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Validation Of Thermally Induced Internal Cracking In Asphalt Mixtures Using Indirect Tensile Test
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Book Synopsis Validation of Thermally Induced Internal Cracking in Asphalt Mixtures Using Indirect Tensile Test by : Joshua Oklu
Download or read book Validation of Thermally Induced Internal Cracking in Asphalt Mixtures Using Indirect Tensile Test written by Joshua Oklu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: s stated in the House Bill 62 Transportation Budget in Brief, roughly 5 billion dollars is spent yearly on road pavement construction in the state of Ohio, with a significant chunk for maintenance. Moreover, maintenance activities and their associated costs are increased in the colder regions of the US where damages and distress on roadways are associated to the Low Temperature Cracking (LTC) phenomena or at least in combination with other distress like rutting and fatigue cracking. Thermally induced internal cracking is a mechanism that occurs under low temperature conditions. Akentuna et al. (2017) postulated that the differential in Coefficient of Thermal Contraction (CTC) values in asphalt binder and aggregate gives rise to thermally induced internal cracking at low temperatures. Owing to its potential significance and effect on LTC modeling, this study investigated the thermally induced thermal cracking phenomena using the Indirect Tensile (IDT) test. The IDT test was selected since it is the test procedure used in fracture property investigation in the AASHTOWare Pavement Mechanistic Empirical (ME) Design program for low temperature cracking modeling. In addition, a study on the effect of loading rate and temperature on asphalt mixtures during the ITS test was also investigated. Although thermally induced internal cracking was observed by Li et al. (2007) using the acoustic emissions test and Behnia et al. (2014) using the Disc-shaped Compact Test (DCT), its quantified effect has not been studied. The results garnered from this study validated the occurrence of thermally induced internal cracking, evidenced by significant reduction in IDT peak strengths and energy at peak stress to averaged magnitudes of 4% and 12% respectively. The second objective of this study on varying loading rate and temperature during the IDT strength tests proved that the standard test loading rate of 12.5mm/min rate was too fast and not representative of field loading rate. In addition, knowing that LTC could occur even at lower stress compared to the IDT strengths, ‘Creep to fail’ tests were performed to analyze the behavior of mixtures in such circumstances. Results showed that creep loads at extremely lower percentages of IDT strengths still fractured asphalt samples with output parameters offering valuable information on crack behavior under low temperature conditions. Time to fracture and crack speed parameters were shown to decrease 62% and increase 46% in thermally induced internal cracking samples.
Book Synopsis Evaluation of Indirect Tensile Test (IDT) Procedures for Low-temperature Performance of Hot Mix Asphalt by : Donald W. Christensen
Download or read book Evaluation of Indirect Tensile Test (IDT) Procedures for Low-temperature Performance of Hot Mix Asphalt written by Donald W. Christensen and published by Transportation Research Board. This book was released on 2004 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction and Research Approach -- Findings -- Interpretation, Appraisal, and Applications -- Conclusions and Recommendations -- References -- Appendixes.
Book Synopsis Standard Test Method for Determining Thermal Cracking Properties of Asphalt Mixtures Through Measurement of Thermally Induced Stress and Strain by :
Download or read book Standard Test Method for Determining Thermal Cracking Properties of Asphalt Mixtures Through Measurement of Thermally Induced Stress and Strain written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Laboratory Study to Predict the Rutting and Fatigue Behavior of Asphalt Concrete Using the Indirect Tensile Test by : Haifang Wen
Download or read book A Laboratory Study to Predict the Rutting and Fatigue Behavior of Asphalt Concrete Using the Indirect Tensile Test written by Haifang Wen and published by . This book was released on 2013 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rutting, fatigue, moisture susceptibility, and thermal cracking are the primary distresses of asphalt pavement. Currently several test methods are used to predict the rutting and fatigue behavior of asphalt concrete. This study uses the indirect tensile (IDT) test to evaluate both the rutting and fatigue behavior of asphalt. Recycled concrete aggregate (RCA) and virgin aggregate are blended at different percentages (0 %, 20 %, 40 %, 60 %, 80 %, and 100 %) to produce mixes with a variety of fatigue and rutting performance. The IDT rutting test was performed by running high temperature IDT flow time and strength tests. In addition, flow number tests were performed using an asphalt mixture performance tester (AMPT). A strong correlation is observed between the high temperature IDT flow time/strength and flow number from AMPT. The test results show that IDT tests can be used to predict the rutting behavior of asphalt concrete at high temperatures. To characterize fatigue, cyclic IDT and monotonic fracture energy tests were performed at intermediate temperatures. At intermediate temperatures, good correlation is found between the fatigue life obtained from cyclic IDT test results and the fracture energy obtained from monotonic fracture test results. Based on the laboratory test results, the IDT test can be used to evaluate both the fatigue and rutting behavior of asphalt concrete. Considering that IDT testing has been used to characterize thermal cracking and moisture susceptibility, the IDT test has the potential to serve as a single performance test for fatigue, rutting, thermal cracking and moisture damage. Validation of the findings with more materials and field performance are recommended.
