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Developing Best Practices For Rehabilitation Of Concrete With Hot Mix Asphalt Hma Overlays Related To Density And Reflective Cracking
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Book Synopsis Developing Best Practices for Rehabilitation of Concrete with Hot Mix Asphalt (HMA) Overlays Related to Density and Reflective Cracking by : Eshan V. Dave
Download or read book Developing Best Practices for Rehabilitation of Concrete with Hot Mix Asphalt (HMA) Overlays Related to Density and Reflective Cracking written by Eshan V. Dave and published by . This book was released on 2021 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt overlays are commonly used to rehabilitate deteriorated Portland cement concrete (PCC) pavements. However, mechanically or thermally driven movements at joints and cracks in the underlying pavement usually lead to development of reflective cracks in the overlay. The formation and propagation of reflection cracking is controlled by the mechanical properties of the asphalt and the condition of the overlaid pavement. Current state of practice for asphalt overlay design is policy oriented and lacking an engineered design approach. There is need for establishing state of practice in design of overlays as well as for assessment of PCC pavement condition and recommending improvements to existing pavement prior to overlay construction. The objective of this study is to develop a simple decision tree-based tool for selecting suitable asphalt mixtures and overlay designs to prolong overlay lives by lowering reflective cracking and improving in-situ density. This research will leverage the current National Road Research Alliance (NRRA) effort of constructing, instrumenting, and monitoring 12 MnROAD test sections, laboratory performance tests on asphalt mixtures from the test sections, and past field performance data. The proposed tool incorporates field performance data, performance modelling, and life-cycle cost analysisto develop best practices for rehabilitation of PCC with asphalt overlays.
Book Synopsis Modeling Reflective Cracking Development in Hot-mix Asphalt Overlays and Quantification of Control Techniques by : Jongeun Baek
Download or read book Modeling Reflective Cracking Development in Hot-mix Asphalt Overlays and Quantification of Control Techniques written by Jongeun Baek and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot-mix asphalt (HMA) overlay is regarded as an efficient method to rehabilitate moderately deteriorated pavements. Despite the application of an adequately designed overlay, when HMA overlays are built on jointed concrete pavement (JCP) or a cracked surface, reflective cracking can develop shortly after the overlay application due to traffic loads and environmental changes. Several remedial techniques, including interlayer systems, have been incorporated into HMA overlays to control reflective cracking. This study examined the behavior of traffic-induced reflective cracking using a finite element (FE) model for an HMA overlay with and without interlayer systems, and evaluated the performance of interlayer systems in controlling reflective cracking. To achieve these objectives, a three-dimensional FE model was built for a typical HMA overlay constructed over JCP. A linear viscoelastic model and a bilinear cohesive zone model (CZM) were incorporated into the FE model to characterize continuum and fracture behavior of the HMA. Using the bilinear CZM, reflective cracking initiation and propagation were simulated. Transient moving vehicular loading was applied across a joint to develop reflective cracking. In order to force reflective cracking development by one pass of load application, various levels of overload were applied. Two distinct interlayer systems, sand mix and steel netting with slurry seal, were examined for their effectiveness in controlling reflective cracking. The sand mix was modeled with the LVE model and bilinear CZM. The steel netting interlayer system was modeled with beam elements for steel wires and membrane elements for slurry seal. To quantify the status of reflective cracking development, a representative fractured area (RFAOL), that is an equivalent stiffness degradation in the entire HMA overlay, was used. A limit state load approach was used to determine the resistance of the HMA overlay to reflective cracking in terms of normalized axle load of an overload equivalent to a 80-kN single-axle load. The service life of the HMA overlay regarding reflective cracking was specified by the number of load repetitions based on the Paris law. A reflective cracking control factor was defined as the ratio of the service life to the HMA overlay without an interlayer system; the factor was used to evaluate the performance effectiveness of these interlayer systems in controlling reflective cracking. It was found that the bearing capacity of existing JCP played an important role in developing reflective cracking. Reflective cracking potential increased inversely with the modulus of base and subgrade layers. Interface bonding conditions, especially bonding strength, affected the development of reflective cracking. Lower interface bonding strength resulted in greater potential for developing reflective cracking. The study concluded that the sand mix interlayer system extended the service life of the HMA overlay regarding reflective cracking due to its relatively high fracture energy. A macro-crack level of reflective cracking was initiated in the wearing course in the HMA, so-called crack jumping. The softer the sand mix, the tougher it may be, but it may cause shear rutting in HMA overlay. Hence, sand mix fracture energy and thickness thresholds should be identified. The steel netting interlayer system performed better than the sand mix; the performance of the latter is thickness and fracture energy dependent. When the steel netting interlayer system was installed properly, the reflective cracking service life of the HMA overlay was found to be six times longer than that of the HMA. The performance was still better than sand mix when localized deboning induced. However, severe debonding of steel netting can be detrimental to its performance.
