Development of the Strategy to Select Optimum Reflective Cracking Mitigation Methods for the Hot-mixed Asphalt Overlays in Florida PDF Download

Author: Hamid Maherinia
Publisher:
ISBN:
Category :
Languages : en
Pages : 119

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Book Description
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.

Author: R. Christopher Williams
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 142

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Book Description
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.

Author: Eshan V. Dave
Publisher:
ISBN:
Category : Pavements
Languages : en
Pages : 236

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Book Description
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.

Author: A. Vanelstraete
Publisher: CRC Press
ISBN: 0203627237
Category : Architecture
Languages : en
Pages : 136

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Book Description
Crack reflection through a road structure is one of the main causes of premature pavement deterioration. This is a widespread problem in many countries and highway maintenance authorities are having to find economic means of repairing and upgrading their pavements. This book is the eagerly awaited state-of-the-art report which considers all different aspects of the subject including assessment and use of overlay systems.

Author: Jongeun Baek
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
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.

Author: Thomas Bennert
Publisher:
ISBN:
Category : Pavements, Asphalt concrete
Languages : en
Pages : 203

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Book Description
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.

Author: Robert L. Lytton
Publisher: Transportation Research Board National Research
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 76

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Book Description
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--

Author: Elie Y. Hajj
Publisher:
ISBN:
Category : Pavements, Asphalt concrete
Languages : en
Pages : 27

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Book Description
This report summarizes all the findings and recommendations from the Phase I and Phase II of the Nevada Department of Transportation (NDOT) study initiated in 2006 to mitigate reflective cracking in hot mix asphalt (HMA) overlays. Based on the analysis of the various findings it was recommended to further evaluate the stress relief course (SRC) as a reflective cracking mitigation technique under Nevada's conditions. It should be noted that the SRC used by NDOT was not specifically designed or checked for its reflective cracking resistance and only consisted of a 1-inch of the typical Type II (1" max size) dense graded HMA mix placed between the existing HMA and the overlay. This NDOT study revealed promising performance for the SRC when specifically designed to resist reflective cracking. Additionally, for a good overall performance, the SRC needs to be coupled with an overlay mix with a good resistance to reflective cracking. Current state highway agencies' specifications for SRCs were reviewed and are summarized in this report. The review revealed specifications for SRCs in six different states. Four of those states: Arizona, California, Florida, and Massachusetts, specify an asphalt-rubber stress absorbing membrane interlayer (SAMI) which consists of an application of asphalt rubber binder followed by an application of aggregate. Texas DOT specifies a Crack Attenuating Mixture (CAM) which consists of an HMA mix designed according to the Superpave design procedure to a target air void of 2% at 50 gyrations along with criteria for the Hamburg Wheel and the Texas Transportation Institute (TTI) Overlay tests. The Utah DOT specifies a reflective cracking relief bituminous mixture which meets the general requirements specified for an HMA mixture except the mix is designed to a target air void of 0.5-2.5% at 50 design gyrations along with criteria for voids in mineral aggregate (VMA), Hveem stability, and flexural beam fatigue testing at optimum binder content.

Author: Rahul Padamkumar Jain
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
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.

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