Efforts to Reduce Reflective Cracking of Bituminous Concrete Overlays of Portland Cement Concrete Pavements

Efforts to Reduce Reflective Cracking of Bituminous Concrete Overlays of Portland Cement Concrete Pavements
Author: Kenneth H. McGhee
Publisher:
Total Pages: 52
Release: 1975
Genre: Pavements
ISBN:

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.

Installation and Initial Evaluation of Paving Fabric Interlayers for Mitigating Reflective Cracking in Pavements

Installation and Initial Evaluation of Paving Fabric Interlayers for Mitigating Reflective Cracking in Pavements
Author: Harikrishnan Nair
Publisher:
Total Pages: 37
Release: 2020
Genre: Pavements
ISBN:

Propagation of cracks from existing pavements into a new asphalt concrete overlay (reflective cracking) is a major problem for both rigid and flexible pavements. Reflective cracking in pavements compromises ride quality and reduces the service life of the pavement. Reflective cracking of the asphalt layer over jointed concrete pavement is a perennial problem in Virginia and elsewhere. State transportation agencies continue to try various available treatment methods to delay or prevent reflective cracking with corrective or restorative maintenance. Some of those treatments include using paving fabric as an interlayer. Virginia has anecdotal experience with paving fabric interlayers, but little well-documented history with which to assess performance. The objective of this study was to establish a performance baseline for fabric interlayers in conjunction with asphalt concrete overlays on existing flexible, rigid, and composite pavements by documenting the installation and initial field performance of several projects in Virginia. Two types of interlayer fabric were used. One of the interlayers needed an asphalt leveling course for placement based on the manufacturer's specifications. As expected, all of the sections with interlayers are performing well. However, most of the sections were placed in 2017 and 2018, and hence the performance data are preliminary. These sections need to be monitored continuously to track pavement distress and performance over time. The cost of using interlayers in pavement ranged from 6 .0 dollars to 8 .0 dollars per square yard, depending on the type of fabric and installation method. Long-term performance data are needed to assess the benefit-cost effectiveness of using paving fabric interlayers in pavements.

Fabrics in Asphalt Overlays and Pavement Maintenance

Fabrics in Asphalt Overlays and Pavement Maintenance
Author: Richard D. Barksdale
Publisher:
Total Pages: 84
Release: 1991
Genre: Technology & Engineering
ISBN:

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.

Structural Overlay Strategies for Jointed Concrete Pavements

Structural Overlay Strategies for Jointed Concrete Pavements
Author: Walter P. Kilareski
Publisher:
Total Pages: 136
Release: 1990
Genre: Pavements
ISBN:

A major field study and evaluation has been conducted into the effectiveness of three structural overlay types for portland cement concrete (PCC) pavements. These include sawing and sealing asphalt concrete (AC) overlays of PCC pavements, cracking and seating PCC pavements prior to AC overlay, and constructing a thin bonded PCC overlay on top of the existing PCC pavement. Condition surveys, deflection testing, and roughness measurements were performed on a total of 55 sections. The performance of these sections was evaluated and the effectiveness of each overlay type analyzed.

Minimizing Reflection Cracking of Pavement Overlays

Minimizing Reflection Cracking of Pavement Overlays
Author: George Sherman
Publisher:
Total Pages: 48
Release: 1982
Genre: Technology & Engineering
ISBN:

"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.

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:
Total Pages: 266
Release: 1996
Genre: Geosynthetics
ISBN:

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.

Geotextile Fabrics Under an Asphalt Concrete Overlay to Retard Reflective Cracking

Geotextile Fabrics Under an Asphalt Concrete Overlay to Retard Reflective Cracking
Author: Steve Armstrong
Publisher:
Total Pages: 0
Release: 1994
Genre: Geotextiles
ISBN:

In 1991, the City of Portland selected a section of East Burnside from 39th Avenue to 47th Avenue to grind-out and overlay asphalt concrete over an old Portland cement concrete (PCC) pavement. Geotextiles were used to provide reinforcement and retard reflective joint cracking. A test section on the eastbound lanes of Burnside between 44th Avenue and 45 Avenue was placed in September 1991. The test section included four cracks, which were covered with Glasgrid 8501 or Polyguard NW-75. A control section in the westbound lanes between 44th and 45th Avenue was also constructed about the same time.

Breaking/cracking and Seating Concrete Pavements

Breaking/cracking and Seating Concrete Pavements
Author: Marshall R. Thompson
Publisher:
Total Pages: 52
Release: 1989
Genre: Technology & Engineering
ISBN:

This synthesis will be of interest to pavement designers, maintenance engineers, and others interested in reducing reflection cracking of asphalt overlays on portland cement concrete (PCC) pavement. Information is presented on the technique of breaking or cracking of the concrete pavement into small segments before overlaying with asphalt concrete. Asphalt concrete overlays on existing PCC pavements are subject to reflection cracking induced by thermal movements of PCC pavement. This report of the Transportation Research Board discusses the technique of breaking/cracking and seating of the existing PCC before an overlay as a means to reduce or eliminate reflection cracking.