Book Synopsis A Rational Approach to the Prediction of Reflective Cracking in Bituminous Overlays for Concrete Pavements by : Thomas Bennert
Download or read book A Rational Approach to the Prediction of Reflective Cracking in Bituminous Overlays for Concrete Pavements written by Thomas Bennert and published by . This book was released on 2009 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot mix asphalt (HMA) is used as the primary overlying material of concrete pavements during rehabilitation because of its inexpensive nature when compared to most Portland cement concrete (PCC) rehabilitation/reconstruction alternatives. However, due to the majority of the PCC pavements being in average to poor condition, many HMA overlays are exposed to extreme movements (both vertical and horizontal). The combination of associated load and environmentally induced movements creates complex stresses and strains in the vicinity of expansion joints and cracks in the PCC, thus dramatically reducing the life of the HMA overlay, typically in the form of reflective cracking. Reflective cracking is a fatigue cracking distress, which is initiated at the bottom of the HMA overlay and propagates to the surface. When the crack reaches the HMA overlay surface, not only does it affect the ride quality and overall integrity of the pavement surface, but it also creates a path for which water can migrate down into and below the PCC layer. This can ultimately reduce the overall structural support of the composite (HMA and PCC) pavement and result in a complete pavement failure. Medium to high severity reflective cracking results in poor surface conditions that could lead to poor driving conditions and higher accident rates. Therefore, this research is timely in that it not only addresses the structural integrity of the pavement system, but also the safety of the driving public, which is one of the main objectives of the administration at state agencies. To better understand the mechanisms associated with the development of reflective cracking, an extensive literature review was conducted. Analysis of the literature review indicated significant gaps in the current state of the practice in using bituminous overlays on PCC pavements. To fill in these gaps, a survey was developed, distributed to the state transportation agencies of all fifty states, and compiled to better define the scope of the research. The survey clearly identified that a major gap in the current state of the practice is linking the field conditions (climate, deflections, traffic levels) to appropriate laboratory testing protocols. Therefore, field test sections were selected with appropriate field forensic testing and traffic collection. During construction of the bituminous overlays, loose mix was collected and brought back to the laboratory for material characterization testing that would simulate the loading conditions associated with the respective test section. The research conducted during the development of this thesis has led to a rational approach in the prediction of reflective cracking potential in HMA overlays placed on PCC pavements. This methodology utilizes field forensic information that would normally be collected during the evaluation of the PCC/composite pavement prior to rehabilitation and laboratory fatigue and stiffness characterization of the HMA mixture(s), to predict the potential for reflective cracking in the bituminous overlay mixture(s). The extensive laboratory testing and field calibration/verification information utilized in the research has also led to "decision tree" methodology that would allow state agencies to properly select asphalt mixtures for overlaying PCC pavements.
