costs, and labor costs, while increased productivity and... Mercado , E. A., A. Epps Martin, E. S. Park, C. Spiegelman, and C. J. Glover, “Factors Affecting Binder Properties between Production and Construction

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

    African Journals Online (AJOL)

    Assessment of asphalt concrete used for pavement construction in southwest Nigeria was carried out to determine the causes of untimely failure of newly constructed/rehabilitated asphalt roads. Samples of asphalt concrete and bitumen were collected from three asphalt plants selected for the study. Samples from each plant ...

  11. Effect of Cement on Emulsified Asphalt Mixtures

    Science.gov (United States)

    Oruc, Seref; Celik, Fazil; Akpinar, M. Vefa

    2007-10-01

    Emulsified asphalt mixtures have environmental, economical, and logistical advantages over hot mixtures. However, they have attracted little attention as structural layers due to their inadequate performance and susceptibility to early life damage by rainfall. The objective of this article is to provide an improved insight into how the mechanical properties of emulsion mixtures may be improved and to determine the influence of cement on emulsified asphalt mixtures. Laboratory tests on strength, temperature susceptibility, water damage, creep and permanent deformation were implemented to evaluate the mechanical properties of emulsified asphalt mixtures. The test results showed that mechanical properties of emulsified asphalt mixtures have significantly improved with Portland cement addition. This experimental study suggested that cement modified asphalt emulsion mixtures might be an alternate way of a structural layer material in pavement.

  12. ASSESSMENT OF THE PROPERTIES OF ASPHALT MODIFIED WITH USED TIRES

    Directory of Open Access Journals (Sweden)

    Olufikayo Aderinlewo

    2017-04-01

    Full Text Available This study investigates the properties of asphalt mix modified with ground tire. The ground tire was introduced into the asphalt in a melted form at varying percentages of 2%, 4%, 6%, 8% and 10% by weight of the asphalt. The properties of the asphalt mixed with the ground tire were then obtained through penetration, softening point, flash and fire point and ductility tests. These properties were then compared with those of the control asphalt to determine the effectiveness of the ground tire in improving the asphalt properties. The results showed that the ground tire additive improved the asphalt properties considerably.

  13. Estimating exposures in the asphalt industry for an international epidemiological cohort study of cancer risk.

    Science.gov (United States)

    Burstyn, Igor; Boffetta, Paolo; Kauppinen, Timo; Heikkilä, Pirjo; Svane, Ole; Partanen, Timo; Stücker, Isabelle; Frentzel-Beyme, Rainer; Ahrens, Wolfgang; Merzenich, Hiltrud; Heederik, Dick; Hooiveld, Mariëtte; Langård, Sverre; Randem, Britt G; Järvholm, Bengt; Bergdahl, Ingvar; Shaham, Judith; Ribak, Joseph; Kromhout, Hans

    2003-01-01

    An exposure matrix (EM) for known and suspected carcinogens was required for a multicenter international cohort study of cancer risk and bitumen among asphalt workers. Production characteristics in companies enrolled in the study were ascertained through use of a company questionnaire (CQ). Exposures to coal tar, bitumen fume, organic vapor, polycyclic aromatic hydrocarbons, diesel fume, silica, and asbestos were assessed semi-quantitatively using information from CQs, expert judgment, and statistical models. Exposures of road paving workers to bitumen fume, organic vapor, and benzo(a)pyrene were estimated quantitatively by applying regression models, based on monitoring data, to exposure scenarios identified by the CQs. Exposures estimates were derived for 217 companies enrolled in the cohort, plus the Swedish asphalt paving industry in general. Most companies were engaged in road paving and asphalt mixing, but some also participated in general construction and roofing. Coal tar use was most common in Denmark and The Netherlands, but the practice is now obsolete. Quantitative estimates of exposure to bitumen fume, organic vapor, and benzo(a)pyrene for pavers, and semi-quantitative estimates of exposure to these agents among all subjects were strongly correlated. Semi-quantitative estimates of exposure to bitumen fume and coal tar exposures were only moderately correlated. EM assessed non-monotonic historical decrease in exposures to all agents assessed except silica and diesel exhaust. We produced a data-driven EM using methodology that can be adapted for other multicenter studies. Copyright 2003 Wiley-Liss, Inc.

  14. Solar thermal roofs; Zonthermische daken

    Energy Technology Data Exchange (ETDEWEB)

    Van de Waerdt, J. [DWA installatie- en energieadvies, Bodegraven (Netherlands)

    2012-11-15

    The purpose of the brochure is to increase the effective application of solar thermal roofs. The target group includes consultants, installers, architects and contractors. Attention is paid to the design, parameters for comparison, yield simulations and experiences gained in projects [Dutch] Het doel van de brochure is het vergroten van de effectieve toepassing van zonthermische daken. Tot de doelgroep behoren installatieadviseurs, installateurs, architecten en opdrachtgevers in de bouw. Aandacht wordt besteed aan het ontwerp, parameters voor vergelijking, opbrengstsimulaties en ervaringen opgedaan in projecten.

  15. Million Solar Roofs Flyer (Revision)

    Energy Technology Data Exchange (ETDEWEB)

    2000-11-01

    The Million Solar Roofs Initiative, announced in June 1997, assists businesses and communities in installing solar energy systems on one million buildings across the United States by 2010. The US Department of Energy leads this trailblazing initiative by partnering with the building industry, local governments, state agencies, the solar industry, electric service providers, and non-governmental organizations to remove barriers and strengthen the demand for solar technologies.

  16. Factors Influencing Arthropod Diversity on Green Roofs

    Directory of Open Access Journals (Sweden)

    Bracha Y. Schindler

    2011-01-01

    Full Text Available Green roofs have potential for providing substantial habitat to plants, birds, and arthropod species that are not well supported by other urban habitats. Whereas the plants on a typical green roof are chosen and planted by people, the arthropods that colonize it can serve as an indicator of the ability of this novel habitat to support a diverse community of organisms. The goal of this observational study was to determine which physical characteristics of a roof or characteristics of its vegetation correlate with arthropod diversity on the roof. We intensively sampled the number of insect families on one roof with pitfall traps and also measured the soil arthropod species richness on six green roofs in the Boston, MA area. We found that the number of arthropod species in soil, and arthropod families in pitfall traps, was positively correlated with living vegetation cover. The number of arthropod species was not significantly correlated with plant diversity, green roof size, distance from the ground, or distance to the nearest vegetated habitat from the roof. Our results suggest that vegetation cover may be more important than vegetation diversity for roof arthropod diversity, at least for the first few years after establishment. Additionally, we found that even green roofs that are small and isolated can support a community of arthropods that include important functional groups of the soil food web.

  17. Polyurethane adhesives in flat roofs

    Directory of Open Access Journals (Sweden)

    Bogárová Markéta

    2017-01-01

    Full Text Available It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is to calculate the exact amount of adhesive, which is required to guarantee the resistance against wind suction. In this problematic we can not find help neither in technical data sheets provided by the manufactures. Some of these data sheets contain at least information about amount of adhesive depending on location in roof plane and building height, but they do not specify the strength of such connection. It was therefore resorted to select several representatives polyurethane adhesives and their subsequent testing on specimens simulating the flat roof segment. The paper described the test methodology and results for two types of polyurethane adhesives.

  18. Demonstration of energy savings of cool roofs

    Energy Technology Data Exchange (ETDEWEB)

    Konopacki, S.; Gartland, L.; Akbari, H. [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Rainer, L. [Davis Energy Group, Davis, CA (United States)

    1998-06-01

    Dark roofs raise the summertime air-conditioning demand of buildings. For highly-absorptive roofs, the difference between the surface and ambient air temperatures can be as high as 90 F, while for highly-reflective roofs with similar insulative properties, the difference is only about 20 F. For this reason, cool roofs are effective in reducing cooling energy use. Several experiments on individual residential buildings in California and Florida show that coating roofs white reduces summertime average daily air-conditioning electricity use from 2--63%. This demonstration project was carried out to address some of the practical issues regarding the implementation of reflective roofs in a few commercial buildings. The authors monitored air-conditioning electricity use, roof surface temperature, plenum, indoor, and outdoor air temperatures, and other environmental variables in three buildings in California: two medical office buildings in Gilroy and Davis and a retail store in San Jose. Coating the roofs of these buildings with a reflective coating increased the roof albedo from an average of 0.20--0.60. The roof surface temperature on hot sunny summer afternoons fell from 175 F--120 F after the coating was applied. Summertime average daily air-conditioning electricity use was reduced by 18% (6.3 kWh/1000ft{sup 2}) in the Davis building, 13% (3.6 kWh/1000ft{sup 2}) in the Gilroy building, and 2% (0.4 kWh/1000ft{sup 2}) in the San Jose store. In each building, a kiosk was installed to display information from the project in order to educate and inform the general public about the environmental and energy-saving benefits of cool roofs. They were designed to explain cool-roof coating theory and to display real-time measurements of weather conditions, roof surface temperature, and air-conditioning electricity use. 55 figs., 15 tabs.

  19. About Coloured Cold Asphaltic Mixtures

    Directory of Open Access Journals (Sweden)

    Loredana Judele

    2008-01-01

    Full Text Available The first coloured bitumen was obtained by using bitumen from Peru and then bitumen from the Middle East, with a low content of asphaltenes, also called "colourable" bitumens. The colours obtained by adding iron oxides led nevertheless to dark colours, due to the presence of asphaltenes. Nowadays the coloured asphalt is obtained from synthesis binders with translucent aspect. The colours are obtained by adding inorganic pigments, mainly iron oxide for red, chromic oxide for green, titanic dioxide for white. The properties and behaviour of the coloured bitumen during its lifetime are comparable with the ones of classic bitumen, sometimes even better.

  20. Characteristics of Ceramic Fiber Modified Asphalt Mortar.

    Science.gov (United States)

    Wan, Jiuming; Wu, Shaopeng; Xiao, Yue; Liu, Quantao; Schlangen, Erik

    2016-09-21

    Ceramic fiber, with a major composition of Al₂O₃ and SiO₂, has advantages of stability at relatively high temperature, big specific surface area and resistance to external mechanical vibration. It has the potential contribution of improving the rutting resistance and temperature sensitivity of modified asphalt binder by proper modification design. In this research, ceramic fiber was introduced into both pen 60/80 and pen 80/100 asphalt binder by different weight ratios. An asphalt penetration test, softening point test, ductility test and dynamic viscoelastic behavior were conducted to characterize and predict the ceramic fiber modified asphalt mortar (CFAM). Research results indicated that the ceramic fiber has a great effect on reinforcement of asphalt, which makes the asphalt stiffer so that the asphalt can only undertake less strain under the same stress. The heat insulation effect of the ceramic fiber will improve the temperature stability. Complex modulus and phase angle results indicate that the ceramic fiber can significantly enhance the high temperature resistance of soft binder.

  1. Electrical and mechanical properties of asphalt concrete containing conductive fibers and fillers

    NARCIS (Netherlands)

    Wang, H.; Yang, Jun; Liao, Hui; Chen, Xianhua

    2016-01-01

    Electrically conductive asphalt concrete has the potential to satisfy multifunctional applications. Designing such asphalt concrete needs to balance the electrical and mechanical performance of asphalt concrete. The objective of this study is to design electrically conductive asphalt concrete

  2. National Economic Development Procedures Manual - Urban Flood Damage. Volume 2: Primer for Surveying Flood Damage for Residential Structures and Contents

    Science.gov (United States)

    1991-10-01

    92 7 0 R8-1 October 1991 IWR Report 91-R-10 REPORT DOCUMENTATION PAGE Sur veinaFoo I. AwUNOOR(S) Wilam3 ane n_____________ punk , f O re aw o t oallon...Brick 3 Stucco 6 Masonry Veneer 9 Stone COlo Roofing 1 Composition Shingle 4 Wood Shake 7 Galvanized Metal 10 Plastic Tile 2 Built-up Rock 5 Concrete Tile...ONE NUMBER) I. COMPOSITION SHINGLE 6. CLAY TILE 2. BUILT-UP ROCK 7. GALVANIZED METAL (EMBEDDED IN ASPHALT) 8. SLATE 3. WOOD SHINGLE 9. COMPOSITION

  3. Realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2013-11-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces isolated from the boundary of P or even local minima, which are undesirable for several practical reasons. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs and show that the straight skeleton induces a realistic roof with maximum height and volume. We also show that the maximum possible number of distinct realistic roofs over P is ((n-4)(n-4)/4 /2⌋) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n4) preprocessing time. We also present an O(n5)-time algorithm for computing a realistic roof with minimum height or volume. © 2013 Elsevier B.V.

  4. Green roofs provide habitat for urban bats

    Directory of Open Access Journals (Sweden)

    K.L. Parkins

    2015-07-01

    Full Text Available Understanding bat use of human-altered habitat is critical for developing effective conservation plans for this ecologically important taxon. Green roofs, building rooftops covered in growing medium and vegetation, are increasingly important conservation tools that make use of underutilized space to provide breeding and foraging grounds for urban wildlife. Green roofs are especially important in highly urbanized areas such as New York City (NYC, which has more rooftops (34% than green space (13%. To date, no studies have examined the extent to which North American bats utilize urban green roofs. To investigate the role of green roofs in supporting urban bats, we monitored bat activity using ultrasonic recorders on four green and four conventional roofs located in highly developed areas of NYC, which were paired to control for location, height, and local variability in surrounding habitat and species diversity. We then identified bat vocalizations on these recordings to the species level. We documented the presence of five of nine possible bat species over both roof types: Lasiurus borealis, L. cinereus, L. noctivagans, P. subflavus,andE. fuscus. Of the bat calls that could be identified to the species level, 66% were from L. borealis. Overall levels of bat activity were higher over green roofs than over conventional roofs. This study provides evidence that, in addition to well documented ecosystem benefits, urban green roofs contribute to urban habitat availability for several North American bat species.

  5. RELATIONSHIP BETWEEN FOAMING BEHAVIOR AND SURFACE ENERGY OF ASPHALT BINDER

    Directory of Open Access Journals (Sweden)

    Jian-ping Xu

    2017-12-01

    Full Text Available To solve the problem of insufficiency in microscopic performance of foamed asphalt binder, surface energy theory was utilized to analyze the foaming behavior and wettability of asphalt binder. Based on the surface energy theory, the Wilhelmy plate method and universal sorption device method were employed to measure the surface energy components of asphalt binders and aggregates, respectively. Combined with the traditional evaluation indictor for foamed asphalt, the relationship between the foaming property and surface energy of asphalt binder was analyzed. According to the surface energy components, the wettability of asphalt binder to aggregate was calculated to verify the performance of foamed asphalt mixture. Results indicate that the foaming behavior of asphalt will be influenced by surface energy, which will increase with the decline of surface energy. In addition, the surface energy of asphalt binder significantly influences the wettability of asphalt binder to aggregates. Meanwhile, there is an inversely proportional relationship between surface energy of asphalt binder and wettability. Therefore, it can be demonstrated that surface energy is a good indictor which can be used to evaluate the foaming behavior of the asphalt binder. And it is suggested to choose the asphalt binder with lower surface energy in the process of design of foamed asphalt mixture.

  6. Shingles Immunity and Health Functioning in the Elderly: Tai Chi Chih as a Behavioral Treatment

    Directory of Open Access Journals (Sweden)

    Michael Irwin

    2004-01-01

    Full Text Available Both the incidence and severity of herpes zoster (HZ or shingles increase markedly with increasing age in association with a decline in varicella zoster virus (VZV-specific immunity. Considerable evidence shows that behavioral stressors, prevalent in older adults, correlate with impairments of cellular immunity. Moreover, the presence of depressive symptoms in older adults is associated with declines in VZV-responder cell frequency (VZV-RCF, an immunological marker of shingles risk. In this review, we discuss recent findings that administration of a relaxation response-based intervention, tai chi chih (TCC, results in improvements in health functioning and immunity to VZV in older adults as compared with a control group. TCC is a slow moving meditation consisting of 20 separate standardized movements which can be readily used in elderly and medically compromised individuals. TCC offers standardized training and practice schedules, lending an important advantage over prior relaxation response-based therapies. Focus on older adults at increased risk for HZ and assay of VZV-specific immunity have implications for understanding the impact of behavioral factors and a behavioral intervention on a clinically relevant end-point and on the response of the immune system to infectious pathogens.

  7. Quantitative characterization of microstructure of asphalt mixtures

    Science.gov (United States)

    2010-10-01

    The microstructure of the fine aggregate matrix has a significant influence on the : mechanical properties and evolution of damage in an asphalt mixture. However, very little : work has been done to define and quantitatively characterize the microstr...

  8. Preventive maintenance of asphalt concrete pavements

    Science.gov (United States)

    1988-01-01

    Preventive maintenance of asphalt concrete can often extend the pavement life for a number of years at relatively low costs. The types of preventive maintenance that are discussed in this report include rejuvenators, slurry seals, surface treatments,...

  9. Properties of sulfur-extended asphalt concrete

    Directory of Open Access Journals (Sweden)

    Gladkikh Vitaliy

    2016-01-01

    Full Text Available Currently, increased functional reliability of asphalt concrete coatings associated with various modifying additives that improve the durability of pavements. Promising builder is a technical sulfur. Asphalt concrete, made using a complex binder consisting of petroleum bitumen and technical sulfur, were calledsSulfur-Extended Asphalt Concrete. Such asphalt concrete, due to changes in the chemical composition of particulate and bitumen, changes the intensity of the interaction at the interface have increased rates of physical and mechanical properties. There was a lack of essential knowledge concerning mechanical properties of the sulfur-bituminous concrete with such an admixture; therefore, we had carried out the necessary examination. It is revealed that a new material satisfies local regulations in terms of compressive and tensile strength, shear resistance, and internal friction.

  10. Linking asphalt binder fatigue to asphalt mixture fatigue performance using viscoelastic continuum damage modeling

    Science.gov (United States)

    Safaei, Farinaz; Castorena, Cassie; Kim, Y. Richard

    2016-08-01

    Fatigue cracking is a major form of distress in asphalt pavements. Asphalt binder is the weakest asphalt concrete constituent and, thus, plays a critical role in determining the fatigue resistance of pavements. Therefore, the ability to characterize and model the inherent fatigue performance of an asphalt binder is a necessary first step to design mixtures and pavements that are not susceptible to premature fatigue failure. The simplified viscoelastic continuum damage (S-VECD) model has been used successfully by researchers to predict the damage evolution in asphalt mixtures for various traffic and climatic conditions using limited uniaxial test data. In this study, the S-VECD model, developed for asphalt mixtures, is adapted for asphalt binders tested under cyclic torsion in a dynamic shear rheometer. Derivation of the model framework is presented. The model is verified by producing damage characteristic curves that are both temperature- and loading history-independent based on time sweep tests, given that the effects of plasticity and adhesion loss on the material behavior are minimal. The applicability of the S-VECD model to the accelerated loading that is inherent of the linear amplitude sweep test is demonstrated, which reveals reasonable performance predictions, but with some loss in accuracy compared to time sweep tests due to the confounding effects of nonlinearity imposed by the high strain amplitudes included in the test. The asphalt binder S-VECD model is validated through comparisons to asphalt mixture S-VECD model results derived from cyclic direct tension tests and Accelerated Loading Facility performance tests. The results demonstrate good agreement between the asphalt binder and mixture test results and pavement performance, indicating that the developed model framework is able to capture the asphalt binder's contribution to mixture fatigue and pavement fatigue cracking performance.

  11. Finite element simulation of asphalt fatigue testing

    DEFF Research Database (Denmark)

    Ullidtz, Per; Kieler, Thomas Lau; Kargo, Anders

    1997-01-01

    The traditional interpretation of fatigue tests on asphalt mixes has been in terms of a logarithmic linear relationship between the constant stress or strain amplitude and the number of load repetitions to cause failure, often defined as a decrease in modulus to half the initial value. To accomod...... tests are that the extrapolation from laboratory tests to insitu conditions is facilitated and that the gradual deterioration of the asphalt may be predicted, which is useful for pavement management purposes....

  12. Observation of asphalt binder microstructure with ESEM.

    Science.gov (United States)

    Mikhailenko, P; Kadhim, H; Baaj, H; Tighe, S

    2017-09-01

    The observation of asphalt binder with the environmental scanning electron microscope (ESEM) has shown the potential to observe asphalt binder microstructure and its evolution with binder aging. A procedure for the induction and identification of the microstructure in asphalt binder was established in this study and included sample preparation and observation parameters. A suitable heat-sampling asphalt binder sample preparation method was determined for the test and several stainless steel and Teflon sample moulds developed, finding that stainless steel was the preferable material. The magnification and ESEM settings conducive to observing the 3D microstructure were determined through a number of observations to be 1000×, although other magnifications could be considered. Both straight run binder (PG 58-28) and an air blown oxidised binder were analysed; their structures being compared for their relative size, abundance and other characteristics, showing a clear evolution in the fibril microstructure. The microstructure took longer to appear for the oxidised binder. It was confirmed that the fibril microstructure corresponded to actual characteristics in the asphalt binder. Additionally, a 'bee' micelle structure was found as a transitional structure in ESEM observation. The test methods in this study will be used for more comprehensive analysis of asphalt binder microstructure. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  13. Operational properties of nanomodified stone mastic asphalt

    Directory of Open Access Journals (Sweden)

    Inozemtsev Sergey Sergeevich

    2015-03-01

    Full Text Available In order to prolong the lifetime and to improve the quality of pavements made of asphalt concrete it is necessary to apply innovative solutions in the process of design of such building materials. In order to solve the problem of low durability of asphalt concrete a modifier was proposed, which consists of diatomite, iron hydroxide sol (III and silica sol. Application of the diatomite with nanoscale layer of nanomodifier allows getting a stone mastic asphalt, which has high values of physical and mechanical properties and allows refusing from expensive stabilizing additive. Mineral filler was replaced by diatomite, which has been modified by iron hydroxide sol (III and silica sol. Modified diatomite allows sorption of bitumen and increase the cohesive strength and resistance to shear at positive temperatures. The modified asphalt has higher resistance to rutting at high temperature, abrasion resistance at low temperature and impact of climatic factors: alternate freezing and thawing, wetting-drying, UV and IR radiations. It is achieved by formation of solid and dense bitumen film at the phase interface and controlling the content of light fractions of the bitumen. The modifier consists of sol of iron hydroxide, which blocks the oxidation and polymerization of bitumen during operation. The proposed material allows controlling the initial structure formation of stone mastic asphalt. It was shown that modern test methods allow assessing the durability of asphalt in the design phase compositions.

  14. Integrated roof wind energy system

    Directory of Open Access Journals (Sweden)

    Moonen S.P.G.

    2012-10-01

    Full Text Available Wind is an attractive renewable source of energy. Recent innovations in research and design have reduced to a few alternatives with limited impact on residential construction. Cost effective solutions have been found at larger scale, but storage and delivery of energy to the actual location it is used, remain a critical issue. The Integrated Roof Wind Energy System is designed to overcome the current issues of urban and larger scale renewable energy system. The system is built up by an axial array of skewed shaped funnels that make use of the Venturi Effect to accelerate the wind flow. This inventive use of shape and geometry leads to a converging air capturing inlet to create high wind mass flow and velocity toward a vertical-axis wind turbine in the top of the roof for generation of a relatively high amount of energy. The methods used in this overview of studies include an array of tools from analytical modelling, PIV wind tunnel testing, and CFD simulation studies. The results define the main design parameters for an efficient system, and show the potential for the generation of high amounts of renewable energy with a novel and effective system suited for the built environment.

  15. Integrated roof wind energy system

    Science.gov (United States)

    Suma, A. B.; Ferraro, R. M.; Dano, B.; Moonen, S. P. G.

    2012-10-01

    Wind is an attractive renewable source of energy. Recent innovations in research and design have reduced to a few alternatives with limited impact on residential construction. Cost effective solutions have been found at larger scale, but storage and delivery of energy to the actual location it is used, remain a critical issue. The Integrated Roof Wind Energy System is designed to overcome the current issues of urban and larger scale renewable energy system. The system is built up by an axial array of skewed shaped funnels that make use of the Venturi Effect to accelerate the wind flow. This inventive use of shape and geometry leads to a converging air capturing inlet to create high wind mass flow and velocity toward a vertical-axis wind turbine in the top of the roof for generation of a relatively high amount of energy. The methods used in this overview of studies include an array of tools from analytical modelling, PIV wind tunnel testing, and CFD simulation studies. The results define the main design parameters for an efficient system, and show the potential for the generation of high amounts of renewable energy with a novel and effective system suited for the built environment.

  16. Asphalt wear and pollution transport

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, Asa [Division of Traffic Engineering, Lulea University of Technology Lulea (Sweden)

    1996-09-06

    Studded tires cause extensive wear of road surfaces during winter producing small particles. Besides transporting different adsorbed pollutants these particles also discharge metal ions by their own natural content. The major part (95%) of the asphalt is composed of stone fractions. The rest consists mainly of bitumen, which contains trace quantities of metals. Laboratory studies in this study have demonstrated different adsorbing properties of metal ions, as well as differences in adsorption when comparing stone materials. Two stone materials, a gabbro and a porphyry, have been tested for their adsorption properties concerning Pb, Cu, Zn and Cd. The gabbro showed better adsorption capacity than the porphyry. Gabbro has coarser grains, it is softer, and also has a higher content of most metals compared to the porphyry. In all tests lead and copper are more adsorbed than zinc and cadmium. All metal ions are released at about the same pH ({approx}4)

  17. Improving the durability of flat roof constructions

    DEFF Research Database (Denmark)

    Rudbeck, Claus Christian; Svendsen, Sv Aa Højgaard

    1999-01-01

    as there is no easy method of drying it. To be able to dry the insulation, and thereby regain the functional requirements of the roofing system, two new solutions for insulating flat roofs with existing materials are proposed for high density mineral wool and expanded polystyrene. Monitoring equipment are part...

  18. Do green roofs cool the air?

    NARCIS (Netherlands)

    Solcerova, A.; van de Ven, F.H.M.; Wang, Mengyu; Rijsdijk, Michiel; van de Giesen, N.C.

    2017-01-01

    Rapid urbanization and an increasing number and duration of heat waves poses a need to mitigate extremely high temperatures. One of the repeatedly suggested measures to moderate the so called urban heat island are green roofs. This study investigates several extensive sedum-covered green roofs in

  19. Wind loads on solar energy roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bentum, C.A. van

    2007-01-01

    This paper presents an overview of the wind loads on roofs, equipped with solar energy products, so called Active Roofs. Values given in this paper have been based on wind tunnel and full scale measurements, carried out at TNO, and on an interpretation of existing rules and guidelines. The results

  20. Fatigue and rutting performance of conventional asphalt and bitumen-rubber asphalt under accelerated trafficking.

    CSIR Research Space (South Africa)

    Rust, FC

    1994-10-01

    Full Text Available continuously-graded asphalt overlay was investigated. Secondly, the cracking behaviour of a 75 mm thick continuously-graded overlay was compared with that of a 38 mm thick bitumen-rubber asphalt overlay. A laboratory evaluation of the materials was conducted...

  1. Durability of European Asphalt Mixtures Containing Reclaimed Asphalt and Warm-Mix Additives

    NARCIS (Netherlands)

    Varveri, A.; Avgerinopoulos, S.; Scarpas, Athanasios

    2016-01-01

    This paper investigates the moisture susceptibility of European asphalt mixtures (SMA) containing reclaimed asphalt (RA) and warm mix (WMA) additives. Test sections of a typical SMA mixture have been laid, from which cylindrical samples were cored and utilized for laboratory testing. Four variants

  2. Prevent Shingles

    Science.gov (United States)

    ... Emergency Preparedness & Response Environmental Health Healthy Living Injury, Violence & Safety Life Stages & Populations Travelers’ Health Workplace Safety & Health Features Media Sign up for Features Get Email Updates To ...

  3. Shingles - aftercare

    Science.gov (United States)

    ... blistering skin rash that is caused by the varicella-zoster virus. This is the same virus that causes chickenpox. ... chap 101. Whitley RJ. Chickenpox and herpes zoster (varicella-zoster virus). In: Bennett JE, Dolin R, Blaser MJ, eds. ...

  4. Use of porous asphalt on major roads in Johannesburg

    CSIR Research Space (South Africa)

    Horak, E

    1994-10-01

    Full Text Available promising road noise attenuation measure. Porous asphalt is a new generation noise absorbent road surfacing. Research and development were done on this specific noise absorbent asphalt surfacing type by the Division for Roads and Transport Technology...

  5. Asphalt mix characterization using dynamic modulus and APA testing.

    Science.gov (United States)

    2005-11-01

    final report summarizes two research efforts related to asphalt mix characterization: dynamic modulus and Asphalt Pavement Analyzer testing. One phase of the research consisted of a laboratory-based evaluation of dynamic modulus of Oregon dense-grade...

  6. Fracture properties and fatigue cracking resistance of asphalt binders.

    Science.gov (United States)

    2012-03-01

    Several different types of modifiers are increasingly bring used to improve the performance of asphalt binders or to : achieve desired mixture production characteristics (e.g., Warm Mix Asphalt). However, current Superpave : performance specification...

  7. Appropriate models for estimating stresses and strains in asphalt layers

    CSIR Research Space (South Africa)

    Jooste, FJ

    1998-09-01

    Full Text Available The broad objective is to make recommendations for appropriate modelling procedures to be used in the structural design of asphalt layers. Findings of this investigation are intended to be used in refining and validating existing asphalt pavement...

  8. Fatigue performance of asphalt pavements containing RAS and RAP.

    Science.gov (United States)

    2015-01-01

    Rising oil and gas prices spurs development of methods and technologies for reducing fuel consumption and increased use of : recycled materials. With increased environmental awareness, using reclaimed asphalt pavement (RAP) and reclaimed asphalt : sh...

  9. Laboratory evaluation of asphalt binder rutting, fracture, and adhesion tests.

    Science.gov (United States)

    2014-04-01

    The current performance grading (PG) specification for asphalt binders was developed based on the Strategic Highway : Research Program (SHRP) and is based primarily on the study of unmodified asphalt binders. Over the years, experience has : proven t...

  10. Non-stationary behavior of roof drainage systems

    Directory of Open Access Journals (Sweden)

    Koláček Martin

    2017-01-01

    Full Text Available This paper reports the non-stationary behavior of a roof drainage during experimental measurement in the climate simulator. Many buildings use a fully or partially flat roof where it is necessary to use the roof drainage. Thermal behavior of roof drainage is very important from the point of view of heat transfer and potential condensation. The placement of a roof drain slightly deteriorates thermal transmittance of the roof. This experiment evaluates roof drains in the specific climate simulator where thermal conditions were dynamically controlled in the specific temperature range. The measurement was performed for two types of roof drains. The first drainage is a simple single-shell and the second is double-shell drainage. The results show the effect on the thermal transmittance of the roof section and also the minimal effect of condensation on the non-insulation part of the drainage. Both roof drains showed minimal deterioration of thermal transmittance of the roof construction.

  11. New experiences with foamed bitumen asphalts in hungarian road building

    Directory of Open Access Journals (Sweden)

    Puchard Zoltan

    2015-12-01

    Full Text Available The use of low temperature (LT asphalt products can result in a significant decrease of temperature required for asphalt production. This reduces energy costs and consumption. Moreover, safety during asphalt production and laying improves because the amount of potentially harmful vapours and aerosols decreases. Temperature decrease, in addition to the above, reduces the short-term ageing of bitumen in the asphalt production process, and ultimately has a positive impact on the durability of pavements.

  12. 0-6674 : improving fracture resistance measurement in asphalt binder specification with verification on asphalt mixture cracking performance.

    Science.gov (United States)

    2014-08-01

    The current performance grading (PG) specification for asphalt binders is based primarily on the study of unmodified asphalt binders. Over the years, experience has proven that the PG grading system, while good for ensuring overall quality, fails in ...

  13. PERFORMANCE PROPERTIES OF ASA POLYMER MODIFIED ASPHALT BINDERS AND MIXTURES

    Directory of Open Access Journals (Sweden)

    SHABAN ISMAEL ALBRKA

    2016-08-01

    Full Text Available Asphalt is commonly used as a binder in the construction of highways and runways, due to its good viscoelastic properties, natural asphalt cement does not have sufficient strength to resist sudden stresses of excessive loading or stress from low and high temperatures. Therefore, modification of asphalt is necessary in order to improve its material temperature sensitivity, adhesion, durability, oxidation and aging resistance. The property of base asphalt and polymer modified asphalt binders and mixtures has been characterized using the conventional tests and dynamic creep tests. It has been found that, the addition of Acrylate Styrene Acrylonhrtilrei (ASA polymer content has magnificent influence on the properties of the asphalt binders and mixtures. The temperature susceptibility of modified asphalt binders was reduced compared with base asphalt binder as the penetration increase and softening point decrease. The reduction in penetration was up to 69%, while the improvement in softening point was up to 19%. Moreover, it was approved from the storage stability test that, the ASA polymer has a great compatibility with asphalt binder up to 5% ASA. In addition, it was observe reduction in permanent deformation of modified asphalt mixtures with increase of modifier up to 5% ASA, which lead to better resistance to rutting at high temperatures, and the reduction was up to 36%. As a result, the modification of asphalt binder and mixture with ASA polymer can be considered a proper alternative technique to improve the properties of asphalt binder and mixture and 5% ASA was the optimum content of the modifier.

  14. SRB/SLEEC (Solid Rocket Booster/Shingle Lap Extendible Exit Cone) feasibility study, volume 1

    Science.gov (United States)

    Baker, William H., Jr.

    1986-01-01

    A preliminary design and analysis was completed for a SLEEC (Shingle Lap Extendible Exit Cone) which could be incorporated on the Space Transportation System (STS) Solid Rocket Booster (SRB). Studies were completed which predicted weights and performance increases and development plans were prepared for the full-scale bench and static test of SLEEC. In conjunction with the design studies, a series of supporting analyses were performed to assure the validity and feasibility of performance, fabrication, cost, and reliability for the selected design. The feasibility and required amounts of bench, static firing, and flight tests considered necessary for the successful incorporation of SLEEC on the Shuttle SRBs were determined. Preliminary plans were completed which define both a follow on study effort and a development program.

  15. Intravenous Vitamin C in the treatment of shingles: Results of a multicenter prospective cohort study

    Science.gov (United States)

    Schencking, Martin; Vollbracht, Claudia; Weiss, Gabriele; Lebert, Jennifer; Biller, Andreas; Goyvaerts, Birgit; Kraft, Karin

    2012-01-01

    Summary Background Vitamin C is an immune-relevant micronutrient, which is depleted in viral infections and this deficiency seems to play a critical role in the pathogenesis of herpes infections and in the development of postherpetic neuralgia. The objective of this observational multicenter study was to evaluate the utilization, safety and efficacy of intravenously administrated vitamin C in patients with shingles. Material/Methods Between April 2009 and December 2010 16 general practitioners recorded data of 67 participants with symptomatic herpes zoster who received vitamin C intravenously (Pascorbin® 7.5 g/50 ml) for approximately 2 weeks in addition to standard treatment. The assessment of pain (VAS) and the dermatologic symptoms of shingles such as hemorrhagic lesions and the number of efflorescences were investigated in a follow-up observation phase of up to 12 weeks. Results Mean declines of pain scores (VAS), number of affected dermatomes and efflorescences, and the presence of hemorrhagic vesicles between the baseline and follow-up assessments at 2 and 12 weeks were statistically significant. Overall, 6.4% of the participants experienced post-herpetic neuralgia. Common complaints such as general fatigue and impaired concentration also improved during the study. The effects and the tolerability of the treatment were evaluated positively by the physicians. The risk of developing PHN was reduced. Conclusions The data presented here provide evidence that concomitant use of intravenously administered ascorbic acid may have beneficial effects on herpes zoster-associated pain, dermatologic findings and accompanying common complaints. To confirm our findings, randomized, placebo-controlled clinical studies are necessary. PMID:22460093

  16. CMC thermal protection system for future reusable launch vehicles: Generic shingle technological maturation and tests

    Science.gov (United States)

    Pichon, T.; Barreteau, R.; Soyris, P.; Foucault, A.; Parenteau, J. M.; Prel, Y.; Guedron, S.

