The Use of Fabric Reinforced Overlays to Control Reflection Cracking of Composite Pavements PDF Download

Author: Kenneth H. McGhee
Publisher:
ISBN:
Category :
Languages : en
Pages : 14

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Book Description
Fabric reinforcement was used in an attempt to prevent reflection cracking of two bituminous concrete layers overlying an 8-inch plain (unreinforced, unjointed) concrete base that was underlain by a portland cement stabilized subbase material. On these pavements it was expected that the extremely rigid base and subbase layers would reduce vertical motion to a minimum. Similar pavements constructed with no overlay reinforcement readily showed reflection cracking in the bituminous layers, presumably because of horizontal, thermally induced movements of shrinkage cracks in the concrete base.

Author: Kenneth H. McGhee
Publisher:
ISBN:
Category : Concrete roads
Languages : en
Pages : 14

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Book Description
A study of the installation and three-year performance evaluation of a fabric-reinforced bituminous concrete overlay of a jointed concrete pavement is reported. The fabric, a polypropylene in an asphaltic mastic, was shown to act as a significant deterrent to the development of reflection cracks in an overlay exposed to over 30,000 vehicles per day for the evaluation period. A recommendation for further use of the fabric is included.

Author: Kenneth H. McGhee
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 52

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Book Description
Studies of efforts in Virginia to reduce the incidence of reflection cracking when portland cement concrete pavements or bases are overlayed with asphaltic concrete are reported. The methods of reflection crack reduction discussed are: (1) The use of sand as a bond breaker between portland cement concrete pavements and asphaltic overlays, (2) the use of a high tensile strength fabric as a stress relieving layer between two asphaltic concrete overlays of an old portland cement concrete pavement on a weak subbase, and (3) the use of two types of fabric as stress relieving layers between asphaltic layers and a concrete base on a very strong subbase and subgrade. The following conclusions were drawn. 1. Neither sand as a bond breaker nor high strength fabrics as stress relieving layers are effective in reducing reflection cracking where vertical joint movement (differential deflection) is a significant factor. 2. When differential deflections are greater than about 0.002 in (0.05 mm) reflection cracks form early. Such cracking is delayed for lower differential deflection but may occur as the magnitude and frequency of wheel loadings increase. 3. Both an asphalt impregnated polypropylene fabric and an unwoven, spun-bonded nylon fabric, when placed to span joints in portland cement concrete base and covered with an asphaltic concrete, overlay, are able to sustain the formation of reflection cracking in the overlaying layer without undergoing damage. 4. An asphalt impregnated polypropylene fabric spanning the joints in portland cement concrete pavements, and placed between the pavement and an asphaltic overlay, may be effective in reducing the infiltration of surface water to pavement sub-layers. There is some evidence that pavement pumping may be reduced by this method. 5. Both an asphalt impregnated polypropylene fabric and an unwoven, spun-bonded nylon fabric can delay the formation of reflection cracking. There is strong evidence, however, that such cracking is fatigue in nature and will eventually develop under the application of repetitive wheel loadings.

Author: Richard D. Barksdale
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 84

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Book Description
This synthesis will be of interest to pavement designers, maintenance engineers, and others interested in methods and procedures for reducing reflection cracking of asphalt overlays. Information is provided on the use of paving fabrics and membranes in pavement rehabilitation. Reflection cracking of pavement overlays results in decreased pavement performance with respect to ride quality, structural support, skid resistance, and safety. The use of fabrics is one of the alternatives that are available to reduce or delay reflection cracking. This report of the Transportation Research Board describes the experiences of agencies in the use of fabrics and membranes for reduction of reflection cracking.

Author: George Sherman
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 48

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Book Description
"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.

Author: Douglas W. Bish
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 20

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Book Description
This report summarizes the installation and performance of three geotextile fabrics used to retard reflective cracking in an asphalt overlay test project.

Author: L. Francken
Publisher: CRC Press
ISBN: 1482271796
Category : Architecture
Languages : en
Pages : 576

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Book Description
Proceedings of RILEM TC-PRC third conference on this subject. Papers from road authorities, engineers, researchers, contractors and manufacturers discussing the implementation and the long term behaviour of overlay systems. The following topics are covered: prevention and cracking assessment, choice and design of overlay systems, practical implemen

Author: Mostafa A. Elseifi
Publisher:
ISBN:
Category :
Languages : en
Pages : 2

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Book Description
Reflection cracks are caused by discontinuities (cracks or joints) in underlying layers, which propagate through a hot-mix asphalt (HMA) overlay due to continuous movement at the crack prompted by thermal and traffic loading. If the new overlay is bonded to the distressed layer, cracks in the existing pavement usually propagate to the surface within one to five years and even as early as few months have been reported. Excessive seasonal temperature variations and movements of a cement-treated base layer may also result in shrinkage cracking, which extends to the pavement surface to cause reflection block cracks. Reflection cracking leads to premature failure of overlays by allowing water infiltration through the cracks, which cause stripping in HMA layers and weakening and deterioration of the base and/or subgrade. Since the early 1930s, considerable resources and efforts have been spent to find new and relatively inexpensive techniques to delay reflection cracking. Different methods, including the use of interlayer systems (e.g., glassgrid, stress absorbing membranes, paving fabrics, etc.) and rubblization, have been suggested for enhancing pavement resistance to reflective cracking. Experimental investigations of these crack control treatments indicate that their performances have been mixed and cannot be considered conclusive. Louisiana has experience with various techniques and treatments to control reflection cracking since the 1970s; however, the cost-effectiveness and performance of these methods have not been reliably evaluated. In addition, scientific evaluation and testing of these treatment methods was not performed on many projects. To ensure successful control of this distress and effective allocation of maintenance funds, there is a critical need to assess the performance of pavement sections across the state built with various treatment methods and to determine the most cost-effective techniques to delay or to prevent reflection cracking in composite pavements.

Author: M. T. Mukhtar
Publisher:
ISBN:
Category : Geosynthetics
Languages : en
Pages : 266

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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.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

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Book Description
Prevention or control of reflection cracks in asphaltic concrete overlays has been a problem from the inception of this type of construction. The many different treatments that have been tried in an effort to solve this problem are: (1) reinforcement within and below the overlay, (2) bond breakers, (3) stress-relieving layers, (4) asphalt-mix additives, and (5) placement of fabrics between the existing pavement and the overlay. At the present time, no treatment has been tried that will completely prevent the formation of reflection cracks. Some treatments do delay the formation of cracks, while others do not appear to help at all. Indications are that fabrics do have some beneficial effects, such as a moisture barrier, even though the overlays develop reflection cracks. The fabrics that have been tried for the control of reflection cracks included: (1) Petromat, (2) Bidim, (3) Typar, (4) Cerex, (5) Mirafi, (6) Structofors, (7) Bituthene, (8) Protecto-Wrap, and (9) Fiberglass. Asphalt-rubber interlayers, as formulated by the Arizona Refining Company and the Sahuaro Petroleum Company, show promise in retarding reflection cracks. (Author).