Book Synopsis Low-temperature Cracking by : D. H. Jung
Download or read book Low-temperature Cracking written by D. H. Jung and published by National Research Council. This book was released on 1994 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the thermal stress restrained specimen test (TSRST), which was selected to evaluate the low-temperature cracking resistance of asphalt concrete mixtures. The TSRST system includes a load frame, step-motor-driven load ram, data acquisition hardware and software, temperature controller, and specimen alignment stand. An experiment design that considered a range of mixture and test condition variables was developed to evaluate the suitability of TSRST for characterizing low-temperature cracking resistance of asphalt concrete mixtures. Four asphalts and two aggregates were selected for the experiment. The mixture variables included asphalt type, aggregate type, and air voids content; the test condition variables included specimen size, stress relaxation, aging, and cooling rate.
Book Synopsis Low-temperature Cracking by : Hannele K. Kanerva
Download or read book Low-temperature Cracking written by Hannele K. Kanerva and published by National Research Council. This book was released on 1994 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the field validation program was to evaluate the thermal stress restrained specimen test (TSRST) as the accelerated performance test to predict low-temperature cracking of asphalt concrete mixtures. Construction histories, cracking observations, and temperature data were collected for five test roads. In addition, a validation program was conducted at the United States Army Cold Regions Research and Engineering Laboratory. The laboratory test program consisted of performing the TSRST on specimens fabricated in the laboratory with original materials from the test roads and asphalt concrete pavement specimens cut from the actual test sections. In addition, the field pavements were monitored for crack history and, where possible, crack initiation. TSRST fracture temperature correlated with field cracking temperature and crack frequency. TSRST results can be used to predict field low-temperature cracking of asphalt-aggregate mixtures. Preliminary models to predict cracking frequency and temperature for the test roads were developed.
Book Synopsis A Simple Test Procedure for Evaluating Low Temperature Crack Resistance of Asphalt Concrete by : Sang Soo Kim
Download or read book A Simple Test Procedure for Evaluating Low Temperature Crack Resistance of Asphalt Concrete written by Sang Soo Kim and published by . This book was released on 2009 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current means of evaluating the low temperature cracking resistance of HMA relies on extensive test methods that require assumptions about material behaviors and the use of complicated loading equipment. The purpose of this study was to develop and validate a simple test method to directly measure the cracking resistance of hot mix asphalt under field-like conditions. A ring shape asphalt concrete cracking device (ACCD) was developed. ACCD utilizes the low thermal expansion coefficient of Invar steel to induce tensile stresses in a HMA sample as temperature is lowered. The results of the tests of the notched ring shaped specimens compacted around an ACCD Invar ring showed good repeatability with less than 1.0°C (1.8°F) standard deviation in cracking temperature. A laboratory validation indicated that ACCD results of five mixes correlate well with thermal stress restrained specimen test (TSRST) results with the coefficient of determination , r2 = 0.86. To prepare a sample and complete TSRST measurement, it takes minimum 2-3 days. For ACCD, two samples can be easily prepared and tested in a single day with a small test set-up. The capacity of ACCD can be increased easily with minimal cost to accommodate a larger number of samples. Among factors affecting the low temperature performance of HMA, the coefficient of thermal expansion (CTE) of aggregate has been overlooked for years. A composite model of HMA is proposed to describe the low temperature cracking phenomenon. Due to the orthotropic and composite nature of asphalt pavement contraction during cooling, the effects of aggregate CTE is amplified up to 18 times for a typical HMA. Of 14 Ohio aggregates studied, the maximum and the minimum CTEs are 11.4 and 4.0 x 10-6/°C, respectively. During cooling, the contraction of Ohio aggregate with high CTE can double the thermal strain of asphalt binders in the asphalt mix and may cause asphalt pavement thermal cracking at warmer temperature.