    2009-07-01

    Experimental re-entry demonstrators are currently being developed in Europe, with the objective of increasing the technology readiness level (TRL) of technologies applicable to future reusable launch vehicles. Among these are the Pre-X programme, currently funded by CNES, the French Space Agency, and which is about to enter into development phase B, and the IXV, within the future launcher preparatory programme (FLPP) funded by ESA. One of the major technologies necessary for such vehicles is the thermal protection system (TPS), and in particular the ceramic matrix composites (CMC) based windward TPS. In support of this goal, technology maturation activities named "generic shingle" were initiated beginning of 2003 by SPS, under a CNES contract, with the objective of performing a test campaign of a complete shingle of generic design, in preparation of the development of a re-entry experimental vehicle decided in Europe. The activities performed to date include: the design, manufacturing of two C/SiC panels, finite element model (FEM) calculation of the design, testing of technological samples extracted from a dedicated panel, mechanical pressure testing of a panel, and a complete study of the attachment system. Additional testing is currently under preparation on the panel equipped with its insulation, seal, attachment device, and representative portion of cold structure, to further assess its behaviour in environments relevant to its application The paper will present the activities that will have been performed in 2006 on the prediction and preparation of these modal characterization, dynamic, acoustic as well as thermal and thermo-mechanical tests. Results of these tests will be presented and the lessons learned will be discussed.

  17. Assessment of The Asphalt Produced in Some Factories of Asphalt in Al-Hilla City

    Directory of Open Access Journals (Sweden)

    Mohammed Karem Abd

    2018-02-01

    Full Text Available The purpose of this study is to present an evaluation of  the properties and characteristics of asphalt concrete of several hot mix asphalt (HMA from five factories in Al-Hilla city. The research is divided into two parts. The first part included the laboratory analysis of samples. The second part is evaluation of results according to standard specifications.      The test results included (Asphalt content percent, stability, creep compliance, voids ratio, density, flow, crushed aggregate percent, Loss Angless abrasion and SO3 percent.The results of laboratorial tests indicated that all properties of asphalt mixes were susceptible and possible to be used in the asphaltic roads. The mixes types prepared and tested according to Marshall method. The values of Marshall stability, creep and density are (9.4, 5.4, 9.8, 9, 8.6, (2.5, 2.7, 2.7, 2.6, 2.3 and (2.334, 2.336, 2.337, 2.333, 2.338 with asphalt content between (4.2 to 4.6 % for all asphalt mixes of different factories.

  18. Ethanol based foamed asphalt as potential alternative for low emission asphalt technology

    Directory of Open Access Journals (Sweden)

    Mohd Rosli Mohd Hasan

    2016-04-01

    Full Text Available Foamed asphalt typically relies on water as a foaming agent because water becomes gaseous at elevated temperatures, generating numerous tiny bubbles in the asphalt and causing spontaneous foaming. In this study, ethanol was used as a potential alternative to water as a foaming agent. Ethanol is expected to be a physical blowing agent in the same manner as water, except it requires less energy to foam due to its 78 °C boiling point. This study compares the performance of water and ethanol as foaming agents through the measurements of rotational viscosity, the reduction in temperature during foaming, and volatile loss. The ethanol-foamed asphalt binders were prepared at 80 °C and 100 °C, while the water-foamed asphalt binders were prepared at 100 °C and 120 °C. Additionally, the rolling thin film oven (RTFO was used to generate short-term aging of the foamed asphalt binders. A rotational viscometer was used to determine the viscosity of the asphalt binders at 80 °C, 100 °C, 120 °C, 140 °C, and 160 °C. Overall, ethanol can function in the same manner as water but requires less energy to foam. It is proven based on the smaller drop in temperature of the asphalt binder foamed using ethanol compared with that prepared with water. This is due to the lower latent heat capacity of ethanol, which requires less energy to vaporize compared with water. Through the rotational viscometer test, ethanol performs better in lowering the viscosity of asphalt binders, which is essential in allowing production processes at low temperatures, as well as a better workability and aggregate coating. Ethanol can be expelled from the foamed asphalt binders at a higher rate due to its lower boiling point and latent heat.

  19. Evaluating The Performance of Asphalt Concrete Mixes by Utilizing Carbon Black as Asphalt Modifier

    Directory of Open Access Journals (Sweden)

    Aliaa Faleh Al.ani

    2018-02-01

    Full Text Available Carbon black produced from several factories in Iraq is expected to provide a reinforcing agent for asphalt paving materials. Carbon black has many characteristics that distinguish  it from conventional mineral fillers, as well as their different function in pavement mixtures. Theory and exercise advanced  in the inclusive utilize of carbon black as a reinforcing agent for rubber has led to concept of asphalt reinforcement. The very fine particles of micro filler added in different contents will be dispersed in asphalt cement improving the mechanical properties of asphalt concrete mixes. In this Four percentages rates were utilized; 0, 3, 6, and 9 percent adding to asphalt grade (60-70. Mixes of asphalt concrete were destined at their optimum asphalt content (OAC then experienced to assess their engineering characteristics that contain moisture of damage, permanent deformation, modulus of resilient and characteristics of fatigue. These characteristics have been assessed utilizing indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Mixtures improved with carbon black were existed to have amended permanent deformation and fatigue characteristics, else exhibited high resilient modulus and lower moisture susceptibility. Result showed that a rate changed from 3 to 9 percent has shown an increase in resilient modulus for increment of carbon black and modulus of resilient for mixes with 9 percent carbon black was 1.4 times that for mixes with 0 percent carbon black. The altering of carbon black from a range (3-9 percent has modified the fatigue property of the asphalt concrete mixes as determined by flexural test, Significantly, to modify the asphalt concrete manner taken the  percent of carbon black 6, and to produce the mixes more durable , higher resistance to distresses by adding the local knowledge.

  20. 30 CFR 75.206 - Conventional roof support.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conventional roof support. 75.206 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.206 Conventional roof support. (a) Except in anthracite mines using non-mechanized mining systems, when conventional roof support...

  1. Influence of reclaimed asphalt with polymer modified bitumen on properties of different asphalts for a wearing course

    NARCIS (Netherlands)

    Komačka, J.; Remišová, E.; Liu, G.; Leegwater, G.; Nielsen, E.

    2014-01-01

    A laboratory investigation was performed to study the effect of reclaimed asphalt with polymer modified bitumen on the properties describing asphalt performance. Three types of asphalts used for wearing courses in Europe (SMA 11, AC 11 and PA 8) were investigated. Five combinations of reclaimed

  2. Analysis of using porous asphalt on the surfaces of bridges

    Directory of Open Access Journals (Sweden)

    Ryszard Chmielewski

    2016-09-01

    Full Text Available The article concerns the analysis of the use of modern technology while paving the road bridges. It shall assess the possibility of using porous asphalt paving of road bridges. Based on the results of laboratory tests of selected porous asphalt, such as: determination of free space in the mixture of mineral-asphalt, runoff of the binder, sensitivity to water and frost, the loss of grains in the mixture, the design of porous asphalt mixture has been completed.[b]Keywords[/b]: construction of bridges, road bridges pavements, porous asphalt, dehydration of the bridges

  3. Roof instability characteristics and pre-grouting of the roof caving zone in residual coal mining

    Science.gov (United States)

    Zhao, Tong; Liu, Changyou

    2017-12-01

    Abandoned roadways and roof caving zones are commonly found in residual coal, and can destroy the integrity of the coal seam and roof. Resulting from mining-induced stress, continuous collapse and fracture instability in roof caving zones (RCZs) jeopardize the safety and efficiency of residual coal mining. Based on the engineering geology conditions of remining face 3101 in Shenghua Mine, the roof fracture and instability features of the RCZ were analyzed through physical simulation, theoretical analysis, and field measurements. In this case, influenced by the RCZ, the main roof across the RCZ fractured and rotated towards the goaf, greatly increasing the working resistance, and crushing the supports. The sudden instability of the coal pillars weakened its support of the main roof, thus resulting in long-key blocks across the RCZ and hinged roof structures, which significantly decreased the stability of the underlying immediate roof. This study establishes a mechanical model for the interactions between the surrounding rock and the supports in the RCZ, determines the reasonable working resistance, and examines the use of pre-grouting solidification restoration technology (PSRT) to solidify the RCZ and reinforce the coal pillars—thus increasing their bearing capacity. Field measurements revealed no roof flaking, inhomogeneous loading or support crushing, indicating that the PSRT effectively controlled the surrounding rock of the RCZ.

  4. ROOF GARDENS AS LANDSCAPING IN MODERN TIMES

    Directory of Open Access Journals (Sweden)

    Vaska Sandeva

    2017-02-01

    Full Text Available As we know we live in a process of industrialization and massive building of residential buildings, both individually and as a collective housing. Given all that happens even with the procedural other things to come up with all this, the country remains less green space that is required for a single environment, so the roof gardens are the best choice for all of this to get a beautiful country. For roof gardens should be given the explanation that, roof gardens, call it beautiful, flat roofs, and with gentle slope, with rich composition intensively maintained and often impose a constructive adaptation of the building and benefits by the architectural beauty, insulation, absorption. Commonly found in urban areas and almost always are placed foliage with not very high growth.

  5. MC Contracting, Paint, & Roofing, LLC Information Sheet

    Science.gov (United States)

    MC Contracting, Paint, & Roofing, LLC, d/b/a M.C. Painting & Contractor and M.C. Painting Group (the Company) is located in Philadelphia, Pennsylvania. The settlement involves renovation activities conducted at property constructed prior to 1978.

  6. Million Solar Roofs: Partners Make Markets

    Energy Technology Data Exchange (ETDEWEB)

    2004-06-01

    Million Solar Roofs (MSR) Partners Make Markets Executive Summary is a summary of the MSR Annual Partnership Update, a report from all the partners and partnerships who participate in the MSR Initiative.

  7. Thermal Stress Measurements in Asphalt Concrete

    Science.gov (United States)

    1993-07-01

    The stiffness of the asphalt cement is then used/- -• with either the Heukelom and Klomp (1964) rela- -o0- • tionship between asphalt and mixture...predicted by either Teperaturc a-rea time qf loading (>2 h Jr) the Heukelom or McLeod estimation methods. S’C) (nm~) (kg) As with the direct tension test...deflection due to dP that the stiffnesses obtained from the creep test or I = moment of inertia. 10 Heukelom Method o McLeod 0) 7 Method .~i 5 0 (I) Creep

  8. Practical experiences with new types of highly modified asphalt binders

    Science.gov (United States)

    Špaček, Petr; Hegr, Zdeněk; Beneš, Jan

    2017-09-01

    As a result of steadily increasing traffic load on the roads in the Czech Republic, we should be focused on the innovative technical solutions, which will lead to extending the life time of asphalt pavements. One of these ways could be the future use of bitumen with a higher degree of polymer modification. This paper discusses experience with comparison of new highly polymer modified asphalt binder type with conventional polymer modified asphalt binder and unmodified binder with penetration grade 50/70. There are compared the results of various types laboratory tests of asphalt binders, as well as the results of asphalt mixtures laboratory tests. The paper also mentions the experience with workability and compactability of asphalt mixture with highly polymer modified asphalt binder during the realization of the experimental reference road section by the Skanska company in the Czech Republic.

  9. Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Sleiman, Mohamad [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kirchstetter, Thomas W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Berdahl, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gilbert, Haley E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Quelen, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Marlot, Lea [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Preble, Chelsea V. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Chen, Sharon [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Montalbano, Amandine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rosseler, Olivier [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Akbari, Hashem [Concordia Univ., Montreal (Canada); Levinson, Ronnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Destaillats, Hugo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-09

    Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.

  10. State-of-the-art and prospect for self-healing asphalt concrete

    Science.gov (United States)

    Xiao, Dong

    2017-08-01

    In order to solve the problem of asphalt concrete pavement cracks, this paper summarizes the principle of self-healing asphalt concrete, and describes asphalt concrete self-healing technology in various countries. This paper also analyses the factors of influencing the self-healing ability of asphalt concrete and the evaluation index, and describes the prospect of asphalt concrete self-healing technology.

  11. Investigating In Situ Properties of Recycled Asphalt Pavement with Foamed Asphalt as Base Stabilizer

    Directory of Open Access Journals (Sweden)

    Christina Plati

    2010-01-01

    Full Text Available The objective of the present study was to conduct a comprehensive field experiment for the in situ assessment of in-depth recycled asphalt pavement using foamed asphalt as a stabilization treatment for base works. For this purpose Nondestructive Testing (NDT data collected using the Falling Weight Deflectometer (FWD and Ground Penetrating Radar (GPR along a foamed asphalt recycled pavement section was thoroughly analysed. Critical issues including the stabilized material curing and the contribution of the asphalt layers to the structural properties of the in-depth recycled pavement are discussed. In addition, recommendations concerning the improvement of the structural condition of the in-depth recycled pavement are developed based on this practical approach of investigation using NDT.

  12. Volumetric characteristics and compactability of asphalt rubber mixtures with organic warm mix asphalt additives

    Directory of Open Access Journals (Sweden)

    A. M. Rodríguez-Alloza

    2017-04-01

    Full Text Available Warm Mix Asphalt (WMA refers to technologies that reduce manufacturing and compaction temperatures of asphalt mixtures allowing lower energy consumption and reducing greenhouse gas emissions from asphalt plants. These benefits, combined with the effective reuse of a solid waste product, make asphalt rubber (AR mixtures with WMA additives an excellent environmentally-friendly material for road construction. The effect of WMA additives on rubberized mixtures has not yet been established in detail and the lower mixing/compaction temperatures of these mixtures may result in insufficient compaction. In this sense, the present study uses a series of laboratory tests to evaluate the volumetric characteristics and compactability of AR mixtures with organic additives when production/compaction temperatures are decreased. The results of this study indicate that the additives selected can decrease the mixing/compaction temperatures without compromising the volumetric characteristics and compactability.

  13. Performance Evaluation of Stone Mastic Asphalt and Hot Mix Asphalt Mixtures Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Mohammad Saeed Pourtahmasb

    2014-01-01

    Full Text Available Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions. The current paper presents an experimental research on the possibility of utilizing recycled concrete aggregates (RCA in stone mastic asphalt (SMA and hot mix asphalt (HMA mixtures. Three categories of RCA in various percentages were mixed with virgin granite aggregates to produce SMA and HMA specimens. The obtained results indicated that, regardless of the RCA particular sizes, the use of RCA to replace virgin aggregates increased the needed binder content in the asphalt mixtures. Moreover, it was found that even though the volumetric and mechanical properties of the asphalt mixtures are highly affected by the sizes and percentages of the RCA but, based on the demands of the project and traffic volume, utilizing specific amounts of RCA in both types of mixtures could easily satisfy the standard requirements.

  14. Investigation of the use of recycled polymer-modified asphalt in asphaltic concrete pavements.

    Science.gov (United States)

    2004-06-30

    This report presents issues associated with recycling polymer modified asphalt cements (PMACs), particularly blending aged PMAC with new PMAC. A styrene-butadiene-styrene (SBS) PMAC was selected and graded using the Superpave Performance Grading (PG)...

  15. Utilization of Recycled Asphalt Concrete with Warm Mix Asphalt and Cost-Benefit Analysis: e116180

    National Research Council Canada - National Science Library

    Julide Oner; Burak Sengoz

    2015-01-01

      The asphalt paving industries are faced with two major problems. These two important challenges are generated with an increase in demand for environmentally friendly paving mixtures and the problem of rapidly rising raw materials...

  16. Utilization of recycled asphalt concrete with warm mix asphalt and cost-benefit analysis

    National Research Council Canada - National Science Library

    Oner, Julide; Sengoz, Burak

    2015-01-01

    The asphalt paving industries are faced with two major problems. These two important challenges are generated with an increase in demand for environmentally friendly paving mixtures and the problem of rapidly rising raw materials...

  17. Bright is the New Black - Multi-Year Performance of Generic High-Albedo Roofs in an Urban Climate

    Science.gov (United States)

    Gaffin, S. R.; Imhoff, M.; Rosenzweig, C.; Khanbilvardi, R.; Pasqualini, A.; Kong, A. Y. Y.; Grillo, D.; Freed, A.; Hillel, D.; Hartung, E.

    2012-01-01

    High-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross-section of the dominant white membrane options for U.S. flat roofs: (1) an ethylene propylene diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane and; (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane however shows evidence of low emissivity. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years after installation. Given that the acrylic approach is an important "do-it-yourself," low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.

  18. Research notes : recycling roads and roofs.

    Science.gov (United States)

    2010-06-01

    One objective of the larger study is to develop recommendations for a design process for selecting the grade of virgin asphalt binder for HMAC mixtures containing RAP or RAS, or combinations of RAP and RAS, such that the blended binder meets the desi...

  19. Evaluation of asphalt rubber membrane interlayer (ARMI) using the University of Florida's composite system interface cracking (CSIC) test.

    Science.gov (United States)

    2012-05-01

    Since the late 1970s, FDOT : has applied an interlayer : of Asphalt Rubber : Membrane Interlayer : (ARMI) to asphalt roadway : surfaces. ARMI layers are : constructed by spraying : asphalt rubber binder onto : the asphalt, covering the : layer with n...

  20. Evaluation of asphalt rubber membrane interlayer (ARMI) using the University of Florida's composite system interface cracking (CSIC) test [summary].

    Science.gov (United States)

    2012-01-01

    Since the late 1970s, FDOT : has applied an interlayer : of Asphalt Rubber : Membrane Interlayer : (ARMI) to asphalt roadway : surfaces. ARMI layers are : constructed by spraying : asphalt rubber binder onto : the asphalt, covering the : layer with n...

  1. Effects of Short-Term Aging on Asphalt Binders and Hot Mix Asphalt at Elevated Temperatures and Extended Aging Time

    Directory of Open Access Journals (Sweden)

    Lolly Rubben

    2017-01-01

    Full Text Available The production process of Hot Mix Asphalt (HMA causes a short term aging (STA to asphalt binder due to the heating of both asphalt binder and aggregates before mixing together. Laboratory protocols are followed to simulate the STA conditions for both asphalt binders and asphalt mixtures. STA protocols expose asphalt binders or asphalt mixtures to specific aging temperature for a specific period of time to produce stiffening that is similar to that of actual production conditions. Successful construction of HMA in cold season/regions may require elevating the production temperature of HAM to achieve proper compaction of HMA layers. Producing HMA mixtures at elevated temperatures may cause further increase in the binder stiffness and negatively affect the future field performance of asphalt pavements. This negative affect can be even worse especially if it is coupled with extended exposer time increase. This study aims to investigate effect of elevated production (mixing and STA temperatures and exposure time on the stiffening of binders and asphalt mixtures. The binder experiment involved aging of two Performance Graded (PG binders (PG 76-16 and PG 64-22 at two different temperatures and aging durations. The asphalt mixture experiment involved the STA of asphalt mixtures produced in the laboratory at mixing and STA temperatures 25°F above standard practice and aging time 2 and 4 hours longer than standard practices. The effect of different aging times and temperatures was investigated by running viscosity tests on binders and dynamic modulus |E*| and Indirect Diametrical Strength (IDT tests on asphalt mixtures. The results showed that increasing the mixing and STA temperatures by 25°F seems to have no significant effect on the asphalt mixture properties while doubling the standard STA time seems to have a significant effect on binder and asphalt mixture properties.

  2. Extending the Lifespan of Porous Asphalt Concrete

    NARCIS (Netherlands)

    Molenaar, A.A.A.; Wu, S.P.; Zhang, Y.

    Porous Asphalt (PA) concrete is widely used as a surfacing layer on highways in the Netherlands. The service life of PA wearing courses is limited because of the fact that it is vulnerable to raveling. The possibilities of applying preventive maintenance to PA wearing courses by means of spraying

  3. Steady-State Creep of Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Alibai Iskakbayev

    2017-02-01

    Full Text Available This paper reports the experimental investigation of the steady-state creep process for fine-grained asphalt concrete at a temperature of 20 ± 2 °С and under stress from 0.055 to 0.311 MPa under direct tension and was found to occur at a constant rate. The experimental results also determined the start, the end point, and the duration of the steady-state creep process. The dependence of these factors, in addition to the steady-state creep rate and viscosity of the asphalt concrete on stress is satisfactorily described by a power function. Furthermore, it showed that stress has a great impact on the specific characteristics of asphalt concrete: stress variation by one order causes their variation by 3–4.5 orders. The described relations are formulated for the steady-state of asphalt concrete in a complex stressed condition. The dependence is determined between stress intensity and strain rate intensity.

  4. Application of Conductive Materials to Asphalt Pavement

    Directory of Open Access Journals (Sweden)

    Hai Viet Vo

    2017-01-01

    Full Text Available Snow-melting pavement technique is an advanced preservation method, which can prevent the forming of snow or ice on the pavement surface by increasing the temperature using an embedded heating system. The main scope of this study is to evaluate the impact of conductive additives on the heating efficiency. The electrical resistivity and thermal conductivity were considered to investigate effects of conductive additives, graphite, and carbon fibers on the snow-melting ability of asphalt mixtures. Also, the distribution of the conductive additives within the asphalt concrete body was investigated by microstructural imaging. An actual test was applied to simulate realistic heating for an asphalt concrete mixture. Thermal testing indicated that graphite and carbon fibers improve the snow-melting ability of asphalt mixes and their combination is more effective than when used alone. As observed in the microstructural image, carbon fibers show a long-range connecting effect among graphite conductive clusters and gather in bundles when added excessively. According to the actual test, adding the conductive additives helps improve snow-melting efficiency by shortening processing time and raising the surface temperature.

  5. Microbial life in a liquid asphalt desert.

    Science.gov (United States)

    Schulze-Makuch, Dirk; Haque, Shirin; de Sousa Antonio, Marina Resendes; Ali, Denzil; Hosein, Riad; Song, Young C; Yang, Jinshu; Zaikova, Elena; Beckles, Denise M; Guinan, Edward; Lehto, Harry J; Hallam, Steven J

    2011-04-01

    Pitch Lake in Trinidad and Tobago is a natural asphalt reservoir nourished by pitch seepage, a form of petroleum that consists of mostly asphaltines, from the surrounding oil-rich region. During upward seepage, pitch mixes with mud and gases under high pressure, and the lighter portion evaporates or is volatilized, which produces a liquid asphalt residue characterized by low water activity, recalcitrant carbon substrates, and noxious chemical compounds. An active microbial community of archaea and bacteria, many of them novel strains (particularly from the new Tar ARC groups), totaling a biomass of up to 10(7) cells per gram, was found to inhabit the liquid hydrocarbon matrix of Pitch Lake. Geochemical and molecular taxonomic approaches revealed diverse, novel, and deeply branching microbial lineages with the potential to mediate anaerobic hydrocarbon degradation processes in different parts of the asphalt column. In addition, we found markers for archaeal methane metabolism and specific gene sequences affiliated with facultative and obligate anaerobic sulfur- and nitrite-oxidizing bacteria. The microbial diversity at Pitch Lake was found to be unique when compared to microbial communities analyzed at other hydrocarbon-rich environments, which included Rancho Le Brea, a natural asphalt environment in California, USA, and an oil well and a mud volcano in Trinidad and Tobago, among other sites. These results open a window into the microbial ecology and biogeochemistry of recalcitrant hydrocarbon matrices and establish the site as a terrestrial analogue for modeling the biotic potential of hydrocarbon lakes such as those found on Saturn's largest moon Titan.

  6. Extending the Lifespan of Porous Asphalt Concrete

    NARCIS (Netherlands)

    Zhang, Y.

    2015-01-01

    Porous Asphalt (PA) concrete is widely used as a surfacing layer on highways in the Netherlands. The service life of PA wearing courses is limited because of the fact that it is vulnerable to raveling. The possibilities of applying preventive maintenance to PA wearing courses by means of spraying

  7. The use of asphalt in hydraulic engineering

    NARCIS (Netherlands)

    Van de Velde, P.A.; Ebbens, E.H.; Van Herpen, J.A.

    1985-01-01

    Asphalt products have been used in the Netherlands in hydraulic engineering for a long time on a large scale, especially after the great disaster in 1953 when a large part of western Holland was flooded by the sea. After the disaster a great number of dikes had to be repaired very quickly and this

  8. Plastic Bottles Waste Utilization as Modifier for Asphalt Mixture Production

    Directory of Open Access Journals (Sweden)

    Jan Hakeem

    2017-01-01

    Full Text Available Plastic Bottles was used as the polymeric waste to investigate performance of asphalt mixture Aggregates obtained from Margalla, Burhan and Karak quarries. 12 samples were prepared for conventional asphalt mixtures and 48 samples were prepared for PB modified asphalt mixture of each quarries at various proportions of PB waste. The PB used for modification according to wet process are 15%, 20%, 25% and 30% by weight of Optimum Bitumen Content (OBC. OBC of 4.2 % was concluded for conventional asphalt mixtures. The stability and flow values of the conventional and modified Asphalt Mixture were compared. The average Stability of the modified Margalla asphalt mixtures when 15% PB was used was much higher as compared to conventional asphalt mixtures. But when PB was used beyond 15%, the Marshall stability showed a decreasing trend for Margalla aggregates, increasing trend for Karak aggregates and decreasing trend for Burhan aggregates. This decline in stability is attributed to a decline in interlocking of aggregates due to lubricating effect. The corresponding flow for the Modified asphalt mixtures first showed a decreasing trend for Margalla aggregates at 15% PB modification but beyond 15%, an increasing trend in flow as compared to conventional asphalt mixtures The decrease in flow or increase in Marshall Stability is attributed to improvement in interlocking and decline in flow or stability is attributed to a decline in interlocking offered by binder and PB coated aggregate particles in modified asphalt.

  9. Study of Antiultraviolet Asphalt Modifiers and Their Antiageing Effects

    Directory of Open Access Journals (Sweden)

    Jinxuan Hu

    2017-01-01

    Full Text Available Ultraviolet (UV radiation causes serious ageing problems on pavement surface. In recent years, different UV blocking materials have been used as modifiers to prevent asphalt ageing during the service life of the pavement. In this study, three different materials have been used as modifiers in base asphalt to test their UV blocking effects: layered double hydroxides (LDHs, organomontmorillonite (OMMT, and carbon black (CB. UV ageing was applied to simulate the ageing process and softening point, penetration, ductility, DSR (Dynamic Shear Rheometer test, and Fourier Transform Infrared Spectroscopy (FTIR test were conducted to evaluate the anti-UV ageing effects of the three UV blocking modifiers. Physical property tests show that base asphalt was influenced more seriously by UV radiation compared to the modified asphalt. DSR test results indicate that the complex modulus of asphalt before UV ageing is increased because of modifiers, while the complex modulus of base asphalt after UV ageing is higher than that of the modified asphalt, which shows that the UV blocking modifiers promote the antiageing effects of asphalt. FTIR test reveals that the increment of carbonyl groups and sulfoxide groups of modified asphalt is less than that in base asphalt. Tests indicate the best UV blocking effect results for samples with LDHs and the worst UV blocking effect results for samples with CB.

  10. Numerical evaluation of induction heating assisted compaction technology for low temperature asphalt pavement construction

    NARCIS (Netherlands)

    Zhou, C.; Liu, X.; Apostolidis, P.

    2017-01-01

    Low Temperature Asphalt (LTA) technologies are utilized in asphalt pavement industry to lower energy demands and greenhouse gas emission during mixing and construction processes. Although these technologies are currently available and hope to demonstrate similar performance with Hot Mix Asphalt

  11. Retention capacity of extensive green roofs

    Directory of Open Access Journals (Sweden)

    Sobczyk Małgorzata

    2016-09-01

    Full Text Available Climate change causes a more frequent occurrence of extreme events. The result of these phenomena is the occurrence of floods and flooding, and periods of drought. Particularly unfavorable is intensive rainfall over the urban catchments. To prevent the negative consequences of these phenomena, unconventional solutions should be used. The use of green roofs in urban areas will serve the sustainable development of cities and the impact on local ecological changes. The study was performed at two green roof platforms 1.2×1.2×0.1 m each. An analysis was performed at different intensities given for precipitation. 20 min for the rain to stop was observed from 68 to 100% precipitation. The study was divided into two parts. The first part of the study has been performed in the dry period. In contrast, another round of tests was repeated in other conditions after rainfall. The amount of water at two experimental green roofs platforms before the test was 11.0 dm3. The research relates to the impact of green roofs on local hydrological changes. Development of technologies for green roofs had a positive impact on mitigating the effects of climate change associated with the occurrence of flooding the city.

  12. Floating roof tank drainage system improvements

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Wagner Andrade da; Holdack, Ricardo; Ruza, Adilson; Schraml, Karina Chacur; Fujikawa, Mauro Yutaka [Petrobras Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Silva, Adilson Batista da [ATP Engenharia Ltda., Parnamirim, RN (Brazil)

    2009-07-01

    TRANSPETRO's tank TQ-8803 is a floating roof tank, used for storing gasoline at atmospheric pressure. This tank presented a roof movement restriction at a certain height in the receiving and sending operations, besides problems in draining the rainwater from the floating roof. The roof drain was a central articulated pipe, with a single intake spot. The tank had an anti-rotational 12-inch guide tube and a separate 8-inch gauging tube. It was verified that there were signs of friction between the tubes and their nozzles, and that both the tubes were out of plummet. The solution was removing both the tubes and installing a single anti-rotational guide tube, which received the level and temperature gauges, besides being used for manual gauging and as sampling nozzle. A new drainage system was also projected. It uses a flexible tube, supported in a spiral form on the bottom of the tank, and has a main and four auxiliary drainage boxes, positioned in the center of the roof and next to the pontoon, below the mobile stairs. These boxes were provided with elastomer duckbill check valves, substituting the swing check valves previously installed. After the maintenance conclusion, the anomalies found before were solved. (author)

  13. Skew angle effects in shingled magnetic recording system with double/triple reader head array

    Science.gov (United States)

    Elidrissi, Moulay Rachid; Sann Chan, Kheong; Greaves, Simon; Kanai, Yasushi; Muraoka, Hiroaki

    2014-05-01

    Shingled Magnetic Recording (SMR) is a scheme used to extend the life of the current perpendicular magnetic recording technology. SMR enables writing narrow tracks with a wide writer. Currently, SMR employs a single reader and will suffer inter-track interference (ITI) as the tracks become comparable in width to the reader. ITI can be mitigated by using narrower readers; however, narrower readers suffer from increased reader noise. Another approach to combat ITI is to process 2D readback and use ITI cancellation schemes to retrieve the data track. Multiple readbacks can be obtained either with a single reader and multiple revolutions or with a reader array. The former suffers from increased readback latency. In this work, we focus on the latter. When using a reader array, the skew angle poses major challenges. During writing, there is increased adjacent track erasure, and during readback the effective reader pitch varies and there is an increase in the 2D intersymbol interference caused by the rotated reader profile. In this work, we run micromagnetic simulations at different skew angles to train the grain flipping probability model, and then evaluate raw bit channel error rate performance at skew. In particular, we investigate the performance degradation caused by skewing of the 2 or 3 read head array for various read-head geometries.

  14. Snowy roofs--a potential hazard.

    Science.gov (United States)

    Eriksson, A; Björnstig, U; Kullenberg, K

    1988-01-01

    An accumulation of injuries and fatal accidents associated with shovelling snow from roofs was observed in the beginning of 1986 in Northern Sweden. Injury mechanisms and injury panorama are analyzed and preventive measures are suggested. Slipping on roofs or ladders, often caused by sliding snow, was a common cause of accident. Five subjects died of suffocation after having been buried under sliding snow. We would like to emphasize the importance of a co-worker when shovelling snow off roofs, of being well anchored by a safety-line and, if using a ladder, taking care that the ladder is well anchored and that the shovelling is not done on an ascent. Special snow conditions should also be noticed.

  15. Flat roof integration. CPT solar (AET IV)

    Energy Technology Data Exchange (ETDEWEB)

    Chianese, D.; Pola, I.; Bernasconi, A.; Bura, E.; Cereghetti, N.; Realini, A.; Pasinelli, P.; Rioggi, S.

    2007-11-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at a 15.4 kWp solar power installation in Trevano, Switzerland, that features flexible amorphous silicon triple-junction modules, mounted nearly horizontally and directly laminated to flexible polyolefin membranes that form the covering of a flat roof. The main objective of this study was to verify in which order of magnitude the better thermal behaviour of amorphous silicon cells can compensate for losses due to the quasi-horizontal roof integration (lower irradiation and higher reflection), and thus be competitive in the flat roof construction and refurbishment markets. The modules used and their characteristics are described. Performance, temperature levels and energy-production are reviewed for the panels of the installation. The performance of the inverter used is also reviewed. Data on temperatures and production are presented in graphical form and optical losses are examined.

  16. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers

    Directory of Open Access Journals (Sweden)

    Byong Chol Bai

    2015-01-01

    Full Text Available This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal properties. The combination of conductive filler with carbon fiber in asphalt mixture was evaluated. Also, rheological properties of modified asphalt binders with conductive fillers were measured using dynamic shear rheometer and bending beam rheometer at grade-specific temperatures. Based on rheological testing, the conductive fillers improve rutting resistance and decrease thermal cracking resistance. Thermal testing indicated that graphite and carbon black improve the thermal properties of asphalt mixes and the combined conductive fillers are more effective than the single filler.

  17. Performance of Recycled Porous Hot Mix Asphalt with Gilsonite Additive

    Directory of Open Access Journals (Sweden)

    Ludfi Djakfar

    2015-01-01

    Full Text Available The objective of the study is to evaluate the performance of porous asphalt using waste recycled concrete material and explore the effect of adding Gilsonite to the mixture. As many as 90 Marshall specimens were prepared with varied asphalt content, percentage of Gilsonite as an additive, and proportioned recycled and virgin coarse aggregate. The test includes permeability capability and Marshall characteristics. The results showed that recycled concrete materials seem to have a potential use as aggregate in the hot mix asphalt, particularly on porous hot mix asphalt. Adding Gilsonite at ranges 8–10% improves the Marshall characteristic of the mix, particularly its stability, without decreasing significantly the permeability capability of the mix. The use of recycled materials tends to increase the asphalt content of the mix at about 1 to 2% higher. With stability reaching 750 kg, the hot mix recycled porous asphalt may be suitable for use in the local roads with medium vehicle load.

  18. Study of asphalt performance impact with ultraviolet aging

    Science.gov (United States)

    Luo, Min

    2017-09-01

    To solve the problem of strong ultraviolet radiation on the road asphalt aging, ultraviolet aging environment box analog wild aging condition to be used to experiment, Through dynamic shear rheometer respectively to study the effect of SBS modified asphalt and asphalt matrix high temperature, low temperature and fatigue performance with the aging time to change. The results show that SBS modified asphalt can produce serious aging under strong ultraviolet light, the Main aspects is fatigue performance and low temperature performance greatly reduced, high temperature performance is further improved, They have a closer relationship with aging time; At the same time, along with the test temperature, aging time on the influence of G*/sinδ, G*sinδ of amplitude decreases. That ultraviolet on SBS modified asphalt aging has temperature sensitivity. The research conclusion can choose the light aging resistance of airport pavement asphalt to provide good technical support.

  19. Increasing the rate of recycled asphalt: an experimental study

    Directory of Open Access Journals (Sweden)

    Marjan TUŠAR

    2014-09-01

    Full Text Available Asphalt is material that can be recycled. In particular reclaimed asphalt (RA contains aged binder, which limits the reuse of RA. In this study the rate of recycled asphalt was increased by adding a rejuvenator containing paraffin. The authors investigated the effect of the rejuvenator in laboratory and in plant prepared samples of asphalt mixture. In laboratory samples with different percentage of RA (0%, 10%, 30%, 50% and rejuvenator were prepared. In asphalt plant only asphalt mixture with highest amount of RA and rejuvenator and control mixture without RA were prepared. On samples were conducted different tests, e.g. determining softening point, Fraass breaking point, penetration, indirect tensile strength. Results on extracted bitumen showed increase in softening point and decrease in Fraass breaking point with increasing percentage of RA and rejuvenator, meaning that service temperature of binders increased. Asphalt samples prepared in asphalt plant were laid on test field. Asphalt with RA and rejuvenator was built in at lower temperature (round 100 °C. Mixtures with RA and rejuvenator have better low temperature properties confirmed with Thermal Stress Restrained Specimen Test (TSRST method, but are less resistant to compaction and less sensitive to water than control mixture. For comparison of long term behaviour wheel tracking test was performed on mixtures built in test field. A week after paving, the control mixture showed better properties, but one year later the results were opposite, asphalt containing RA and rejuvenator was more resistant to rutting. From the results of this experimental study the following was concluded: the amount of RA can be increased by using rejuvenator and the quality of such asphalt mixture is in most cases equal or even better than asphalt mixture made of virgin materials. By using RA we preserve nature, reduce usage of virgin raw materials, but it is cost effective only if recycling degree is high

  20. The Development of Moisture Sensitivity Test for Compacted Asphalt

    OpenAIRE

    M.K. Shamshuddin; M.E. Abdullah; Rhasbudin Shah, S.M.

    2011-01-01

    Moisture damage is one of the major issues in asphalt distress. It is due to the adhesive and cohesive failure of asphalt mixture and it will shorten pavement life. Moisture-sensitive mixtures need to be identified during the course of the mixture design process which fulfills the specified minimum standard. The laboratory testing procedures currently available for compacted Hot Mix Asphalt (HMA) to test the moisture sensitivity were primarily developed to determine the degree ...