Book Synopsis Guidelines and Methodologies for the Rehabilitation of Rigid Highway Pavements Using Asphalt Concrete Overlays by :
Download or read book Guidelines and Methodologies for the Rehabilitation of Rigid Highway Pavements Using Asphalt Concrete Overlays written by and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this study was to develop guidelines for the practical and cost-effective use of hot mix asphalt (HMA) overlays to rehabilitate deteriorating portland cement concrete (PCC) highway pavements. The particular procedures covered by the study were: (1) crack and seat; (2) break and seat; (3) rubblize; and (4) saw and sealing. This executive summary presents the major findings of this extensive nationwide research study.
Book Synopsis Prediction of Reflection Cracking in Hot Mix Asphalt Overlays by : Fang-Ling Tsai
Download or read book Prediction of Reflection Cracking in Hot Mix Asphalt Overlays written by Fang-Ling Tsai and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflection cracking is one of the main distresses in hot-mix asphalt (HMA) overlays. It has been a serious concern since early in the 20th century. Since then, several models have been developed to predict the extent and severity of reflection cracking in HMA overlays. However, only limited research has been performed to evaluate and calibrate these models. In this dissertation, mechanistic-based models are calibrated to field data of over 400 overlay test sections to produce a design process for predicting reflection cracks. Three cracking mechanisms: bending, shearing traffic stresses, and thermal stress are taken into account to evaluate the rate of growth of the three increasing levels of distress severity: low, medium, and high. The cumulative damage done by all three cracking mechanisms is used to predict the number of days for the reflection crack to reach the surface of the overlay. The result of this calculation is calibrated to the observed field data (severity and extent) which has been fitted with an S-shaped curve. In the mechanistic computations, material properties and fracture-related stress intensity factors are generated using efficient Artificial Neural Network (ANN) algorithms. In the bending and shearing traffic stress models, the traffic was represented by axle load spectra. In the thermal stress model, a recently developed temperature model was used to predict the temperature at the crack tips. This process was developed to analyze various overlay structures. HMA overlays over either asphalt pavement or jointed concrete pavement in all four major climatic zones are discussed in this dissertation. The results of this calculated mechanistic approach showed its ability to efficiently reproduce field observations of the growth, extent, and severity of reflection cracking. The most important contribution to crack growth was found to be thermal stress. The computer running time for a twenty-year prediction of a typical overlay was between one and four minutes.
Book Synopsis Reflective Crack Mitigation Guide for Flexible Pavements by : R. Christopher Williams
Download or read book Reflective Crack Mitigation Guide for Flexible Pavements written by R. Christopher Williams and published by . This book was released on 2015 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflective cracks form in pavements when hot-mix asphalt (HMA) overlays are placed over jointed and/or severely cracked rigid and flexible pavements. In the first part of the research, survival analysis was conducted to identify the most appropriate rehabilitation method for composite pavements and to evaluate the influence of different factors on reflective crack development. Four rehabilitation methods, including mill and fill, overlay, heater scarification (SCR), and rubblization, were analyzed using three performance indicators: reflective cracking, international roughness index (IRI), and pavement condition index (PCI). It was found that rubblization can significantly retard reflective cracking development compared to the other three methods. No significant difference for PCI was seen among the four rehabilitation methods. Heater scarification showed the lowest survival probability for both reflective cracking and IRI, while an overlay resulted in the poorest overall pavement condition based on PCI. In addition, traffic level was found not to be a significant factor for reflective cracking development. An increase in overlay thickness can significantly delay the propagation of reflective cracking for all four treatments. Soil types in rubblization pavement sites were assessed, and no close relationship was found between rubblized pavement performance and subgrade soil condition. In the second part of the research, the study objective was to evaluate the modulus and performance of four reflective cracking treatments: full rubblization, modified rubblization, crack and seat, and rock interlayer. A total of 16 pavement sites were tested by the surface wave method (SWM), and in the first four sites both falling weight deflectometer (FWD) and SWM were conducted for a preliminary analysis. The SWM gave close concrete layer moduli compared to the FWD moduli on a conventional composite pavement. However, the SWM provided higher moduli for the rubblized concrete layer. After the preliminary analysis, another 12 pavement sites were tested by the SWM. The results showed that the crack and seat method provided the highest moduli, followed by the modified rubblization method. The full rubblization and the rock interlayer methods gave similar, but lower, moduli. Pavement performance surveys were also conducted during the field study. In general, none of the pavement sites had rutting problems. The conventional composite pavement site had the largest amount of reflective cracking. A moderate amount of reflective cracking was observed for the two pavement sites with full rubblization. Pavements with the rock interlayer and modified rubblization treatments had much less reflective cracking. It is recommended that use of the modified rubblization and rock interlayer treatments for reflective cracking mitigation are best.