Book Synopsis Selection and Performance Evaluation of a Test Method to Assess Thermal Cracking Resistance of Asphalt-aggregate Mixtures by : Duhwoe Jung
Download or read book Selection and Performance Evaluation of a Test Method to Assess Thermal Cracking Resistance of Asphalt-aggregate Mixtures written by Duhwoe Jung and published by . This book was released on 1993 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal distress in asphalt concrete pavements is a widespread problem around the world. Thermal cracking can be divided into two modes of distress: low temperature cracking and thermal fatigue cracking. Low temperature cracking results from extremely cold temperatures; thermal fatigue cracking results from daily temperature cycles. Low temperature cracking is attributed to tensile stresses induced in the asphalt concrete pavement as the temperature drops to an extremely low temperature. If the pavement is cooled, tensile stresses develop as a result of the pavement's tendency to contract. The friction between the pavement and the base layer resists the contraction. If the tensile stress equals the strength of the mixture at that temperature, a micro-crack develops at the surface of the pavement. Under repeated temperature cycles, the crack penetrates the full depth and across the asphalt concrete layer. The thermal stress restrained specimen test (TSRST) was identified as an accelerated laboratory test to evaluate the thermal cracking resistance of asphalt concrete mixtures. The TSRST system developed at OSU includes a load system, data control/acquisition system and software, temperature control system, and specimen alignment stand. The overall system is controlled by a personal computer. A TSRST is conducted by cooling an asphalt concrete specimen at a specified rate while monitoring the specimen at constant length. A typical thermally-induced stress curve is divided into two parts: relaxation and non-relaxation. The temperature at which the curve is divided into two parts is termed the transition temperature. The temperature at fracture is termed the fracture temperature and the maximum stress is the fracture strength. An extensive number of TSRSTs over a wide range of conditions were performed to investigate the thermal cracking resistance of asphalt concrete mixtures. The TSRST results provided a very strong indication of low temperature cracking resistance for all mixtures considered. A ranking of mixtures for low temperature cracking resistance based on the TSRST fracture temperature was in excellent agreement with a ranking based on the physical properties of the asphalt cements. It is highly recommended that the TSRST be used in mix evaluation to identify low temperature cracking resistance of asphalt concrete mixtures. The TSRST showed very promising results regarding the effect of all variables which are currently considered to affect the low temperature cracking of mixtures. The variables considered to have significant affect on the low temperature cracking resistance of mixtures in this study include asphalt type, aggregate type, degree of aging, cooling rate, and stress relaxation.
Book Synopsis Enhancement of the Asphalt Thermal Cracking Analyser (ATCA) Test to Allow Measuring Critical Properties Affecting Cracking of Asphalt Mixtures by : Tirupan Mandal
Download or read book Enhancement of the Asphalt Thermal Cracking Analyser (ATCA) Test to Allow Measuring Critical Properties Affecting Cracking of Asphalt Mixtures written by Tirupan Mandal and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal cracking in asphalt pavement is a major concern in colder regions as well as in areas that experience extreme daily temperature variances. As the temperature drops, the restrained pavement cannot shrink, causing tensile stresses to build up to a critical point at which strength of the asphalt mixture is exceeded and a crack is formed. There have been a number of fracture tests -- the Asphalt Thermal Cracking Analyzer (ATCA) test, the Single-Edge Notched Beam (SENB) test, the semicircular bend (SCB) test, the Indirect Tensile (IDT) Test, and the Disc-Shaped Compact Tension (DCT) test -- developed to understand this distress. With the exception of the ACTA test, all these tests induce the low-temperature cracking using mechanical loading, rather than thermal loading. These tests also do not allow measuring the coefficients of contractions (CTCs), ignoring glass transition (Tg) change and physical hardening that appears to be important for a fracture test of asphalt mixtures. While the ATCA test appears to be a better test for simulating thermal loading of a pavement, and allows direct measures of CTCs and Tg, it does not allow estimating fracture mechanics parameters as it does not include notched samples. To date no comprehensive research has been conducted to quantitatively investigate the importance of crack propagation measurements in the ATCA test. In this study, the effects of using notched samples and various cooling rates on the performance of mixtures in the ATCA test are investigated. Further, the effect of various mix design parameters were studied using the enhanced ATCA test and compared to the DCT test and finite element simulation using the software ABAQUS. The findings indicate that the ATCA test can be enhanced by using notched samples to simulate crack propagation performance. The ATCA is also found to provide a significant advantage as compared to the other cracking tests including the DCT and the SCB test because all required properties (including relaxation modulus, cracking propagation resistance, and CTCs) can be measured. These three properties are necessary for effective evaluation and/or prediction of the cracking resistance of asphalt mixtures at low-temperatures.