  1. Assessment of Asphalt Concrete Reinforcement Grid in Flexible Pavements

    Science.gov (United States)

    2016-05-01

    ER D C/ CR RE L TR -1 6- 7 New Hampshire DOT SPR2 Program Assessment of Asphalt Concrete Reinforcement Grid in Flexible Pavements Co ld...the asphalt concrete layer of a flexible pavement as an effective rehabilitation method to reduce or arrest cracking. The New Hampshire Department...4. TITLE AND SUBTITLE Assessment of Asphalt Concrete Reinforcement Grid in Flexible Pavements 5a. CONTRACT NUMBER CRADA 13-CRL-01 5b

  2. Cover for maintaining roofing in cleaning shafts

    Energy Technology Data Exchange (ETDEWEB)

    Altukhov, V.I.; Bazarov, V.D.; Belostotskiy, B.Kh.; Kuzmenko, N.S.; Mukhin, Ye.P.; Podolyako, N.I.

    1983-01-01

    The purpose of the invention is to improve reliability of maintaining roofing of inclined beds. This goal is achieved because in the cover for maintaining roofing in the extraction drifts, which includes upper sections with openings interconnected by a beam with a spacing wedge equipped with an axis for installation of an opening in the upper section and cantilevers for the upper sections and spacing wedge and arranged eccentrically in relation to the longitudinal axis of the cover, the beam axis is made with outer annular groove.

  3. Hanford Permanent Isolation Barrier Program: Asphalt technology development

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, H.D.; Romine, R.A.

    1994-11-01

    An important component of the Hanford Permanent Isolation Barrier is the use of a two-layer composite asphalt system, which provides backup water diversion capabilities if the primary capillary barrier fails to meet infiltration goals. Because of asphalt`s potential to perform to specification over the 1000-year design life criterion, a composite asphalt barrier (HMAC/fluid-applied polymer-modified asphalt) is being considered as an alternative to the bentonite clay/high density poly(ethylene) barriers for the low-permeability component of the Hanford Permanent Isolation Barrier. The feasibility of using asphalt as a long-term barrier is currently being studied. Information that must be known is the ability of asphalt to retain desirable physical properties over a period of 1000 years. This paper presents the approach for performing accelerated aging tests and evaluating the performance of samples under accelerated conditions. The results of these tests will be compared with asphalt artifact analogs and the results of modeling the degradation of the selected asphalt composite to make life-cycle predictions.

  4. Performance Evaluation of Semiplastic Recycled Cold Asphalt Using Noncement Binders

    Directory of Open Access Journals (Sweden)

    Byung Jae Lee

    2015-01-01

    Full Text Available The optimal mixing conditions for semiplastic recycled cold asphalt, which recycled waste asphalt and used noncement binders (NCB, were assessed through verification of the performance. The NCB of 6% desulfurization gypsum mixing was found to have the most outstanding properties. For the Marshall stability, 4% (NCB filler mixing brought about a 1.92-time strength increase effect compared to OPC (2% and was improved when using modified asphalt and SBR. The flow test results showed that although an increase dosage of filler and SBR decreased the flow value of the semiplastic recycled cold asphalt, an increase dosage of asphalt emulsion improved the flow value. The indirect tensile strength and liquid immersion residual stability for the condition with greatest Marshall stability were most outstanding with 0.95 MPa and 83.6%, respectively. Evaluation of the recycled cold asphalt abrasion durability revealed that for the case of mixing more than 4% NCB the mass loss rate was lower than 20%. The abrasion durability was found to improve when using modified emulsified asphalt and SBR substitution. From the test results, it was found that the optimal mixing proportion of semiplastic recycled cold asphalt satisfied mechanical properties and durability is NCB with 4%, emulsified asphalt with 3%, and SBR substitution with 20%.

  5. The Self-Drying Concept for Flat Roofs

    DEFF Research Database (Denmark)

    Korsgaard, Vagn; Bunch-Nielsen, Tommy; Rode, Carsten

    1996-01-01

    Moisture in flat roof systems with an insulation layer has been a long-standing issue for the roof industry. It is now realised, that it is unrealistic and too costly to try to completely keep moisture from entering a roof assembly during its service life. The approach, therefore, should be to keep...... cold- and warm deck roof systems in climate zones where a vapor retarder is needed, if the traditional water proof vapor retarder is substituted by a water permeable vapor retarder....

  6. Effects of reclaimed asphalt pavement on indirect tensile strength test of foamed asphalt mix tested in dry condition

    Science.gov (United States)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    Indirect tensile strength (ITS) test was conducted to analyse strength of the foamed asphalt mixes incorporating reclaimed asphalt pavement. Samples were tested for ITS after cured in the oven at 40°C for 72 hours. This testing condition known as dry condition or unconditioned. Laboratory results show that reclaimed asphalt pavement (RAP) contents insignificantly affect the ITS results. ITS results significantly affected by foamed bitumen contents.

  7. Asphalt mix reinforced with vegetable fibers

    Science.gov (United States)

    Gallo, Peter

    2017-09-01

    The use of a larger share of renewable materials in road construction is a trend that in the long term cannot be avoided. In some cases, due to this pressure, new innovative opportunities are generated. This article attempts to outline and bring one of such opportunity. The article describes selection and the use of special natural fibers from renewable natural resources adapted for use in various types of asphalt mixtures to improve the range of properties. Experimental results showed an improvement in stiffness modulus, indirect tensile strength (ITS) and good resistance to permanent deformation of blends containing vegetable fibers. This is a new topic in the road construction. But the results have so far proven that the used type of fibers can be a perspective way, as simple and in line with the policy of sustainable development, to improve the properties (reinforce) of the asphalt mixtures.

  8. 40 CFR 63.1042 - Standards-Separator fixed roof.

    Science.gov (United States)

    2010-07-01

    ... are no visible cracks, holes, gaps, or other open spaces between roof section joints or between the interface of the roof edge and the separator wall. (3) Each opening in the fixed roof shall be equipped with... position there are no visible cracks, holes, gaps, or other open spaces in the closure device or between...

  9. Green Roof Technology- Mitigate Urban Heat Island (UHI Effect

    Directory of Open Access Journals (Sweden)

    Odli Z.S. M.

    2016-01-01

    Full Text Available Alterations on the land surfaces, which are attributed by human activities, especially in cities, cause many implications to the ecosystem. The increase of buildings in cities is reflecting the growth of human activities resulted in a significant temperature increase and warmer pattern in the urban area than the surrounding countryside. The phenomenon defined as urban heat island. This study investigates the application and efficiency of the green roof as an approach to mitigate urban heat island and reducing indoor temperature in a building. Two types of roof models, which consist of vegetative roof and non-vegetative roof, were built to investigate the efficiency of vegetated roof in reducing indoor temperature compared to the non-vegetated roof. The outdoor and indoor temperature and humidity of each roof model were monitored by using RH520 Thermo Hygrometer. The data was collected for three times in a week for 9 weeks at 9:00am to 5:00pm. It was found that the indoor average temperature data for vegetative roof could be reduced 2.4°C from the outdoor average temperature and 0.8°C for non-vegetative roof. The difference of temperature reduction for vegetative roof was greater than the nonvegetative roof, thus indicate that green roof was highly efficient in reducing indoor temperature and mitigate urban heat island impact.

  10. Ageing evolution of foamed warm mix asphalt combined with reclaimed asphalt pavement

    Directory of Open Access Journals (Sweden)

    M. Perez-Martinez

    2017-07-01

    Full Text Available The combination of high rates of reclaimed asphalt pavement (RAP and warm mix asphalt (WMA technologies is still ambiguous in terms of durability. With the aim of clarifying this issue, a study comparing a hot mix asphalt with a WMA prepared using the foaming process technology. Both mixes contain 50% of RAP and are submitted to a laboratory ageing procedure. The long term related performance of the mixtures is compared by means of complex modulus and fatigue testing. Penetration and ring and ball tests are undertaken on the recovered bitumens, as well as the ageing evolution, characterised by the Fourier Transform Infrared analysis. Finally, the Apparent Molecular Weight Distribution (AMWD of the binders is calculated from rheological measurements using the δ-method. Results show a relation between ageing evolution and mechanical performance. After ageing, the overall tendencies are similar for both processes.

  11. Studying viscosity of asphalt binders and effect of varied production temperatures on engineering properties of hot mix asphalt mixtures

    National Research Council Canada - National Science Library

    Diab, Aboelkasim

    2017-01-01

    The objectives of this paper are studying the viscosity characteristics of asphalt binders containing different additives, ethylene vinyl acetate, polypropylene, and hydrated lime, and the influence...

  12. Porous Asphalt Clogging Performance Under Swedish Conditions

    OpenAIRE

    Ahmed, Fuad

    2015-01-01

    Porous asphalt has gradually gained a lot of popularity in the past ten years for its ability to reduce traffic noise, especially noise generated between tire and road surface. The acoustical absorption properties are mainly due to the pore structure and the texture of the mixture. However, the percentage of these pores decrease during the lifetime. The main reason is that dirt and organic material get stuck in the air void structure and eventually cause clogging. In Nordic countries, particl...

  13. Microbial Life in a Liquid Asphalt Desert

    OpenAIRE

    Schulze-Makuch, Dirk; Haque, Shirin; Antonio, Marina Resendes de Sousa; Ali, Denzil; Hosein, Riad; Song, Young C.; Yang, Jinshu; Zaikova, Elena; Beckles, Denise M.; Guinan, Edward; Lehto, Harry J.; Hallam, Steven J.

    2010-01-01

    An active microbiota, reaching up to 10 E+7 cells/g, was found to inhabit a naturally occurring asphalt lake characterized by low water activity and elevated temperature. Geochemical and molecular taxonomic approaches revealed novel and deeply branching microbial assemblages mediating anaerobic hydrocarbon degradation, metal respiration and C1 utilization pathways. These results open a window into the origin and adaptive evolution of microbial life within recalcitrant hydrocarbon matrices, an...

  14. One Roof Judicial System in Indonesia

    Directory of Open Access Journals (Sweden)

    - Sufiarina

    2012-09-01

    Full Text Available Judicial power as an independent and autonomous power must be free from any intervention and power, thus ensuring that judges possess independence and impartiality in handling cases. One of the measures for enhancing the independence and autonomy of the judiciary is by placing it under the one roof judicial arrangement developed by the Supreme Court, both from the judicial as well as the non-judicial technical aspects. Up to the present time, endeavors for bringing the four court jurisdictions under the one roof judicial arrangement developed by the Supreme Court have not been completely materialized, due to the existing dualism in judicial power at various courts. The objective of this research is to understand the developments in the endeavors towards bringing the Indonesian judicial system under the one roof judicial arrangement developed by the Supreme Court. The type of research applied is descriptive normative juridical research, namely legal research based on examining secondary data. As the research results indicate, the one roof system developed by the Supreme Court is already being implemented, with the exception of the Military Court and the Tax Court within the State Administration Court jurisdiction.

  15. Load-Bearing Capacity of Roof Trusses

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Damkilde, Lars; Munch-Andersen, J.

    2004-01-01

    systems such as roof trusses are established and statistical characteristics of the load bearing capacity are determined. The results show that there is a significant increase in the characteristic (nominal) value and a reduction in the coefficient of variation (COV) for typical loads such as permanent...

  16. Effective roof support for tabular stopes.

    CSIR Research Space (South Africa)

    Ottermann, RW

    2002-09-01

    Full Text Available This project follows on from project GAP 708, The Design and Development of an Effective Support System for Tabular Stopes in Gold and Platinum Mines. The primary output of this project is to develop and surface test an effective roof support system...

  17. Roof Shield for Advance and Retreat Mining

    Science.gov (United States)

    Lewis, E. V.

    1985-01-01

    Shield sections change their configuration to suit mining mode. Articulation cylinders raise rear shield to advance position, and locking cylinders hold it there. To change to retreat position articulation cylinders lower shield. Locking pins at edge of outermost shield plate latch shield to chock base. Shield accommodates roof heights ranging from 36 to 60 inches (0.9 to 1.52 meters).

  18. Accidents due to falls from roof slabs

    Directory of Open Access Journals (Sweden)

    Bruno Alves Rudelli

    Full Text Available CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%. Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%, and flying a kite was the most prevalent game (37.9%. In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  19. Microtexture diagnostics of asphalt pavement surfaces

    Science.gov (United States)

    Florková, Zuzana; Pepucha, L.'ubomír

    2017-09-01

    The microtexture of asphalt pavement surface is an essential parameter from the traffic safety point of view and it closely relates to a geometrical, petrological and physical properties of aggregate particle used in asphalt pavement. Microtexture has a significant influence for assurance basic friction values between tire and pavement in relation to a skid resistance properties. Therefore, the microtexture detecting methods are necessary. The British pendulum tester measurements have been carried out on selected sections of roads with different asphalt surfaces. Individual grains of aggregates were taken from the surface of each section from the sliding path and also from the core sample after the extraction. The laboratory profilometry measurements have been practiced on these aggregate samples and subsequently the surface microtexture was investigated based on commonly used texture characteristics and the filtration approach was applied in calculation process. The results have shown the degradation of microtexture values occurs due to polishing of aggregate under loading from traffic in relation to the type of used aggregate. Some correlation between BPN values and texture characteristics was found.

  20. Dynamic modulus of nanosilica modified porous asphalt

    Science.gov (United States)

    Arshad, A. K.; Masri, K. A.; Ahmad, J.; Samsudin, M. S.

    2017-11-01

    Porous asphalt (PA) is a flexible pavement layer with high interconnected air void contents and constructed using open-graded aggregates. Due to high temperature environment and increased traffic volume in Malaysia, PA may have deficiencies particularly in rutting and stiffness of the mix. A possible way to improve these deficiencies is to improve the asphalt binder used. Binder is normally modified using polymer materials to improve its properties. However, nanotechnology presently is being gradually used for asphalt modification. Nanosilica (NS), a byproduct of rice husk and palm oil fuel ash is used as additive in this study. The aim of this study is to enhance the rutting resistance and stiffness performance of PA using NS. This study focused on the performance of PA in terms of dynamic modulus with the addition of NS modified binder to produce better and more durable PA. From the result of Dynamic SPT Test, it shows that the addition of NS was capable in enhancing the stiffness and rutting resistance of PA. The addition of NS also increase the dynamic modulus value of PA by 50%.

  1. Ethanol based foamed asphalt as potential alternative for low emission asphalt technology

    OpenAIRE

    Mohd Hasan, Mohd Rosli; You, Zhanping

    2016-01-01

    Foamed asphalt typically relies on water as a foaming agent because water becomes gaseous at elevated temperatures, generating numerous tiny bubbles in the asphalt and causing spontaneous foaming. In this study, ethanol was used as a potential alternative to water as a foaming agent. Ethanol is expected to be a physical blowing agent in the same manner as water, except it requires less energy to foam due to its 78 °C boiling point. This study compares the performance of water and ethanol as f...

  2. Evolution of cool-roof standards in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Akbari, Hashem; Levinson, Ronnen

    2008-07-11

    Roofs that have high solar reflectance and high thermal emittance stay cool in the sun. A roof with lower thermal emittance but exceptionally high solar reflectance can also stay cool in the sun. Substituting a cool roof for a noncool roof decreases cooling-electricity use, cooling-power demand, and cooling-equipment capacity requirements, while slightly increasing heating-energy consumption. Cool roofs can also lower citywide ambient air temperature in summer, slowing ozone formation and increasing human comfort. Provisions for cool roofs in energy-efficiency standards can promote the building- and climate-appropriate use of cool roofing technologies. Cool-roof requirements are designed to reduce building energy use, while energy-neutral cool-roof credits permit the use of less energy-efficient components (e.g., larger windows) in a building that has energy-saving cool roofs. Both types of measures can reduce the life-cycle cost of a building (initial cost plus lifetime energy cost). Since 1999, several widely used building energy-efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool-roof credits or requirements. This paper reviews the technical development of cool-roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discusses the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool-roof provisions can be used as models to address cool roofs in building energy-efficiency standards worldwide.

  3. Status of cool roof standards in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Levinson, Ronnen

    2007-06-01

    Since 1999, several widely used building energy efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool roof credits or requirements. We review the technical development of cool roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discuss the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool roof provisions can be used as models to address cool roofs in building energy standards worldwide.

  4. Including asphalt cooling and rolling regimes in laboratory compaction procedures

    NARCIS (Netherlands)

    Bijleveld, Frank; Doree, Andries G.; Kim,

    2014-01-01

    Given the various changes occurring in the asphalt construction industry, improved process and quality control is becoming essential. The significance of appropriate rolling and compaction for the quality of asphalt is widely acknowledged and vital for improved process control. But what constitutes

  5. Occupational Renal Dysfunction Among Asphalt Workers In Sharkia ...

    African Journals Online (AJOL)

    Background: Occupational exposure to bitumen fumes emitted during hot application of asphalt carries the risk of exposure to significant amount of hydrocarbon compounds that may cause toxic nephropathy. Objectives: Investigation of renal dysfunction among asphalt-exposed workers and identification of some factors that ...

  6. Characterization of Failure and Permanent Deformation Behaviour of Asphalt Concrete

    NARCIS (Netherlands)

    Molenaar, A.A.A.; Wu, S.P.; Wang, J.G.

    Asphalt concrete is a viscoelastic material consisting of aggregates, filler and bitumen. The response of asphalt concrete is highly dependent on temperature, loading rate and confining pressure. Permanent deformation is one of the most important distresses developing during the flexible pavement

  7. Crack repair of asphalt concrete with induction energy

    NARCIS (Netherlands)

    García, A.; Schlangen, E.; Van de Ven, M.; Van Vliet, D.

    It is well known that the healing rates of asphalt courses increase with the temperature. A new method, induction heating, is used in this paper to increase the lifetime of asphalt concrete pavements. Mastic will be first made electrically conductive by the addition of conductive fibers. Then it

  8. Crack repair of asphalt concrete with induction energy

    NARCIS (Netherlands)

    García, A.; Schlangen, E.; Ven, M. van de; Vliet, D. van

    2011-01-01

    It is well known that the healing rates of asphalt courses increase with the temperature. A new method, induction heating, is used in this paper to increase the lifetime of asphalt concrete pavements. Mastic will be first made electrically conductive by the addition of conductive fibers. Then it

  9. Estimation of fatigue characteristics of asphaltic mixes using simple tests

    NARCIS (Netherlands)

    Medani, T.O.; Molenaar, A.A.A.

    2000-01-01

    A simplified procedure for estimation of fatigue characteristics of asphaltic mixes is presented. The procedure requires the determination of the so-called master curve (Le. the relationship between the mix stiffness, the loading time and the temperature), the asphalt properties and the mix

  10. Terrestrial radiation level in selected asphalt plants in Port Harcourt ...

    African Journals Online (AJOL)

    An environmental radiation survey in asphalt processing plants in Rivers State was been carried out using a well calibrated Radalert survey meter. Measurements were carried out in four different locations of asphalt processing plants at different strategic points. Measured average values of 0.0223 ± 0.0017 mR/hr, 0.0225 ...

  11. 7 CFR 2902.36 - Concrete and asphalt release fluids.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Concrete and asphalt release fluids. 2902.36 Section... PROCUREMENT Designated Items § 2902.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete or...

  12. Laboratory and Field Asphalt Fatigue Performance, Matching Theory with Practice

    NARCIS (Netherlands)

    Pramesti, F.P.

    2015-01-01

    This thesis investigates the relationship between predicted and observed fatigue life of asphalt. This study also investigates the positive effects of modifying bitumen with Retona, a bitumen modifier produced in Indonesia from natural asphalt rock sources, on pavement performance in terms of

  13. Lead and zinc removal with storage period in porous asphalt ...

    African Journals Online (AJOL)

    Porous asphalt pavements have been used as an effective technique to overcome road runoff challenges, and to improve efficiency of rainwater utilisation in urban areas. Using porous asphalt pavements with reservoir storage and harvesting facilities is an important consideration for the future. This study monitored ...

  14. Characterization of Failure and Permanent Deformation Behaviour of Asphalt Concrete

    NARCIS (Netherlands)

    Wang, J.G.

    2015-01-01

    Asphalt concrete is a viscoelastic material consisting of aggregates, filler and bitumen. The response of asphalt concrete is highly dependent on temperature, loading rate and confining pressure. Permanent deformation is one of the most important distresses developing during the flexible pavement

  15. Investigation of stress and heat strain in asphalt workers

    Directory of Open Access Journals (Sweden)

    Mohammad Hosein Beheshti

    2017-07-01

    Full Text Available Heat stress is one of the harmful factors in workplaces. Asphalt workers are exposed to thermal stress due to the open environment and process. The aim of this study was to assess the heat stress and strain in asphalt workers. This study was conducted on 29 employees of asphalt workstation. The heat stress was measured based on Wet-Bulb Globe Temperature (WBGT. Also, physiological parameters such as blood pressure and heart rate of asphalt workers were measured. The mean of WBGT index for drivers of asphalt machinery, trowels, shovels people and burner servicemen were 27.77, 27.77 and 29.61°C respectively whereas this value was 29.81, 29.85 and 3.23°C for workers of asphalt workstations respectively. The process of asphalting has significant effect on heat stress and physiological parameters of individuals. The pearson correlation between WBGT and heart rate, systolic blood pressure and diastolic blood pressure was significant. Asphalt workers are exposed to heat stress caused by different sources which may generate a host of heat strains in these people so special attention should be paid to control heat stress.

  16. Impact of Modificated Asphalt Mixtures on Paving Functioning and Environment

    Directory of Open Access Journals (Sweden)

    Gediminas Gribulis

    2016-10-01

    Full Text Available Atmospheric pollution began to increase in the beginning of 19th century, when the global economy and industrial development started the signal grow. The current problem of global warming is partly related with emission of carbon dioxide (CO2 to environment, which one of the sources are industrial production companies. Warm asphalt mix is usually used in the practice of Lithuania and the world for equipment of road paving. These mixes are produced in specialized asphalt mixers where stone dosing, drying and its mixing with bituminous binders are performed. The temperature of produced hot asphalt mix in mixer reach 150–180 °C and 120–160 °C of mixture laying on the road. Various pollutants, carbon dioxide, formaldehydes, and other are spread to the environment. The carried out researches in Lithuania and the world have showed that while using special additives it is possible to reduce the temperatures of warm asphalt production and laying on the road. Such reduction of temperature helps not to worsen the quality of asphalt layer, to lower the emission of pollutants to environment, to improve the conditions of road workers and to economically use the gas for production of asphalt mixes. Production technologies of different asphalt mixes, their advantages and disadvantages, and results of laboratory tests are analyzed in this article. Equipment samples of experimental road sections, using the warm mixing asphalt mixtures are given.

  17. Improving the quality of asphalt coating with carbon nanomodifiers

    Science.gov (United States)

    Larisa, Urkhanova; Nikolay, Shestakov; Aleksandr, Semenov; Natalya, Smirnyagina; Irina, Semenova

    2015-07-01

    This article deals with the possibility of modifying the binder by adding carbon nanomodifier to bitumen to improve the quality of asphalt. Addition of 0.05%-0.5% of nanomodifier significantly changes the properties of bitumen. Asphalt with this astringent has increased strength, heat resistance and shear resistance.

  18. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Science.gov (United States)

    2010-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable to discharges...

  19. 40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

    Science.gov (United States)

    2010-07-01

    ... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to discharges...

  20. Establishing green roof infrastructure through environmental policy instruments.

    Science.gov (United States)

    Carter, Timothy; Fowler, Laurie

    2008-07-01

    Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated

  1. Laboratory Mix Design of Asphalt Mixture Containing Reclaimed Material

    Directory of Open Access Journals (Sweden)

    Davide Lo Presti

    2014-01-01

    Full Text Available This paper presents a study on the production of asphalt test specimens in the laboratory containing reclaimed asphalt. The mixtures considered were stone mastic asphalt concrete mixtures containing up to 30% of reclaimed asphalt. Specimens were compacted to the reference density obtained from the Marshall mix design. Gyration compaction method was used for preparing specimens for the experimental programme, while coring and cutting methods and X-ray computed tomography (CT were used to investigate the change in properties within the specimens and to validate the selected methodology. The study concluded that gyratory compaction is suitable to produce homogeneous test specimens also for mixtures containing high amount of reclaimed asphalt. Nevertheless, preliminary trials for each material are mandatory, as well as final coring and trimming of the specimens due to side effects.

  2. Recycling of Reclaimed Asphalt Pavement in Portland Cement Concrete

    Directory of Open Access Journals (Sweden)

    Salim Al-Oraimi

    2009-06-01

    Full Text Available Reclaimed Asphalt Pavement (RAP is the result of removing old asphalt pavement material. RAP consists of high quality well-graded aggregate coated with asphalt cement. The removal of asphalt concrete is done for reconstruction purposes, resurfacing, or to obtain access to buried utilities. The disposal of RAP represents a large loss of valuable source of high quality aggregate. This research investigates the properties of concrete utilizing recycled reclaimed asphalt pavement (RAP. Two control mixes with normal aggregate were designed with water cement ratios of 0.45 and 0.5. The control mixes resulted in compressive strengths of 50 and 33 MPa after 28 days of curing. The coarse fraction of RAP was used to replace the coarse aggregate with 25, 50, 75, and 100% for both mixtures. In addition to the control mix (0%, the mixes containing RAP were evaluated for slump, compressive strength, flexural strength, and modulus of elasticity. Durability was evaluated using surface absorption test.

  3. Preparation of Flame Retardant Modified with Titanate for Asphalt Binder

    Directory of Open Access Journals (Sweden)

    Bo Li

    2014-01-01

    Full Text Available Improving the compatibility between flame retardant and asphalt is a difficult task due to the complex nature of the materials. This study explores a low dosage compound flame retardant and seeks to improve the compatibility between flame retardants and asphalt. An orthogonal experiment was designed taking magnesium hydroxide, ammonium polyphosphate, and melamine as factors. The oil absorption and activation index were tested to determine the effect of titanate on the flame retardant additive. The pavement performance test was conducted to evaluate the effect of the flame retardant additive. Oxygen index test was conducted to confirm the effect of flame retardant on flame ability of asphalt binder. The results of this study showed that the new composite flame retardant is more effective in improving the compatibility between flame retardant and asphalt and reducing the limiting oxygen index of asphalt binder tested in this study.

  4. Utilization of recycled asphalt concrete with warm mix asphalt and cost-benefit analysis.

    Directory of Open Access Journals (Sweden)

    Julide Oner

    Full Text Available The asphalt paving industries are faced with two major problems. These two important challenges are generated with an increase in demand for environmentally friendly paving mixtures and the problem of rapidly rising raw materials. Recycling of reclaimed asphalt pavement (RAP is a critical necessity to save precious aggregates and reduce the use of costly bitumen. Warm Mix Asphalt (WMA technology provides not only the option of recycling asphalt pavement at a lower temperature than the temperature maintained in hot mixtures but also encourages the utilization of RAP and therefore saves energy and money. This paper describes the feasibility of utilizing three different WMA additives (organic, chemical and water containing at recommended contents with different percentages of RAP. The mechanical properties and cost-benefit analysis of WMA containing RAP have been performed and compared with WMA without RAP. The results indicated that, 30%, 10% and 20% can be accepted as an optimum RAP addition related to organic, chemical and water containing additives respectively and organic additive with 30% RAP content has an appreciable increase in tensile strength over the control mix. It was also concluded that the RAP with WMA technology is the ability to reduce final cost compared to HMA and WMA mixtures.

  5. Utilization of recycled asphalt concrete with warm mix asphalt and cost-benefit analysis.

    Science.gov (United States)

    Oner, Julide; Sengoz, Burak

    2015-01-01

    The asphalt paving industries are faced with two major problems. These two important challenges are generated with an increase in demand for environmentally friendly paving mixtures and the problem of rapidly rising raw materials. Recycling of reclaimed asphalt pavement (RAP) is a critical necessity to save precious aggregates and reduce the use of costly bitumen. Warm Mix Asphalt (WMA) technology provides not only the option of recycling asphalt pavement at a lower temperature than the temperature maintained in hot mixtures but also encourages the utilization of RAP and therefore saves energy and money. This paper describes the feasibility of utilizing three different WMA additives (organic, chemical and water containing) at recommended contents with different percentages of RAP. The mechanical properties and cost-benefit analysis of WMA containing RAP have been performed and compared with WMA without RAP. The results indicated that, 30%, 10% and 20% can be accepted as an optimum RAP addition related to organic, chemical and water containing additives respectively and organic additive with 30% RAP content has an appreciable increase in tensile strength over the control mix. It was also concluded that the RAP with WMA technology is the ability to reduce final cost compared to HMA and WMA mixtures.

  6. Effect of asphalt rejuvenating agent on aged reclaimed asphalt pavement and binder properties

    Science.gov (United States)

    Sabahfar, Nassim

    Hot in-place recycling (HIR) preserves distressed asphalt pavements while minimizing use of virgin binder and aggregates. The final quality of an HIR mixture depends on characteristics of the original binder, aging of the pavement surface during service, and whether or not new binder or rejuvenator was added to the mixture. An HIR mixture should maintain desired properties for additional service periods, making asphalt binder modification inevitable. Asphalt binder modifications in HIR are commonly done by adding an asphalt rejuvenating agent (ARA). However, ARA may adversely affect the qualities of new HIR and potentially fail to improve the quality of the final surface. The objective of this research was to investigate the effects of rejuvenation on HIR performance characteristics by assessing critical performance indicators such as stiffness, permanent deformation, moisture susceptibility, and cracking resistance. A two-step experimental program was designed that included mechanical property measurements of the HIR mixture and rheological properties of the extracted binder. The level of mixing occurring between new and aged binder with ARA was also investigated. HIR Samples were obtained from three Kansas Department of Transportation projects, and Hamburg wheel-tracking device, dynamic modulus, flow number, Texas overlay, thermal stress restrained specimen, and moisture susceptibility tests were conducted on mixtures with and without ARA. Rheological studies on the extracted binder included dynamic shear rheometer and bending beam rheometer tests. The miscibility of new and aged binder was investigated using scanning electron microscope (SEM) images, energy dispersive X-ray spectroscopy (EDXS), and the exudation droplet test (EDT). Study results showed significant variability in the mechanical performance of HIR mixtures, which was attributed to the variability of binders as observed in EDT, SEM and EDXS studies. Life cycle cost analysis (LCCA) showed that HIR

  7. The first engineered self-healing asphalt road: How is it performing?

    OpenAIRE

    Liu, Q.; Schlangen, H.E.J.G.; Van Bochove, G.

    2013-01-01

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the surface layer, is the main damage mechanism of porous asphalt surface wearing courses. In this research, an induction healing approach (namely, activating the healing process of asphalt concrete through ...

  8. INFLUENCE OF SEA WATER ON THE MECHANICAL PROPERTIES OF POROUS ASPHALT CONTAINING LIQUID ASBUTON

    OpenAIRE

    N, Ali; L, Samang; Tjaronge, M.W.; A.Rahman, Djamaluddin

    2011-01-01

    The Buton Asphalt or Asbuton is natural rock asphalt that deposited on South Buton Island in southeast Sulawesi Island, Indonesia. The refining process reduces the mineral content to produce the liquid Asbuton. Porous asphalt is an asphalt pavement that has enough voids within to allow water to pass freely through it. This paper reports on experimental investigation conducted to determine the influence of sea water on the mechanical properties of porous asphalt containing liqui...

  9. Rating system for coal mine roofs

    CSIR Research Space (South Africa)

    Canbulat, I

    2002-09-01

    Full Text Available Highly weathered creamy orange to greyBeaufort (?) mudstone. 18 Unweathered grey Beaufort (?) mudstone. 19 Massive khaki to grey mudstone associatedwith diamictite. 20 Dark greyish black gritty diamictite with angular 0-4 mmmatrix supported clasts 21... Dark greyish black pebbly diamictite with , angular matrixsupported clasts > 4 mm diameter. Not applicable. 22 Coal mixed dull and bright. More stable roof rock than facies 1-3. 23 Mixed coal and mudstone. 24 Massive greyish black carbonaceous...

  10. Construction of Experimental Polyvinyl Chloride (PVC) Roofing.

    Science.gov (United States)

    1984-04-01

    checks were made when the gravel spreader tires ran over a single stone. No punctures Nailers were installed around all roof penetra- in the membrane...lateral run of strips was welded, the mem- at the perimeter nailers with a I in. (25-mm) lap. As brane was folded progressively across adjacent rows... nailers around the perimeters were re- od to use. Xylene was used to clean the discs and - used. To make them flush with the insulation sur- toluene

  11. Installation of a Roof Mounted Photovoltaic System

    Science.gov (United States)

    Lam, M.

    2015-12-01

    In order to create a safe and comfortable environment for students to learn, a lot of electricity, which is generated from coal fired power plants, is used. Therefore, ISF Academy, a school in Hong Kong with approximately 1,500 students, will be installing a rooftop photovoltaic (PV) system with 302 solar panels. Not only will these panels be used to power a classroom, they will also serve as an educational opportunity for students to learn about the importance of renewable energy technology and its uses. There were four different options for the installation of the solar panels, and the final choice was made based on the loading capacity of the roof, considering the fact that overstressing the roof could prove to be a safety hazard. Moreover, due to consideration of the risk of typhoons in Hong Kong, the solar panel PV system will include concrete plinths as counterweights - but not so much that the roof would be severely overstressed. During and after the installation of the PV system, students involved would be able to do multiple calculations, such as determining the reduction of the school's carbon footprint. This can allow students to learn about the impact renewable energy can have on the environment. Another project students can participate in includes measuring the efficiency of the solar panels and how much power can be produced per year, which in turn can help with calculate the amount of money saved per year and when we will achieve economic parity. In short, the installation of the roof mounted PV system will not only be able to help save money for the school but also provide learning opportunities for students studying at the ISF Academy.

  12. Use of emulsion for warm mix asphalt

    Directory of Open Access Journals (Sweden)

    Mahabir Panda

    2017-06-01

    Full Text Available Due to increase in energy costs and emission problems in hot mix asphalt usually used, it brought a great interest to the researchers to develop the warm mix technology for pavement constructions. Commonly known as warm mix asphalt (WMA, it is a typical method in the bituminous paving technology, which allows production and placement of bituminous mixes at lower temperatures than that used for hot mix asphalt (HMA. The WMA involves an environmental friendly production process that utilises organic additives, chemical additives and water based technologies. The organic and chemical additives are normally very costly and still involve certain amount of environmental issues. These factors motivated the authors to take up this technology using simple, environment friendly and somewhat cost effective procedure. In this study, an attempt has been made to prepare warm mixes by first pre-coating the aggregates with medium setting bitumen emulsion (MS and then mixing the semi-coated aggregates with VG 30 bitumen at a lower temperature than normally required. After a number of trials it was observed that mostly three mixing temperatures, namely temperatures 110 °C, 120 °C and 130 °C were appropriate to form the bituminous mixes with satisfactory homogeneity and consistency and as such were maintained throughout this study. Marshall samples for paving mixes were prepared using this procedure for dense bituminous macadam (DBM gradings as per the specifications of Ministry of Road Transport and Highways (MORTH and subsequently Marshall properties of the resultant mixes were studied with the main objective of deciding the different parameters that were considered for development of appropriate warm mix asphalt. In this study it has been observed that out of three mixing temperatures tried, the mixes prepared at 120 °C with bitumen-emulsion composition of 80B:20E for DBM warm mix, offer highest Marshall stability and highest indirect tensile strength

  13. Microbial Life in a Liquid Asphalt Desert

    CERN Document Server

    Schulze-Makuch, Dirk; Antonio, Marina Resendes de Sousa; Ali, Denzil; Hosein, Riad; Song, Young C; Yang, Jinshu; Zaikova, Elena; Beckles, Denise M; Guinan, Edward; Lehto, Harry J; Hallam, Steven J

    2010-01-01

    An active microbiota, reaching up to 10 E+7 cells/g, was found to inhabit a naturally occurring asphalt lake characterized by low water activity and elevated temperature. Geochemical and molecular taxonomic approaches revealed novel and deeply branching microbial assemblages mediating anaerobic hydrocarbon degradation, metal respiration and C1 utilization pathways. These results open a window into the origin and adaptive evolution of microbial life within recalcitrant hydrocarbon matrices, and establish the site as a useful analog for the liquid hydrocarbon environments on Saturn's moon Titan.