Book Synopsis Rehabilitation of Concrete Pavements Utilizing Rubblization and Crack and Seat Methods by :
Download or read book Rehabilitation of Concrete Pavements Utilizing Rubblization and Crack and Seat Methods written by and published by . This book was released on 2005 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deterioration in Portland Cement Concrete (PCC) pavements can occur due to distresses caused by a combination of traffic loads and weather conditions. Hot mix asphalt (HMA) overlay is the most commonly used rehabilitation technique for such deteriorated PCC pavements. However, the performance of these HMA overlaid pavements is hindered due to the occurrence of reflective cracking, resulting in significant reduction of pavement serviceability. Various fractured slab techniques, including rubblization, crack and seat, and break and seat are used to minimize reflective cracking by reducing the slab action. The main objective of this project is to develop a mechanistic-empirical (ME) design aproach for the HMA overlay thickness design for fractured PCC pavements. In this design procedure, failure criteria such as the tensile strain at the bottom of HMA layer and the vertical compressive strain on the surface of subgrade are used to consider HMA fatigue and subgrade rutting, respectively. The developed ME design system is also implemented in a Visual Basic computer program.
Author :American Association of State Highway and Transportation Officials Publisher :AASHTO ISBN 13 :1560510552 Total Pages :622 pages Book Rating :4.5/5 (65 download)
Book Synopsis AASHTO Guide for Design of Pavement Structures, 1993 by : American Association of State Highway and Transportation Officials
Download or read book AASHTO Guide for Design of Pavement Structures, 1993 written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 1993 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design related project level pavement management - Economic evaluation of alternative pavement design strategies - Reliability / - Pavement design procedures for new construction or reconstruction : Design requirements - Highway pavement structural design - Low-volume road design / - Pavement design procedures for rehabilitation of existing pavements : Rehabilitation concepts - Guides for field data collection - Rehabilitation methods other than overlay - Rehabilitation methods with overlays / - Mechanistic-empirical design procedures.
Book Synopsis Evaluation of Various Hot Mix Asphalt Pavement Thicknesses Over Rubblized Concrete Pavement by : Irene K. Battaglia
Download or read book Evaluation of Various Hot Mix Asphalt Pavement Thicknesses Over Rubblized Concrete Pavement written by Irene K. Battaglia and published by . This book was released on 2010 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Assessment of Asphalt Interlayer Designed on Jointed Concrete by : R. Christopher Williams
Download or read book Assessment of Asphalt Interlayer Designed on Jointed Concrete written by R. Christopher Williams and published by . This book was released on 2014 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Superpave Mix Design by : Asphalt Institute
Download or read book Superpave Mix Design written by Asphalt Institute and published by . This book was released on 2001-01-01 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of the Strategy to Select Optimum Reflective Cracking Mitigation Methods for the Hot-mixed Asphalt Overlays in Florida by : Hamid Maherinia
Download or read book Development of the Strategy to Select Optimum Reflective Cracking Mitigation Methods for the Hot-mixed Asphalt Overlays in Florida written by Hamid Maherinia and published by . This book was released on 2013 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The key input parameters in selecting optimum mitigation techniques are: 1) overlay characterization, 2) existing pavement condition, 3) base and subgrade structural condition, 4) environmental condition and 5) traffic level. In addition, to understand the current practices how reflective cracking is managed in each state, a nationwide survey was conducted by distributing the survey questionnaire (with the emphasis on flexible pavement) to all other highway agencies. Based on the responses, the most successful method of treatment is to increase the thickness of HMA overlay. Crack arresting layer is considered to be in the second place among its users. Lack of cost analysis and low rate of successful practices raise the necessity of conducting more research on this subject. Considering Florida's special conditions (climate, materials, distress type, and geological conditions) and the RC mechanism, two RC mitigation techniques have been proposed: 1) overlay reinforcement (i.e. geosynthetic reinforcement) for the existing flexible pavements and 2) Stress Absorbing Membrane Interlayer (SAMI) for the existing rigid pavements. As the final products of this study, decision trees to select an optimum RC mitigation technique for both flexible and rigid pavements were developed. The decision trees can provide a detailed guideline to pavement engineer how to consider the affecting parameters in the selection of RC mitigation technique.
