Download or read book Effects of Climate Aging and Traffic in Characterization of Asphalt Binder Fatigue Using the Las Test written by Hui Chen (Ph.D.) and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The linear amplitude sweep (LAS) test is considered a useful tool for evaluating fatigue of asphalt binders. The effects of oxidative aging, temperature, and loading frequency remain difficult to measure or model in a simple format. In this study, the combined effects of strain, aging and temperature are investigated using the LAS procedure, and a method for estimating binder fatigue behavior at different combinations of these effects from limited measurements is introduced. Recently, the Glover-Rowe (G-R) parameter has also been introduced as a measure of binder cracking resistance and its change with oxidative aging. This approach differs than the LAS in the time required for testing, the range in strain used, and temperature of the tests required to derive the binder fatigue parameters. In addition, there is confusion about what could be the specification acceptance limits to be used and how to consider the temperature of pavement, and traffic volume and speed in the specification criteria for the G-R. In this study, the effect of strain using in testing on the G-R parameter are investigated and a modified criterion for using it in specifications with accounting for traffic conditions and temperature, are introduced. The results of this study show that LAS parameters, A and B, after different aging durations or at different temperatures, have a good relationship with the binder complex modulus (G*) measured at the corresponding conditions. Therefore, a new fatigue life (Nf) model accounting for strain level, temperature and aging is proposed using a power function of the binder G*. The model offers a simple reliable method to predicted values of fatigue life at a wider range of aging, temperature and strain level conditions. Following the concept of Jnr limits for different traffic grades used for the Multiple Stress Creep and Recovery (MSCR) test, the threshold values of the allowable strain in LAS results, and maximum allowable G-R limits, under different traffic volume and speed conditions are defined. Similar to the MSCR approach, four fatigue traffic grades including S, H, V, and E are used in the proposed criteria. To verify that the LAS and G-R parameters are related to asphalt mixtures cracking resistance, and that the binder specification limits are logical, the results of binder testing are compared with mixture testing results and the comparison show clear evidence of the role of binders in mixture behavior in the IDEAL-CT mixture tests.

Download or read book Effects of Climate Aging and Traffic in Characterization of Asphalt Binder Fatigue Using the Las Test written by Hui Chen (Ph.D.) and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The linear amplitude sweep (LAS) test is considered a useful tool for evaluating fatigue of asphalt binders. The effects of oxidative aging, temperature, and loading frequency remain difficult to measure or model in a simple format. In this study, the combined effects of strain, aging and temperature are investigated using the LAS procedure, and a method for estimating binder fatigue behavior at different combinations of these effects from limited measurements is introduced. Recently, the Glover-Rowe (G-R) parameter has also been introduced as a measure of binder cracking resistance and its change with oxidative aging. This approach differs than the LAS in the time required for testing, the range in strain used, and temperature of the tests required to derive the binder fatigue parameters. In addition, there is confusion about what could be the specification acceptance limits to be used and how to consider the temperature of pavement, and traffic volume and speed in the specification criteria for the G-R. In this study, the effect of strain using in testing on the G-R parameter are investigated and a modified criterion for using it in specifications with accounting for traffic conditions and temperature, are introduced. The results of this study show that LAS parameters, A and B, after different aging durations or at different temperatures, have a good relationship with the binder complex modulus (G*) measured at the corresponding conditions. Therefore, a new fatigue life (Nf) model accounting for strain level, temperature and aging is proposed using a power function of the binder G*. The model offers a simple reliable method to predicted values of fatigue life at a wider range of aging, temperature and strain level conditions. Following the concept of Jnr limits for different traffic grades used for the Multiple Stress Creep and Recovery (MSCR) test, the threshold values of the allowable strain in LAS results, and maximum allowable G-R limits, under different traffic volume and speed conditions are defined. Similar to the MSCR approach, four fatigue traffic grades including S, H, V, and E are used in the proposed criteria. To verify that the LAS and G-R parameters are related to asphalt mixtures cracking resistance, and that the binder specification limits are logical, the results of binder testing are compared with mixture testing results and the comparison show clear evidence of the role of binders in mixture behavior in the IDEAL-CT mixture tests.