  14. Performance Modification of Asphalt Binders using Thermoplastic Polymers

    Directory of Open Access Journals (Sweden)

    H. I. Al-Abdul Wahhab

    2004-12-01

    Full Text Available There is a need to improve the performance of asphalt binders to minimize stress cracking that occurs at low temperatures and plastic deformation at high temperatures. Importation of used asphalt-polymers from abroad, leads to an increase in the total construction cost as compared to the cost if the used polymers were of local origin. The main objective of this research was to modify locally produced asphalt. Ten polymers were identified as potential asphalt modifiers based on their physical properties and chemical composition. After preliminary laboratory evaluation for the melting point of these polymers, five polymers were selected for local asphalt modification. In the initial stage, required mixing time was decided based on the relation between shear loss modulus and mixing time .The optimum polymer content was selected based on Superpave binder performance grade specifications.The suitability of improvement was verified through the evaluation of permanent deformation and fatigue behavior of laboratory prepared asphalt concrete mixes. The results indicated that the rheological properties of the modified binders improved significantly with sufficient polymer content (3%. The aging properties of the modified binders were found to be dependent on the type of polymer.The fatigue life and resistance to permanent deformation were significantly improved due to enhanced binder rheological properties.  Thus, local asphalts can be modified using thermoplastic polymers.

  15. Voids characteristics of asphaltic concrete containing coconut shell

    Science.gov (United States)

    Ezree Abdullah, Mohd; Hannani Madzaili, Amirah; Putra Jaya, Ramadhansyah; Yaacob, Haryati; Hassan, Norhidayah Abdul; Nazri, Fadzli Mohamed

    2017-07-01

    Asphalt durability is often linked to the thickness of the asphalt coating on the aggregate particles. In order to have adequate film thickness in asphaltic concrete, there must be sufficient space between the aggregate particles in the compacted pavement. This void space is referred to as voids in total mix (VTM), voids with filled bitumen (VFB), and voids in mineral aggregate (VMA). Hence, this study investigates the performance of coconut shell (CS) as coarse aggregate replacement on voids characteristics of asphaltic concrete. Four CS were used as coarse aggregates replacement in asphalt mixture namely 0%, 10%, 20%, 30%, and 40% (by weight volume). The voids properties of asphalt mixture were determined based on Marshall Mix design test. Test results show that VTM and VMA values were decrease with the increasing bitumen content where VFB was increase with increasing bitumen content. Furthermore, increasing the percentage of coconut shell in asphalt mixture was found to increases the voids value up to a peak level and then decreases with further additions of CS.

  16. Green Roofs: Federal Energy Management Program (FEMP) Federal Technology Alert

    Energy Technology Data Exchange (ETDEWEB)

    Scholz-Barth, K.; Tanner, S.

    2004-09-01

    In a ''green roof,'' a layer of vegetation (e.g., a roof garden) covers the surface of a roof to provide shade, cooler indoor and outdoor temperatures, and effective storm-water management to reduce runoff. The main components are waterproofing, soil, and plants. There are two basic kinds: intensive and extensive. An intensive green roof often features large shrubs and trees, and it can be expensive to install and maintain. An extensive green roof features shallow soil and low-growing, horizontally spreading plants that can thrive in the alpine conditions of many rooftops. These plants do not require a lot of water or soil, and they can tolerate a significant amount of exposure to the sun and wind. This Federal Technology Alert focuses on the benefits, design, and implementation of extensive green roofs and includes criteria for their use on federal facilities.

  17. Numerical simulation of asphalt mixtures fracture using continuum models

    Science.gov (United States)

    Szydłowski, Cezary; Górski, Jarosław; Stienss, Marcin; Smakosz, Łukasz

    2018-01-01

    The paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasi-continuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate and the air voids composing the material. The model directly captures random nature of material parameters and aggregate distribution in specimens. Initial results of the analysis are presented here.

  18. TECHNICAL CONSIDERATIONS FOR THE PLANNING OF ROOF GARDENS

    Directory of Open Access Journals (Sweden)

    Nizamettin KOÇ

    1998-01-01

    Full Text Available Increases in population, buildings, traffic density and air pollution is the most specific characteristics of metropol cities. These conditions effect the living quality negatively. That is why architectures and planners should find both aesthetic and functional planning approach in urban areas. Roof gardens, which affect positively urban ecology in many ways, have an important place in this approach. Planning aproach of roof gardens are rather different compare to ground level design. Structural elements under the roof gardens againist the infiltration of water. That is why it is important that roof garden plannings should have some layers shuclh as drainage, insulation, waterproofing, filter layers and irrigation andf drainage systems.

  19. Mathematical and experimental investigations of modeling, simulation and experiment to promote the life-cycle of polymer modified asphalt.

    Science.gov (United States)

    2014-07-01

    The formulation of constitutive equations for asphaltic pavement is based on rheological models which include the asphalt mixture, additives, and the bitumen. In terms of the asphalt, the rheology addresses the flow and permanent deformation in time,...

  20. Three-Dimensional Surface Texture of Asphalt Pavements Containing Reclaimed Asphalt Concrete

    OpenAIRE

    Liu, Qingfan; Esfandiarpour, Saman; Shalaby, Ahmed

    2015-01-01

    The type, shape, and gradation of aggregate have significant influence upon surface texture and its durability. The properties of reclaimed asphalt pavement (RAP) are different from virgin aggregate. Previous research found that the presence of RAP influenced negatively the pavement surface terminal friction value and surface polishing rate. The objective of this research is to assess the impact of high content of RAP on pavement surface texture after five years of environmental and traffic l...

  1. Phosphate Leaching from Green Roof Substrates—Can Green Roofs Pollute Urban Water Bodies?

    Directory of Open Access Journals (Sweden)

    Agnieszka Karczmarczyk

    2018-02-01

    Full Text Available Green roofs are an effective stormwater measure due to high water retention capacity and the ability of delaying stormwater runoff. However, low importance is still given to the pollutant leaching potential of substrates used in green roof construction. The aim of the study is to estimate the concentrations and loads of P-PO43− in runoff from extensive and intensive substrates. To achieve this goal, several commonly-used fresh substrates were analyzed for P-PO43− leaching potential in different scale experiments, from laboratory batch tests, leaching column experiments, and long-term monitoring of open air green roof containers. The results of the study confirmed that fresh green roof substrates contain phosphorus in significant amounts of 17–145 mg∙P-PO43−/kg and, thus, can contribute to eutrophication of freshwater ecosystems. High correlation between phosphate content estimated by HCl extraction and cumulative load in leachate tests suggests that the batch HCl extraction test can be recommended for the comparison and selection of substrates with low potential P leaching. Volume-weighted mean concentrations and UALs of P-PO43− leaching from fresh substrates were higher in cases of intensive substrates, but there was no clear relationship between substrate type and the observed P-PO43− concentration range. To avoid increasing eutrophication of urban receivers the implementation of P reduction measures is strongly recommended.

  2. Roof renovation of buildings 128 and 129

    CERN Document Server

    2015-01-01

    The roof renovation of buildings 128 and 129 is scheduled to take place from 17 August to 15 October 2015.   During this period, access to the "raw material" workshop will be limited and controlled due to asbestos removal. Collecting your orders directly from the building will be difficult, or even impossible, and urgent requests will be difficult to carry out. We therefore ask you to create your requests via EDH, so that delivery may be carried out as soon as possible. Thank you for your understanding. GS Department

  3. Insulation Retrofit under Low-Slope Roofs.

    Science.gov (United States)

    1982-02-01

    manufactured by Thermo Products Company, is a cellulose material with a 3 SURVEY RESULTS density of about 2.5 lb/cu ft (40 kg/m 3 ). An adhesive material...a glass-fiber-reinforced, few products that can be used under the roof deck polyisocyanurate plastic core. The plastic foam core are available; most...syrstemJs that use various ty’pes of me1chanical fastening 20. It has a high- impact-resistant surface wArith a low d evices. in which either adhesive -applied

  4. High Efficiency Solar Integrated Roof Membrane Product

    Energy Technology Data Exchange (ETDEWEB)

    Partyka, Eric; Shenoy, Anil

    2013-05-15

    This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

  5. Risk management of low air void asphalt concrete mixtures.

    Science.gov (United States)

    2013-07-01

    Various forms of asphalt pavement distress, such as rutting, shoving and bleeding, can be attributed, in many cases, to low air voids in : the mixtures during production and placement. The occurrence of low air void contents during plant production m...

  6. Relation of asphalt chemistry to physical properties and specifications.

    Science.gov (United States)

    1984-01-01

    This report constitutes a synthesis of published information concerning the chemical composition and characteristics of asphalt cements used in highway construction. The general relations between chemical composition and physical properties and speci...

  7. Bettis Asphalt and Construction, Inc. - Clean Water Act Public Notice

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Bettis Asphalt and Construction, Inc. for alleged violations at its facility located at 2350 Northwest Water Works Drive, Topeka, KS 66606.

  8. Developing model asphalt systems using molecular simulation : final model.

    Science.gov (United States)

    2009-09-01

    Computer based molecular simulations have been used towards developing simple mixture compositions whose : physical properties resemble those of real asphalts. First, Monte Carlo simulations with the OPLS all-atom force : field were used to predict t...

  9. Lead and zinc removal with storage period in porous asphalt ...

    African Journals Online (AJOL)

    2013-03-01

    . ABSTRACT. Porous asphalt pavements have been used as an effective technique to overcome road runoff challenges, and to improve efficiency of ...... FIELD R, MASTERS H and SINGER M (1982) An overview of porous.

  10. Storm Water General Permit 3 for Rock and Asphalt

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — General permit #3 for storm water discharges associated with industrial activity for Asphalt Plants, Concrete Batch Plants, Rock Crushing Plants and Construction...

  11. Development of bio-based polymers for use in asphalt.

    Science.gov (United States)

    2014-02-01

    Asphalt binder is typically modified with poly type (styrene-butadiene-styrene or SBS) polymers to improve its rheological properties and performance grade. The elastic and principal component of SBS polymers is butadiene. For the last decade, butadi...

  12. Towards analytical mix design for large-stone asphalt mixes.

    CSIR Research Space (South Africa)

    Rust, FC

    1992-08-01

    Full Text Available This paper addresses the development of an analytically based design procedure for large-aggregate asphalt and its application in thirteen trial sections. The physical and engineering properties of the various materials are discussed and related...

  13. 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...

  14. Predicting low-temperature cracking in asphalt pavements : [research brief].

    Science.gov (United States)

    2011-12-01

    In Wisconsin's winter climate, low temperatures can cause asphalt pavements to contract and crack, reducing their ride quality and service lives. To help engineers more accurately determine how well certain pavement designs will fare in such conditio...

  15. Improving DMS 9210 requirements for limestone rock asphalt - final report.

    Science.gov (United States)

    2015-03-01

    Limestone Rock Asphalt (LRA) mixtures have been produced and placed for several decades using : specification requirements currently listed under DMS 9210. Several districts have had placement issues : and premature failures at the beginning of 2010....

  16. Density measurement verification for hot mixed asphalt concrete pavement construction.

    Science.gov (United States)

    2010-06-01

    Oregon Department of Transportation (ODOT) requires a minimum density for the construction of dense-graded hot mix asphalt concrete (HMAC) pavements to ensure the likelihood that the pavement will not experience distresses that reduce the expected se...

  17. Density measurement verification for hot mix asphalt concrete pavement construction.

    Science.gov (United States)

    2010-06-01

    Oregon Department of Transportation (ODOT) requires a minimum density for the construction of dense-graded hot mix asphalt concrete (HMAC) pavements to ensure the likelihood that the pavement will not experience distresses that reduce the expected se...

  18. Evaluation of tack coating practices for asphalt overlays in Nebraska.

    Science.gov (United States)

    2017-04-03

    The strength of the bond between asphalt layers affects the lifespan of pavement structures. It is also a key factor in preventing major pavement distresses, such as slippage cracking and delamination. This research project evaluates and compares the...

  19. Building Asphalt Pavement with SBS-based Compound Added Using a Dry Process in Greenland

    DEFF Research Database (Denmark)

    Lee, Hosin; Kim, Yongjoo; Geisler, Nivi

    2009-01-01

    PMA where it is formulated to melt and blend with asphalt quickly during a batch mixing process. The main objectives of this study are to (1) build asphalt pavement using asphalt mixtures with SBS-based compound added using a “dry” process at the batch plant and (2) evaluate its performance under......-based compound seemed to affect the asphalt mix to become more flexible under the heavy loads. By adding SBS-based compound to asphalt mixtures using a “dry” process, it is expected that the pavement would become more resistant to rutting than a typical asphalt mixture used in Greenland while enduring its arctic...

  20. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  1. Comparing wildlife habitat and biodiversity across green roof type

    Energy Technology Data Exchange (ETDEWEB)

    Coffman, R.R. [Oklahoma Univ., Tulsa, OK (United States). Dept. of Landscape Architecture

    2007-07-01

    Green roofs represent restorative practices within human dominated ecosystems. They create habitat, increase local biodiversity, and restore ecosystem function. Cities are now promoting this technology as a part of mitigation for the loss of local habitat, making the green roof necessary in sustainable development. While most green roofs create some form of habitat for local and migratory fauna, some systems are designed to provide specific habitat for species of concern. Despite this, little is actually known about the wildlife communities inhabiting green roofs. Only a few studies have provided broad taxa descriptions across a range of green roof habitats, and none have attempted to measure the biodiversity across green roof class. Therefore, this study examined two different vegetated roof systems representative of North America. They were constructed under alternative priorities such as energy, stormwater and aesthetics. The wildlife community appears to be a result of the green roof's physical composition. Wildlife community composition and biodiversity is expected be different yet comparable between the two general types of green roofs, known as extensive and intensive. This study recorded the community composition found in the two classes of ecoroofs and assessed biodiversity and similarity at the community and group taxa levels of insects, spiders and birds. Renyi family of diversity indices were used to compare the communities. They were further described through indices and ratios such as Shannon's, Simpson's, Sorenson and Morsita's. In general, community biodiversity was found to be slightly higher in the intensive green roof than the extensive green roof. 26 refs., 4 tabs., 4 figs.

  2. Ten years of extensive green roof experience in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Grau, U.; Siemsen, M. [Humboldt Univ., Berlin (Germany). Inst. for Agrarian and Urban Ecological Projects; Gomez, G.N. [Chapingo Autonomous Univ., Chapingo (Mexico)

    2005-07-01

    This paper described the installation of an extensive green roof in Mexico City as part of a collaboration between a German and a Mexican university. While the plants used in the project were indigenous to Mexico, most of the materials and green roof technologies came from Germany. The aim of the project was to create an extensive green roof system on a low maintenance basis without additional irrigation, and to determine the limits of growth and development of the vegetation. The project was conducted on 4 identical adjacent flat roofs. After a layer of filter cloth was installed to avoid damage to the waterproof membrane, a drainage layer of expanded clay was installed with different thicknesses on each of the 4 roofs. The growing medium was composed of Mexican volcanic material, a mineral material from Germany, and organic material consisting of coco fibers and sugarcane residues. Eight different substrate mixtures were tested. After several years it became clear that it was possible to implement an extensive green roof under extreme climatic conditions. However, it was observed that some plant specimens only survived in certain areas of the roof. The roofs underwent a complete renovation, and surviving specimens were salvaged. Vulnerable areas where leakage occurred were detected near air conditioning units and perimeter areas. Overheating of the areas led to distortion and contraction of the membrane, which led to its failure. All perimeter areas were covered by a zinc sheet to avoid direct solar radiation on the unprotected membrane. The selected plant material required supplemental irrigation during the first 2 months. No further additional watering was given. Ten months later, the vegetation was well established and had covered the surface density. One of the roofs was instrumented to measure a series of factors such as precipitation, stormwater runoff, temperature underneath a roof membrane. It was concluded that some plant species are capable of surviving

  3. Cyclic elasto-viscoplastic model for asphalt concrete materials

    OpenAIRE

    Nguyen, DT; Nedjar, B.; P. Tamagny

    2007-01-01

    These last few years, many interests have been devoted to the study of rutting problems. In fact, under high traffic loadings together with the extreme environmental conditions, permanent deformations of asphalt pavements appear and become more and more severe demanding more efforts on developing suitable predictive models. In this paper, a three-dimensional elasto-viscoplasticity model is developed and applied to describe the behaviour of asphalt concrete materials under cyclic loadings. The...

  4. Impulse radar evaluation of concrete, asphalt and waterproofing membrane

    Science.gov (United States)

    Chung, T.; Carter, C. R.; Masliwec, T.; Manning, D. G.

    1994-04-01

    Impulse radar has proved to be effective in the nondestructive testing of bridge decks composed of layers of dielectric materials such as asphalt, waterproofing membrane, and reinforced concrete. In this work, the waveforms reflected from these materials are modeled and analyzed theoretically. The relative dielectric constants are measured using sample blocks, and the reflected radar waveforms are related to the actual physical structures. It is found that asphalt thickness and cover over reinforcement can be accurately determined.

  5. Performance of Recycled Porous Hot Mix Asphalt with Gilsonite Additive

    OpenAIRE

    Ludfi Djakfar; Hendi Bowoputro; Bangun Prawiro; Nugraha Tarigan

    2015-01-01

    The objective of the study is to evaluate the performance of porous asphalt using waste recycled concrete material and explore the effect of adding Gilsonite to the mixture. As many as 90 Marshall specimens were prepared with varied asphalt content, percentage of Gilsonite as an additive, and proportioned recycled and virgin coarse aggregate. The test includes permeability capability and Marshall characteristics. The results showed that recycled concrete materials seem to have a potential...

  6. Estimation of Asphalt Pavement Surfaces Using Image Analysis Technique

    OpenAIRE

    Mohammad A. Khasawneh

    2014-01-01

    Asphalt concrete pavements gradually lose their skid resistance causing safety problems especially under wet conditions and high driving speeds. In order to enact the actual field polishing and wearing process of asphalt pavement surfaces in a laboratory setting, several laboratory-scale accelerated polishing devices were developed by different agencies. To mimic the actual process, friction and texture measuring devices are needed to quantify surface deterioration at different polishing inte...

  7. DURABILITY OF ASPHALT CONCRETE MIXTURES USING DOLOMITE AGGREGATES

    Directory of Open Access Journals (Sweden)

    Imad Al-Shalout

    2015-12-01

    Full Text Available This study deals with the durability of asphalt concrete, including the effects of different gradations, compaction temperatures and immersion time on the durability potential of mixtures. The specific objectives of this study are: to investigate the effect of compaction temperature on the mechanical properties of asphalt concrete mixtures; investigate the effect of bitumen content and different aggregate gradations on the durability potential of bituminous mixtures.

  8. Airfield Repairs in Austere Locations Using Pelletized Asphalt Technology (Preprint)

    Science.gov (United States)

    2009-08-01

    and on demand to create DGA or SMA paving HMA.       FIGURE 1 Pelletized asphalt consists of asphalt binder, fine aggregate and filler materials...the SMA mixtures. The selected aggregate was limestone due to its availability for the Tyndall AFB field testing. Table 1 includes the aggregate...on the existing concrete runway at the Silver Flag training field at Tyndall AFB, FL. One section was built with the DGA mixture with conventional

  9. Laboratory Evaluation of Ground Tire Rubber in Stone Mastic Asphalt

    Directory of Open Access Journals (Sweden)

    R. Muniandy

    2004-12-01

    Full Text Available Stone mastic asphalt (SMA is a gap-graded mix whereby stiffer asphalt cement is required to bind the stone matrix or arrangement of stones together. Although various asphalt additives are traditionally available, the use of rubber crumbs in SMA is still a new rresearch endeavor. Many countries around the world are facing serious problems on what to do with reject or discarded tires. In the present study, commercial truck tires, containing 70% natural rubber, were ground and pre-blended in 80-100 penetration asphalt for use in SMA mixtures. An assessment was made of the laboratory performance of rubberized SMA in terms of stability, resilent modulus, dynamic creep and tensile strength ratio. It was observed that the performance of SMA with ground tire rubber was for superior as compared to SMA mix with unmodified asphalt. Sulfur and Styrene Butadeline Rubber (SBR were used in rubberized SMA mixes as additives to test the sensitivity of SMA mixtures. As standard practice a 0.3% newly developed cellulose oil palm fiber was used in SMA to minimize the asphalt drain-down effects.

  10. Performance of macro clay on the porous asphalt mixture properties

    Science.gov (United States)

    Nurulain, C. M.; Ramadhansyah, P. J.; Haryati, Y.; Norhidayah, A. H.; Abdullah, M. E.; Ibrahim, M. H. Wan

    2017-11-01

    Porous asphalt pavement already well known as one type of pavement since many decades, however due to lack in strength it is not been widely used in road construction especially in high stresses areas. Many research had been conducted by researchers in order to improve the durability and increase the service life of the road. One of the methods that commonly used is through asphalt modification. Objectives of this study are to discuss influence of macro-clay in terms of physical and rheological properties and their effect on performance of porous asphalt mixture. Various percentage of macro-clay (starting from 2% to 8%) was blended in an asphalt binder and compacted using the Marshall compactor. The blended asphalt was characterized using penetration, softening point test and penetration index compared with unmodified binder. Performance tests of asphalt mixture were carried out such as Los Angeles Abrasion Value (LAAV) and Stability and Flow test in order to determine the strength and durability. The results show that the addition of macro-clay would increase in softening point but decrease in binder penetration. Based on the results, while macro-clay changes physical and rheological properties of bitumen and increase stiffness, it also improves strength and durability resistance, as well. Generally, the best improvements in the modified binders were obtained with 4% of macro-clay.

  11. Performance of Hot Asphalt Mixtures Containing Plastic Bottles as Additive

    Directory of Open Access Journals (Sweden)

    Jan Hakeem

    2017-01-01

    Full Text Available This study focuses on evaluating the resistance of polymer modified asphalt mixes and the role played by asphalt in the realm of construction is undeniably important. Addition of polymers(PB as additives to asphalt helps to improve the strength and water repellent property of the mix and as well as helps environment in various ways and at the same time, analyzing its lower maintenance activities and service life is most important. The use of inexpensive polymers, in this case, waste polymers has without any doubt proven to be the most convenient way of reducing the cost of construction and at the same time maintaining quality. The main resolve for this research was to establish the effects of the use of plastic bottles on hot asphalt and its mixtures. In order to put this into perspective, varying percentages of asphalt mixtures were calculated and subjected to laboratory tests. The two-factor variance analysis (ANOVA was conducted to determine the significance at various confidence limits. The results indicate that the inclusion of Polyethylene Terephthalate (PET had a particularly substantial effect on the properties of asphalt. Consequently, it can encourage the re-utilization of waste in the manufacturing industry in an ecologically friendly and cost-effective way.

  12. The use of waste materials in asphalt concrete mixtures.

    Science.gov (United States)

    Tuncan, Mustafa; Tuncan, Ahmet; Cetin, Altan

    2003-04-01

    The purpose of this study was to investigate (a) the effects of rubber and plastic concentrations and rubber particle sizes on properties of asphalt cement, (b) on properties of asphalt concrete specimens and (c) the effects of fly ash, marble powder, rubber powder and petroleum contaminated soil as filler materials instead of stone powder in the asphalt concrete specimens. One type of limestone aggregate and one penetration-graded asphalt cement (75-100) were used. Three concentrations of rubber and plastic (i.e. 5%, 10% and 20% of the total weight of asphalt cement), three rubber particle sizes (i.e. No. 4 [4.75mm] - 20 [0.85 mm], No. 20 [0.85mm] - 200 [0.075mm] and No. 4 [4.75mm] - 200 [0.075mm]) and one plastic particle size (i.e. No. 4 [4.75mm] - 10 [2.00mm]) were also used. It was found that while the addition of plastic significantly increased the strength of specimens, the addition of rubber decreased it. No. 4 [4.75mm] - 200 [0.075mm] rubber particles showed the best results with respect to the indirect tensile test. The Marshall stability and indirect tensile strength properties of plastic modified specimens increased. Marble powder and fly ash could be used as filler materials instead of stone powder in the asphalt concrete pavement specimens.

  13. Reinforcement of Recycled Foamed Asphalt Using Short Polypropylene Fibers

    Directory of Open Access Journals (Sweden)

    Yongjoo Kim

    2013-01-01

    Full Text Available This paper presents the reinforcing effects of the inclusion of short polypropylene fibers on recycled foamed asphalt (RFA mixture. Short polypropylene fibers of 10 mm length with a 0.15% by weight mixing ratio of the fiber to the asphalt binder were used. The Marshall stability test, the indirect tensile strength test, the resilient modulus test, and wheel tracking test of the RFA mixtures were conducted. The test results were compared to find out the reinforcing effects of the inclusion of the fiber and the other mixtures, which included the conventional recycled foamed asphalt (RFA mixtures; the cement reinforced recycled foamed asphalt (CRFA mixtures; the semihot recycled foamed asphalt (SRFA mixtures; and recycled hot-mix asphalt (RHMA mixtures. It is found that the FRFA mixture shows higher Marshall stability than the RFA and SRFA mixtures, higher indirect tensile strength than the RFA mixture, and higher rut resistance than the RFA, SRFA, and RHMA mixtures as seen from the wheel tracking test.

  14. A Roof for the Lion's House

    Science.gov (United States)

    1978-01-01

    Fans of the National Football League's Detroit Lions don't worry about gameday weather. Their magnificent new Pontiac Stadium has a domed, air-supported, fabric roof that admits light but protects the playing field and patrons from the elements. The 80,000-seat "Silverdome" is the world's largest fabric-covered structure-and aerospace technology played an important part in its construction. The key to economical construction of the Silverdome-and many other types of buildings-is a spinoff of fiber glass Beta yarn coated with Teflon TFE fluorocarbon resin. The big advance it offers is permanency. Fabric structures-tents, for example have been around since the earliest years of human civilization. But their coverings-hides, canvas and more recently plastics-were considered temporary; though tough, these fabrics were subject to weather deterioration. Teflon TFE-coated Beta Fiberglas is virtually impervious to the effects of weather and sunlight and it won't stretch, shrink, mildew or rot, thus has exceptional longevity; it is also very strong, lightweight, flame resistant and requires no periodic cleaning, because dirt will not stick to the surface of Teflon TFE. And to top all that, it costs only 30 to 40 percent as much as conventional roofing.

  15. Comparative properties of ceramic-based roofing sheets from local ...

    African Journals Online (AJOL)

    Ceramic roofing sheets were fabricated in the laboratory by using ideal raw materials. The fabricating materials are coiled coconut fibre, palm fruit fibre, fresh water, river sand, polymeric dust, saw dust and cement. The resulting product was compared with factory -produced ceramic-based roofing sheets that are easily ...

  16. Bamboo Fibre Reinforced Cement Used as a Roofing Sheet | Alade ...

    African Journals Online (AJOL)

    This study examines the use of bamboo fibre as reinforcement in cement mortar roofing sheets. The bamboo was beaten into meshes of needle like shape and used in varying proportions in the production of cement roofing sheets. A constant cement, sand ratio of 1:3 was used. Batching, Moulding, demoulding and curing of ...

  17. Common Causes of Leakages in Parapet Roof Construction in Ghana

    African Journals Online (AJOL)

    In Ghana, especially Kumasi, the second largest city after Accra, the country\\'s capital, parapet roof construction became fashionable in building construction in the 1970\\'s. It entailed hiding the roofs of buildings from view behind parapet walls. This concept is popularly known as “Bohyemu”, literally meaning “construct it ...

  18. Opportunities Green Roofs Can Offer Ghanaians and their Cities

    African Journals Online (AJOL)

    Lone Star College System

    2015-08-17

    Aug 17, 2015 ... development in Ghana in this era of climate change and variability. Key words: Green roof, urban, environmental quality, best management practice, ecosystem services. INTRODUCTION. Green roofs, which ..... public health problems like higher risk of asthma and other respiratory diseases in addition to ...

  19. 40 CFR 63.902 - Standards-Tank fixed roof.

    Science.gov (United States)

    2010-07-01

    ... installed in a manner such that there are no visible cracks, holes, gaps, or other open spaces between roof section joints or between the interface of the roof edge and the tank wall. (3) Each opening in the fixed... there are no visible cracks, holes, gaps, or other open spaces in the closure device or between the...

  20. Snow loads on roofs in areas of heavy snowfall

    Science.gov (United States)

    Robert D. Doty; Glenn H. Deitschman

    1966-01-01

    This study tested the feasibility of estimating snow loads on roofs from measurements of depth and water content of snow on nearby ground. The water content, and therefore the weight, of snow on the ground proved comparable to that of snow on roofs.

  1. Comparative Study Of Asbestos And Rice Husk As Roofing Materials

    African Journals Online (AJOL)

    The need to get a replacement for asbestos as a roofing material cannot be overemphasized. Therefore, the researcher in this study critically analyses the characteristics of rice husk as compared to the characteristics of asbestos. Series of tests were carried out on rice husk roofing sheet while the results of tests carried out ...

  2. Single-Sided Natural Ventilation through a Velux Roof Window

    DEFF Research Database (Denmark)

    Li, Zhigang; Nielsen, Peter Vilhelm; Fransson, J.

    2004-01-01

    This paper investigates the single-sided natural ventilation through a VELUX centre pivot roof window under natural weather conditions. The aim of the investigation is to develop an empirical formulation for air flow rate through a roof window based on CFD and tracer gas decay measurement methods...

  3. Common causes of leakages in parapet roof construction

    African Journals Online (AJOL)

    ben

    2008-12-03

    Dec 3, 2008 ... the building stands, with occasional periods of maintenance. Absolute freedom from mainte- nance is, however, not possible since every building material has it life span and as such the roof finishing may need to be replaced after a period of time. Finally, as said earlier, roofs if well designed contribute in a ...

  4. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  5. Variability of Rain Water Quality due to Roof Characteristics | Utsev ...

    African Journals Online (AJOL)

    ... varying effects on the characteristics of rainwater. From the experimental result, the roof drainage water quality in Gboko can be used as grey water for domestic purposes but requires treatment to be used as drinking water. KEYWORDS: Rainwater quality, Water availability, Rainwater harvesting, Variability, Roof drainage ...

  6. Calculation of parameters of combined frame and roof bolting

    Science.gov (United States)

    Ivanov, S. I.; Titov, N. V.; Privalov, A. A.; Trunov, I. T.; Sarychev, V. I.

    2017-10-01

    The paper presents the method of calculation of the combined frame and roof bolting. Recommendations on providing joint operation of roof bolting with steel support frames are given. Graphs for determining standard rock movement, as well as for defining proof load on the yielding support, were developed.

  7. Hydrologic Restoration in the Urban Environment Using Green Roofs

    Directory of Open Access Journals (Sweden)

    Anna Palla

    2010-04-01

    Full Text Available Loss of natural soil and vegetation within the urban environment can significantly affect the hydrologic cycle by increasing storm water runoff rates and volumes. In order to mitigate these modifications in urban areas engineered systems are developed, such as green roofs, to mimic and replace functions (evapo-transpiration, infiltration, percolation which have been altered due to the impact of human development. Green roofs, also known as vegetated roof covers, eco-roofs or nature roofs, are composite complex layered structures with specific environmental benefits. They are increasingly being used as a source control measure for urban storm water management. Indeed, they are able to re-establish the natural water cycle processes and to operate hydrologic control over storm water runoff with a derived peak flow attenuation, runoff volume reduction and increase of the time of concentration. Furthermore green roofs exhibit the capacity to reduce storm water pollution; they generally act as a storage device, consequently pollutants are accumulated in the substrate layer and released when intensive rainwater washes them out. In order to investigate the hydrologic response of a green roof, the University of Genova recently developed a joint laboratory and full-scale monitoring programme by installing a “controlled” laboratory test-bed with known rainfall input and a companion green roof experimental site (40 cm depth in the town of Genoa. In the paper, data collected during the monitoring programme are presented and compared with literature data.

  8. Rooftop PV system. Final technical progress report, Phase II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    Under this four-year PV:BONUS Program, ECD and United Solar are developing and demonstrating two new lightweight flexible building integrated Photovoltaic (BIPV) modules specifically designed as exact replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and address the even larger roofing replacement market. The modules are designed to be installed by roofing contractors without special training which minimizes the installation and balance of system costs. The modules will be fabricated from high-efficiency, multiple-junction a-Si alloy solar cells developed by ECD and United Solar. Under the Phase I Program, which ended in March 1994, we developed two different concept designs for rooftop PV modules: (1) the United Solar overlapping (asphalt shingle replacement) shingle-type modules and (2) the ECD metal roof-type modules. We also developed a plan for fabricating, testing and demonstrating these modules. Candidate demonstration sites for our rooftop PV modules were identified and preliminary engineering designs for these demonstrations were developed; a marketing study plan was also developed. The major objectives of the Phase II Program, which started in June 1994 was (1) to develop, test, and qualify these new rooftop modules; (2) to develop mechanical and electrical engineering specifications for the demonstration projects; and (3) to develop a marketing/commercialization plan.

  9. Modelling of green roof hydrological performance for urban drainage applications

    DEFF Research Database (Denmark)

    Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen

    2014-01-01

    , the model was used to evaluate the variation of the average annual runoff from green roofs as a function of the total available storage and vegetation type. The results show that even a few millimeters of storage can reduce the mean annual runoff by up to 20% when compared to a traditional roof......Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes...... surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data...

  10. Design strategies for integration of green roofs in sustainable housing

    Directory of Open Access Journals (Sweden)

    Avi Friedman

    2015-12-01

    Full Text Available Green roofs are the integration of plant material and its supporting structures in buildings. Such an approach provides a habitat for local flora and fauna, helps manage storm water, reduces heat demand in winter and the cooling load in the summer, enhances the aesthetic values of dwellings, provides the occupants with comfort and amenities and strengthens environmental responsibility. Because roofs represent approximately 40 percent to 50 percent of the surfaces in urban areas, green roofs have an important role in drainage and as a result water management as well. In fact, when a green roof is installed on 50 percent or more of the roof’s surface, it guarantees 2 points and can contribute 7 additional points toward LEED certification - almost 20 percent of the required rating. This paper classifies green roofs and offers strategies for their integration in residential buildings and examines their benefits, construction principles and applications.

  11. Thermal Behavior of Green Roofs Applied to Tropical Climate

    Directory of Open Access Journals (Sweden)

    Grace Tibério Cardoso

    2013-01-01

    Full Text Available The main goal of this paper is to present results on an experimental field about the green roofs thermal behavior, compared to other traditional roof covering systems. On the one hand, it intends to describe shortly the constructive system of a green roof with a lightweight building system, which has a sustainable building materials character and, on the other, it worries with the water reuse and with the run-off delay. The main methodological procedure adopted to study the thermal behavior of green roof was installing thermocouples to collect surface temperatures and indoor air, later comparing them with existing prototypes in an experimental plot. The thermal behavior analysis of cover systems was assessed by a representative episode of the climate fact, based on the dynamic climate approach. The experimental results from internal air temperature measurements show that the green roofs applied to warm and dry climates also provide an interesting time lag with surface and internal air temperature reduction.

  12. Entire cities could benefit from green roofs : Heleen Mees is investigating how five metropolises are greenifying their roofs

    NARCIS (Netherlands)

    Mees, Heleen|info:eu-repo/dai/nl/345727002

    Rotterdam is making good progress with its creation of green roofs. Heleen Mees, researcher at Utrecht University, drew this conclusion from her research, in which she compared the green roof policy of four different cities with that of Rotterdam. Rotterdam awards grants to those wishing to create a

  13. Analysis of the impact of thermal resistance of the roof on the performance of photovoltaic roof tiles

    Directory of Open Access Journals (Sweden)

    Kurz Dariusz

    2017-01-01

    Full Text Available The paper explores the issues related to the impact of thermal resistance of the roof on the electrical parameters of photovoltaic roof tiles. The methodology of determination of the thermal resistance and thermal transmittance factor was presented in accordance with the applicable legal regulations and standards. A test station was presented for the purpose of measurement of the parameters of photovoltaic roof tiles depending on the structure of the roof substrate. Detailed analysis of selected building components as well as their impact on the design thermal resistance factor and thermal transmittance factor was carried out. Results of our own studies, which indicated a relation between the type of the roof structure and the values of the electricity generated by photovoltaic tiles, were presented. Based on the calculations, it was concluded that the generated outputs in the respective constructions differ by maximum 6%. For cells with the highest temperature, the performance of the PV roof tiles on the respective roof constructions fell within the range between 0.4% and 1.2% (depending on the conducted measurement and amounted to 8.76% (in reference to 9.97% for roof tiles with the lowest temperature.

  14. Professionalising the asphalt construction process: aligning information technologies, operators' knowledge and laboratory practices

    NARCIS (Netherlands)

    Bijleveld, Frank

    2015-01-01

    This research addresses the need to professionalise the asphalt construction process. A distinctive action research strategy is designed and carried out to progressively improve operational strategies of asphalt teams from technological, human (operator) and laboratory perspectives. Using

  15. Experimental placement of stone matrix asphalt : project STP-8724 (00) X South Portland.

    Science.gov (United States)

    2004-01-01

    In September 2003 the Maine Department of Transportation used stone matrix asphalt and Superpave to : renovate two intersections in South Portland, Maine. The experimental placement of stone matrix asphalt : (SMA) and Superpave with modified binder w...