Book Synopsis Cost Effective Prevention of Reflective Cracking in Composite Pavements by : Mostafa Elseifi
Download or read book Cost Effective Prevention of Reflective Cracking in Composite Pavements written by Mostafa Elseifi and published by . This book was released on 2011 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Refl ection of cracks in hot mix asphalt (HMA) overlays represents a serious challenge associated with pavement rehabilitation. Since the early 1930s, considerable resources and eff orts have been spent to fi nd new and relatively inexpensive techniques to delay refl ection cracking. Diff erent methods, including the use of interlayer systems, have been suggested for enhancing pavement resistance to refl ection cracking. Experimental investigations in the early 1980s showed that interlayer systems might be used to delay or to prevent the refl ection of cracks through a new overlay placed over an old cracked pavement. Louisiana experimented with various techniques and treatments to control refl ection cracking since the 1970s; however, the performance and cost-eff ectiveness of these methods were not evaluated in many projects. Performance and economical assessments of these various treatment methods present a critical need to ensure successful control of this distress and eff ective use of available funds. Therefore, it is necessary to analyze various pavements across the state in which these treatments were used to establish the performance and cost eff ectiveness of these crack control methods.
Book Synopsis Models for Predicting Reflection Cracking of Hot-mix Asphalt Overlays by : Robert L. Lytton
Download or read book Models for Predicting Reflection Cracking of Hot-mix Asphalt Overlays written by Robert L. Lytton and published by Transportation Research Board National Research. This book was released on 2010 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 669: Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays explores mechanistic-based models for predicting the extent and severity of reflection cracking in hot-mix asphalt overlays. Appendices A through T to NCHRP Report 669 are available online--
Book Synopsis Tolerable Strains for Hot Mix Asphalt Overlays Over Concrete Pavements by :
Download or read book Tolerable Strains for Hot Mix Asphalt Overlays Over Concrete Pavements written by and published by . This book was released on 2013 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to change of temperature and/or moisture, freezing-thaw cycles, loss of subgrade support by erosion, and traffic loading, concrete pavements can develop different types of distresses during service life. Hot mix asphalt (HMA) overlays are commonly used to improve the serviceability of damaged concrete pavements. The most challenging issue for HMA overlays over concrete pavements is the development of reflection cracks through the overlays at the locations of joints and existing cracks on concrete pavements. Even though different techniques have been used to overcome this issue, they often do not yield satisfactory results and performance. Cracking of HMA overlays results from intolerable tensile strain and/or shear movement developed in the overlays due to the movement of concrete pavements. Limited studies have been conducted so far to determine the tolerable tensile strain and shear deformation of HMA overlays on concrete pavements. If the strain and shear deformation the HMA can endure are known, the methods that will limit or prevent that strain and deformation can be sought. This research experimentally determined the tolerable tensile strain and the relative shear movement of the HMA overlays. Direct shear tests and semi-circular bend tests of HMA specimens and HMA overlay loading tests under static and cyclic loading on gapped concrete blocks were conducted in this research. HMA materials from two Kansas Department of Transportation (KDOT) projects, namely 089 C-4318-01 (Mix 1) and 56-29 KA-1087-01 (Mix 2), were used in the laboratory study. All testing was conducted at room temperature. Considering typical HMA overlay thicknesses used in Kansas, the selected thicknesses of the HMA overlays were 1.5 and 2.0 inches. Direct