Download or read book Viscoelastic Analysis and Fatigue Characterization of Bituminous Materials in Two Length Scales Under the Influene of Aging written by Santosh Reddy Kommidi and published by . This book was released on 2017 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking in asphalt concrete (AC) is of immense importance to pavement design and analysis because it is one of the most important forms of distress that can lead to structural failure in pavement. Once started, these types of cracks can be combined with other environmental factors leading to detrimental effects such as faster rates of pavement deterioration and shortened pavement life and functionality. Currently AASHTO TP101, also known as linear amplitude sweep (LAS) specification, is being widely used to evaluate the ability of an asphalt binder to resist fatigue. The LAS method, although mechanistic in its approach, has certain drawbacks. First, the test is performed on an aged 2-mm thick binder sample, which in reality may never exist in the AC where there is a varying non-uniform thickness of the binder across the components of the AC. Secondly, the test methodology predicts an increased fatigue resistance at lower strain levels of load when the binder ages. This is in contrast to the general belief among researchers that aging is one of the primary contributors to the acceleration of pavement cracking. This study aims to evaluate fatigue resistance in a more realistic approach that is more likely to exist in AC by incorporating sand asphalt mixtures. First, the linear viscoelastic properties of binder and sand asphalt mixture samples were evaluated to obtain the material properties under the influence of aging. Later, the fatigue tests on the sand asphalt mixture were investigated to understand the influence of a thin film of binder on the fatigue resistance. It was observed that based energy dissipation criterion for the binder evaluated a reasonable estimate for fatigue damage at relatively lower temperatures, but was limited to capture the influence of aging. Moreover, it was observed that fatigue testing on a binder at an intermediate temperature of 25 °C could cause edge effects to dominate as seen in the plateau regime for the phase angle in the time sweep tests. In order to overcome the edge effects in the binder LAS tests, the sand asphalt mixture testing was used for analyzing the binder fatigue resistance. Sand asphalt mixture testing could capture the microcracking and macrocracking phases more distinctively when compared to binder testing. In the case of pressure aging vessel (PAV) aged samples, it was observed that the macrocracking phase disappeared and was replaced by sudden changes in the material properties, indicating that the PAV aged mixture was more susceptible to fatigue cracking. By using the simplified viscoelastic continuum damage approach, the fatigue resistance of the binder and sand asphalt mixture was evaluated. The sand asphalt mixture testing was better to capture the influence of aging and changes in the microstructure during fatigue in comparison to binder fatigue tests..

Download or read book Fatigue of Asphalt Binders written by Wilfung Martono and published by . This book was released on 2008 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rheological Chemical and Microstructural Characterization of Asphalt Binders Aged at Different Conditions and Evaluation of the Use of Antioxidants and Copolymers to Retard Aging written by Mohammad Solaiman Khan and published by . This book was released on 2017 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rheological, chemical and microstructural properties of asphalt binders change with oxidative aging which is accelerated at elevated temperatures. Aging stiffens asphalt binders and increases the embrittlement of asphalt mixtures which would lead to fatigue cracking and eventually pavement failure under repetitive traffic loading. This study explored the feasibility of using antioxidant additives and copolymers with antioxidant agents to retard oxidative aging of asphalt binders. The performance of the additives was evaluated at the binder and mastic levels. The laboratory experiments included two unmodified binders, various antioxidant additives and copolymers, and three aggregate types. The fatigue characteristics of asphalt binders and mastic were determined before and after aging and an aging index was defined to evaluate the effect of the additives on aging. The results demonstrated that certain antioxidants and copolymers such as Redicote AP, Solprene, and Calprene may retard the aging and improve the rheological properties of the asphalt binders. In addition, the results of mastic testing confirmed the favorable effect of certain antioxidants on improving the resistance to fatigue cracking. Furthermore, the type of aggregate was found to influence the rate of aging of asphalt mixtures. Based on the rheological and fracture test results on asphalt binders and mastic, the effect of antioxidants was further investigated and validated at spectroscopic, chemical and microstructural level using Fourier-transform infrared spectroscopy (FTIR), Gel-permeation chromatography (GPC) and Atomic Force Microscopy (AFM), respectively. The spectroscopic analysis with FTIR supported the efficacy of the additives in retarding aging by reducing the carbonyl growth in aged binders. The chemical analysis with GPC confirmed that both Redicote and Solprene were capable of reducing the large molecular size fraction in binders subjected to long-term aging. The image analysis with AFM provided insight on the spatial distribution, surface roughness parameters and micromechanical properties (i.e., adhesion, stiffness) of various phases and the effect of aging on the micro-rheology of antioxidant-modified binders. The last part of this study examined the effect of aging on the viscoelastic response of asphalt mixture using the Prony series representation and a newly developed parameter called aging state variable 'A'. The dynamic modulus test data was used for the analysis. The aging state variable 'A' was found to capture the effect of aging temperature and duration of aging on the viscoelastic properties of asphalt mixtures.