  16. Characterization of asphalt cements modified with crumbed rubber from discarded tires : final report.

    Science.gov (United States)

    1994-11-01

    The potential legislative requirement for incorporation of scrap rubber into asphalt blends mandated a thorough evaluation of the influence of scrap rubber additives on the physical properties and aging characteristics of rubber/asphalt blends. Blend...

  17. Enhanced road functionality with porous asphalt on the Ben Schoeman Highway

    CSIR Research Space (South Africa)

    De Kock, TJ

    1994-10-01

    Full Text Available of highly trafficked urban roads. Porous asphalt offers definitive advantages in wet weather in respect of minimization of backsplash, better overall visibility, retention of skid resistance and road noise reduction. A need for porous asphalt surface courses...

  18. Impact of low asphalt binder for coarse HMA mixes : final report.

    Science.gov (United States)

    2017-06-01

    Asphalt mixtures are commonly specified using volumetric controls in combination with aggregate gradation limits, like most transportation agencies, MnDOT also uses this approach. Since 2010 onward, several asphalt paving projects for MnDOT have been...

  19. Simulation of Permanent Deformation in High-Modulus Asphalt Pavement with Sloped and Horizontally Curved Alignment

    National Research Council Canada - National Science Library

    Mulian Zheng; Lili Han; Chongtao Wang; Zhanlei Xu; Hongyin Li; Qinglei Ma

    2017-01-01

    .... Based on the creep test, the Prony series representation of Burgers model parameters for different asphalt mixtures were obtained and used in the deformation simulation of a high-modulus asphalt...

  20. Mechanical characterization of porous asphalt mixes modified with fatty acid amides -FAA-

    Directory of Open Access Journals (Sweden)

    Vanessa Senior Arrieta

    2017-01-01

    Full Text Available Porous asphalt mixes (PAM, form a special road surface for asphalt pavement structures, have a special particle size distribution that lets infiltrate to the runoff storm water through of it because of its voids content about 20 %. Many researchers conducted studies and have concluded that the use of modified asphalts is completely necessary to design PAM. Organic and chemical additives and special procedures as foamed asphalt have enhanced the performance of PAM, during their service life. This paper is focused on the mechanical characterization of PAM and how the asphalt modified with fatty acid amides, influenced on their behavior and performance. Based on an experimental methodology with laboratory tests aimed at establishing a comparison between porous asphalt mixes, using for its design and production a penetration 60-70 pure asphalt and another one asphalt modified with fatty acid amides.

  1. A Review of the Application of Zeolite Materials in Warm Mix Asphalt Technologies

    Directory of Open Access Journals (Sweden)

    Agnieszka Woszuk

    2017-03-01

    Full Text Available Among warm mix asphalt (WMA technologies, asphalt foaming techniques offer high potential in terms of decreasing production temperature. Reluctance of manufacturers to introduce this technology is connected with the concerns of a large investment costs. However, there are known additives which, through asphalt foaming, allow a decrease in temperatures by approximately 30 °C; the use of these additives do not involve expensive investment in order to change the asphalt mix production method. These additives are zeolites, that is, minerals of the aluminosilicate group, the crystalline structure of which contains water bound in a specific way. Its release, at mix asphalt production temperatures, causes asphalt foaming. It is currently known that zeolites can be used in WMA, including natural and synthetic zeolites obtained using chemical reagents and waste. This review presents the results of studies of WMA technology, including the effects of zeolite addition on asphalt properties and mix asphalt, as well as related environmental, economic, and technological benefits.

  2. Evaluation of Georgia asphalt mixture properties using a Hamburg wheel-tracking device.

    Science.gov (United States)

    2017-05-01

    This study used a Hamburg Wheel-Tracking Device (HWTD) to evaluate the resistance of Georgia asphalt mixtures to rutting and stripping. It aimed to develop an HWTD test procedure and criteria aligned with GDOTs asphalt materials and mixture design...

  3. Validity of multiple stress creep recovery (MSCR) test for DOTD asphalt binder specification : technical summary.

    Science.gov (United States)

    2017-09-01

    Higher traffic coupled with heavier loads led the asphalt industry to introduce polymer-modified binders to enhance the durability and strength of hot mix asphalt (HMA) pavements. When the Superpave Performance Graded (PG) binder specification (AASHT...

  4. Development of a non-solvent based test method for evaluating reclaimed asphalt pavement mixes.

    Science.gov (United States)

    2004-09-01

    The percent of reclaimed asphalt pavement (RAP) used in hot mix asphalt (HMA) is currently established either by arbitrarily setting maximum percent limits, or alternatively, by evaluating both the virgin and recovered binder properties. The first ap...

  5. 0-6686 : improving DMS 9210 requirements for limestone rock asphalt : [project summary].

    Science.gov (United States)

    2013-08-01

    Limestone rock asphalt (LRA) mixtures have : been produced and placed for several decades : using specification requirements currently listed : under DMS 9210, Limestone Rock Asphalt (LRA). : Several Texas Department of Transportation : (TxDOT) distr...

  6. Fatigue and fracture properties of aged binders in the context of reclaimed asphalt mixes.

    Science.gov (United States)

    2014-08-01

    Evidence in the literature indicates that the stiffness of the asphalt binder increases and ductility of the binder decreases : with oxidative aging. Typically for unmodified asphalt binders, increase in stiffness or decrease in ductility is regarded...

  7. Quantifying Asphalt Emulsion-Based Chip Seal Curing Times Using Electrical Resistance Measurements.

    Science.gov (United States)

    2017-04-15

    Chip sealing typically consists of covering a pavement surface with asphalt emulsion into which aggregate chips are embedded. The asphalt emulsion cures through the evaporation of water, thus providing mechanical strength to adhere to the pavement wh...

  8. Stormwater quality from extensive green roofs in a subtropical region

    Science.gov (United States)

    Onis Pessoa, Jonas; Allasia, Daniel; Tassi, Rutineia; Vaz Viega, Juliana; Fensterseifer, Paula

    2016-04-01

    Green roofs have increasingly become an integral part of urban environments, mainly due to their aesthetic benefits, thermal comfort and efficiency in controlling excess runoff. However, the effects of this emerging technology in the qualitative characteristics of rainwater is still poorly understood. In this study was evaluated the effect of two different extensive green roofs (EGRs) and a traditional roof built with corrugated fiber cement sheets (control roof) in the quality of rainwater, in a subtropical climate area in the city of Santa Maria, in southern Brazil. The principal variant between the two EGRs were the type of plant species, time since construction, soil depth and the substrate characteristics. During the monitoring period of the experiment, between the months of April and December of 2015 fourteen rainfall events were selected for qualitative analysis of water from the three roofs and directly from rainfall. It was analyzed physical (turbidity, apparent color, true color, electrical conductivity, total solids, dissolved solids, suspended solids and temperature), chemical (pH, phosphate, total nitrogen, nitrate, nitrite, chloride, sulfate, BOD, iron and total hardness), heavy metals (copper, zinc, lead and chromium) and microbiological parameters (total coliforms and E. coli). It was also characterized the substrates used in both extensive green roofs. The results showed that the quality of the water drained from EGR s was directly influenced by their substrates (in turn containing significant levels of nutrients, organic matter and some metals). The passage of rainwater through green roofs and control roof resulted in the elevation of pH, allowing the conversion of the slightly acidic rainfall into basic water. Similarly, on both types of roofs occurred an increase of the values of most of the physical, chemical and microbiological parameters compared to rainwater. This same trend was observed for heavy metals, although with a much smaller degree

  9. IMPROVING OF RECLAIMED ASPHALT PAVEMENTS USING STYRENE-BUTYL ACRYLATE POLYMER

    OpenAIRE

    Abdelzaher E. A. Mostafa; Nasser, A M

    2017-01-01

    According to the most recent surveys, the European area produced 265 mil tons of asphalt for road applications in 2014, while the amount of available Reclaimed Asphalt Pavement (RAP) was more than 50 mil tons. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. This study investigates the potential use of styrene-bacrylate polymer and extracted Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) with different percentages b...

  10. IMPROVING OF RECLAIMED ASPHALT PAVEMENTS USING VINYL ACETATE-BUTYL ACRYLATE POLYMER

    OpenAIRE

    Nasser, A M; Abd El-Wahab

    2017-01-01

    According to the most recent surveys, the European area produced 265 mil tons of asphalt for road applications in 2014, while the amount of available Reclaimed Asphalt Pavement (RAP) was more than 50 mil tons. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. This study investigates the potential use of vinyl acetate-bacrylate polymer and extracted Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) with different percent...

  11. Investigating the Properties of Asphalt Concrete Containing Glass Fibers and Nanoclay

    OpenAIRE

    Hasan Taherkhani

    2016-01-01

    The performance of asphaltic pavements during their service life is highly dependent on the mechanical properties of the asphaltic layers. Therefore, in order to extend their service life, scientists and engineers are constantly trying to improve the mechanical properties of the asphaltic mixtures. One common method of improving the performance of asphaltic mixtures is using different types of additives. This research investigated the effects of reinforcement by randomly distributed glass fib...

  12. The first engineered self-healing asphalt road : How is it performing?

    NARCIS (Netherlands)

    Liu, Q.; Schlangen, H.E.J.G.; Van Bochove, G.

    2013-01-01

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the

  13. The first engineered self-healing asphalt road : How is it performing?

    NARCIS (Netherlands)

    Liu, Q.; Schlangen, H.E.J.G.; Van Bochove, G.

    Porous asphalt shows excellent performance in both noise reduction and water drainage. Although porous asphalt has these great qualities, its service life is much shorter (sometimes only half) compared to dense graded asphalt roads. Ravelling, which is the loss of aggregate particles from the

  14. Visualizing asphalt roller trajectories in context: acquiring, processing, and representing sensor readings

    NARCIS (Netherlands)

    Vasenev, Alexandr

    2015-01-01

    The asphalt compaction process relies heavily on the skills and knowledge of roller operators who act alongside other stakeholders involved in asphalt paving. It is essential that these construction specialists: (1) are adequately informed about the initial temperature distribution of the asphalt

  15. Preparation and Performance of Asphalt Compound Modified with Waste Crumb Rubber and Waste Polyethylene

    Directory of Open Access Journals (Sweden)

    Yuqiao Yang

    2016-01-01

    Full Text Available Three kinds of modified asphalt were prepared by adding waste crumb rubber (WCR, waste polyethylene (WPE, and WCR/WPE to base asphalt, respectively. The influence of different doses on the performance of modified asphalt, such as 25°C penetration, softening point, 5°C ductility, and 135°C, 165°C viscosity, was studied, and the modification mechanism of modified asphalt was discussed through the fluorescence microscope. As the waterproofing materials, the waterproofness of WCR/WPE compound modified asphalt was tested. The results show that the WPE modified asphalt has excellent resistance to high temperature and WCR modified asphalt has good low temperature resistance. The resistance to deformation ability of WPE modified asphalt is better than that of the WCR modified asphalt. The 135°C viscosity of compound modified asphalt is better than that of WPE and WCR modified asphalt. In addition, the waterproofness of compound modified asphalt using waterproofing materials is better than that of common waterproofing materials.

  16. Specifications and Construction Methods for Asphalt Concrete and Other Plant-Mix Types, 3rd Edition.

    Science.gov (United States)

    Asphalt Inst., College Park, MD.

    The purpose of this publication is to assist engineers in the analysis, design and control of paving projects that use asphalt concrete and other asphalt plant-mixes. The scope of this new third edition has been enlarged, and changes necessitated by advances in asphalt technology have been incorporated. Chapters I and II and Appendices A and B…

  17. Chemical composition of water from roofs in Gdansk, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Tsakovski, Stefan, E-mail: stsakovski@chem.uni-sofia.b [Chair of Physical Chemistry, Faculty of Chemistry, University of Sofia, J Bourchier Blvd. 1, 1164 Sofia (Bulgaria); Tobiszewski, Marek [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Simeonov, Vasil, E-mail: vsimeonov@chem.uni-sofia.b [Chair of Analytical Chemistry, Faculty of Chemistry, University of Sofia, 1164 Sofia (Bulgaria); Polkowska, Zaneta [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Namiesnik, Jacek, E-mail: chemanal@pg.gda.p [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland)

    2010-01-15

    This study deals with the assessment of roof runoff waters from the region of Gdansk collected during the winter season (2007/2008). The chemical analysis includes 16 chemical variables: major ions, PAHs and PCBs measured at 3 sampling sites for 6-14 rain events. Although the data set is of limited volume the statistical data treatment using self-organizing maps (SOM) reveals the main factors controlling roof runoff water quality even for a data set with small dimension. This effort for explanation of the identified factors by the possible emission sources of the urban environment and air-particulate formation seems to be very reliable. Additionally to the roof runoff water quality factors the rain events patterns are found: 'background' group of events and groups formally named 'PAHs', 'PCBs' and 'air-borne particles' - dominated events. The SOM classification results give an opportunity to uncover the role of roof 'impact' on the runoff waters. Rain runoff water quality is described by four latent factors and the 'roof' impact is uncovered. - Identification of the urban roof runoff water quality factors and 'roof' impact by self-organizing map classification.

  18. Multi functional roof structures of the energy efficient buildings

    Directory of Open Access Journals (Sweden)

    Krstić Aleksandra

    2006-01-01

    Full Text Available Modern architectural concepts, which are based on rational energy consumption of buildings and the use of solar energy as a renewable energy source, give the new and significant role to the roofs that become multifunctional structures. Various energy efficient roof structures and elements, beside the role of protection, provide thermal and electric energy supply, natural ventilation and cooling of a building, natural lighting of the indoor space sunbeam protection, water supply for technical use, thus according to the above mentioned functions, classification and analysis of such roof structures and elements are made in this paper. The search for new architectural values and optimization in total energy balance of a building or the likewise for the urban complex, gave to roofs the role of "climatic membranes". Contemporary roof forms and materials clearly exemplify their multifunctional features. There are numerous possibilities to achieve the new and attractive roof design which broadens to the whole construction. With such inducement, this paper principally analyze the configuration characteristics of the energy efficient roof structures and elements, as well as the visual effects that may be achieved by their application.

  19. Typology of Retractable Roof Structures in Stadiums and Sports Halls

    Directory of Open Access Journals (Sweden)

    Andrej Mahovič

    2015-10-01

    Full Text Available Retractable roof structures are one of the four fundamental systems (in addition to the playing area, stands and facade in a stadium and sports hall. The roof protects users against various weather conditions and creates optimum circumstances for carrying out different activities. Stadiums and sports halls with retractable roof structures can host a greater variety of activities, improve the quality of their implementation and the quality of visitors’ experience, and affect the perception and experience of people using or observing such buildings. A retractable roof structure allows for natural lighting and ventilation of the venue, gives optimal conditions for grass growth on the playing field, and reduces costs of use and maintenance of the building. Different typologies of movement of roof structures (frequency of opening and closing, design of the structure, and methods of movement are categorised in terms of their architectural and structural design. Application of different retractable roof systems worldwide is indicator of their effectiveness and efficiency, and is basis for use of movement also in other fundamental systems of stadiums and sports halls. Research and identification of characteristics of retractable roof structures lead to the design of new moving systems that can with the application of the moving principle change the purpose of movable elements or assume the characteristics of other fundamental systems.

  20. Basic Performance of Fibre Reinforced Asphalt Concrete with Reclaimed Asphalt Pavement Produced In Low Temperatures with Foamed Bitumen

    Science.gov (United States)

    Chomicz-Kowalska, Anna; Iwański, Mateusz M.; Mrugała, Justyna

    2017-10-01

    During the reconstruction of road pavements, the reclaimed asphalt pavement (RAP), which is obtained through milling of the worn out existing asphalt, is commonly used for producing new base courses in cold recycling processes. Two of these techniques are most popular: one using mineral-cement-emulsion mixes and one utilizing mineral cement mixes with foamed bitumen. Additionally, some amounts of RAP can be incorporated into traditional hot mix asphalt. The demand for energy efficient and environmentally friendly solutions however, results in a need for development of new techniques that would result in cheaper and more reliable solutions with smaller carbon footprint. The reduction of processing temperatures with simultaneous incorporation of reclaimed material is the most efficient way of obtaining these objectives, but it often results in the overall decrease of bituminous mix quality. The paper presents the possibility of using RAP for producing asphalt concrete in warm mix asphalt (WMA) production process by the use of foamed bitumen modified with Fischer-Tropsch synthetic wax and polymer-basalt fibers. Additionally, a series of reference mixtures were produced to investigate the effects of the additives and of the warm process. The carried out analyses and tests shown that the experimental warm mix asphalt produced with RAP and foamed bitumen returned satisfactory performance. The introduction of synthetic F-T wax in the warm foam bitumen mixes resulted in a significantly improved compaction levels and moisture and frost resistance and the addition of polymer-basalt fibers has further improved the permanent deformation resistance of the mixes. All of the designed and tested mixes have fulfilled the requirements for binding course asphalt concrete with medium traffic loads.

  1. Cool roofs as an energy conservation measure for federal buildings

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Haider; Akbari, Hashem

    2003-04-07

    We have developed initial estimates of the potential benefits of cool roofs on federal buildings and facilities (building scale) as well as extrapolated the results to all national facilities under the administration of the Federal Energy Management Program (FEMP). In addition, a spreadsheet ''calculator'' is devised to help FEMP estimate potential energy and cost savings of cool roof projects. Based on calculations for an average insulation level of R-11 for roofs, it is estimated that nationwide annual savings in energy costs will amount to $16M and $32M for two scenarios of increased roof albedo (moderate and high increases), respectively. These savings, corresponding to about 3.8 percent and 7.5 percent of the base energy costs for FEMP facilities, include the increased heating energy use (penalties) in winter. To keep the cost of conserved energy (CCE) under $0.08 kWh-1 as a nationwide average, the calculations suggest that the incremental cost for cool roofs should not exceed $0.06 ft-2, assuming that cool roofs have the same life span as their non-cool counterparts. However, cool roofs usually have extended life spans, e.g., 15-30 years versus 10 years for conventional roofs, and if the costs of re-roofing are also factored in, the cutoff incremental cost to keep CCE under $0.08 kWh-1 can be much higher. In between these two ends, there is of course a range of various combinations and options.

  2. Laboratory Evaluation of Aging Behaviour of SBS Modified Asphalt

    Directory of Open Access Journals (Sweden)

    Jie Wang

    2017-01-01

    Full Text Available To study the effect of aging SBS modified asphalt on the performance of asphalt pavement, aging at various times and temperatures was conducted with thin film oven, and then tests were made about the penetration, softening point, ductility, viscosity, toughness, and fluorescence microscopy of modified asphalt with different aging levels. The results show that, with the increasing of aging time, the penetration and ductility of modified asphalt decrease while its softening point and viscosity increase, and the variation trend of the toughness and tenacity is related to the aging temperature; the aging dynamic model with viscosity as parameter can well characterize the aging process of modified asphalt; at microlevel, with the decreasing of SBS particle size, the uniformity of particle size is better. Analysis of macroscopic properties, microscopic characteristics, and significance shows that the SBS particle area ratio has a significant correlation with tenacity as the aging temperature changes. When the aging temperature is 163°C, the SBS particle area ratio still has a significant correlation with tenacity as the aging time changes.

  3. The Utilization of Graphene Oxide in Traditional Construction Materials: Asphalt

    Directory of Open Access Journals (Sweden)

    Wenbo Zeng

    2017-01-01

    Full Text Available In the advanced research fields of solar cell and energy storing materials, graphene and graphene oxide (GO are two of the most promising materials due to their high specific surface area, and excellent electrical and physical properties. However, they was seldom studied in the traditional materials because of their high cost. Nowadays, graphene and GO are much cheaper than before with the development of production technologies, which provides the possibility of using these extraordinary materials in the traditional construction industry. In this paper, GO was selected as a nano-material to modify two different asphalts. Then a thin film oven test and a pressure aging vessel test were applied to simulate the aging of GO-modified asphalts. After thermal aging, basic physical properties (softening point and penetration were tested for the samples which were introduced at different mass ratios of GO (1% and 3% to asphalt. In addition, rheological properties were tested to investigate how GO could influence the asphalts by dynamic shearing rheometer tests. Finally, some interesting findings and potential utilization (warm mixing and flame retardants of GO in asphalt pavement construction were explained.

  4. Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

    Directory of Open Access Journals (Sweden)

    Fullová Daša

    2016-12-01

    Full Text Available The issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

  5. Experimental Study on Color Durability of Color Asphalt Pavement

    Science.gov (United States)

    Ning, Shi; Huan, Su

    2017-06-01

    Aiming at the poor Color durability and the lack of research on Color asphalt pavement, spraying an anti-tire trace seal resin emulsion on the surface, a Color durable asphalt pavement was proposed. After long-term rolling and long-term aging test, the Color durability was evaluated by RGB function in Photoshop and trace residue rate formula. Test results proved that the Evaluation method was simple and effective. After long-term rolling, the Color of the road surface tends to a constant value. Spraying the emulsion on the road surface can resist tire traces. After long-term aging test, the resistance to tire traces was increased by 26.6% compared with the conventional type, while the former was 44.1% higher than the latter without long-term aging. The Color durable asphalt pavement can effectively improve the ability of Color asphalt pavement to resist tire traces, and significantly improve the Color durability of Color asphalt pavement.

  6. Assessing The Durability of Polymer Modified Asphalt Emulsions Slurry Seal

    Science.gov (United States)

    Singgih, C.; Handayani, D.; Setyawan, A.

    2017-02-01

    Slurry Seal is an application of road preservation in the form of impermeable nonstructural thin layer with maximum thickness of 10 mm, which consisting of a cold laid mixture of asphalt emulsion with continuous graded fine aggregate, mineral filler, water and other added ingredients. Road preservation use slurry seal only functioning as a surface layer on the existing pavement structure. This preliminary research was conducted to determine the value of consistency, setting time, and indirect tensile strength of polymer modified slurry seal. The laboratory tests were conducted to determine the optimum residual asphalt content. The results show that the value of the optimum water content by pre-wetting 5% is getting smaller with increasing levels of residual asphalt emulsion. The addition of water 0 - 2.5% with 5% water for pre-wetting, the mixture provides a sufficient consistency in accordance with the specifications. The increasing levels of residual asphalt emulsion obtained the longer setting time at all slurry seal mixtures, but all of the mixtures still meet the specifications. The use of polymer modified asphalt emulsion on slurry seal was improved durability significantly, based on the value of indirect tensile strength.

  7. Partial substitution of asphalt pavement with modified sulfur

    Directory of Open Access Journals (Sweden)

    E.R. Souaya

    2015-12-01

    Full Text Available The use of sulfur in pavement laying was developed in 1980 but it was restricted in the late 19th century due to its environmental problems and its high reactivity toward oxidation processes which give sulfuric acid products that are capable of destroying the asphalt mixture. The study involved the conversion of elemental sulfur to a more stable modified one using a combination of byproducts of olefin hydrocarbons that were obtained from petroleum fractional distillates and cyclic hydrocarbon bituminous residue at 145 °C. The changes in the structural characteristics and morphology of prepared modified sulfur were studied using XRD and SEM respectively. Also DSC curves help us to elucidate the changes in sulfur phases from α-orthorhombic to β-mono clinic structure. The technique of nanoindentation helps us to compare the mechanical properties of modified and pure sulfur including modulus of elasticity and hardness. The hot mixture asphalt designs were prepared according to the Marshall Method in which the asphalt binder content was partially substituted with 20%, 30%, 40%, and 50% modified sulfur. The mechanical properties were measured including Marshall Stability, flow, air voids, and Marshall Stiffness. From the overall study, the results indicated that asphalt could partially be substituted with modified sulfur with no significant deleterious effect on performance and durability of hot mixed asphalt.

  8. Tetrapyrroles and associated compounds in Dead Sea asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Aizenshtat, Z. (Hebrew Univ. of Jerusalem, Israel); Dinur, D.; Nissenbaum, A.

    1979-01-01

    Metallo- and free porphyrins (1000 to 1500 ppM) isolated from asphalts occurring as huge blocks floating in the northern part of the Dead Sea, have been analyzed by visible-uv (v-uv) spectrophotometry and by mass spectrometry. The concentration of vanadyl porphyrins in the asphalts exceeds by far that of the Ni-porphyrins, despite the l:3 V/Ni ratio found in the total asphalt sample. The free porphyrins resemble those from the Uinta Basin (USA) gilsonite and contain a mixture of homologous Aetio- and deoxyphyllo-erythroaetioporphyrins (DPEP). The non-porphyrin fraction of the asphalt showed an identical aliphatic, hydrocarbon distribution with that of heavy crude oil from the same area. The more polar fraction associated with the porphyrins was compared with the polar fraction of the previously described ozokerite from the Dead Sea area. From high-resolution MS, IR, v-uv and NMR spectra, combined with hydrolysis and GLC analysis, it is suggested that even-numbered (C/sub 12/, C/sub 16/, C/sub 18/, C/sub 18/ /sub 1/, C/sub 22/) fatty acids are associated with the asphaltic porphyrins, probably in the triglyceride form.

  9. The mechanical behavior of two warm-mix asphalts

    Directory of Open Access Journals (Sweden)

    H. A. Rondón-Quintana

    2016-09-01

    Full Text Available This paper presents results stemming from a comparative experimental analysis of two warm-mix asphalts (WMA and a dense-graded hot-mix asphalt (HMA. In order to evaluate asphalt mixture behavior, physical and rheological tests were conducted, including tests on resilient modulus, resistance to moisture-induced damage, resistance to fatigue and resistance to permanent deformation. Samples studied were subjected to short (STOA and long-term (LTOA aging. As far as asphalt mixture composition is concerned, the same particle size distribution and coarse aggregate were employed for both mixture types. The control HMA mixture was produced with AC 60-70, and the WMAs used the same asphalt cement modified with two chemical additives (Rediset WMX® and Cecabase RT®. The modified mixtures exhibited better resistance to permanent deformation, aging and moisture-induced damage (versus the control mixture. Likewise, WMAs generally saw increased fatigue resistance under controlled-stress loading, which rheological characterization showed is mainly attributable to binder additives and their concomitant modifications.

  10. UTILIZATION OF WASTE PLASTIC BOTTLES IN ASPHALT MIXTURE

    Directory of Open Access Journals (Sweden)

    TAHER BAGHAEE MOGHADDAM

    2013-06-01

    Full Text Available Nowadays, large amounts of waste materials are being produced in the world. One of the waste materials is plastic bottle. Generating disposable plastic bottles is becoming a major problem in many countries. Using waste plastic as a secondary material in construction projects would be a solution to overcome the crisis of producing large amount of waste plastics in one hand and improving the structure’s characteristics such as resistance against cracking on the other hand. This study aimed to investigate the effects of adding plastic bottles in road pavement. Marshall properties as well as specific gravity of asphalt mixture containing different percentages of plastic bottles were evaluated. Besides, Optimum Asphalt Content (OAC was calculated for each percentages of plastic bottles used in the mix. The stiffness and fatigue characteristics of mixture were assessed at OAC value. Results showed that the stability and flow values of asphalt mixture increased by adding waste crushed plastic bottle into the asphalt mixture. Further, it was shown that the bulk specific gravity and stiffness of mixtures increased by adding lower amount of plastic bottles; however, adding higher amounts of plastic resulted in lower specific gravity and mix stiffness. In addition, it was concluded that the mixtures containing waste plastic bottles have lower OAC values compared to the conventional mixture, and this may reduce the amount of asphalt binder can be used in road construction projects. Besides, the mixtures containing waste plastic showed significantly greater fatigue resistance than the conventional mixture.

  11. The Utilization of Graphene Oxide in Traditional Construction Materials: Asphalt.

    Science.gov (United States)

    Zeng, Wenbo; Wu, Shaopeng; Pang, Ling; Sun, Yihan; Chen, Zongwu

    2017-01-07

    In the advanced research fields of solar cell and energy storing materials, graphene and graphene oxide (GO) are two of the most promising materials due to their high specific surface area, and excellent electrical and physical properties. However, they was seldom studied in the traditional materials because of their high cost. Nowadays, graphene and GO are much cheaper than before with the development of production technologies, which provides the possibility of using these extraordinary materials in the traditional construction industry. In this paper, GO was selected as a nano-material to modify two different asphalts. Then a thin film oven test and a pressure aging vessel test were applied to simulate the aging of GO-modified asphalts. After thermal aging, basic physical properties (softening point and penetration) were tested for the samples which were introduced at different mass ratios of GO (1% and 3%) to asphalt. In addition, rheological properties were tested to investigate how GO could influence the asphalts by dynamic shearing rheometer tests. Finally, some interesting findings and potential utilization (warm mixing and flame retardants) of GO in asphalt pavement construction were explained.

  12. Effects of Solar Photovoltaic Panels on Roof Heat Transfer

    Science.gov (United States)

    Dominguez, A.; Klessl, J.; Samady, M.; Luvall, J. C.

    2010-01-01

    Building Heating, Ventilation and Air Conditioning (HVAC) is a major contributor to urban energy use. In single story buildings with large surface area such as warehouses most of the heat enters through the roof. A rooftop modification that has not been examined experimentally is solar photovoltaic (PV) arrays. In California alone, several GW in residential and commercial rooftop PV are approved or in the planning stages. With the PV solar conversion efficiency ranging from 5-20% and a typical installed PV solar reflectance of 16-27%, 53-79% of the solar energy heats the panel. Most of this heat is then either transferred to the atmosphere or the building underneath. Consequently solar PV has indirect effects on roof heat transfer. The effect of rooftop PV systems on the building roof and indoor energy balance as well as their economic impacts on building HVAC costs have not been investigated. Roof calculator models currently do not account for rooftop modifications such as PV arrays. In this study, we report extensive measurements of a building containing a flush mount and a tilted solar PV array as well as exposed reference roof. Exterior air and surface temperature, wind speed, and solar radiation were measured and thermal infrared (TIR) images of the interior ceiling were taken. We found that in daytime the ceiling surface temperature under the PV arrays was significantly cooler than under the exposed roof. The maximum difference of 2.5 C was observed at around 1800h, close to typical time of peak energy demand. Conversely at night, the ceiling temperature under the PV arrays was warmer, especially for the array mounted flat onto the roof. A one dimensional conductive heat flux model was used to calculate the temperature profile through the roof. The heat flux into the bottom layer was used as an estimate of the heat flux into the building. The mean daytime heat flux (1200-2000 PST) under the exposed roof in the model was 14.0 Watts per square meter larger than

  13. The impact of roofing material on building energy performance

    Science.gov (United States)

    Badiee, Ali

    The last decade has seen an increase in the efficient use of energy sources such as water, electricity, and natural gas as well as a variety of roofing materials, in the heating and cooling of both residential and commercial infrastructure. Oil costs, coal and natural gas prices remain high and unstable. All of these instabilities and increased costs have resulted in higher heating and cooling costs, and engineers are making an effort to keep them under control by using energy efficient building materials. The building envelope (that which separates the indoor and outdoor environments of a building) plays a significant role in the rate of building energy consumption. An appropriate architectural design of a building envelope can considerably lower the energy consumption during hot summers and cold winters, resulting in reduced HVAC loads. Several building components (walls, roofs, fenestration, foundations, thermal insulation, external shading devices, thermal mass, etc.) make up this essential part of a building. However, thermal insulation of a building's rooftop is the most essential part of a building envelope in that it reduces the incoming "heat flux" (defined as the amount of heat transferred per unit area per unit time from or to a surface) (Sadineni et al., 2011). Moreover, more than 60% of heat transfer occurs through the roof regardless of weather, since a roof is often the building surface that receives the largest amount of solar radiation per square annually (Suman, and Srivastava, 2009). Hence, an argument can be made that the emphasis on building energy efficiency has influenced roofing manufacturing more than any other building envelope component. This research project will address roofing energy performance as the source of nearly 60% of the building heat transfer (Suman, and Srivastava, 2009). We will also rank different roofing materials in terms of their energy performance. Other parts of the building envelope such as walls, foundation

  14. Can green roof act as a sink for contaminants? A methodological study to evaluate runoff quality from green roofs.

    Science.gov (United States)

    Vijayaraghavan, K; Joshi, Umid Man

    2014-11-01

    The present study examines whether green roofs act as a sink or source of contaminants based on various physico-chemical parameters (pH, conductivity and total dissolved solids) and metals (Na, K, Ca, Mg, Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb). The performance of green roof substrate prepared using perlite, vermiculite, sand, crushed brick, and coco-peat, was compared with local garden soil based on improvement of runoff quality. Portulaca grandiflora was used as green roof vegetation. Four different green roof configurations, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). In general, the vegetated green roof assemblies generated better-quality runoff with less conductivity and total metal ion concentration compared to un-vegetated assemblies. Of the different green roof configurations examined, P. grandiflora planted on green roof substrate acted as sink for various metals and showed the potential to generate better runoff. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Viscoelastic behaviour of cold recycled asphalt mixes

    Science.gov (United States)

    Cizkova, Zuzana; Suda, Jan

    2017-09-01

    Behaviour of cold recycled mixes depends strongly on both the bituminous binder content (bituminous emulsion or foamed bitumen) and the hydraulic binder content (usually cement). In the case of cold recycled mixes rich in bitumen and with low hydraulic binder content, behaviour is close to the viscoelastic behaviour of traditional hot mix asphalt. With decreasing bituminous binder content together with increasing hydraulic binder content, mixes are characteristic with brittle behaviour, typical for concrete pavements or hydraulically bound layers. The behaviour of cold recycled mixes with low content of both types of binders is similar to behaviour of unbound materials. This paper is dedicated to analysing of the viscoelastic behaviour of the cold recycled mixes. Therefore, the tested mixes contained higher amount of the bituminous binder (both foamed bitumen and bituminous emulsion). The best way to characterize any viscoelastic material in a wide range of temperatures and frequencies is through the master curves. This paper includes interesting findings concerning the dependency of both parts of the complex modulus (elastic and viscous) on the testing frequency (which simulates the speed of heavy traffic passing) and on the testing temperature (which simulates the changing climate conditions a real pavement is subjected to).

  16. Laboratorium Study of Asphalt Starbit E-55 Polymer Modified Application on Asphalt Concrete Wearing Course (Ac-Wc

    Directory of Open Access Journals (Sweden)

    Damianus Kans Pangaraya

    2015-09-01

    Full Text Available The conventional asphalt road has almost been considered fail to serve the transportation needs. It is indicated by the occurrence of premature damage which is caused by vehicle load and climate. Starbit E-55, the polymer modified bitumen, is formulated to meet the requirement of transport development. Considering those needs, it is important to investigate the feasibility level of that modified bitumen as alternate asphalt instead of the conventional one. This research began with the measurement of the properties of hard layered AC-WC Starbit E-55, then comparing the result to 60/70 penetration of Pertamina asphalt. The next step is then, to determine the converted value so as to be close to that of Pertamina (60/70 penetration. This step is conducted by applying durability and ITS tests on the mixture. Result of the tests showed that hard layered AC-WC Starbit E-55 has better characteristic at 5.7% optimum level asphalt and 6.4% of Pertamina asphalt (60/70 penetration. Starbit E-55 converted level within hard-layered ACWC is 5.6%. The performance test result on immersion with variance of 1, 3, 5, 7 and 14 days shows that durability value of Starbit E-55 AC-WC has better performance. During the process, Starbit E-55 required 15.38% higher energy consumption.

  17. Kinerja Campuran Split Mastic Asphalt (SMA) Yang Menggunakan Serat Selulosa Alami Dedak Padi

    OpenAIRE

    Tahir, Anas

    2011-01-01

    Split Mastic Asphalt (SMA) is one of the hot mix asphalt concretes use with open graded and it has high coarse agregate content (70% - 80%) and a high asphalt content. Since the content of the high asphalt needs requires additional material such as cellulosa fiber to stabilize the asphalt. Through with this study, the another try to use rice bran as the additional material. In addition, rice bran is a natural cellulose fiber which cames from the rice milling proces. It was relatifevely cheape...

  18. The effect of aggregate density on pavement performance of SMA-13 asphalt mixture

    Directory of Open Access Journals (Sweden)

    Qiao Yinping

    2016-05-01

    Full Text Available This paper chooses the top layer SMA-13 asphalt mixture material as the research object. Basalt was selected as pavement material, and modified SBS asphalt was used as a cementing material. Two basalt aggregates with different densities were used to carry out standard Marshall test in the laboratory.Aimed at the volume parameters of the asphalt mixture carry on anaiysis,and obtian the effect of aggregate density on pavement performance of SMA-13 asphalt mixture, which is that the density of aggregate has a significant effect on the void ratio, saturation, and the gap rate of the aggregate, thus affecting the pavement performance of the asphalt mixture

  19. Asphalt emulsion sealing of uranium mill tailings. 1980 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, J.N.; Koehmstedt, P.L; Esterl, D.J.; Freeman, H.D.; Buelt, J.L.; Nelson, D.A.; Elmore, M.R.

