Interlayer Stress Absorbing Composite (ISAC) for Mitigating Reflection Cracking in Asphalt Concrete Overlays
Interlayer Stress Absorbing Composite (ISAC) for Mitigating Reflection Cracking in Asphalt Concrete Overlays

Author: M. T. Mukhtar

Publisher:

Published: 1996

Total Pages: 266

ISBN-13:

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To approach the reflection cracking problem in asphalt concrete (AC) overlays systematically the properties of the materials intended to be used in an interlayer stress absorbing composite (ISAC) system were first identified. Various thermal/structural models and laboratory equipment were used for this purpose. A number of woven and nonwoven geotextiles were selected and tested for their engineering properties such as tensile strength, initial modulus, modulus at failure, and percent shrinkage. Several samples of rubber asphalt were prepared by blending different ratios of crumb rubber with various types and ratios of asphalt cements at 400 deg F. These rubber asphalts were tested at different temperatures and the effects of temperature and rate of deformation on their stiffness were evaluated. An ISAC layer was fabricated in the laboratory using the materials considered appropriate. Testing equipment was developed to evaluate the interfacial shear strength and laboratory testing was performed to determine the shear strength of the fabricated ISAC layer under an AC overlay. The ISAC layer was evaluated for its effectiveness against reflection cracking. A laboratory pavement section with an AC overlay over a jointed portland cement concrete slab was constructed and placed in an environmental chamber. A mechanical device was used to simulate thermal strain in the slab and the joint was opened and closed at an extremely slow rate. The testing was conducted at 30 deg F and deterioration in the overlay was monitored using a sensitive LVDT device. The results from the laboratory evaluation testing program indicated that the ISAC layer was highly effective in preventing reflection cracking in a 2.5-in. AC overlay. When compared to a control test section and a section using a commercially available reflection cracking control material, the ISAC layer provided for superior performance. A field pavement test section utilizing the ISAC layer was constructed in the Summer of 1994 and field evaluation is ongoing.

Minimizing Reflection Cracking of Pavement Overlays
Minimizing Reflection Cracking of Pavement Overlays

Author: George Sherman

Publisher:

Published: 1982

Total Pages: 48

ISBN-13:

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"This synthesis will be of special interest to pavement designers, materials specialists, maintenance engineers, and others concerned with the performance of pavement overlays. Methods are presented for reducing reflection cracking in overlays."--Avant-propos.

7th RILEM International Conference on Cracking in Pavements
7th RILEM International Conference on Cracking in Pavements

Author: A. Scarpas

Publisher: Springer Science & Business Media

Published: 2012-08-30

Total Pages: 1340

ISBN-13: 9400745664

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In the recent past, new materials, laboratory and in-situ testing methods and construction techniques have been introduced. In addition, modern computational techniques such as the finite element method enable the utilization of sophisticated constitutive models for realistic model-based predictions of the response of pavements. The 7th RILEM International Conference on Cracking of Pavements provided an international forum for the exchange of ideas, information and knowledge amongst experts involved in computational analysis, material production, experimental characterization, design and construction of pavements. All submitted contributions were subjected to an exhaustive refereed peer review procedure by the Scientific Committee, the Editors and a large group of international experts in the topic. On the basis of their recommendations, 129 contributions which best suited the goals and the objectives of the Conference were chosen for presentation and inclusion in the Proceedings. The strong message that emanates from the accepted contributions is that, by accounting for the idiosyncrasies of the response of pavement engineering materials, modern sophisticated constitutive models in combination with new experimental material characterization and construction techniques provide a powerful arsenal for understanding and designing against the mechanisms and the processes causing cracking and pavement response deterioration. As such they enable the adoption of truly "mechanistic" design methodologies. The papers represent the following topics: Laboratory evaluation of asphalt concrete cracking potential; Pavement cracking detection; Field investigation of pavement cracking; Pavement cracking modeling response, crack analysis and damage prediction; Performance of concrete pavements and white toppings; Fatigue cracking and damage characterization of asphalt concrete; Evaluation of the effectiveness of asphalt concrete modification; Crack growth parameters and mechanisms; Evaluation, quantification and modeling of asphalt healing properties; Reinforcement and interlayer systems for crack mitigation; Thermal and low temperature cracking of pavements; and Cracking propensity of WMA and recycled asphalts.