Book Synopsis Effects of Thermo-volumetric Properties of Modified Asphalt Mixtures on Low-temperature Cracking by : Kitae Nam
Download or read book Effects of Thermo-volumetric Properties of Modified Asphalt Mixtures on Low-temperature Cracking written by Kitae Nam and published by . This book was released on 2005 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enhancement of the Asphalt Thermal Cracking Analyser (ATCA) Test to Allow Measuring Critical Properties Affecting Cracking of Asphalt Mixtures by : Tirupan Mandal
Download or read book Enhancement of the Asphalt Thermal Cracking Analyser (ATCA) Test to Allow Measuring Critical Properties Affecting Cracking of Asphalt Mixtures written by Tirupan Mandal and published by . This book was released on 2016 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal cracking in asphalt pavement is a major concern in colder regions as well as in areas that experience extreme daily temperature variances. As the temperature drops, the restrained pavement cannot shrink, causing tensile stresses to build up to a critical point at which strength of the asphalt mixture is exceeded and a crack is formed. There have been a number of fracture tests -- the Asphalt Thermal Cracking Analyzer (ATCA) test, the Single-Edge Notched Beam (SENB) test, the semicircular bend (SCB) test, the Indirect Tensile (IDT) Test, and the Disc-Shaped Compact Tension (DCT) test -- developed to understand this distress. With the exception of the ACTA test, all these tests induce the low-temperature cracking using mechanical loading, rather than thermal loading. These tests also do not allow measuring the coefficients of contractions (CTCs), ignoring glass transition (Tg) change and physical hardening that appears to be important for a fracture test of asphalt mixtures. While the ATCA test appears to be a better test for simulating thermal loading of a pavement, and allows direct measures of CTCs and Tg, it does not allow estimating fracture mechanics parameters as it does not include notched samples. To date no comprehensive research has been conducted to quantitatively investigate the importance of crack propagation measurements in the ATCA test. In this study, the effects of using notched samples and various cooling rates on the performance of mixtures in the ATCA test are investigated. Further, the effect of various mix design parameters were studied using the enhanced ATCA test and compared to the DCT test and finite element simulation using the software ABAQUS. The findings indicate that the ATCA test can be enhanced by using notched samples to simulate crack propagation performance. The ATCA is also found to provide a significant advantage as compared to the other cracking tests including the DCT and the SCB test because all required properties (including relaxation modulus, cracking propagation resistance, and CTCs) can be measured. These three properties are necessary for effective evaluation and/or prediction of the cracking resistance of asphalt mixtures at low-temperatures.