    1981-05-01

    Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.

  20. Hanford Permanent Isolation Barrier Program: Asphalt technology test plan

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, H.D.; Romine, R.A.

    1994-05-01

    The Hanford Permanent Isolation Barriers use engineered layers of natural materials to create an integrated structure with backup protective features. The objective of current designs is to develop a maintenance-free permanent barrier that isolates wastes for a minimum of 1000 years by limiting water drainage to near-zero amounts. Asphalt is being used as an impermeable water diversion layer to provide a redundant layer within the overall barrier design. Data on asphalt barrier properties in a buried environment are not available for the required 100-year time frame. The purpose of this test plan is to outline the activities planned to obtain data with which to estimate performance of the asphalt layers.

  1. Laboratory evaluation of resistance to moisture damage in asphalt mixtures

    Directory of Open Access Journals (Sweden)

    Ahmed Ebrahim Abu El-Maaty Behiry

    2013-09-01

    Full Text Available Moisture damage in asphalt mixtures refers to loss in strength and durability due to the presence of water. Egypt road network is showing severe deterioration such as raveling and stripping because the bond between aggregates and asphalt film is broken due to water intrusion. To minimize moisture damage, asphalt mixes are investigated to evaluate the effect of air voids, degree of saturation, media of attack and the conditioning period. Two medias of attack are considered and two anti-stripping additives are used (hydrated lime and Portland cement. The retained Marshall stability and tensile strength ratio are calculated to determine the resistance to moisture damage. The results showed that both lime and cement could increase Marshall stability, resilient modulus, tensile strength and resistance to moisture damage of mixtures especially at higher condition periods. Use of hydrated lime had better results than Portland cement.

  2. Diaphragm Effect of Steel Space Roof Systems in Hall Structures

    Directory of Open Access Journals (Sweden)

    Mehmet FENKLİ

    2015-09-01

    Full Text Available Hall structures have been used widely for different purposes. They have are reinforced concrete frames and shear wall with steel space roof systems. Earthquake response of hall structures is different from building type structures. One of the most critical nodes is diaphragm effect of steel space roof on earthquake response of hall structures. Diaphragm effect is depending on lateral stiffness capacity of steel space roof system. Lateral stiffness of steel space roof system is related to modulation geometry, support conditions, selected sections and system geometry. In current paper, three representative models which are commonly used in Turkey were taken in to account for investigation. Results of numerical tests were present comparatively

  3. Optimal Adoption of Green Roofs: Hydrology and Public Finance Applications

    National Research Council Canada - National Science Library

    Stumme, Luke D

    2008-01-01

    ... infrastructure to convey and treat stormwater discharge. A municipality can introduce planned percentages of green roof coverage which will diminish infrastructure improvement costs over time and increase the population's sustainable footprint...

  4. Modeling a Hydrologically Optimal Green Roof Media Mixture

    Science.gov (United States)

    Background/Questions/MethodsA key environmental concern in managing urban ecosystems is controlling stormwater runoff to ameliorate pollution problems and sewage overflows. Vegetated green roofs have become an important green infrastructure tool to collect, store, and gradually r...

  5. Rutting Prediction in Asphalt Pavement Based on Viscoelastic Theory

    Directory of Open Access Journals (Sweden)

    Nahi Mohammed Hadi

    2016-01-01

    Full Text Available Rutting is one of the most disturbing failures on the asphalt roads due to the interrupting it is caused to the drivers. Predicting of asphalt pavement rutting is essential tool leads to better asphalt mixture design. This work describes a method of predicting the behaviour of various asphalt pavement mixes and linking these to an accelerated performance testing. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating the laboratory testing of asphalt mixes in Hamburg Wheel Rut Tester (HWRT for rutting. The creep parameters C1, C2 and C3 are developed from the triaxial repeated load creep test at 50°C and at a frequency of 1 Hz and the modulus of elasticity and Poisson’ s ratio determined at the same temperature. Viscoelastic model (creep model is adopted using a FE simulator (ANSYS in order to calculate the rutting for various mixes under a uniform loading pressure of 500 kPa. An eight-node with a three Degrees of Freedom (UX, UY, and UZ Element is used for the simulation. The creep model developed for HWRT tester was verified by comparing the predicted rut depths with the measured one and by comparing the rut depth with ABAQUS result from literature. Reasonable agreement can be obtained between the predicted rut depths and the measured one. Moreover, it is found that creep model parameter C1 and C3 have a strong relationship with rutting. It was clear that the parameter C1 strongly influences rutting than the parameter C3. Finally, it can be concluded that creep model based on finite element method can be used as an effective tool to analyse rutting of asphalt pavements.

  6. Effect of Material Composition and Environmental Condition on Thermal Characteristics of Conductive Asphalt Concrete.

    Science.gov (United States)

    Pan, Pan; Wu, Shaopeng; Hu, Xiaodi; Liu, Gang; Li, Bo

    2017-02-23

    Conductive asphalt concrete with high thermal conductivity has been proposed to improve the solar energy collection and snow melting efficiencies of asphalt solar collector (ASC). This paper aims to provide some insight into choosing the basic materials for preparation of conductive asphalt concrete, as well as determining the evolution of thermal characteristics affected by environmental factors. The thermal properties of conductive asphalt concrete were studied by the Thermal Constants Analyzer. Experimental results showed that aggregate and conductive filler have a significant effect on the thermal properties of asphalt concrete, while the effect of asphalt binder was not evident due to its low proportion. Utilization of mineral aggregate and conductive filler with higher thermal conductivity is an efficient method to prepare conductive asphalt concrete. Moreover, change in thermal properties of asphalt concrete under different temperature and moisture conditions should be taken into account to determine the actual thermal properties of asphalt concrete. There was no noticeable difference in thermal properties of asphalt concrete before and after aging. Furthermore, freezing-thawing cycles strongly affect the thermal properties of conductive asphalt concrete, due to volume expansion and bonding degradation.

  7. Adhesion Evaluation of Asphalt-Aggregate Interface Using Surface Free Energy Method

    Directory of Open Access Journals (Sweden)

    Jie Ji

    2017-02-01

    Full Text Available The influence of organic additives (Sasobit and RH and water on the adhesion of the asphalt-aggregate interface was studied according to the surface free energy theory. Two asphalt binders (SK-70 and SK-90, and two aggregate types (limestone and basalt were used in this study. The sessile drop method was employed to test surface free energy components of asphalt, organic additives and aggregates. The adhesion models of the asphalt-aggregate interface in dry and wet conditions were established, and the adhesion work was calculated subsequently. The energy ratios were built to evaluate the effect of organic additives and water on the adhesiveness of the asphalt-aggregate interface. The results indicate that the addition of organic additives can enhance the adhesion of the asphalt-aggregate interface in dry conditions, because organic additives reduced the surface free energy of asphalt. However, the organic additives have hydrophobic characteristics and are sensitive to water. As a result, the adhesiveness of the asphalt-aggregate interface of the asphalt containing organic additives in wet conditions sharply decreased due to water damage to asphalt and organic additives. Furthermore, the compatibility of asphalt, aggregate with organic additive was noted and discussed.

  8. Effect of Material Composition and Environmental Condition on Thermal Characteristics of Conductive Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Pan Pan

    2017-02-01

    Full Text Available Conductive asphalt concrete with high thermal conductivity has been proposed to improve the solar energy collection and snow melting efficiencies of asphalt solar collector (ASC. This paper aims to provide some insight into choosing the basic materials for preparation of conductive asphalt concrete, as well as determining the evolution of thermal characteristics affected by environmental factors. The thermal properties of conductive asphalt concrete were studied by the Thermal Constants Analyzer. Experimental results showed that aggregate and conductive filler have a significant effect on the thermal properties of asphalt concrete, while the effect of asphalt binder was not evident due to its low proportion. Utilization of mineral aggregate and conductive filler with higher thermal conductivity is an efficient method to prepare conductive asphalt concrete. Moreover, change in thermal properties of asphalt concrete under different temperature and moisture conditions should be taken into account to determine the actual thermal properties of asphalt concrete. There was no noticeable difference in thermal properties of asphalt concrete before and after aging. Furthermore, freezing–thawing cycles strongly affect the thermal properties of conductive asphalt concrete, due to volume expansion and bonding degradation.

  9. Causes of falls of roof in South African collieries

    CSIR Research Space (South Africa)

    Van der Merwe, JN

    2001-08-01

    Full Text Available length, spacing, installation quality, timing of support and A general investigation f the surrounding area, including slips and faults, dimensions, other falls. Following that, the team would reassemble and reach consensus on the cause of the roof... fall. The team would then view specific areas of interest that were found during the detailed individual inspections. Finally, the team tested their diagnosis by establishing why the roof did not fall in the adjacent areas. During the underground...

  10. Statistical Building Roof Reconstruction from WORLDVIEW-2 Stereo Imagery

    Science.gov (United States)

    Partovi, T.; Huang, H.; Krauß, T.; Mayer, H.; Reinartz, P.

    2015-03-01

    3D building reconstruction from point clouds is an active research topic in remote sensing, photogrammetry and computer vision. Most of the prior research has been done on 3D building reconstruction from LiDAR data which means high resolution and dense data. The interest of this work is 3D building reconstruction from Digital Surface Models (DSM) of stereo image matching of space borne satellite data which cover larger areas than LiDAR datasets in one data acquisition step and can be used also for remote regions. The challenging problem is the noise of this data because of low resolution and matching errors. In this paper, a top-down and bottom-up method is developed to find building roof models which exhibit the optimum fit to the point clouds of the DSM. In the bottom up step of this hybrid method, the building mask and roof components such as ridge lines are extracted. In addition, in order to reduce the computational complexity and search space, roofs are classified to pitched and flat roofs as well. Ridge lines are utilized to estimate the roof primitives from a building library such as width, length, positions and orientation. Thereafter, a topdown approach based on Markov Chain Monte Carlo and simulated annealing is applied to optimize roof parameters in an iterative manner by stochastic sampling and minimizing the average of Euclidean distance between point cloud and model surface as fitness function. Experiments are performed on two areas of Munich city which include three roof types (hipped, gable and flat roofs). The results show the efficiency of this method in even for this type of noisy datasets.

  11. On the Design of Suspended Roofs with Paraboloidal Surfaces

    Directory of Open Access Journals (Sweden)

    N. Ungureanu

    2006-01-01

    Full Text Available Some considerations concerning the design of the paraboloidal suspended roofs are made. The main geometric aspects are first time presented. For the roofs we propose, as pattern, the equivalent continuum membranes, and the efforts in the cable are determined by using the membrane efforts and their equations. Two examples are analyzed: elliptic paraboloide and hyperbolic paraboloide, with horizontal projection under the form of an ellipse.

  12. Orbital Roof Fractures as an Indicator for Concomitant Ocular Injury

    Science.gov (United States)

    2017-11-12

    Indicator for Concomitant Ocular Injury Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER Capt Santamaria, Joseph Se. TASK...NOTES Society of Military Ophthalmologists, New Orleans, LA, Nov 12th, 2017 14. ABSTRACT Title: Orbital Roof Fractures as an Indicator for...7.0 Title: Orbital Roof Fractures as an Indicator for Concomitant Ocular Injury Authors: Joseph Santamaria MD, Aditya Mehta MD, Donovan Reed MD

  13. Automated titration method for use on blended asphalts

    Science.gov (United States)

    Pauli, Adam T [Cheyenne, WY; Robertson, Raymond E [Laramie, WY; Branthaver, Jan F [Chatham, IL; Schabron, John F [Laramie, WY

    2012-08-07

    A system for determining parameters and compatibility of a substance such as an asphalt or other petroleum substance uses titration to highly accurately determine one or more flocculation occurrences and is especially applicable to the determination or use of Heithaus parameters and optimal mixing of various asphalt stocks. In a preferred embodiment, automated titration in an oxygen gas exclusive system and further using spectrophotometric analysis (2-8) of solution turbidity is presented. A reversible titration technique enabling in-situ titration measurement of various solution concentrations is also presented.

  14. Reliability Analysis of a Green Roof Under Different Storm Scenarios

    Science.gov (United States)

    William, R. K.; Stillwell, A. S.

    2015-12-01

    Urban environments continue to face the challenges of localized flooding and decreased water quality brought on by the increasing amount of impervious area in the built environment. Green infrastructure provides an alternative to conventional storm sewer design by using natural processes to filter and store stormwater at its source. However, there are currently few consistent standards available in North America to ensure that installed green infrastructure is performing as expected. This analysis offers a method for characterizing green roof failure using a visual aid commonly used in earthquake engineering: fragility curves. We adapted the concept of the fragility curve based on the efficiency in runoff reduction provided by a green roof compared to a conventional roof under different storm scenarios. We then used the 2D distributed surface water-groundwater coupled model MIKE SHE to model the impact that a real green roof might have on runoff in different storm events. We then employed a multiple regression analysis to generate an algebraic demand model that was input into the Matlab-based reliability analysis model FERUM, which was then used to calculate the probability of failure. The use of reliability analysis as a part of green infrastructure design code can provide insights into green roof weaknesses and areas for improvement. It also supports the design of code that is more resilient than current standards and is easily testable for failure. Finally, the understanding of reliability of a single green roof module under different scenarios can support holistic testing of system reliability.

  15. Proposed Measures to Protect Temporary Roofs from Unwanted Heat Gains

    Directory of Open Access Journals (Sweden)

    Omar S. Asfour

    2017-06-01

    Full Text Available This study focuses on the uncompleted multi-storey residential buildings located in hot climates. This construction pattern is common in the case of incremental housing, where additional floors are added to the building as housing needs grow. Top roofs in these buildings are usually left without thermal insulation until the rest of upper floors are erected. This causes higher thermal discomfort in the top flats compared to the lower ones. Thus, the aim of this study is to investigate thermal effect of some proposed temporary measures that are intended to protect these roofs from unwanted heat gains until the rest of storeys are constructed. This has been carried out using thermal modelling to find out the effect of these measures on the amount of heat transfer through the roof in both summer and winter times. The analysis showed that it is possible to achieve competent thermal protection of the top roof compared to the layered thermal insulation using simple, cost-effective, and reversible measures. Among the examined measures, covering the roof with white foldable sheets and the use of pergolas have been found to be the most effective measures. In both cases, a reduction of 38% in conductive heat transfer through the top roof in summer was observed compared to the unprotected modelling case.

  16. Modelling of green roofs' hydrologic performance using EPA's SWMM.

    Science.gov (United States)

    Burszta-Adamiak, E; Mrowiec, M

    2013-01-01

    Green roofs significantly affect the increase in water retention and thus the management of rain water in urban areas. In Poland, as in many other European countries, excess rainwater resulting from snowmelt and heavy rainfall contributes to the development of local flooding in urban areas. Opportunities to reduce surface runoff and reduce flood risks are among the reasons why green roofs are more likely to be used also in this country. However, there are relatively few data on their in situ performance. In this study the storm water performance was simulated for the green roofs experimental plots using the Storm Water Management Model (SWMM) with Low Impact Development (LID) Controls module (version 5.0.022). The model consists of many parameters for a particular layer of green roofs but simulation results were unsatisfactory considering the hydrologic response of the green roofs. For the majority of the tested rain events, the Nash coefficient had negative values. It indicates a weak fit between observed and measured flow-rates. Therefore complexity of the LID module does not affect the increase of its accuracy. Further research at a technical scale is needed to determine the role of the green roof slope, vegetation cover and drying process during the inter-event periods.

  17. A Roof for the Lions' House

    Science.gov (United States)

    1978-01-01

    Fans of the National Football League s Detroit Lions don't worry about game day weather. Their magnificent new Pontiac Stadium has a domed, air-supported, fabric roof that admits light but protects the playing field and patrons from the elements. The 80,000-seat Silverdome is the world s largest fabric-covered structure-and aerospace technology played an important part in its construction. The key to economical construction of the Silverdome--and many other types of buildings--is a spinoff of fiber glass Beta yarn coated with Teflon TFE fluorocarbon resin. The big advance it offers is permanency.The team of DuPont, Chemical Fabrics and Birdair have collaborated on a number of fabric structures. Some are supported by air pressure, others by cables alone. Most of the structures are in the recreational category. With conventional construction costs still on the upswing, you're likely to see a great many more permanent facilities enclosed by the aerospace spinoff fabric.

  18. Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Konopacki, Steve; Bretz, Sarah

    2002-12-15

    Roofs that have high solar reflectance (high ability to reflect sunlight) and high thermal emittance (high ability to radiate heat) tend to stay cool in the sun. The same is true of low-emittance roofs with exceptionally high solar reflectance. Substituting a cool roof for a noncool roof tends to decrease cooling electricity use, cooling power demand, and cooling-equipment capacity requirements, while slightly increasing heating energy consumption. Cool roofs can also lower the ambient air temperature in summer, slowing ozone formation and increasing human comfort. DOE-2.1E building energy simulations indicate that use of a cool roofing material on a prototypical California nonresidential building with a low-sloped roof yields average annual cooling energy savings of approximately 300 kWh/1000 ft2 [3.2 kWh/m2], average annual natural gas deficits of 4.9 therm/1000 ft2 [5.6 MJ/m2], average source energy savings of 2.6 MBTU/1000 ft2 [30 MJ/m2], and average peak power demand savings of 0. 19 kW/1000 ft2 [2.1 W/m2]. The 15-year net present value (NPV) of energy savings averages $450/1000 ft2 [$4.90/m2] with time dependent valuation (TDV), and $370/1000 ft2 [$4.00/m2] without TDV. When cost savings from downsizing cooling equipment are included, the average total savings (15-year NPV + equipment savings) rises to $550/1000 ft2 [$5.90/m2] with TDV, and to $470/1000 ft2 [$5.00/m2] without TDV. Total savings range from 0.18 to 0.77 $/ft2 [1.90 to 8.30 $/m2] with TDV, and from 0.16 to 0.66 $/ft2 [1.70 to 7.10 $/m2] without TDV, across California's 16 climate zones. The typical cost premium for a cool roof is 0.00 to 0.20 $/ft2 [0.00 to 2.20 $/m2]. Cool roofs with premiums up to $0.20/ft2 [$2.20/m2] are expected to be cost effective in climate zones 2 through 16; those with premiums not exceeding $0.18/ft2 [$1.90/m2] are expected to be also cost effective in climate zone 1. Hence, this study recommends that the year-2005 California building energy efficiency code (Title

  19. Effect of Waste Plastic as Bitumen Modified in Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Abdullah Mohd Ezree

    2017-01-01

    Full Text Available The objectives of this study are to investigate the engineering properties of the asphalt mixtures containing waste plastic at different percentages i.e. 4%, 6%, 8%, and 10% by weight of bitumen. The experimental tests performed in the study were stability, tensile strength, resilient modulus and dynamic creep test. Results showed that the mixture with 4% plastic has the highest stability (184kN. However, the stability slightly decreases with the increase of plastic additive. On the other hand, the highest tensile strength among the modified asphaltic concrete is 1049kPa (8% plastic added. The modified asphalt mixture with 8% plastic has the highest resilient modulus, which is 3422 MPa (25°C and 494Mpa (40°C. Where the highest creep modulus recorded is 73.30Mpa at 8% plastic added. It can be concluded that the addition of 8% plastic gave the highest value properties of asphalt mixture. Finally, it can be said that 8% plastic is the optimum value adding.

  20. Warm mix asphalt with natural zeolite for road pavements

    OpenAIRE

    Dubravský, Marián; Mandula, Ján

    2013-01-01

    The paper deals with a method to reduce temperature of asphalt mix using the ingredients of natural zeolite. In this article we discuss a proposal of the warm mix asphalt mixtures based on natural zeolite and determine the density, maximum density and sensitivity of asphalt test specimens on water. The results are compared with the reference hot mix asphalt. Розглядається метод зменшення температури асфальтових сумішей з використанням природного цеоліту. Обговорений підбір ск...

  1. Properties of polymer - and fibre-modified porous asphalt mixes

    CSIR Research Space (South Africa)

    Verhaeghe, Benoit MJA

    1994-10-01

    Full Text Available was defined. This paper addresses the relative performance of modified porous asphalt mixes and aspects relating to the design of such mixes, based on a laboratory study. It was found that polymer-modification of the binder enhances the relevant engineering...

  2. Using critical state theory for modelling of asphalt mix compaction.

    NARCIS (Netherlands)

    ter Huerne, Henny L.; van Maarseveen, Martin F.A.M.; Molenaar, Andre A.A.; van de Ven, Martin F.C.

    2014-01-01

    This paper focuses on modeling of Hot Mix Asphalt (HMA) material behavior during compaction. During compaction the particle configuration inside the HMA is changing from a relatively loose into a denser one while the bitumen is fluid. Initially particle reorientation is easily possible due to the

  3. Mechanistic and Economical Characteristics of Asphalt Rubber Mixtures

    Directory of Open Access Journals (Sweden)

    Mena I. Souliman

    2016-01-01

    Full Text Available Load associated fatigue cracking is one of the major distress types occurring in flexible pavement systems. Flexural bending beam fatigue laboratory test has been used for several decades and is considered to be an integral part of the new superpave advanced characterization procedure. One of the most significant solutions to prolong the fatigue life for an asphaltic mixture is to utilize flexible materials as rubber. A laboratory testing program was performed on a conventional and Asphalt Rubber- (AR- gap-graded mixtures to investigate the impact of added rubber on the mechanical, mechanistic, and economical attributes of asphaltic mixtures. Strain controlled fatigue tests were conducted according to American Association of State Highway and Transportation Officials (AASHTO procedures. The results from the beam fatigue tests indicated that the AR-gap-graded mixtures would have much longer fatigue life compared with the reference (conventional mixtures. In addition, a mechanistic analysis using 3D-Move software coupled with a cost analysis study based on the fatigue performance on the two mixtures was performed. Overall, analysis showed that AR modified asphalt mixtures exhibited significantly lower cost of pavement per 1000 cycles of fatigue life per mile compared to conventional HMA mixture.

  4. LABORATORY EVALUATION OF COMPACTABILITY AND PERFORMANCE OF WARM MIX ASPHALT

    Directory of Open Access Journals (Sweden)

    Allex Eduardo Álvarez Lugo

    Full Text Available Warm mix asphalt (WMA is the term used to describe the set of technologies that allow fabrication of asphalt mixtures at lower temperatures than those specified for conventional hot mix asphalt (HMA. This temperature reduction leads to advantages, compared to construction of HMA, that include energy savings, reduced emissions, and safer working conditions. However, WMA is a relatively new technology and several aspects are still under evaluation. This paper assesses some of these aspects including laboratory compactability and its relation to mixture design, and performance of WMA (i.e., permanent deformation and cracking resistance fabricated with three WMA additives, namely Advera®, Sasobit®, and Evotherm®. Corresponding results showed better or equivalent laboratory compactability for the WMA, as compared to that of the HMA used as reference (or control-HMA, leading to smaller optimum asphalt contents selected based on a specific target density (i.e., 96%. In terms of performance, inclusion of the WMA additives led to decrease the mixture resistance to permanent deformation, although the mixture resistance to cracking can remain similar or even improve as compared to that of the control-HMA.

  5. Thermal segregation of asphalt material in road repair

    Directory of Open Access Journals (Sweden)

    Juliana Byzyka

    2017-08-01

    Full Text Available This paper presents results from a field study of asphaltic pavement patching operations performed by three different contractors working in a total of ten sites. It forms part of an ongoing research programme towards improving the performance of pothole repairs. Thermal imaging technology was used to record temperatures of the patching material throughout the entire exercise, from the stage of material collection, through transportation to repair site, patch forming, and compaction. Practical complications occurring during patch repairs were also identified. It was found that depending on the weather conditions, duration of the travel and poor insulation of the transported hot asphalt mix, its temperature can drop as high as 116.6 °C over the period that the reinstatement team travel to the site and prepare the patch. This impacting is on the durability and performance of the executed repairs. Cold spots on the asphalt mat and temperature differentials between the new hot-fill asphalt mix and existing pavement were also identified as poorly compacted areas that were prone to premature failure. For example, over the five-minute period, the temperature at one point reduced by 33% whereas the temperatures of nearby areas decreased by 65% and 71%. A return visit to the repair sites, three months later, revealed that locations where thermal segregation was noted, during the patching operation, had failed prematurely.

  6. Development of a Mixture Design Procedure for Stone Matrix Asphalt

    Science.gov (United States)

    1997-03-01

    Stone Matrix Asphalt (SMA) has been used successfully in Europe for over 20 : years to provide better rutting resistance and to resist studded tire wear. : Since 1991, the use of SMA has increased steadily in the United States. At : present, some sta...

  7. The Acoustical Durability of Thin Noise Reducing Asphalt Layers

    Directory of Open Access Journals (Sweden)

    Cedric Vuye

    2016-05-01

    Full Text Available Within the context of the European Noise Directive, traffic noise action plans have been established. One of those actions is to deepen the knowledge about low noise roads, as they are considered the most cost-efficient measure for traffic noise abatement. Therefore, ten test sections were installed in May 2012 in Belgium, with the objective of integrating Thin noise-reducing Asphalt Layers (TAL in the Flemish road surface policy in a later stage. Eight test sections are paved with TAL with a thickness of a maximum of 30 mm and a maximum content of accessible voids of 18%. The other two sections consist of a Double-layer Porous Asphalt Concrete (DPAC and a Stone Mastic Asphalt (SMA-10 as a reference section. The acoustical quality of the asphalt surfaces has been monitored in time using Statistical Pass-By (SPB and Close-ProXimity (CPX measurements up to 34 months after construction. Texture measurements performed with a laser profilometer are linked to the noise measurement results. Very promising initial noise reductions were found, up to 6 dB(A, but higher than expected acoustic deterioration rates and the presence of raveling led to noise reductions of a max. of 1 dB(A after almost three years. It is shown that the construction process itself has a large influence on the acoustical quality over time.

  8. Design tool for the thermal energy potential of asphalt pavements

    NARCIS (Netherlands)

    Loomans, M.G.L.C.; Oversloot, H.P.; Bondt, A. de; Jansen, R.; Rij, H. van

    2003-01-01

    This paper describes the development of a design tool for the calculation of the thermal energy potential of a so-called asphalt collector. Two types of numerical models have been developed and validated against experimental results from a full-scale test-site. The validation showed to be a tedious

  9. Modeling of asphalt and experiments with a discrete particles method

    NARCIS (Netherlands)

    Ormel, T.J.; Magnanimo, Vanessa; ter Huerne, Henderikus L.; Luding, Stefan; Wilson, D.; Costello, S.; Henning, T.; Black, P.; Olsen, C.

    2012-01-01

    Asphalt is an important road paving material. Besides an acceptable price, durability, surface conditions (like roughening and evenness), age-, weather- and traffic-induced failures and degradation are relevant aspects. In the professional road-engineering branch empirical models are used to

  10. Characterization of Bitumen Extracted from used Asphalt Pavement ...

    African Journals Online (AJOL)

    The objectives of the research were principally to characterize extracted bitumen from Used Asphalt Pavement (UAP) on twelve selected roads through the determination of engineering properties (penetration and viscosity) and establishment of appropriate mathematical relationship between principal parameters of the ...

  11. The relation between surface texture of asphalt pavements and ...

    African Journals Online (AJOL)

    Poor pavement surface conditions have been recognized to be contributory factors for road accidents. Empirical relationship between accident explanatory variables (traffic flow, road geometry and road features) on link secti-ons of asphalted trunk roads were investigated using 617 test lengths selected from three ...

  12. Direct tensile test to assess healing in asphalt

    NARCIS (Netherlands)

    Leegwater, G.A.; Scarpas, T.; Erkens, S.

    2016-01-01

    Asphalt concrete has the advantageous ability to heal. During rest periods, damage present in the material is restored to a certain extent. Healing of the material can be observed in its regaining of strength and stiffness after rest periods. In this paper, a new test method is presented. It was

  13. Material acceptance risk analysis : superpave hot mix asphalt.

    Science.gov (United States)

    2010-09-01

    The objective of this study is to review Superpave Hot Mix asphalt used by other state DOTs and make recommendation to Idaho Transportation Department (ITD) in using this product in its roadways and in particular in low-traffic roadways. Based on the...

  14. The adoption of innovative asphalt equipment in road construction

    NARCIS (Netherlands)

    Habets, M.J.M.; Voordijk, Johannes T.; van der Sijde, Peter

    2011-01-01

    Purpose – The purpose of this paper is to provide insight into the adoption process of innovative asphalt equipment in road construction and how the level of knowledge as characterised by the level of education in the companies affects this process. The emphasis is on equipment used for transporting

  15. Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete

    Directory of Open Access Journals (Sweden)

    Fidelis O. OKAFOR

    2010-12-01

    Full Text Available Recycled asphalt pavement (RAP is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely differing water/cement ratios and mix proportions were made using RAP as coarse aggregate. The properties tested include the physical properties of the RAP aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar concretes made with natural gravel aggregate. Results of the tests suggest that the strength of concrete made from RAP is dependent on the bond strength of the “asphalt-mortar” (asphalt binder-sand-filler matrix coatings on the aggregates and may not produce concrete with compressive strength above 25 MPa. However, for middle and low strength concrete, the material was found to compare favorably with natural gravel aggregate.

  16. Comparison of Software Models for Energy Savings from Cool Roofs

    Energy Technology Data Exchange (ETDEWEB)

    New, Joshua Ryan [ORNL; Miller, William A [ORNL; Huang, Yu (Joe) [White Box Technologies; Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

    2014-01-01

    A web-based Roof Savings Calculator (RSC) has been deployed for the United States Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs modern web technologies, usability design, and national average defaults as an interface to annual simulations of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim in order to provide estimated annual energy and cost savings. In addition to cool reflective roofs, RSC simulates multiple roof and attic configurations including different roof slopes, above sheathing ventilation, radiant barriers, low-emittance roof surfaces, duct location, duct leakage rates, multiple substrate types, and insulation levels. A base case and energy-efficient alternative can be compared side-by-side to estimate monthly energy. RSC was benchmarked against field data from demonstration homes in Ft. Irwin, California; while cooling savings were similar, heating penalty varied significantly across different simulation engines. RSC results reduce cool roofing cost-effectiveness thus mitigating expected economic incentives for this countermeasure to the urban heat island effect. This paper consolidates comparison of RSC s projected energy savings to other simulation engines including DOE-2.1E, AtticSim, Micropas, and EnergyPlus, and presents preliminary analyses. RSC s algorithms for capturing radiant heat transfer and duct interaction in the attic assembly are considered major contributing factors to increased cooling savings and heating penalties. Comparison to previous simulation-based studies, analysis on the force multiplier of RSC cooling savings and heating penalties, the role of radiative heat exchange in an attic assembly, and changes made for increased accuracy of the duct model are included.

  17. Evaluation of permanent deformation and durability of epoxidized natural rubber modified asphalt mix

    Science.gov (United States)

    Al-Mansob, Ramez A.; Ismail, Amiruddin; Rahmat, Riza Atiq O. K.; Nazri Borhan, Muhamad; Alsharef, Jamal M. A.; Albrka, Shaban Ismael; Rehan Karim, Mohamed

    2017-09-01

    The road distresses have caused too much in maintenance cost. However, better understandings of the behaviours and properties of asphalt, couples with greater development in technology, have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, modifiers such as polymers are the most popular modifiers used to improve the performance of asphalt mix. This study was conducted to investigate the use of epoxidized natural rubber (ENR) to be mixed with asphalt mix. Tests were conducted to investigate the performance characteristics of ENR-asphalt mixes, where the mixes were prepared according to the wet process. Mechanical testing on the ENR-asphalt mixes have demonstrated that the asphalt mix permanent deformation performance at high temperature was found to be improved compared to the base mixes. However, the durability studies have indicated that ENR-asphalt mixes are slightly susceptible with the presence of moisture. The durability of the ENR-asphalt mixes were found to be enhanced in term of permanent deformation at high and intermediate temperatures compared to the base asphalt mixes. As conclusion, asphalt pavement performance can be enhanced by using ENR as modifier to face the major road distresses.

  18. Some Properties of Emulsified Asphalt Paving Mixture at Iraqi Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Shakir.A.Al-Mishhadani* Hasan.H.Al-Baid

    2014-04-01

    Full Text Available Cold emulsified asphalt mixture is generally a mix made of emulsified asphalt withaggregate. Emulsified asphalt is manufactured from base asphalt, emulsifier agent and waterwith approximate percentage of 40% to 75% asphalt, 0.1% to 2.5% emulsifier and 25% to60% water plus some minor components. This study aims to use the cold emulsified asphaltmixtures for road construction and maintenance in Iraq as an alternative to the hot asphaltmixtures, due to its economical, practical and environmental advantages. This studyfocusedto test and evaluates the emulsified asphalt material properties to be used as paving mixture.The tested properties of emulsified asphalt mixture were bulk density, air voids, dry Marshallstability, wet Marshall stability, retained Marshall stability, flow tests and compared with thecommon used specification.The results indicate that the emulsified asphalt type cationic slowsetting low viscosity (CSS-1 is very suitable with quartz type of aggregate from Al-Nibaayquarry. From many trial mixes it is found that the best percentages of initial residual bitumencontent to produced adequateresults for coating test ,mixing ,compaction ,curing and Marshallstability were ranged from (2.5%, 3%,3.5%,4% and 4.5%, andthe optimum percentage is(3.5%.Finally it can be conducted that the emulsified asphalt mixture is a suitable alternativemixture to the hot asphalt mixture for road construction and maintenance in Iraq.  

  19. Influence of the Microwave Heating Time on the Self-Healing Properties of Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Jose Norambuena-Contreras

    2017-10-01

    Full Text Available This paper aims to evaluate the influence of the microwave heating time on the self-healing properties of fibre-reinforced asphalt mixtures. To this purpose, self-healing properties of dense asphalt mixtures with four different percentages of steel wool fibres were evaluated as the three-point bending strength before and after healing via microwave heating at four different heating times. Furthermore, the thermal behaviour of asphalt mixtures during microwave heating was also evaluated. With the aim of quantifying the efficiency of the repair process, ten damage-healing cycles were done in the test samples. In addition, self-healing results were compared with the fibre spatial distribution inside asphalt samples evaluated by CT-scans. Crack-size change on asphalt samples during healing cycles was also evaluated through optical microscopy. It was found that the heating time is the most influential variable on the healing level reached by the asphalt mixtures tested by microwave radiation. CT-Scans results proved that fibre spatial distribution into the asphalt mixtures play an important role in the asphalt healing level. Finally, it was concluded that 40 s was the optimum heating time to reach the highest healing levels with the lowest damage on the asphalt samples, and that heating times over 30 s can seal the cracks, thus achieving the self-healing of asphalt mixtures via microwave heating.

  20. The Variation Test and Extraction Equipment to Optimum Asphalt by Using Gasoline Solvent

    Science.gov (United States)

    Soehardi, Fitridawati

    2017-12-01

    Based on the Binamarga Specification 2010 at third revision, the extraction test should be carried out using the specimen from the loose asphalt mixture extracted from the back of the finisher bitumen machine. The purpose of this research is to find out the result of pretest and posttest extraction asphalt content. The Extraction test using two equipment, they are Soklet and Centrifuge. The specimens was used AMP, Asphalt Finisher and Core, which involved gasoline solvent. Based on the asphalt level extraction test results, the appropriate equipment was used centrifuge with the level accuracy as requirement of Binamarga Specification 2010 at third revision and the level of ease used as equipment in the field study. The asphalt content obtained for AMP 5,51%, Asphalt Finisher5,46% and Core 5.34%. As for the socket asphalt content obtained is AMP 5.55%, Asphalt Finisher 5.50% and Core core 5. 41%. The extract test value of asphalt content decreased, so it can be formulated KA JMF Asphalt Finisher

  1. Molecular Simulation Study on Modification Mechanism of Red Mud Modified Asphalt

    Science.gov (United States)

    Tao, FU; Hui-ming, BAO; xing-xing, Duan

    2017-12-01

    This article used red mud, the aluminum industrial wastes, as modified asphalt material, through the study of the routine test of modified asphalt properties, and the micro test of electron microscope scanning, infrared spectrum and differential scanning calorimetry analysis etc. to discuss its performance and modification mechanism . The test results show that after mixing red mud, asphalt’s penetration index and 15 °C ductility reduced, softening point enhanced, thus the temperature sensitivity and high temperature stability of asphalt improved; Red mud after mixing the matrix asphalt, can form a uniform, stable and matrix asphalt blending system, and improve the asphalt’s thermal stability. Using molecular simulation technology to analyze the asphalt with the temperature change of energy and find in the process of asphalt melting, the largest is the key to influence on bituminous, and van der waals energy is small. It concludes that red mud -modified asphalt material is mainly controlled by bond energy, in order to obtain its favorable property of modification mechanism, red mud of senior activation and molecular bond energy of asphalt is needed to be enhanced.The results of molecular simulation show that the main component of hematite in red mud is the most adsorbed in the asphalt, the asphaltene is the second, the colloid is the worst, but the adsorption capacity of the colloid is the highest.