An Evaluation of Asphalt-rubber Mixtures for Use in Pavement Systems
An Evaluation of Asphalt-rubber Mixtures for Use in Pavement Systems

Author: Dale S. Decker

Publisher:

Published: 1979

Total Pages: 88

ISBN-13:

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The design and construction of airfield pavements have not been developed sufficiently to provide pavements that will not crack. Cracking is a response to traffic and environmental conditions or to the construction material. For many years, rubber in several different forms has been added to asphalt with limited success in reducing pavement cracking. This report reviews the efforts to control cracking by incorporating rubber and asphalt for application as membrane interlayers, surface seal coats, crack fillers, and joint sealers. The extensive literature review indicates that conflicting conclusions have been reached regarding varied applications of the asphalt-rubber material. Of the asphalt-rubber products available, those with high percentages of rubber (20 to 30 percent by weight) appear to be the most promising for airfield pavements, although the effectiveness of asphalt-rubber in controlling or reducing pavement cracking has not been conclusively demonstrated. No superiority of one asphalt-rubber product was indicated in the literature. Because of the danger of loose aggregate chips, the literature indicates that chip seal applications should not be used on facilities where loose chips could be a problem. Therefore, the membrane interlayer is the only application of asphalt-rubber that should be considered for military runways at this time.

Evaluation of the Effectiveness of Membranes for Prevention of Crack Reflection in Thin Overlays
Evaluation of the Effectiveness of Membranes for Prevention of Crack Reflection in Thin Overlays

Author: Philip John Vedros (Jr)

Publisher:

Published: 1979

Total Pages: 148

ISBN-13:

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This report is an interim report resulting from case studies of pavement performance conducted by the U.S. Army Engineer Waterways Experiment Station under contract order with the U.S. Army Forces Command. The purpose of this study was to determine if a stress-absorbing layer consisting of an asphalt-rubber membrane or a nonwoven fabric placed under a thin asphaltic concrete overlay (2 in. or less) will stop reflection cracking from occurring in the overlay. Field tests of two asphalt-rubber membrane formulations and three nonwoven fabrics were placed on roads and airfield pavements at five Army installations in various areas of the United States. This report covers the construction of the test areas and performance after a 6-month period. A final report will be prepared on the performance of each material after a number of years of annual inspections. (Author).

Uses of Recycled Rubber Tires in Highways
Uses of Recycled Rubber Tires in Highways

Author: Jon A. Epps

Publisher: Transportation Research Board

Published: 1994

Total Pages: 172

ISBN-13: 9780309053235

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This synthesis on the use of recycled rubber tires in highways will be of interest to administrators and policy-makers; pavement, materials, geotechnical, environmental, and traffic operations engineers; and research engineers involved with highway design and construction issues. Information is provided on the uses of rubber tires in asphalt paving materials as well as other uses, such as on fills and embankments, for erosion control and on railroad grade crossings. Specifically, information is included which identifies the agencies using or implementing applications for recycled rubber tires and defines the design parameters, technical and construction limitations, performance, costs, benefits, environmental limitations, specifications, and availability. This synthesis of information defines the use of recycled rubber tires in highways and is based on a review of nearly 500 references and on information recorded from state highway agency responses to a 1991 survey of practice. Updates are included for as much of the state practice information possible through 1993. The use of scrap tires for highway applications is dynamic with regard to policy and technical issues. Therefore, the reader should keep in mind that the information presented reflects the best available data at a particular time. The synthesis also identifies current research in the topic area, critical research needs, and legislative issues that affect application and use of recycled rubber tires.