shear tests and semi-circular bend tests were conducted on these chosen HMA mixtures to characterize their shear and tensile properties respectively. Overlay loading tests were conducted on HMA overlays adhered to gapped concrete blocks to evaluate the interaction between the HMA overlays and the concrete blocks with a gap subjected to static or cyclic loading. Steel bars having a diameter of 0.25, 0.375, or 0.5 inches were used as spacers to create a gap in a direct shear test in the lab. These gaps simulate joints in concrete pavements. Measured relative shear displacements of these HMA specimens at failure varied from 6.0 % to 9.0 % of the specimen thickness depending upon the simulated gap width. Tolerable tensile strains of Mix 1 specimens under fatigue loading in the semi-circular bend tests were from 1.2% to 4% while those of Mix 2 specimens were from 0.6% to 1.4%. Test results show that the compressive load capacity of a specimen under the semi-circular bend test was linearly correlated to the shear load capacity of the specimen at the same mix and thickness under the direct shear test. Specimens at the onset of cracking in the overlay loading tests had the permanent vertical displacements with similar magnitudes as the shear displacements corresponding to the shear load capacities in the direct shear tests. The tolerable tensile strains of HMA specimens in the overlay tests were smaller than those in the semi-circular bend tests; however, an increase of the applied load or gap width minimized their differences. The overlay loading tests showed that the cracking could be avoided if the tensile strains in the HMA overlays were less than 0.5%. Based on the HMA mixes, the specimen thicknesses, the gaps between the concrete blocks, the load levels, and the test temperatures used in this research, it can be concluded that: (1) the shear failure could be avoided if the shear deformation of the HMA overlay was less than 6% of the overlay thickness and (2) the cracking could be avoided if the tensile strain in the HMA overlay was less than 0.6%. The methods that will limit or prevent reflection cracks due to shear deformation and tensile strain should be sought in a future study.
Book Synopsis Develop Statewide Recommendations for Application of PCC Joint Reflective Cracking Rehabilitation Strategies by : Rahul Padamkumar Jain
Download or read book Develop Statewide Recommendations for Application of PCC Joint Reflective Cracking Rehabilitation Strategies written by Rahul Padamkumar Jain and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete pavements are facing rapid deterioration due to the increasing high traffic volumes. Maintenance, rehabilitation and reconstruction (MRR) have become major activities for all the state highway agencies. Due to shortage of available funding and continuous aging of pavements, many state highway agencies are now seeking cost-effective MRR strategies. This has led a need to develop a systematic and comprehensive decision process for selecting the optimum MRR strategy that considers pavement, traffic and construction issues. This research is an effort to help the state highway agencies select the maintenance, rehabilitation and reconstruction strategy for concrete pavements. The research identifies feasibility, suitability and acceptability criteria that every MRR strategy should meet. The rehabilitation strategies satisfying these criteria are then weighed in decision process to determine the optimum rehabilitation strategy. Research also focuses on developing recommendations for statewide methods for rehabilitating jointed concrete pavements so as to minimize reflective cracking. Data was collected from relevant project case studies to assess and improve the framework for decision process. Further research will be required to enhance the selection process.
Book Synopsis Use of Fabrics and Other Measures for Retarding Reflective Cracking of Asphaltic Concrete Overlays by :
Download or read book Use of Fabrics and Other Measures for Retarding Reflective Cracking of Asphaltic Concrete Overlays written by and published by . This book was released on 1980 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