  2. Some Properties of Emulsified Asphalt Paving Mixture at Iraqi Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Shakir.A.Al-Mishhadani

    2014-02-01

    Full Text Available Cold emulsified asphalt mixture is generally a mix made of emulsified asphalt withaggregate. Emulsified asphalt is manufactured from base asphalt, emulsifier agent and waterwith approximate percentage of 40% to 75% asphalt, 0.1% to 2.5% emulsifier and 25% to60% water plus some minor components. This study aims to use the cold emulsified asphaltmixtures for road construction and maintenance in Iraq as an alternative to the hot asphaltmixtures, due to its economical, practical and environmental advantages. This studyfocusedto test and evaluates the emulsified asphalt material properties to be used as paving mixture.The tested properties of emulsified asphalt mixture were bulk density, air voids, dry Marshallstability, wet Marshall stability, retained Marshall stability, flow tests and compared with thecommon used specification.The results indicate that the emulsified asphalt type cationic slowsetting low viscosity (CSS-1 is very suitable with quartz type of aggregate from Al-Nibaayquarry. From many trial mixes it is found that the best percentages of initial residual bitumencontent to produced adequateresults for coating test ,mixing ,compaction ,curing and Marshallstability were ranged from (2.5%, 3%,3.5%,4% and 4.5%, andthe optimum percentage is(3.5%.Finally it can be conducted that the emulsified asphalt mixture is a suitable alternativemixture to the hot asphalt mixture for road construction and maintenance in Iraq.

  3. Design and Properties of Asphalt Concrete Mixtures Using Renewable Bioasphalt Binder

    Science.gov (United States)

    Setyawan, A.; Djumari; Irfansyah, P. A.; Shidiq, A. M.; Wibisono, I. S.; Fauzy, M. N.; Hadi, F. N.

    2017-02-01

    The needs of petroleum asphalt as materials for pavement is very large, while the petroleum classified as natural resources that cannot be renewable. As a result of petroleum dwindling and prices tend to be more expensive. So that requiring other alternative materials as a substitute for conventional asphalt derived from biomass or often called bioasphalt. This study aims to know the volumetric and Marshall characteristics on Asphalt Cement ( AC ) using the Damar asphalt modification to substitute 60/70 penetration asphalt as a binder. The volumetric and Marshall characteristic are porosity, density, flow, stability, and Marshall quotient. The characteristic of asphalt concrete at optimum bitumen content are compared to the conditions from highway agency 1987 and the general specification of asphalt concrete Bina Marga 2010 the third revision. The research uses experimental method in the laboratory with the samples made using the dasphalt modification as binder and incorporating the aggregate gradation no. VII SNI 03-1737-1989. The research is using 15 samples divided into 5 contents of damar asphalt, they are 5%, 5,5%, 6%, 6,5%, dan 7%. Tests carried out using Marshall test equipment to get the value of flow and stability and then be searched the value of optimum damar asphalt content. The result of asphalt concrete analysis using dasphalt modification as binder gives the value of optimum dasphalt content at 5,242%. The most characteristics already met the requirements and specifications.

  4. Shingle 2.0: generalising self-consistent and automated domain discretisation for multi-scale geophysical models

    Science.gov (United States)

    Candy, Adam S.; Pietrzak, Julie D.

    2018-01-01

    The approaches taken to describe and develop spatial discretisations of the domains required for geophysical simulation models are commonly ad hoc, model- or application-specific, and under-documented. This is particularly acute for simulation models that are flexible in their use of multi-scale, anisotropic, fully unstructured meshes where a relatively large number of heterogeneous parameters are required to constrain their full description. As a consequence, it can be difficult to reproduce simulations, to ensure a provenance in model data handling and initialisation, and a challenge to conduct model intercomparisons rigorously. This paper takes a novel approach to spatial discretisation, considering it much like a numerical simulation model problem of its own. It introduces a generalised, extensible, self-documenting approach to carefully describe, and necessarily fully, the constraints over the heterogeneous parameter space that determine how a domain is spatially discretised. This additionally provides a method to accurately record these constraints, using high-level natural language based abstractions that enable full accounts of provenance, sharing, and distribution. Together with this description, a generalised consistent approach to unstructured mesh generation for geophysical models is developed that is automated, robust and repeatable, quick-to-draft, rigorously verified, and consistent with the source data throughout. This interprets the description above to execute a self-consistent spatial discretisation process, which is automatically validated to expected discrete characteristics and metrics. Library code, verification tests, and examples available in the repository at https://github.com/shingleproject/Shingle. Further details of the project presented at http://shingleproject.org.

  5. Balanced RAP/RAS mix design and performance evaluation system for project-specific service conditions.

    Science.gov (United States)

    2012-11-01

    The use of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) can significantly reduce the increasing cost of hot-mix asphalt paving, conserve energy, and protect the environment. However, the premature cracking problem has been a s...

  6. Evaluation system for CO2 emission of hot asphalt mixture

    Directory of Open Access Journals (Sweden)

    Bo Peng

    2015-04-01

    Full Text Available The highway construction industry plays an important role in economic and development, but is also a primary source of carbon emission. Accordingly, with the global climate change, energy conservation and reduction of carbon emissions have become critical issues in the highway construction industry. However, to date, a model for the highway construction industry has not been established. Hence, to implement a low-carbon construction model for highways, this study divided asphalt pavement construction into aggregate stacking, aggregate supply, and other stages, and compiled a list of energy consumption investigation. An appropriate calculation model of CO2 emission was then built. Based on the carbon emission calculation model, the proportion of carbon emissions in each stage was analyzed. The analytic hierarchy process was used to establish the system of asphalt pavement construction with a judgment matrix, thereby enabling calculation of the weight coefficient of each link. In addition, the stages of aggregate heating, asphalt heating, and asphalt mixture mixing were defined as key stages of asphalt pavement construction. Carbon emissions at these stages accounted for approximately 90% of the total carbon emissions. Carbon emissions at each stage and their impact on the environment were quantified and compared. The energy saving construction schemes as well as the environmental and socioeconomic benefits were then proposed. Through these schemes, significant reductions in carbon emissions and costs can be achieved. The results indicate that carbon emissions reduce by 32.30% and 35.93%, whereas costs reduce by 18.58% and 6.03%. The proposed energy-saving and emission reduction scheme can provide a theoretical basis and technical support for the development of low-carbon highway construction.

  7. Effect of new type of synthetic waxes on reduced production and compaction temperature of asphalt mixture with reclaimed asphalt

    Science.gov (United States)

    Valentová, Tereza; Benešová, Lucie; Mastný, Jan; Valentin, Jan

    2017-09-01

    Lower mixing and paving temperatures of asphalt mixtures, which are an important issue in recent years, with respect to increased energy demand of civil engineering structures during their processing, allow reduction of this demand and result in minimized greenhouse gas production. In present time, there are many possibilities how to achieve reduction of production temperature during the mixing and paving of an asphalt mixture. The existing solutions distinguish in target operating temperature behaviour which has to be achieved in terms of good workability. This paper is focused on technical solutions based on use of new types of selected synthetic and bio-based waxes. In case of bio-based additive sugar cane wax was used, which is free of paraffins and is reclaimed as waste product during processing of sugar cane. The used waxes are added to bituminous binder in form of free-flowing granules or fine-grained powder. Synthetic waxes are represented by new series of Fischer-Tropsch wax in form of fine granules as well as by polyethylene waxes in form of fine-grained powder or granules. Those waxes were used to modify a standard paving grade bitumen dosed into asphalt mixture of ACsurf type containing up to 30 % of reclaimed asphalt (RA).

  8. Comparing Production and Placement of Warm-Mix Asphalt to Traditional Hot-Mix Asphalt for Constructing Airfield Pavements

    Science.gov (United States)

    2013-08-01

    25  Figure 29. Sampling asphalt mixture from delivery trucks . ................................................................. 26...46  Table 8. Transport truck data...the material to a uniform 12-in. depth, pulverizing the material with a rotary mixer , adjusting the moisture content, pulverizing the material again

  9. Cool roofs and the influence on the energy consumption under Danish conditions

    DEFF Research Database (Denmark)

    Brandt, Erik; Bunch-Nielsen, Tommy; Juhl, Lasse

    Experience from countries in warm climates has shown that the color of the roofing material has a significant effect on the energy consumption of the building. Especially changing from black to white roofing material provides reduction in energy consumption. The investigated roofs have been...... that there are no significant advantages of using white roofing felt instead of dark under Danish conditions in common buildings with active heating and passive cooling. Quite to the contrary it appears that dark roofing felts have significant advantages over white roofing felts. The results are discussed in the paper...

  10. A comparative analysis of selected parameters of roofing used in the Polish construction industry

    Directory of Open Access Journals (Sweden)

    Radziszewska-Zielina Elżbieta

    2014-06-01

    Full Text Available Roofing is an important element in the construction of the roof. It is also one of the essential elements of the whole building. The choice of roofing should depend on technical parameters that affect the quality of the materials used and the price. The present paper is a comparative analysis of the properties of five roofing materials selected as examples with respect to twelve parameters. As can be seen from the comparative analysis of the roofing parameters, roofing tile is by far the best material, receiving the highest score in the ranking

  11. Empirically Derived Strength of Residential Roof Structures for Solar Installations.

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, Stephen F.; Sanchez, Alfred; Campos, Ivan A.; Gerstle, Walter H.

    2014-12-01

    Engineering certification for the installation of solar photovoltaic (PV) modules on wood roofs is often denied because existing wood roofs do not meet structural design codes. This work is intended to show that many roofs are actually sufficiently strong given the conservatism in codes, documented allowable strengths, roof structure system effects, and beam composite action produced by joist-sheathing interaction. This report provides results from a testing program to provide actual load carrying capacity of residential rooftops. The results reveal that the actual load carrying capacity of structural members and systems tested are significantly stronger than allowable loads provided by the International Residential Code (IRC 2009) and the national structural code found in Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). Engineering analysis of residential rooftops typically ignores the system affects and beam composite action in determining rooftop stresses given a potential PV installation. This extreme conservatism combined with conservatism in codes and published allowable stress values for roof building materials (NDS 2012) lead to the perception that well built homes may not have adequate load bearing capacity to enable a rooftop PV installation. However, based on the test results presented in this report of residential rooftop structural systems, the actual load bearing capacity is several times higher than published values (NDS 2012).

  12. Effect of Composite Action on the Strength of Wood Roofs

    Directory of Open Access Journals (Sweden)

    Ivan A. Campos Varela

    2015-01-01

    Full Text Available Engineering certification for the installation of solar photovoltaic modules on wood roofs is often denied because existing wood roofs do not meet current building codes. Rather than requiring expensive structural retrofits, we desire to show that many roofs are actually sufficiently strong if the effect of composite action produced by joist-sheathing interaction is considered. In a series of laboratory experiments using a limited number of two-by-four wood joists with and without sheathing panels, conventionally sheathed stud-grade joists, surprisingly, exhibited between 18% and 63% higher nominal strength than similar bare joists. To explain this strength increase, a simple model was developed to predict the strengths of the nailed partially composite sections, but the model only justifies a 1.4% to 3.8% increase in bending strength of joists with an allowable bending strength of 1000 psi. More testing is indicated to resolve this discrepancy between laboratory results and analytical modeling results. In addition to elucidating nonlinear partial composite behavior of existing roof systems, this paper shows that, with minor changes in roof framing practices, strength increases of 70% or more are achievable, compared to the strengths of conventionally sheathed joists.

  13. A fuzzy approach to selecting roof supports in longwall mining

    Directory of Open Access Journals (Sweden)

    Yetkin, M. E.

    2016-05-01

    Full Text Available As a decision-making problem, selecting proper machines and equipment plays a key role for mining sites and companies. Many factors affect this decision, and values belonging to these factors can be expressed numerically and/or non-numerically. In order to make the most appropriate decision, engineers must carry out an evaluation process that comprises all criteria that might affect decision-making. To achieve this, multi-criteria decision-making tools are used. As a result of technological developments, coal outputs in longwall mining have risen tremendously over the last decades, and longwall mechanisation has become unavoidable. The significance of powered roof supports in particular increases day- by-day, since the rate of roof support has to be in accordance with the rate of face advance in longwalls. In this study, an integrated fuzzy analytic hierarchy process and fuzzy goal programming model is used to select the most suitable powered roof supports. The procedure is applied to a real-life underground coal mine that is operated using the longwall method. Seven alternative powered roof supports are compared with each other, taking a total of 24 decision criteria under four main topics into account. In conclusion, the most suitable roof supports for the mine under study are determined and recommended to the decision-makers of the system.

  14. Towards small scale use of asphalt as a fuel. An application of interest to developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Faber, J.

    2002-01-01

    This survey deals with the feasibility of the combustion of asphalt instead of firewood. On the seashores of the numerous islands of Indonesia, especially on those of south and southeast Sulawesi, mangrove forests are endangered by extensive logging, lately on an increasing scale by locals for whom firewood is the sole resource of energy. Urged by Yayasan-Sarna, an Indonesian non-governmental organisation of South East Sulawesi, the Dutch foundation Zephyr-Sama has prompted research on the feasibility to use asphalt from deposits on the island of Buton as a domestic fuel. This research was thought to possibly lead to the development of a porous plug stove, or to a stove in which carbonised bamboo containers filled with asphalt are used as fuel elements. This survey consists of a literature review and an overview of possible routes for controlled combustion of asphalt. Attention has been paid to the environmental effects of the combustion as well. The literature mainly shows side effects of combustion of asphalt, which provide some knowledge on the combustion process. No direct studies on the combustion of asphalt were found. To explore the bottlenecks of the combustion process, an asphalt candle was made, because the taper seemed an ideal capillary active carrier for fluid asphalt. However, this experimental candle did not bum, likely due to high viscosity at the base of the taper and clogging of carbonaceous residue at the liquid/gas interface of the taper. An increase of the porosity of asphalt gives a better chance for a propagating combustion. The pores may increase the diffusion rate of volatile components, thus increasing the combustion rate. However, if asphalt is heated it will melt and the fluid will block the pores. Its melting at a relatively low temperature is a big handicap of asphalt. To overcome this handicap, asphalt could be transported by capillary forces into the combustion zone and combust at solid/liquid/gas interfaces - like is happening in a

  15. ACL Roof Impingement Revisited: Does the Independent Femoral Drilling Technique Avoid Roof Impingement With Anteriorly Placed Tibial Tunnels?

    Science.gov (United States)

    Tanksley, John A; Werner, Brian C; Conte, Evan J; Lustenberger, David P; Burrus, M Tyrrell; Brockmeier, Stephen F; Gwathmey, F Winston; Miller, Mark D

    2017-05-01

    Anatomic femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is now well accepted. The ideal location for the tibial tunnel has not been studied extensively, although some biomechanical and clinical studies suggest that placement of the tibial tunnel in the anterior part of the ACL tibial attachment site may be desirable. However, the concern for intercondylar roof impingement has tempered enthusiasm for anterior tibial tunnel placement. To compare the potential for intercondylar roof impingement of ACL grafts with anteriorly positioned tibial tunnels after either transtibial (TT) or independent femoral (IF) tunnel drilling. Controlled laboratory study. Twelve fresh-frozen cadaver knees were randomized to either a TT or IF drilling technique. Tibial guide pins were drilled in the anterior third of the native ACL tibial attachment site after debridement. All efforts were made to drill the femoral tunnel anatomically in the center of the attachment site, and the surrogate ACL graft was visualized using 3-dimensional computed tomography. Reformatting was used to evaluate for roof impingement. Tunnel dimensions, knee flexion angles, and intra-articular sagittal graft angles were also measured. The Impingement Review Index (IRI) was used to evaluate for graft impingement. Two grafts (2/6, 33.3%) in the TT group impinged upon the intercondylar roof and demonstrated angular deformity (IRI type 1). No grafts in the IF group impinged, although 2 of 6 (66.7%) IF grafts touched the roof without deformation (IRI type 2). The presence or absence of impingement was not statistically significant. The mean sagittal tibial tunnel guide pin position prior to drilling was 27.6% of the sagittal diameter of the tibia (range, 22%-33.9%). However, computed tomography performed postdrilling detected substantial posterior enlargement in 2 TT specimens. A significant difference in the sagittal graft angle was noted between the 2 groups. TT grafts were

  16. Decision of National and Provincial Highway Asphalt Pavement Structure Based on Value Engineering

    Directory of Open Access Journals (Sweden)

    Yingwei Ren

    2014-01-01

    Full Text Available It is important that decision of asphalt pavement structure requires overall considerations of the performance and financial investment. To have asphalt pavement structure fulfilling good reliability, the asphalt pavement structure decision was researched based on value engineering theory. According to the national and provincial highway investigation data in Shandong Province during the last decade, the asphalt pavement performance attenuation rules of traffic levels and asphalt layer thicknesses were developed, and then the road performance evaluation method was presented. In addition, the initial investments, the costs of road maintenance, and middle-scale repair in a period were analyzed. For the light traffic and medium traffic example, using the value engineering method, the pavement performance and costs of which thickness varies from 6 cm to 10 cm were calculated and compared. It was concluded that value engineering was an effective method in deciding the asphalt pavement structure.

  17. Requirements of inverted roofs with a drainage layer

    DEFF Research Database (Denmark)

    Leimer, Hans-Peter; Rode, Carsten; Künzel, Hartwig

    2005-01-01

    This contribution illustrates the application of the standard EN ISO 6946 regarding the heat loss of an inverted roof for different regions of Europe. An addendum to the standard (EN ISO 6946:1996/A1, 2003) introduces a correction to the thermal transmittance of inverted roofs due to rain water...... flowing between the insulation and the waterproofing membrane. It is possible to calculate the extra heat loss of inverted roofs caused by rain water below the heat insulation. The extra heat loss depends on the average rainfall and on which fraction of the rain water that will drain between...... the waterproofing membrane and the thermal insulation. This paper explains the application of the standard for areas of Europe. Furthermore, some constructions are proposed, which have such small extra heat losses caused by rain water that they may be disregarded in the calculation....

  18. Ecological and Energy Efficiency Impacts of Urban Roofs and Pavements

    Energy Technology Data Exchange (ETDEWEB)

    Moll, Gary; Beattie, Jeff

    1999-07-01

    AMERICAN FORESTS is a national leader in analyzing urban ecosystem structure, function and value using GIS technology. After conducting Urban Ecosystem Analyses in several US cities, the organization has developed a desktop computer software program that allows this technology to be transferred to local government and be used on a personal computer. This user-friendly version can be used by local planners and political leaders to make well-informed decisions about the planning and development process. AMERJCAN FORESTS' current GIS-based analyses address the effects of vegetation on air quality energy conservation and stormwater management. This project will expand the interpretive capabilities of the program to include thermal and energy-use response to the use of different roofing surfaces. The program currently analyzes the impacts of trees on home air-conditioning use, and the roof surface module will be an important complementary component. Research has shown that roof products which reflect the sun's heat back into the atmosphere impose lower cooling costs on buildings than roof products which absorb the sun's heat slowly and release it. Reflectance, or albedo, is often higher in lighter-colored products, although the use of certain materials can make a dark-colored roof more reflective. A considerable amount of research has been done in this area by scientists from the Department of Energy, particularly the Lawrence Berkeley Laboratories (LBL), the Florida Solar Energy Center and others. This project makes use of research and modeling results from Lawrence Berkeley Laboratories, in Berkeley, California. This research associates a specific reduction in energy-use with a change of roofing products.

  19. The use of foundry sand in the composition of the asphalt mixture

    OpenAIRE

    Brence, Miran

    2016-01-01

    The main components of asphalt mixtures are fractions of stone aggregates, filler and bitumen. The main component in produced asphalt mixture by mass represents stone fractions with about 85% by weight. When stone materials for the production of asphalt mixtures are replaced with secondary raw materials, then problems associated with acquiring suitable stone fractions can be avoided or at least significantly reduced. The study presents the possibility of use of foundry sand as a secondary raw...

  20. Modified composite material developed on the basis of no-fines asphalt concrete

    OpenAIRE

    Mikhasek Andrey; Ivanov Boris

    2017-01-01

    Being a composite material, asphalt concrete is widely used in hydraulic engineering and road construction. The paper proves one of asphalt concrete modification, which includes first creating a skeleton of no-fines concrete and then its washing-down with bituminous materials by a hot procedure, can be successfully used in hydraulic structures Modified composite material based on no-fines asphalt concrete has a harder skeleton because of links from cement stone and has a technological advanta...

  1. The influence of nanoclay on the durability properties of asphalt mixtures for top and base layers

    Science.gov (United States)

    Blom, Johan; De Kinder, Bram; Meeusen, Jannes; Van den bergh, Wim

    2017-09-01

    To avoid traffic congestion, due to road works, a continuous research into asphalt pavement and especially its durability is of great importance. This research focuses on improving the mechanical performance and the durability of asphalt mixtures by nanoclay modified bitumen. This promising technique of introducing nanoclays or nano particles into bitumen could offer an significant improvement on the fatigue properties and rutting performance and thus the durability of the asphalt top layer.

  2. A micromechanical finite element model for linear and damage-coupled viscoelastic behaviour of asphalt mixture

    Science.gov (United States)

    Dai, Qingli; Sadd, Martin H.; You, Zhanping

    2006-09-01

    This study presents a finite element (FE) micromechanical modelling approach for the simulation of linear and damage-coupled viscoelastic behaviour of asphalt mixture. Asphalt mixture is a composite material of graded aggregates bound with mastic (asphalt and fine aggregates). The microstructural model of asphalt mixture incorporates an equivalent lattice network structure whereby intergranular load transfer is simulated through an effective asphalt mastic zone. The finite element model integrates the ABAQUS user material subroutine with continuum elements for the effective asphalt mastic and rigid body elements for each aggregate. A unified approach is proposed using Schapery non-linear viscoelastic model for the rate-independent and rate-dependent damage behaviour. A finite element incremental algorithm with a recursive relationship for three-dimensional (3D) linear and damage-coupled viscoelastic behaviour is developed. This algorithm is used in a 3D user-defined material model for the asphalt mastic to predict global linear and damage-coupled viscoelastic behaviour of asphalt mixture.For linear viscoelastic study, the creep stiffnesses of mastic and asphalt mixture at different temperatures are measured in laboratory. A regression-fitting method is employed to calibrate generalized Maxwell models with Prony series and generate master stiffness curves for mastic and asphalt mixture. A computational model is developed with image analysis of sectioned surface of a test specimen. The viscoelastic prediction of mixture creep stiffness with the calibrated mastic material parameters is compared with mixture master stiffness curve over a reduced time period.In regard to damage-coupled viscoelastic behaviour, cyclic loading responses of linear and rate-independent damage-coupled viscoelastic materials are compared. Effects of particular microstructure parameters on the rate-independent damage-coupled viscoelastic behaviour are also investigated with finite element

  3. Development of Energy-based Damage and Plasticity Models for Asphalt Concrete Mixtures

    OpenAIRE

    Onifade, Ibrahim

    2017-01-01

    Characterizing the full range of damage and plastic behaviour of asphalt mixtures under varying strain-rates and stress states is a complex and challenging task. One reason for this  is partly due to the strain rate and temperature dependent nature of the material as well as the variation in the properties of the constituent materials that make up the composite asphalt mixture. Existing stress-based models for asphalt concrete materials are developed based on mechanics principles, but these m...

  4. The Influence of Limestone and Calcium Hydroxide Addition in Asphalt Concrete Mixture

    OpenAIRE

    Gunaran Danny; Nasus K. Y; Napitupulu J. P. F; Amelia Makmur

    2016-01-01

    As time passes, flood often occurs in the area of Gunung Sahari, Jakarta Utara. The flood damages concrete asphalt mixture and it needs particular improvement. Therefore, the purpose of this research is to know the effects of the added combination of limestone and calcium hydroxide on concrete asphalt mixture as a filler resistant to flood. Concrete asphalt mixture that filled with the combination of limestone and calcium hydroxide is a mixture that is made with non-uniform aggregat gradation...

  5. The reinforcement and healing of asphalt mastic mixtures by rejuvenator encapsulation in alginate compartmented fibres

    Science.gov (United States)

    Tabaković, A.; Post, W.; Cantero, D.; Copuroglu, O.; Garcia, S. J.; Schlangen, E.

    2016-08-01

    This paper explores the potential use of compartmented alginate fibres as a new method of incorporating rejuvenators into asphalt pavement mixtures. The compartmented fibres are employed to locally distribute the rejuvenator and to overcome the problems associated with spherical capsules and hollow fibres. The work presents proof of concept of the encapsulation process which involved embedding the fibres into the asphalt mastic mixture and the survival rate of fibres in the asphalt mixture. To prove the effectiveness of the alginate as a rejuvenator encapsulating material and to demonstrate its ability survive asphalt production process, the fibres containing the rejuvenator were prepared and subjected to thermogravimetric analysis and uniaxial tensile test. The test results demonstrated that fibres have suitable thermal and mechanical strength to survive the asphalt mixing and compaction process. The CT scan of an asphalt mortar mix containing fibres demonstrated that fibres are present in the mix in their full length, undamaged, providing confirmation that the fibres survived the asphalt production process. In order to investigate the fibres physiological properties and ability to release the rejuvenator into cracks in the asphalt mastic, the environmental scanning electron microscope and optical microscope analysis were employed. To prove its success as an asphalt healing system, compartmented alginate fibres containing rejuvenator were embedded in asphalt mastic mix. The three point bend tests were performed on the asphalt mastic test samples and the degree to which the samples began to self-heal in response was measured and quantified. The research findings indicate that alginate fibres present a promising new approach for the development of self-healing asphalt pavement systems.

  6. Modelling of Asphalt Concrete Stiffness in the Linear Viscoelastic Region

    Science.gov (United States)

    Mazurek, Grzegorz; Iwański, Marek

    2017-10-01

    Stiffness modulus is a fundamental parameter used in the modelling of the viscoelastic behaviour of bituminous mixtures. On the basis of the master curve in the linear viscoelasticity range, the mechanical properties of asphalt concrete at different loading times and temperatures can be predicted. This paper discusses the construction of master curves under rheological mathematical models i.e. the sigmoidal function model (MEPDG), the fractional model, and Bahia and co-workers’ model in comparison to the results from mechanistic rheological models i.e. the generalized Huet-Sayegh model, the generalized Maxwell model and the Burgers model. For the purposes of this analysis, the reference asphalt concrete mix (denoted as AC16W) intended for the binder coarse layer and for traffic category KR3 (5×105 asphalt concrete under steady-state strain was performed using the simple axial compression-tensile test under controlled strain mode. The fixed strain level was set at 25με to guarantee that the stiffness modulus of the asphalt concrete would be tested in a linear viscoelasticity range. The master curve was formed using the time-temperature superposition principle (TTSP). The stiffness modulus of asphalt concrete was determined at temperatures 10°C, 20°C and 40°C and at loading times (frequency) of 0.1, 0.3, 1, 3, 10, 20 Hz. The model parameters were fitted to the rheological models using the original programs based on the nonlinear least squares sum method. All the rheological models under analysis were found to be capable of predicting changes in the stiffness modulus of the reference asphalt concrete to satisfactory accuracy. In the cases of the fractional model and the generalized Maxwell model, their accuracy depends on a number of elements in series. The best fit was registered for Bahia and co-workers model, generalized Maxwell model and fractional model. As for predicting the

  7. Development of asphaltic mix with waste products use

    Directory of Open Access Journals (Sweden)

    Pugin Konstantin Georgievich

    2014-07-01

    Full Text Available The trend of high growth of the vehicle fleet in Russia along with the positive impact on the socio-economic development of the country has a number of adverse consequences, one of which is the high accident rate on the roads. The paper considers modern way to provide the safe vehicles flow with the use of colored asphalt, which is a kind of hot asphalt and can have a variety of colors, which consists of coloring pigments. The conventional method of coloring the asphalt mix is produced by adding color rubble or pigmenting additives. The task, which was put forward, was the establishment of such road concrete mix, from which, without the use of primary materials and without increasing the consumption of bitumen, asphalt concrete road surfaces of acceptable strength could be obtained. As a pigment the dust of gas purification system of electrical furnace DSP - 60 of «Kamastal» plant, Perm, was used. The composition of the dust waste from the furnace consists of metal oxides and silicates. Dust-gas-cleaning is a fine powder with a high specific surface (1.2…2.5 thousand cm /g and bulk density of 3.7…4.2 g/cm . The powder color is dark brown. The density of the ready colored asphalt samples is 2.47...2.49 g/cm , and water saturation is 3.50…3.55 %. As a result of the research the diagrams of the dependence of road concrete mix’s water saturation from dust percentage and a diagram of dependence of concrete mixes’ durability from dust percentage at t = 20° and 50° C were built. After analyzing the obtained curves it can be concluded that the increase of the percentage of dust leads to increase of water saturation of road concrete mix and reduced strength. Thus, the developed asphalt concrete mix allows visually separating the lanes on the road, it has the relevant regulatory requirements durability and water resistance. This mixture corresponds to the type B mark III and can be used in regions I, II, and partly III of road-climatic zones

  8. Crystalline roof glazing - Westside shopping centre, Berne; Kristalline Dachverglasungen

    Energy Technology Data Exchange (ETDEWEB)

    Enkerli, W.

    2009-07-01

    This illustrated article takes a look at the new shopping and leisure centre on the western outskirts of Berne, Switzerland. In particular, the roof of this unusual building over the motorway with its sloping walls and zig-zag design is looked at. The centre's shopping mall, adventure baths and spa, a multiplex cinema, an old peoples' home and a hotel are briefly discussed, as is the embedding of the centre in its suburban environment. The roof construction with its crystalline skylights is examined and discussed in detail. The centre's building technical services are also briefly commented on.

  9. Retention performance of green roofs in representative climates worldwide

    Science.gov (United States)

    Viola, F.; Hellies, M.; Deidda, R.

    2017-10-01

    The ongoing process of global urbanization contributes to an increase in stormwater runoff from impervious surfaces, threatening also water quality. Green roofs have been proved to be innovative stormwater management measures to partially restore natural states, enhancing interception, infiltration and evapotranspiration fluxes. The amount of water that is retained within green roofs depends not only on their depth, but also on the climate, which drives the stochastic soil moisture dynamic. In this context, a simple tool for assessing performance of green roofs worldwide in terms of retained water is still missing and highly desirable for practical assessments. The aim of this work is to explore retention performance of green roofs as a function of their depth and in different climate regimes. Two soil depths are investigated, one representing the intensive configuration and another representing the extensive one. The role of the climate in driving water retention has been represented by rainfall and potential evapotranspiration dynamics. A simple conceptual weather generator has been implemented and used for stochastic simulation of daily rainfall and potential evapotranspiration. Stochastic forcing is used as an input of a simple conceptual hydrological model for estimating long-term water partitioning between rainfall, runoff and actual evapotranspiration. Coupling the stochastic weather generator with the conceptual hydrological model, we assessed the amount of rainfall diverted into evapotranspiration for different combinations of annual rainfall and potential evapotranspiration in five representative climatic regimes. Results quantified the capabilities of green roofs in retaining rainfall and consequently in reducing discharges into sewer systems at an annual time scale. The role of substrate depth has been recognized to be crucial in determining green roofs retention performance, which in general increase from extensive to intensive settings. Looking at the

  10. D0 Silicon Upgrade: Lower Cleanroom Roof Quick Load Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, Russ; /Fermilab

    1995-11-17

    This engineering note documents calculations done to determine the margin of safety for the lower clean room roof. The analysis was done to give me a feeling of what the loads, stresses and capacity of the roof is prior to installation and installation work to be done for the helium refrigerator upgrade. The result of this quick look showed that the calculated loads produce stress values and loads at about half the allowables. Based on this result, I do not think that special precautions above personal judgement are required for the installation work.

  11. Building Integrated Photovoltaic (BIPV) Roofs for Sustainability and Energy Efficiency

    Science.gov (United States)

    2014-04-01

    In addition, the emergence of new CIGS and CdTe PV modules and vendors have led to a much more diverse group of designs since this study started and...California CdTe Cadmium Telluride CIGS Copper Indium Gallium Di-Selenide DC Direct Current DoD Department of Defense DOE Department of...roof and PV system installed separately. The form of BIPV roof in this study used amorphous silicon (a-Si) PV modules adhered to a reflective polyvinyl

  12. Preliminary Guidelines for Maintenance of Polyurethane Foam (PUF) Roofing Systems.

    Science.gov (United States)

    1984-03-01

    establish effective procedures for maintenance of PUF roofing systems. Libr , -Card - Naval Civil Engineering Laboratory PRELIMINARY GUIDELINES FOR...attempted. 1.2.3 Insulation Board. If the roof deck is smooth rather than irregular, as with some metal decks, a patch can be made using PUF or other...VA FNIFI .-NNI (TO (Mfr. Norfolk N\\X 6fDF)P 0W. Corona . C-N (SA Ass Conmn D~es & (io~i IF.NIA) I) R Ilihner Xaiinjton. I)( (MI A lDcs &k 0 n’t.T NI IW

  13. Identification of causes of unsafe acts or neglect resulting in roof or sidewall accidents.

    CSIR Research Space (South Africa)

    Hamilton-Atwell, A

    1997-10-01

    Full Text Available the cause was roof and sidewall accidents. The primary objective of this project was to identify the causes of unsafe acts or neglect resulting in roof and sidewall accidents in coal mines....

  14. Field report: Retrofitting of a 60000 m/sup 2/ roof

    Energy Technology Data Exchange (ETDEWEB)

    Beck-Richter, A.

    Tenders were invited in 1976 for the retrofitting of the defective 60000 m/sup 2/ roof of the Nuernberg fair premises. Structural details on the roof in its retrofitted state, the roof as it was originally planned, and the old roof, the characteristics of trusses, defects of the old roof, and damage to it are followed by a description of structural retrofitting requirements, retrofitting steps, the inspection of the retrofitted/completed roof within the ten years' guarantee, and a hall with a 14000 m/sup 2/ roof erected in 1979 and retrofitted in 1988. The proper service condition of all of the roofs retrofitted was found to be attributable to their routine technical inspection and maintenance. (BR).

  15. EXTRACTION OF ROOF LINES FROM HIGH-RESOLUTION IMAGES BY A GROUPING METHOD

    Directory of Open Access Journals (Sweden)

    A. P. Dal Poz

    2016-06-01

    Full Text Available This paper proposes a method for extracting groups of straight lines that represent roof boundaries and roof ridgelines from highresolution aerial images using corresponding Airborne Laser Scanner (ALS roof polyhedrons as initial approximations. The proposed method is based on two main steps. First, straight lines that are candidates to represent roof ridgelines and roof boundaries of a building are extracted from the aerial image. Second, a group of straight lines that represent roof boundaries and roof ridgelines of a selected building is obtained through the optimization of a Markov Random Field (MRF-based energy function using the genetic algorithm optimization method. The formulation of this energy function considers several attributes, such as the proximity of the extracted straight lines to the corresponding projected ALS-derived roof polyhedron and the rectangularity (extracted straight lines that intersect at nearly 90°. Experimental results are presented and discussed in this paper.

  16. Accurate and Automatic Building Roof Extraction Using Neighborhood Information of Point Clouds

    Directory of Open Access Journals (Sweden)

    ZHAO Chuan

    2017-09-01

    Full Text Available High accuracy building roof extraction from LiDAR data is the key to build topological relationship of building roofs and reconstruct buildings. Aiming at the poor adaptation and low extraction precision of existing roof extraction methods for complex building, an accurate and automatic building roof extraction method using neighborhood information of point clouds is proposed. Point clouds features are calculated by principle component analysis, and reliable seed points are selected after feature histogram construction. Initial roof surfaces are extracted quickly and precisely by the proposed local normal vector distribution density-based spatial clustering of applications with noise (LNVD-DBSCAN. Roof competition problem is solved effectively by the poll model based on neighborhood information. Experimental results show that the proposed method can extract building roofs automatically and precisely, and has preferable adaptation to buildings with different complexity, which is able to provide reliable roof information for building reconstruction.