Download or read book Fatigue Characterization of Asphalt Binders Using a Thin Film Poker Chip Test written by Ramez Muhammad Hajj and published by . This book was released on 2016 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt binder is the adhesive that holds together aggregate particles of different sizes of an asphalt mixture. The tensile properties of an asphalt binder can greatly affect the performance of the asphalt mixture under repeated traffic loading. While the current performance grade specification has been in use for a long time to characterize the asphalt binders with regards to fatigue, it has been shown to be largely ineffective. This study was performed with the goal of investigating a strength-based measure to evaluate the fatigue cracking resistance of the asphalt binder. The poker chip geometry was used for this purpose. The test involved tensile loading of a thin film of asphalt binder between two rigid substrates. The first part of this study focused on determining failure criteria for the test. The second part was a study of the binders that have a similar grade based on the current performance grade specification but are expected to perform differently due to difference in their chemical makeup. Finally, the third part involved a study of the effects of nanomaterials as additives on the strength of the binder based on poker chip test results. The results demonstrated that failure strain criteria is promising as a material property, but still needs further study for validation. It was also observed that binders with similar performance grade had significantly different tensile strength. Finally, it was observed that nanomaterials had a significant impact on the test results of unaged binder, but had less effect on aged asphalt binders.

Download or read book Application of Calibrated Mechanistic Fatigue Analysis with Aging Effects written by and published by . This book was released on 2006 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work contained in this report constitutes Phase II of Texas Department of Transportation (TxDOT) Project 0-4468. The primary objective of Phase II was to provide additional laboratory validation and sensitivity analysis of the calibrated mechanistic with (CMSE) and without (CM) surface energy measurements fatigue analysis approaches recommended in Report 0-4468-2. The second objective was to provide a better understanding of the binder-mixture relationships and effects of binder oxidative aging on both mixture fracture properties and fatigue life (N sub f). The third objective was to explore the possibility of establishing a surrogate fatigue test protocol based on the CMSE approach. These objectives were achieved through fatigue characterization of additional hot-mix asphalt concrete (HMAC) mixtures with different mix-design parameters and materials under varying laboratory aging exposure conditions.

Download or read book Binder Characterization and Evaluation written by David A. Anderson and published by Strategic Highway Research Program (Shrp). This book was released on 1994 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterizing the Temperature Effects on Rutting and Fatigue Properties of Asphalt Binders Based on Time Temperature Superposition Principle written by Chao Wang and published by . This book was released on 2019 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this article is to investigate the effects of temperature on rutting and fatigue cracking resistance of asphalt binders based on the time-temperature superposition principle (TTSP) In this study, the TTSP approach was employed to interpret the results of multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests for both neat and styrene-butadiene-styrene (SBS)modified asphalt binders. The higher stress level of 3.2kPa in the standard MSCR test procedure was extended to 10 and 15kPa to verify the stress sensitivity of the nonrecoverable compliance (Jnr) A loading duration of 5 minutes in the standard LAS test was extended to 10 and 15 minutes to develop the fatigue failure criterion at different conditions. The results demonstrate that the time-strain curves of the neat binder during the MSCR tests under different temperatures can be unified into a single strain master curve using the TTSP shift factors, based on which the predictiveJnrshowed good agreement with the measured values. This TTSP-based analysis approach does not work well for the MSCR results of the SBS-modified binder at high temperatures. However, the fatigue failure criterion determined from the LAS tests under different temperatures was verified to be successfully constructed into a single failure criterion according to the TTSP approach for both the neat and SBS-modified binders. Therefore, only an additional caution is raised for the TTS-based analysis on rutting resistance of the modified binder in a high temperature range.

Download or read book Physical Properties of Asphalt Cement Binders written by John C. Hardin and published by ASTM International. This book was released on 1995 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: A dozen papers from a December 1993 symposium in Dallas/Fort Worth, Texas. Among the topics are why the new proposed rheological properties of asphalt binders are required and how they compare to conventional properties, the development and use of the SHRP direct tension specification test, oxidatio

Download or read book Modeling the Effects of Temperature and Loading Rate on Fatigue Property of Asphalt Binder written by Haifang Wen and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking is one of three major distresses for asphalt pavement. Asphalt binder is a very important component of asphaltic mixture. The fatigue performance of asphalt binder also greatly affects that of asphaltic mixture. Asphalt binder's fatigue characteristics are affected by external conditions, such as temperature and loading rate. It is warranted to study the effects of these external conditions on fatigue of asphalt binder and take them into account. New fatigue tests and properties have been proposed to characterize the fatigue behavior of asphalt binders, such as monotonic constant shear-rate tests. This study investigated the effects of temperature and shear rate on fatigue properties of asphalt binder. Two asphalt binders were tested with a range of temperature and shear rates. It was found that time-temperature superposition principle also applies to critical strain energy density and shear strength of asphalt binders. The values of shift factors for building the master curves of critical strain energy and shear strength are comparable.