Book Synopsis Using Mastic Characterization to Predict Asphalt Mixture Low-temperature Cracking Behavior by :
Download or read book Using Mastic Characterization to Predict Asphalt Mixture Low-temperature Cracking Behavior written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low temperature performance grading currently relies solely on Bending Beam Rheometer (BBR) for determining low temperature creep stiffness (S) and rate of modulus relaxation (m-value) at 60s, both determined at low stress-strain levels, in the pre-failure zones. This aspect raises questions with regard to applicability of properties derived from the linear viscoelastic range for prediction of asphalt binder thermal cracking behavior. Furthermore, many researchers have reported a discrepancy between field cracking severity and predictions based on asphalt binder properties since the asphalt binder-aggregate interaction is non-existent in asphalt binder testing. Therefore evaluation of asphalt mastics properties which could save a considerable amount of time and equipment in comparison to mixture testing should be prioritized. These challenges indicate that considering fracture properties of asphalt mastics could be a better approach for prediction of thermal cracking in asphalt pavements. It is believed that development of failure master curves for the damage characterization of asphalt mastics at different temperatures and loading rates would be beneficial for better characterization of resistance to thermal cracking. Therefore, in this dissertation a mechanistic approach on the development of such asphalt mastic failure master curves was derived using the new BBR-SENB test for damage resistance characterization. The complexity of the viscoelastic behavior of asphalt mastics in terms of time and temperature dependency is also recognized by the sensitivity of the failure properties to changes in loading time and temperature. This dissertation documents the development, calibration, and validation of a fundamental analysis framework of asphalt mixtures thermal cracking behavior using asphalt mastics as the continuous phase of these mixtures. Key conceptual components of this study include applying time temperature superposition principles to large strain failure properties, development of asphalt mastic failure master curves, and investigating relationship between mastic viscosity and aggregate structure of asphalt mixtures in the context of thermo-volumetric properties of mixtures. An analysis framework for predicting thermal cracking of asphalt mixtures was developed which include considering asphalt mastics, aggregate internal structure and temperature dependent thermo-volumetric properties. Results where compared to experimental data measured using the ATCA device, which allowed measuring strain and stress build up during cooling.
Book Synopsis Development of the SHRP Superpave Mixture Specification Test Method to Control Thermal Cracking Performance of Pavements by : WG. Buttlar
Download or read book Development of the SHRP Superpave Mixture Specification Test Method to Control Thermal Cracking Performance of Pavements written by WG. Buttlar and published by . This book was released on 1995 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The indirect tensile creep and failure test at low temperatures (ITLT) was selected by SHRP to control thermal cracking performance within the SUPERPAVE mixture design and analysis system. Fundamental viscoelastic properties and fracture parameters obtained from the test are used in the SUPERPAVE thermal cracking model to predict thermal cracking performance (cracking as a function of time) of asphalt pavements of variable thicknesses in different temperature regimes. This approach gives pavement and mixture designers the capability of determining not only that one mixture is better than another, but also quantifies how much better one mixture is than another in terms of its cracking performance. The background and principles used to identify this test method are presented in this paper along with the results of analytical and laboratory work conducted to identify specific test procedures. Comparisons between cracking predicted using ITLT test results and observed cracking in over 35 test sections in the United States and Canada have indicated that this test is suitable for control of thermal cracking of asphalt mixtures.
Book Synopsis Evaluation of Long-Term Oven Aging of Asphalt Mixtures (AASHTO PP2-95) on Superpave Thermal Cracking Performance Predictions by : P. Romero
Download or read book Evaluation of Long-Term Oven Aging of Asphalt Mixtures (AASHTO PP2-95) on Superpave Thermal Cracking Performance Predictions written by P. Romero and published by . This book was released on 1997 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to determine the effects of long term oven aging of asphalt mixtures (AASHTO PP2-95) on the thermal cracking performance evaluation of mixtures using the SUPERPAVE Indirect Tensile Test (IDT). Asphalt mixtures were aged according to the procedures developed by the Strategic Highway Research Program (SHRP) and tested using the SUPERPAVE Indirect Tensile Test after short- and long-term oven aging. The results were used to make thermal cracking performance predictions using the Penn State Thermal Cracking Model, which is a part of the SUPERPAVE mixture analysis system. The analyses indicated that: 1) long-term oven aging of mixtures produced changes in mixture compliance that led to differences in thermal cracking performance predictions, 2) long-term oven aging can produce excessive aging which results in erroneous (unconservative) performance predictions and 3) the relative ranking of thermal cracking performance of short-term oven-aged mixtures is, for most cases, the same as that of long-term oven aged mixtures. In other words, the system distinguished between mixtures with significantly different performance levels regardless of whether the mixtures were tested after short-term oven aging or long-term oven aging. This finding implies that long-term oven aging may not be justified for mixture specification purposes when the SUPERPAVE low temperature performance evaluations are used.
