Author: Cindy AdamsPublisher:
ISBN:
Category : Asphalt-rubber
Languages : en
Pages : 282
Book Description
Asphalt-rubber Interlayer Field Performance
Author: Cindy AdamsPublisher:
ISBN:
Category : Asphalt-rubber
Languages : en
Pages : 282
Book Description
Aphalt-rubber Interlayer Field Performance
Author: Cindy AdamsAsphalt-Rubber SAMI (Stress-Absorbing Membrane Interlayers) Field Evaluation
Author: R. G. McKeenPublisher:
ISBN:
Category :
Languages : en
Pages : 161
Book Description
This report documents the investigation of asphalt-rubber mixtures for use as stress-absorbing membrane interlayers (SAMIs) for airfield pavements. The project was initiated in 1977 as a state-of-the-art review (Reference 1). That study concluded that use of SAMIs was promising for improving the performance of asphalt-concrete overlays on airfield pavements. A following study addressed material characterization and development of a proposed construction specification (Reference 2). This report covers follow-on monitoring of the performance of an experimental pavement project at Kirtland AFB, Apron A; construction and performance monitoring of two trial sections located at Williams AFB and Coolidge Field in Arizona; and the design and construction of a field experiment at Peterson AFB, Colorado. Based on the results obtained to date, the performance observed cannot be related in a meaningful way to the material characteristics. This results from the small time elapsed since construction of the pavements under observation. Based on experience, a revised proposed construction specification is included in the current report. Continued performance monitoring is recommended in order to obtain the benefit from the investment made in the initial construction documentation. Keywords: Airfield parameters, Asphalt rubber, Performance monitoring, Field observations, Reflection cracking.
Use of Waste Materials in Hot-mix Asphalt
Author: H. Fred WallerPublisher: ASTM International
ISBN: 0803118813
Category : Asphalt emulsion mixtures
Languages : en
Pages : 304
Book Description
In light of requirements that rubber be mixed with any asphalt used in projects receiving federal aid beginning in 1994, and the general increase in the problem of what to do with waste material, 17 papers from a December 1992 symposium in Miami discuss some of the technical and economic considerati
Uses of Recycled Rubber Tires in Highways
Author: Jon A. EppsPublisher: Transportation Research Board
ISBN: 9780309053235
Category : Technology & Engineering
Languages : en
Pages : 172
Book Description
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.
Field Trials of Asphalt Rubber Hot Mix in Virginia
Author: G. W. MaupinPublisher:
ISBN:
Category : Asphalt-rubber
Languages : en
Pages : 42
Book Description
Four test sections using asphalt rubber hot mix were placed in Virginia during the period of 1990 through 1993. The purpose of these installations was to familiarize both contractors and Virginia Department of Transportation (VDOT) personnel with the construction process and compare the performance of different types of mixes containing ground tire rubber. The MacDonald and Rouse processes, both wet processes, were used successfully. Densegraded surface mixes, a gap-graded surface mix, and a base mix were manufactured. A stress absorbing membrane interlayer was also used on one project in an attempt to deter or eliminate a variety of types of cracking. The asphalt rubber mixes have performed as well as the conventional mixes over the short term. More evaluation time is needed to determine if the long-term performance of the asphalt rubber mixes is superior to that of the conventional mixes. The cost of the asphalt rubber mixes was 64 to 102 percent more than that of the conventional mixes; however, this cost would probably decrease if substantial quantities were placed. VDOT has the necessary experience to contract placement of asphalt rubber mixes if the suspended ISTEA mandate is effected.
Evaluation of an Asphalt-rubber Interlayer
Author: Harvey S. AllenPublisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 19
Book Description
Assessment of Asphalt Interlayer Designed on Jointed Concrete
Author: R. Christopher WilliamsPublisher:
ISBN:
Category : Pavements, Asphalt concrete
Languages : en
Pages : 37
Book Description
Reflective cracking in hot mix asphalt (HMA) overlays has been a common cause of poor pavement performance in Iowa for many years. Reflective cracks commonly occur in HMA overlays when deteriorated portland cement concrete is paved over with HMA. This results in HMA pavement surfaces with poor ride quality and increased transportation maintenance costs. To delay the formation of cracks in HMA overlays, the Iowa Department of Transportation (Iowa DOT) has begun to implement a crack-relief interlayer mix design specification. The crack-relief interlayer is an asphalt-rich, highly flexible HMA that can resist cracking in high strain loading conditions. In this project, the field performance of an HMA overlay using a one inch interlayer was compared to a conventional HMA overlay without an interlayer. Both test sections were constructed on US 169 in Adel, Iowa as part of an Iowa DOT overlay project. The laboratory performance of the interlayer mix design was assessed for resistance to cracking from repeated strains by using the four-point bending beam apparatus. An HMA using a highly polymer modified binder was designed and shown to meet the laboratory performance test criteria. The field performance of the overlay with the interlayer exceeded the performance of the conventional overlay that did not have the interlayer. After one winter season, 29 percent less reflective cracking was measured in the pavement section with the interlayer than the pavement section without the interlayer. The level of cracking severity was also reduced by using the interlayer in the overlay.
Interlayer Stress Absorbing Composite (ISAC) for Mitigating Reflection Cracking in Asphalt Concrete Overlays
Author: M. T. MukhtarPublisher:
ISBN:
Category : Geosynthetics
Languages : en
Pages : 268
Book Description
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.
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