  17. Kinerja Campuran Beraspal Hangat Laston Lapis Pengikat (AC-BC dengan Reclaimed Asphalt Pavement (RAP

    Directory of Open Access Journals (Sweden)

    Indra Maha

    2015-04-01

    Full Text Available This paper presents the results of laboratory study of AC-BC asphalt mixture reusing reclaimed asphalt pavement (RAP by warm mix method. 30% of RAP is combined with new aggregate in the mixture. Rejuvenating agent Cyclogen L was used to activate RAP asphalt binder. With 3% organic wax Sasobit, temperature of mixing and paving was set at 135°C and 123°C, 30°C lower than conventional hot mix asphalt (HMA with unmodified asphalt binder 60/70 penetration. Three mixtures were set in this research, consisting of hot mix asphalt conventional mixture (identified as HM, warm mix asphalt mixture (identified as SASO and warm mix asphalt with RAP (identified as SASORAP. Marshall design procedure was used to determine the optimum bitumen content (OBC. OBC for each mixture was 5,2%, 5,2% and 5,3% for HMA, SASO and SASORAP respectively. From Indirect Tensile Stress test result, all asphalt mixture meet moisture sensitvity requirement where Indirect Tensile Stress Ratio (ITSR is higher than 80%. From resilient modulus and fatigue resistance test result, SASO and SASORAP showed a better performance than conventional mixture (HMA.

  18. Application of minerals residues in the asphalt composition; Aplicacao de residuos minerais na composicao do asfalto

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Roberto Carlos da C.; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica; Correia, Julio Cesar Guedes [Centro de Tecnologia Mineral - CETEM, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The performance of asphalt pavements depends mainly on the properties of their constituents: mineral aggregates and asphalt cement. The mineral aggregate represents about 95% in weight of asphalt mixtures having a significant influence on the properties and performance of these mixtures. Asphalt cement (CAP) corresponds to the smaller fraction but it is mainly responsible for adsorption on the mineral aggregates. The objective of this study was to evaluate the interaction between different CAPs with residues from granite saw wills in place of mineral aggregates that run up costs with extraction and processing in asphalt production. This way asphalt production costs as well as the environmental problems that are caused by mineral residue are reduced. Five different asphalt cements, referred to as A, B, C, D and E, and a granite residue were used in this work. The results indicated that the residue strongly absorbs all the CAPs that were studied; particularly CAP A, which is considered the most adequate for the production of asphalt from this residue. Preliminary tests this indicate that asphalt production can use mineral residues instead of mineral aggregates in its composition. (author)

  19. USE OF CRUMB RUBBER FROM USED CAR TIRES IN MINERAL ASPHALT MIXES

    Directory of Open Access Journals (Sweden)

    Andrzej Plewa

    2014-11-01

    Full Text Available With the development of the automotive industry the disposal of used tires is constantly growing problem. Storage of waste rubber is associated with a very long period of decomposition of rubber in the natural conditions. Simultaneously new technologies are developed every year, which in the future may significantly promote recycling of this type of materials. The crumb rubbery modification of the road bitumen is the one of the environmentally safe solutions of rubbery decomposition. Improvement of resistance of the crumb rubbery modification of the road asphalt mixtures is the very important ecological aspect of the future. The article presents the results of research on the fatigue life resistance of asphalt concretes AC16P and AC22P with asphalt-rubber binders. The above analyses have been based on the results of tests of fatigue life of mineral-rubber-asphalt mixes determined by the method of prismatic four-point bending (4PB-PR. Mineral-rubber -asphalt mixes have been diversified according to the amount of the additive of rubber fines in asphalt-rubber binder. On the basis of the test results have been proven improvements functional properties mineral-rubber-asphalt mixes compared with mineral-asphalt mixes with unmodified asphalt.

  20. Influence of hot asphalt mixture using asbuton on road composite pavement

    Science.gov (United States)

    Gaus, Abdul; Darwis, Muhammad; Imran

    2017-11-01

    Construction and rehabilitation of road infrastructure in Indonesia require about 1.2 million tons of asphalt per year, approximately 100% used of petroleum asphalt. Only a half of asphalt demand can be provided domestically, while about 600 thousand tons have to be imported from abroad. Indonesia has natural asphalt with a quite large deposit but has not been fully utilized. Lack of availability of asphalt and the increasing demand of the domestic market will give effect to an increase in bitumen cost in the domestic market. Somehow, this is not a sufficient condition due to the rising cost of road infrastructure. This study aims to determine the effect of using a layer of asphalt concrete pavement asbuton to rigid pavement (PR-modification). Stressing that occur in rigid pavement, asphalt concrete layer and base course measured by using LVDT and for the subgrade using soil pressure transducer. Using asbuton on asphalt concrete will have more benefit on improving the stability of the marshall. The maximum deflection occurring in the PR-modification at 5.19 mm with a maximum stress of 175.10 kN. Vertical and horizontal tension that occur at the base course at -20 cm row by 0.855 MPa and 0.00282 MPa. Addition of layers of asphalt concrete in rigid pavement using asbuton has increased power by 9.5%.

  1. Evaluation of Contractor Quality Control of Built-Up Roofing.

    Science.gov (United States)

    1983-10-01

    content of materials (such as nailers and curbing) at time of installation. D. Allowable Tolerances. The following tolerances establish the range of...assure that a N=rtrip, at least 12 inches wide, is set in steep asphalt or plastic cement and is applied so that 6 inches are set on the nailer around...Insulation 3. Submittals 7. Wood Nailers 4. Materials 8. Wood Vents for Parapet Wall Attachment: Dvg. 40-01-01, Sheet 07241-1 %.. 1. APPLICABLE PUBLICATIONS

  2. Separating drought effects from roof artefacts on ecosystem processes in a grassland drought experiment

    Science.gov (United States)

    Vogel, Anja; Fester, Thomas; Eisenhauer, Nico; Scherer-Lorenzen, Michael; Schmid, Bernhard; Weisser, Wolfgang W.; Weigelt, Alexandra

    2013-04-01

    Given the predictions of increasing risk of long drought periods under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, here called artefacts, on the response variables potentially confounding experimental results and misleading conclusions. Knowing the ecosystem response to such roof artefacts is therefore indispensible to correctly predict the effects of drought on the composition and functioning of ecosystems. We therefore aimed at filling this gap by studying the relevance of roof artefacts in a temperate grassland ecosystem. We compared pure drought effects to roof artefacts by measuring the response of three ecosystem properties (aboveground biomass, litter decomposition and plant metabolite profiles). We realized three treatments: a drought treatment simulated by means of transparent roofs, an unroofed control treatment receiving natural rainfall and a roofed control, with rain water applied according to ambient conditions. The roof constructions in our experiment caused a slight change in air (+0.14 °C during night) and soil (-0.45°C on warm days, +0.25 °C on cold nights) temperatures while photosynthetically active radiation was decreased (-16%) on bright days. Aboveground plant community biomass was reduced in the drought treatment (-41%), but there was no significant difference between the roofed and unroofed control, thus there was no measurable response of aboveground biomass to roof artefacts, but a considerable response to drought. Compared to the unroofed control, litter decomposition was decreased both in the drought treatment (-26%) and in the roofed control treatment (-18%), suggesting a response of litter decomposition to roof artefacts in addition to drought. Similarly, aboveground metabolite profiles in the model plant species Medicago x varia were significantly different

  3. Separating drought effects from roof artifacts on ecosystem processes in a grassland drought experiment.

    Science.gov (United States)

    Vogel, Anja; Fester, Thomas; Eisenhauer, Nico; Scherer-Lorenzen, Michael; Schmid, Bernhard; Weisser, Wolfgang W; Weigelt, Alexandra

    2013-01-01

    1: Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments. 2: We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions. 3: Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (-0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (-16%). Aboveground plant community biomass was reduced in the drought treatment (-41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects. 4: Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (-26%) and in the roofed control treatment (-18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects. 5: Our results stress the need for roofed control treatments

  4. System for monitoring of green roof performance: use of weighing roof segment and non-invasive visualization

    Science.gov (United States)

    Jelinkova, Vladmira; Dohnal, Michal; Picek, Tomas; Sacha, Jan

    2015-04-01

    Understanding the performance of technogenic substrates for green roofs is a significant task in the framework of sustainable urban planning and water/energy management. The potential retention and detention of the anthropogenic, light weight soil systems and their temporal soil structure changes are of major importance. A green roof test segment was built to investigate the benefits of such anthropogenic systems. Adaptable low-cost system allows long-term monitoring of preferred characteristics. Temperature and water balance measurements complemented with meteorological observations and knowledge of physical properties of the substrates provide basis for detailed analysis of thermal and hydrological regime in green roof systems. The first results confirmed the benefits of green roof systems. The reduction of temperature fluctuations as well as rainfall runoff was significant. Depending on numerous factors such substrate material or vegetation cover the test green roof suppressed the roof temperature amplitude for the period analyzed. The ability to completely prevent (light rainfall events) or reduce and delay (medium and heavy rainfall events) the peak runoff was also analyzed. Special attention is being paid to the assessment of soil structural properties related to possible aggregation/disaggregation, root growth, weather conditions and associated structural changes using non-invasive imaging method. X-ray computed microtomography of undisturbed soil samples (taken from experimental segments) is used for description of pore space geometry, evaluation of surface to volume ratio, additionally for description of cracks and macropores as a product of soil flora and fauna activity. The information from computed tomography imaging will be used for numerical modeling of water flow in variable saturated porous media. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech

  5. Investigation of thermal properties of raw materials of asphalt mixtures

    Science.gov (United States)

    Géber, R.; Simon, A.; Kocserha, I.

    2017-02-01

    Asphalt mixtures are composite materials, which are made of different grades of mineral aggregates and bitumen. During the mixing process mineral materials were blended with bitumen at relatively high temperature (∼200 °C). As the binding process come off in these higher temperature range, thermal properties of asphaltic materials are important. The aim of this project is to reveal the thermal properties of raw materials. During our research two types of mineral aggregates were tested (limestone and dolomite) by different methods. Differential thermal analysis, thermal expansion and thermal conductivity were investigated at technologically important temperatures. The results showed that the structure of mineral materials did not change at elevated temperatures, expansion of samples was neglible, while thermal conductivity changed by temperature.

  6. Asphalt Mixture Segregation Detection: Digital Image Processing Approach

    Directory of Open Access Journals (Sweden)

    Mohamadtaqi Baqersad

    2017-01-01

    Full Text Available Segregation determination in the asphalt pavement is an issue causing many disputes between agencies and contractors. The visual inspection method has commonly been used to determine pavement texture and in-place core density test used for verification. Furthermore, laser-based devices, such as the Florida Texture Meter (FTM and the Circular Track Meter (CTM, have recently been developed to evaluate the asphalt mixture texture. In this study, an innovative digital image processing approach is used to determine pavement segregation. In this procedure, the standard deviation of the grayscale image frequency histogram is used to determine segregated regions. Linear Discriminate Analysis (LDA is then implemented on the obtained standard deviations from image processing to classify pavements into the segregated and nonsegregated areas. The visual inspection method is utilized to verify this method. The results have demonstrated that this new method is a robust tool to determine segregated areas in newly paved FC9.5 pavement types.

  7. Who governs climate adaptation? Getting green roofs for stormwater retention off the ground

    NARCIS (Netherlands)

    Mees, H.L.P.; Driessen, P.P.J.; Runhaar, H.A.C.; Stamatelos, J.

    2013-01-01

    Green roofs are an innovative solution for urban stormwater management. This paper examines governance arrangements for green roofs as a ‘no-regrets’ climate adaptation measure in five cities. We analysed who governs green roofs, why and with what outcome. Our results show that hierarchical and

  8. 30 CFR 75.212 - Rehabilitation of areas with unsupported roof.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rehabilitation of areas with unsupported roof... Rehabilitation of areas with unsupported roof. (a) Before rehabilitating each area where a roof fall has occurred... rehabilitation work shall be instructed in the clean-up and support procedures; and (3) Ineffective, damaged or...

  9. Quality of bitumens in asphalt hot-mixes with emphasis on the durability of constructed premix surfacings.

    CSIR Research Space (South Africa)

    Van Assen, EJ

    1992-08-01

    Full Text Available time. Asphalt technologists' ultimate quest is for performance-related specifications that will ensure the procurement of quality bitumens which could produce asphalts with desirable performance during construction, and which will resist physical...

  10. Quantify the energy and environmental effects of using recycled asphalt and recycled concrete for pavement construction phase I : final report.

    Science.gov (United States)

    2009-08-01

    The objective of this study is to quantify the energy and environment impacts from using recycled materials : for highway construction. Specifically, when recycled asphalt pavement is re-used for producing hot mix : asphalt or when recycled concrete ...

  11. Rutting resistance of asphalt mixture with cup lumps modified binder

    Science.gov (United States)

    Shaffie, E.; Hanif, W. M. M. Wan; Arshad, A. K.; Hashim, W.

    2017-11-01

    Rutting is the most common pavement distress in pavement structures which occurs mainly due to several factors such as increasing of traffic volume, climatic conditions and also due to construction design errors. This failure reduced the service life of the pavement, reduced driver safety and increase cost of maintenance. Polymer Modified Binder has been observed for a long time in improving asphalt pavement performance. Research shows that the use of polymer in bituminous mix not only improve the resistance to rutting but also increase the life span of the pavement. This research evaluates the physical properties and rutting performance of dense graded Superpave-designed HMA mix. Two different types of dense graded Superpave HMA mix were developed consists of unmodified binder mix (UMB) and cup lumps rubber (liquid form) modified binder mix (CLMB). Natural rubber polymer modified binder was prepared from addition of 8 percent of cup lumps into binder. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicate that these mixtures were good with respect to durability and flexibility. Furthermore, rutting results from APA rutting test was determined to evaluate the performance of these mixtures. The rutting result of CLMB demonstrates better resistance to rutting than those prepared using UMB mix. Addition of cup lumps rubber in asphalt mixture was found to be significant, where the cup lumps rubber has certainly improves the binder properties and enhanced its rutting resistance due to greater elasticity offered by the cup lumps rubber particles. It shows that the use of cup lumps rubber can significantly reduce the rut depth of asphalt mixture by 41% compared to the minimum rut depth obtained for the UMB mix. Therefore, it can be concluded that the cup lumps rubber is suitable to be used as a modifier to modified binder in order to enhance the properties of the binder and thus improves the performance of asphalt mixes.

  12. Effect of Fibers on Mixture Design of Stone Matrix Asphalt

    OpenAIRE

    Yanping Sheng; Haibin Li; Ping Guo; Guijuan Zhao; Huaxin Chen; Rui Xiong

    2017-01-01

    Lignin fibers typically influence the mixture performance of stone matrix asphalt (SMA), such as strength, stability, durability, noise level, rutting resistance, fatigue life, and water sensitivity. However, limited studies were conducted to analyze the influence of fibers on the percent voids in mineral aggregate in bituminous mixture (VMA) during the mixture design. This study analyzed the effect of different fibers and fiber contents on the VMA in SMA mixture design. A surface-dry conditi...

  13. Evaluation of Different Mineral Filler Aggregates for Asphalt Mixtures

    Science.gov (United States)

    Wasilewska, Marta; Małaszkiewicz, Dorota; Ignatiuk, Natalia

    2017-10-01

    Mineral filler aggregates play an important role in asphalt mixtures because they fill voids in paving mix and improve the cohesion of asphalt binder. Limestone powder containing over 90% of CaCO3 is the most frequently used type of filler. Waste material from the production of coarse aggregate can be successfully used as a mineral filler aggregate for hot asphalt concrete mixtures as the limestone powder replacement. This paper presents the experimental results of selected properties of filler aggregates which were obtained from rocks with different mineral composition and origin. Five types of rocks were used as a source of the mineral filler aggregate: granite, gabbro, trachybasalt, quartz sandstone and rocks from postglacial deposits. Limestone filler was used in this study as the reference material. The following tests were performed: grading (air jet sieving), quality of fines according to methylene blue test, water content by drying in a ventilated oven, particle density using pyknometer method, Delta ring and ball test, Bitumen Number, fineness determined as Blaine specific surface area. Mineral filler aggregates showed significant differences when they were mixed with bitumen and stiffening effect in Delta ring and ball test was evaluated. The highest values were achieved when gabbro and granite fillers were used. Additionally, Scanning Electron Microscopy (SEM) analysis of grain shape and size was carried out. Significant differences in grain size and shape were observed. The highest non-homogeneity in size was determined for quartz sandstone, gabbro and granite filler. Their Blaine specific surface area was lower than 2800 cm2/g, while for limestone and postglacial fillers with regular and round grains it exceeded 3000 cm2/g. All examined mineral filler aggregates met requirements of Polish National Specification WT-1: 2014 and could be used in asphalt mixtures.

  14. Durable high strength cement concrete topping for asphalt roads

    Science.gov (United States)

    Vyrozhemskyi, Valerii; Krayushkina, Kateryna; Bidnenko, Nataliia

    2017-09-01

    Work on improving riding qualities of pavements by means of placing a thin cement layer with high roughness and strength properties on the existing asphalt pavement were conducted in Ukraine for the first time. Such pavement is called HPCM (High Performance Cementitious Material). This is a high-strength thin cement-layer pavement of 8-9 mm thickness reinforced with metal or polymer fiber of less than 5 mm length. Increased grip properties are caused by placement of stone material of 3-5 mm fraction on the concrete surface. As a result of the research, the preparation and placement technology of high-strength cement thin-layer pavement reinforced with fiber was developed to improve friction properties of existing asphalt pavements which ensures their roughness and durability. It must be emphasized that HPCM is a fundamentally new type of thin-layer pavement in which a rigid layer of 10 mm thickness is placed on a non-rigid base thereby improving riding qualities of asphalt pavement at any season of a year.

  15. Representative volume element of asphalt pavement for electromagnetic measurements

    Directory of Open Access Journals (Sweden)

    Terhi Pellinen

    2015-02-01

    Full Text Available The motivation for this study was to investigate the representative volume element (RVE needed to correlate the nondestructive electromagnetic (EM measurements with the conventional destructive asphalt pavement quality control measurements. A large pavement rehabilitation contract was used as the test site for the experiment. Pavement cores were drilled from the same locations where the stationary and continuous Ground Penetrating Radar (GPR measurements were obtained. Laboratory measurements included testing the bulk density of cores using two methods, the surface-saturated dry method and determining bulk density by dimensions. Also, Vector Network Analyzer (VNA and the through specimen transmission configuration were employed at microwave frequencies to measure the reference dielectric constant of cores using two different footprint areas and therefore volume elements. The RVE for EM measurements turns out to be frequency dependent; therefore in addition to being dependent on asphalt mixture type and method of obtaining bulk density, it is dependent on the resolution of the EM method used. Then, although the average bulk property results agreed with theoretical formulations of higher core air void content giving a lower dielectric constant, for the individual cores there was no correlation for the VNA measurements because the volume element seizes deviated. Similarly, GPR technique was unable to capture the spatial variation of pavement air voids measured from the 150-mm drill cores. More research is needed to determine the usable RVE for asphalt.

  16. Microstructural and rheological analysis of fillers and asphalt mastics

    Science.gov (United States)

    Geber, R.; Simon, A.; Kocserha, I.; Buzimov, A.

    2017-01-01

    Pavements are made of different grades of mineral aggregates and organic binder. The aggregates are sorted in different sizes and different amount which are mixed together with bitumen. The finest mineral fraction (dfiller. This component has an important role in asphalt mixture - it fills the gaps between the aggregates and if mixed with bitumen (which is called asphalt mastics) it sticks the larger particles together. Particle size, microstructure and surface properties of fillers highly affect the cohesion with bitumen, therefore the aim of our research was to investigate the microstructure of mineral fillers (limestone, dolomite) which are used in Hungarian road constructions with the use of different techniques (particle size distribution, scanning electronmicroscopy tests, mercury intrusion porosimetry, BET specific surface tests, determination of hydrophobicity). After the tests of fillers, asphalt mastics were prepared and rheological examinations were obtained. These examinations served to observe the interaction and the effect of fillers. The stiffening effect of fillers and the causes of rutting were also investigated. Based on our results, it can be stated that particle size, hydrophobic properties and the amount of fillers highly affect the rheological properties of mastics.

  17. Evaluation of Colemanite Waste as Aggregate Hot Mix Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Nihat MOROVA

    2015-09-01

    Full Text Available In this study usability of waste colemanite which is obtained after cutting block colemanite for giving proper shape to blocks as an aggregate in hot mix asphalt. For this aim asphalt concrete samples were prepared with four different aggregate groups and optimum bitumen content was determined. First of all only limestone was used as an aggregate. After that, only colemanite aggregate was used with same aggregate gradation. Then, the next step of the study, Marshall samples were produced by changing coarse and fine aggregate gradation as limestone and colemanite and Marshall test were conducted. When evaluated the results samples which produced with only limestone aggregate gave the maximum Marshall Stability value. When handled other mixture groups (Only colemanite, colemanite as coarse aggregate-limestone as fine aggregate, colemanite as fine aggregate-limestone as coarse aggregate all groups were verified specification limits. As a result, especially in areas where there is widespread colemanite waste, if transportation costs did not exceed the cost of limestone, colemanite stone waste could be used instead of limestone in asphalt concrete mixtures as fine aggregate

  18. Highly condensed aromatics and their connection to hydrogenation asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Boente, L.

    1944-11-22

    An attempt is made to account for the structure of asphalts and resins which arose in residues upon hydrogenation of coal. The main assumption is that most of these asphalts consisted of highly condensed aromatics, which are considered as derivatives of the substance coronene, which could be described as having the structure consisting of six benzene rings arranged around a central seventh benzene ring. Part of the discussion is speculative, but evidence is given which had led to that speculation. The asphalts had been very hard to analyze exactly, partly because of their very low solubility in most solvents and their very high boiling points. Possible mechanisms for the formation of such highly condensed aromatics during the hydrogenation process are described along with experimental work aimed in part at hydrogenating these aromatics and in part at producing them by condensation reactions of aluminum chloride on coronene. Some of the products of the condensation reactions even resembled coke or soot, while others were red substances which fluoresced green in phenanthrene solution. It is hypothesized that coronene could be looked upon as the basic nucleus for a whole series of highly condensed aromatic molecules, in the same way that benzene is looked upon as the basic nucleus for a whole series of aromatic compounds.

  19. SURVEY OF THE PAGODA TIMBER ROOF IN DERNEBURG CASTLE

    Directory of Open Access Journals (Sweden)

    E. Perria

    2017-05-01

    Full Text Available The work analyses the historical roof of Derneburg Castle, in the municipality of Holle, Hildesheim’s district, Lower Saxony, Germany. The roof is assembled according to Laves Balken’s system (Laves beam’s system, developed by the architect Georg Ludwig Friedrich Laves (1788–1864. The system has the peculiarity to consist of beams that are split along the half of the cross section, and maintained diverged by wooden wedges, distributed along the length of the beam. The system increases the height of the beam, and elevates the bending capacity of it (Weber, 1964. The work has been developed in the frame of an interdisciplinary project in the fields of architecture, engineering and photogrammetry. Main aim of the project is the developing of a structural model to understand the load-carrying capacity of Laves Balken’s system from the laser-scanning model. For this reason, extensive surveys and photo documentation were collected on three areas of the roof construction, characterized by three peculiar usage of Laves Balken’s system. The work presents the survey of the pagoda-roof that covers the tower of the castle, and problems that can be encountered during the survey of very complex timber constructions.

  20. variability of rainwater quality due to roof characteristics

    African Journals Online (AJOL)

    SO4. 2−) are products of fossil fuel combustion (Mouli et al.,. 2005; Polkowska et al., 2005). Nitrate concentrations for all samples ranged between. 0–2.5 mg/l. Mean nitrate concentrations in the six sampling sites in roof drainage water were below.

  1. Green roofs: A possible best management practice for enhancing ...

    African Journals Online (AJOL)

    City expansion typically erodes the natural ability of the locale to perform its ecosystem services. This paper discusses green roofs and their potential benefits for Ghanaian cities in terms of improving environmental quality. Limited analysis shows that daily minimum temperatures of cities like Accra are rising faster than the ...

  2. Urban reconciliation ecology: the potential of living roofs and walls.

    Science.gov (United States)

    Francis, Robert A; Lorimer, Jamie

    2011-06-01

    Reconciling human and non-human use of urban regions to support biological conservation represents a major challenge for the 21st century. The concept of reconciliation ecology, by which the anthropogenic environment may be modified to encourage non-human use and biodiversity preservation without compromising societal utilization, potentially represents an appropriate paradigm for urban conservation given the generally poor opportunities that exist for reserve establishment and ecological restoration in urban areas. Two habitat improvement techniques with great potential for reconciliation ecology in urban areas are the installation of living roofs and walls, which have been shown to support a range of taxa at local scales. This paper evaluates the reconciliation potential of living roofs and walls, in particular highlighting both ecological and societal limitations that need to be overcome for application at the landscape scale. We further consider that successful utilization of living roofs and walls for urban reconciliation ecology will rely heavily on the participation of urban citizens, and that a 'citizen science' model is needed to facilitate public participation and support and to create an evidence base to determine their effectiveness. Living roofs and walls are just one aspect of urban reconciliation ecology, but are particularly important 'bottom-up' techniques for improving urban biodiversity that can be performed directly by the citizenry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Common causes of leakages in parapet roof construction

    African Journals Online (AJOL)

    ben

    2008-12-03

    Dec 3, 2008 ... Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. ABSTRACT. In Ghana, especially Kumasi, the .... reflective paints. With (iii), it is perhaps the most important aspect of the performance require- ments after (iv). A roof must be so designed that rain or storm water does not stay too long ...

  4. Empirical Strengths of Concrete Roof Slabs After 34 Years Service ...

    African Journals Online (AJOL)

    This paper examines the strengths of four reinforced concrete roof slabs which have been in service for over 34years. The non-destructive test hammer was used to obtain data for the empirical determination of the practical strengths of the existing structures. A total of 110 tests were performed on each slab at 11 points ...

  5. Demonstration of Three Corrosion-Resistant Sustainable Roofing Systems

    Science.gov (United States)

    2013-06-01

    UV-resistant acrylic binder (Figure 1). The stone chips provide additional protection from heat and abrasion . The “fawn grey” color that was chosen... peeling , chalking, or any other environmental-related degradation. 3.2.2 Attic environment and roof temperature assessments 3.2.2.1 Stone-coated metal

  6. Roofing: Workbook and Tests. First-Aid Training.

    Science.gov (United States)

    California State Dept. of Education, Sacramento. Bureau of Publications.

    This workbook on first aid is one of a series of nine individual units of instruction for roofing apprenticeship classes in California. The workbook covers 12 topics: introduction to first-aid practices; burns; skeletal injuries; spinal injuries; wounds, bleeding, and bruises; emergencies of the heart and blood circulation system; breathing and…

  7. Fire-induced reradiation underneath photovoltaic arrays on flat roofs

    DEFF Research Database (Denmark)

    Kristensen, Jens Steemann; Merci, Bart; Jomaas, Grunde

    2018-01-01

    The impact of the reflection of fire-induced heat from a gas burner was studied experimentally to gain knowledge on the interaction between photovoltaic (PV) panels and a fire on flat roofs. The heat flux was measured in a total of eight points at the same level as the top of the gas burner. The ...

  8. Evaluation of green roof characteristics in green building assessment

    Directory of Open Access Journals (Sweden)

    Sekulić Mirjana

    2013-01-01

    Full Text Available Methodology of building evaluation based on green building characteristics is rapidly gaining momentum, mainly in foreign, but also in domestic building practice. This methodology is being carried out through different Green Building Certification Systems, which are complex evaluation mechanisms based on numerous criteria of sustainability, addressing both ecological issues, but also economic and social ones. Green roof represents one of the 'must have' features of contemporary buildings aiming to gain green label. This paradigm is based on their numerous characteristics which contribute to different aspects of building sustainability, among which are savings in energy and water consumption, but also ecological balance and quality of built environment. Criteria used for evaluation of green roof solutions and their overall contribution to the building, are integral part of all of the mentioned certification systems, but the way they are structured and formulated inside each system varies significantly, hence causing differences in evaluation results. This paper presents the analysis of green roof related criteria of three characteristic green building certification systems: LEED, BREEAM and CASBEE. These systems are chosen primarily because of the different evaluation methodology, but also because of their market prevalence and perspectives of usage in the domestic practice. Conclusions driven from these analyses and comparisons provide insight into main aspect of green roof planning and construction which are relevant for the overall building sustainability assessment.

  9. Collapse of the roof of a football stadium

    NARCIS (Netherlands)

    Borsje, H.; Renier, B.; Burggraaf, H.G.

    2014-01-01

    In the summer of 2011 the Dutch football club FC Twente was building an extension of their stadium De Grolsch Veste, to increase the capacity of the stadium. On july 7th 2011, during construction, the roof of the partially finished extension collapsed. As a result of this accident two workers were

  10. Survey of the Pagoda Timber Roof in Derneburg Castle

    Science.gov (United States)

    Perria, E.; Sieder, M.; Hoyer, S.; Krafczyk, C.

    2017-05-01

    The work analyses the historical roof of Derneburg Castle, in the municipality of Holle, Hildesheim's district, Lower Saxony, Germany. The roof is assembled according to Laves Balken's system (Laves beam's system), developed by the architect Georg Ludwig Friedrich Laves (1788-1864). The system has the peculiarity to consist of beams that are split along the half of the cross section, and maintained diverged by wooden wedges, distributed along the length of the beam. The system increases the height of the beam, and elevates the bending capacity of it (Weber, 1964). The work has been developed in the frame of an interdisciplinary project in the fields of architecture, engineering and photogrammetry. Main aim of the project is the developing of a structural model to understand the load-carrying capacity of Laves Balken's system from the laser-scanning model. For this reason, extensive surveys and photo documentation were collected on three areas of the roof construction, characterized by three peculiar usage of Laves Balken's system. The work presents the survey of the pagoda-roof that covers the tower of the castle, and problems that can be encountered during the survey of very complex timber constructions.

  11. Wind loads on solar energy systems, mounted on flat roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bentum, C.A. van; Blackmore, P.

    2005-01-01

    Wind loads on solar energy systems are not covered by current wind loading standards. This paper describes results of a parametric study into the wind loads on solar energy systems, which are placed on flat roofs. Wind tunnel measurements have been carried out on a number of configurations. The

  12. Strength and stiffness capacity utilisation of timber members in roof ...

    African Journals Online (AJOL)

    Of all the individual strength properties, the mean bending strength capacity utilised per member was found to be the highest. The results of this study can be used for decision support related to wood property evaluation throughout the structural lumber value chain where roof truss members are the end products. Keywords: ...

  13. Urban heat mitigation by roof surface materials during the East Asian summer monsoon

    Science.gov (United States)

    Lee, Seungjoon; Ryu, Youngryel; Jiang, Chongya

    2017-04-01

    Roof surface materials, such as green and white roofs, have attracted attention in their role in urban heat mitigation, and various studies have assessed the cooling performance of roof surface materials during hot and sunny summer seasons. However, summers in the East Asian monsoon climate region are characterized by significant fluctuations in weather events, such as dry periods, heatwaves, and rainy and cloudy days. This study investigated the efficacy of different roof surface materials for heat mitigation, considering the temperatures both at and beneath the surface of the roof covering materials during a summer monsoon in Seoul, Korea. We performed continuous observations of temperature at and beneath the surface of the roof covering materials, and manual observation of albedo and the normalized difference vegetation index (NDVI) for a white roof, two green roofs (grass [Poa pratensis] and sedum [Sedum sarmentosum]), and a reference surface. Overall, the surface temperature of the white roof was significantly lower than that of the grass and sedum roofs (1.1 and 1.3°C), whereas the temperature beneath the surface of the white roof did not differ significantly from that of the grass and sedum roofs during the summer. The degree of cloudiness significantly modified the surface temperature of the white roof compared with that of the grass and sedum roofs, which depended on plant metabolisms. It was difficult for the grass to maintain its cooling ability without adequate watering management. After considering the cooling performance and maintenance efforts for different environmental conditions, we concluded that white roof performed better in urban heat mitigation than grass and sedum during the East Asian summer monsoon. Our findings will be useful in urban heat mitigation in the region.

  14. Green roofs'retention performances in different climates

    Science.gov (United States)

    Viola, Francesco; Hellies, Matteo; Deidda, Roberto

    2017-04-01

    The ongoing process of global urbanization contributes to increasing stormwater runoff from impervious surfaces, threatening also water quality. Green roofs have been proved to be an innovative stormwater management tool to partially restore natural state, enhancing interception, infiltration and evapotranspiration fluxes. The amount of water that is retained within green roofs depends mainly on both soil properties and climate. The evaluation of the retained water is not trivial since it depends on the stochastic soil moisture dynamics. The aim of this work is to explore performances of green roofs, in terms of water retention, as a function of their depth considering different climate regimes. The role of climate in driving water retention has been mainly represented by rainfall and potential evapotranspiration dynamics, which are simulated by a simple conceptual weather generator at daily time scale. The model is able to describe seasonal (in-phase and counter-phase) and stationary behaviors of climatic forcings. Model parameters have been estimated on more than 20,000 historical time series retrieved worldwide. Exemplifying cases are discussed for five different climate scenarios, changing the amplitude and/or the phase of daily mean rainfall and evapotranspiration forcings. The first scenario represents stationary climates, in two other cases the daily mean rainfall or the potential evapotranspiration evolve sinusoidally. In the latter two cases, we simulated the in-phase or in counter-phase conditions. Stochastic forcings have been then used as an input to a simple conceptual hydrological model which simulate soil moisture dynamics, evapotranspiration fluxes, runoff and leakage from soil pack at daily time scale. For several combinations of annual rainfall and potential evapotranspiration, the analysis allowed assessing green roofs' retaining capabilities, at annual time scale. Provided abacus allows a first approximation of possible hydrological benefits

  15. A Case Study of Effective Support Working Resistance and Roof Support Technology in Thick Seam Fully-Mechanized Face Mining with Hard Roof Conditions

    Directory of Open Access Journals (Sweden)

    Wei-bin Guo

    2017-06-01

    Full Text Available This paper presents the engineering geological properties and roof control tecnology for a thick coal seam fully-mechanized face mining with hard roof conditions (THC at the Jinhuagong Coal Mine (JCM, northwest China. The effective support working resistance and appropriate roof control technology are two critical factors for safe and productive mining in the THC. The load-estimate-method (LOEM is the effective method to determine the support working resistance for normal working conditions (the mining height less than 3.5 m. In order to prevent support crushing accidents from happening and to ensure the safety and high-efficiency in the THC, the LOEM was modified based on the structure of the overlying strata in the THC. The strata which can form the voussoir beam structure in normal working conditions and will break in the form of cantilever beam in the THC is defined as the key strata in the immediate roof. Therefore, the hanging length of the key strata in the immediate roof was considered in the LOEM. Furthermore, a method for calculating the hanging length of the key strata in the immediate roof and its influencing factors were proposed using cantilever beam theory analysis of the structure of the overlying strata. Moreover, in order to fully fill the goaf area with caving roof to reduce the energy accumulation of main roof movement, it was decided to apply destress blasting technique (DEBT at the JCM to control the large hanging length of the hard roof, so as to reduce the impact of the hard main roof movement on the working face. The key technique parameters of the roof caving borehole were also proposed. The obtained results demonstrated that the theoretical analysis is reasonable, and the chosen support type and the DEBT could meet the roof control requirements. The THC has achieved safety and high-efficiency mining.

  16. Shingles (Herpes Zoster)

    Science.gov (United States)

    ... benefits Become a member DermCare Team Professionalism and ethics My account Member directory Publications JAAD JAAD Case ... SkinPAC State societies Scope of practice Truth in advertising Public and patients SPOT Skin Cancer™ Community programs & ...

  17. Chickenpox and Shingles Tests

    Science.gov (United States)

    ... Total Protein and Albumin/Globulin (A/G) Ratio Toxoplasmosis Testing Trace Minerals Transferrin and Iron-binding Capacity ( ... Blood in Urine (Hematuria) Bone Marrow Disorders Breast Cancer Cancer Cardiovascular Disease Celiac Disease Cervical Cancer Chronic ...

  18. Shingles: Hope through Research

    Science.gov (United States)

    ... Barré Syndrome Information Page Headache Information Page Hemicrania Continua Information Page Hemifacial Spasm Information Page Hereditary Spastic ... the Spotlight Find NINDS Clinical Trials Patient & Caregiver Education Fact Sheets Hope Through Research Know Your Brain ...

  19. Genetics Home Reference: shingles

    Science.gov (United States)

    ... JW, Shin DH, Lee KS. Polymorphism of the IL-10 gene is associated with susceptibility to herpes zoster ... M, Nurmikko T, Hurme M. Polymorphism of the IL-10 gene is associated with susceptibility to herpes zoster. ...

  20. Chickenpox and Shingles Tests

    Science.gov (United States)

    ... Zoster Virus by PCR; Varicella Zoster Virus by DFA; Varicella Zoster Virus Antibodies, IgG and IgM Related ... the amount of the virus. Direct Fluorescent Antibody (DFA) – this test visualizes the presence of VZV in ...