Book Synopsis Cold Temperature Creep Compliance and Strength of Missouri Hot Mix Asphalt (HMA) Mixtures Using Indirect Tensile Test by : Steven M. Lusher
Download or read book Cold Temperature Creep Compliance and Strength of Missouri Hot Mix Asphalt (HMA) Mixtures Using Indirect Tensile Test written by Steven M. Lusher and published by . This book was released on 2017 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: MoDOT has for the second time in about 10 years, performed the local calibration of the mechanistic-empirical pavement design guide software, now designated as AASHTOWare Pavement ME Design. Cold-temperature creep compliance and tensile strength of hot mix asphalt (HMA) are the two inputs to the thermal cracking module within the software and are required for local calibration.The test protocol used for this work is American Association of State Highway and Transportation Officials (AASHTO) test method T 322, "Standard Method of Test for Determining the Creep Compliance and Strength of Hot Mix Asphalt (HMA) Using the Indirect Tensile Test Device." MoDOT-supplied materials were a) 18 different sets of the top lifts (layers) separated from six inch diameter pavement cores, and b) 54 boxes of 150 mm diameter gyratory-compacted specimens (GCSs). The 54 boxes of GCSs were produced from 27 different plant-produced mixes compacted to two levels of air voids per mix. Creep testing was performed at 0, -10, and -20°C (32, 14, and -4°F, respectively) and tensile strength testing was performed at -10°C. Poisson's ratio was estimated from the creep testing results. With a few exceptions, expected trends of increasing creep compliance with increasing temperature, and decreasing tensile strength with increasing air voids were confirmed during top-lift core and GCS-derived specimen testing. With a couple of exceptions, GCS-derived specimen testing resulted in the expected trend of increasing creep compliance with increasing air voids, at all temperatures. Although they are not required for local calibration of the thermal cracking module, estimated Poisson's ratio values were reported but did not always follow expected trends (e.g. maximum value of 0.5), especially during the top-lift core testing.
Book Synopsis Critical Behavior of Asphalt Mixtures Undergoing Glass Transition and Physical Hardening by :
Download or read book Critical Behavior of Asphalt Mixtures Undergoing Glass Transition and Physical Hardening written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study a device was developed that simultaneously tests two asphalt mixture beams; one unrestrained, and the other with restrained ends. The unrestrained beam is used to measure the one dimensional change of length with temperature, and consequently the glass transition temperature (Tg) and coefficients of expansion/contraction above and below the Tg. The restrained beam is used to capture the induced thermal stress buildup due to prevented contraction in the sample. The device, referred to as the Asphalt Thermal Cracking Analyzer (ATCA), was used to show how asphalt mixtures undergo isothermal contraction and physical hardening, and the consequences of this behavior for the buildup of thermal stress. A prediction model for the rate of physical hardening at different temperatures and conditioning times was developed based on a creep viscoelastic model, and was used to predict changes in binder stiffness and relaxation rate during isothermal conditioning. The model was then extended to mastics and a conversion factor was derived to shift results for applicability to asphalt mixture thermal strain calculation. The physical hardening model of binders was coupled with relaxation modulus master curves and glass transition measurements to propose a model for the calculation of thermal stress buildup in mixtures as a continuous function of conditioning time and temperature. The model was validated using an elaborate set of experimentally derived input properties for a number of mixtures at different cooling rates. An experimentally calibrated multiphase micro-mechanical model for asphalt mixture undergoing thermal shrinkage and glass transition was also developed in a finite element platform. The results where compared to experimental data measured using the ATCA device, which allowed measuring strain and stress build up during cooling. The results of this study indicate that physical hardening of binders has important effects on the thermal stress and thermal strain accumulation in mixtures during cooling cycles. Failure to consider this time dependent behavior, which varies among binders, could lead to failure in predicting performance. The existing modulus and strain used in predicting thermal cracking of asphalt pavements need revisions to integrate a function for the time dependent changes.
Book Synopsis Identification of Suitable Crack Growth Law for Asphalt Mixtures Using the Superpave Indirect Tensile Test (IDT) by : Zhiwang Zhang
Download or read book Identification of Suitable Crack Growth Law for Asphalt Mixtures Using the Superpave Indirect Tensile Test (IDT) written by Zhiwang Zhang and published by . This book was released on 2000 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