Download or read book Aging written by Chris A. Bell and published by . This book was released on 1994 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research was conducted as part of the Strategic Highway Research Program (SHRP) A-003A contract at Oregon State University to validate the findings of SHRP contracts A-002A and A-003B with regard to aging. One short-term and four long-term aging methods were used to simulate aging of asphalt-aggregate mixes in the field. Four aggregates and eight asphalts for a total of 32 different material combinations were tested using the different aging methods. Results of the aging studies are compared with the A-002A and A-003B studies of asphalt binder or asphalt mixed with fine aggregate. This research concludes that aging of asphalt mixes cannot be predicted by tests on asphalt binder alone since results show that aggregates have considerable influence on aging.

Download or read book Binder Characterization and Evaluation Test methods written by and published by . This book was released on 1994 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Validating the Fatigue Endurance Limit for Hot Mix Asphalt written by Brian D. Prowell and published by Transportation Research Board. This book was released on 2010 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: At head of title: National Cooperative Highway Research Program.

Download or read book Microstructural Characterization of the Chemo mechanical Behavior of Asphalt in Terms of Aging and Fatigue Performance Properties written by Robert Grover Allen and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of asphalt chemo-mechanics requires a basic understanding of the physical properties and chemical composition of asphalt and how these properties are linked to changes in performance induced by chemical modifications. This work uniquely implements the framework of chemo-mechanics by investigating two types of chemical modification processes, natural (oxidative aging) and synthetic (chemical doping) as they relate not only to macro-scale properties of asphalt binder but also to the asphalt microstructure and nanorheology. Furthermore, this study demonstrates the application of atomic force microscopy (AFM) imaging and the extraction of nano-scale engineering properties, i.e. elastic modulus, relaxation modulus, and surface energy, as a method to predict performance related to the fatigue characteristics of asphalt binders by modeling intrinsic material flaws present amongst phase interfaces. It was revealed that oxidative aging induces substantial microstructural changes in asphalt, including variations in phase structure, phase properties, and phase distribution. It has also been shown that certain asphalt chemical parameters have a consistent and measureable effect on the asphalt microstructure that is observed with AFM. In fact, particular phases that emerged via chemical doping revealed a surprising correlation between oxidative aging and the saturates chemical parameter of asphalt in terms of how they explicitly impact durability and performance of asphalt. By implementing a crack initiation model -- which requires measureable microstructural characteristics as an input parameter -- it was found that microstructural flaws (depending on the extremity) can have a more profound impact on asphalt performance than the properties of the material located between the flaws. It was also discovered by comparing the findings to performance data in the Strategic Highway Research Program's (SHRP's) Materials Reference Library (MRL), that the crack initiation model predicts very similar performance as the SHRP's distress resistance indicators. Overall, this body of work yields improved input values for asphalt prediction models and serves as the basis for ongoing studies in the areas of asphalt chemical mapping, modeling of nano-damage, and nano-modification using AFM. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149372

Download or read book Understanding Mechanisms Leading to Asphalt Binder Fatigue written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking is one of the primary modes of failure in asphalt pavements. Cracking typically occurs within the asphalt binder phase of asphalt mixtures. Thus, asphalt binder fatigue resistance is critical in determining overall pavement fatigue performance. One procedure commonly used to characterize asphalt binder fatigue resistance is the time sweep test, which consists of repeated torsional loading of a cylindrical specimen in the Dynamic Shear Rheometer (DSR). Generally, apparent changes in material properties with respect to number of cycles of loading are used to define fatigue failure of the asphalt binder. Results of this test have been shown to correlate well with asphalt mixture fatigue performance. However, the mechanisms responsible for changes in material properties during fatigue testing in the DSR were previously not well understood. Results in this study demonstrate that fracture can account for changes in loading resistance of asphalt binders during time sweep testing. Under cyclic torsional loading of cylindrical specimens, macro fracture is shown to manifest in the form of edge fracture. Edge fracture is a circumferential crack starting at the periphery of a cylindrical sample that propagates inward as loading is applied, reducing the effective sample size. Digital visualization of the fractured specimens allowed for determination of the fractured and intact sample area. Predictions of fracture propagation based on measurements of loading resistance and fracture mechanics concepts agreed favorably with actual measurements based on visualization. Furthermore, the fracture morphology and progression of crack growth of asphalt binders matched those observed for other materials under similar loading conditions. Based on these results, fatigue damage characterization of asphalt binders can be improved by incorporating fracture mechanics into an analysis framework for DSR fatigue test results. An analysis framework based on fracture principles is presented. The proposed model allows predicting fatigue life at any loading amplitude using the results of a single fatigue test. Additionally, it is demonstrated that time-temperature superposition is applicable to fatigue crack propagation of asphalt binders, allowing for efficient prediction of fatigue performance at multiple temperatures. The model is validated using a comparison between asphalt mixture and binder fatigue test results.

Download or read book Long term Aging of Asphalt Mixtures for Performance Testing and Prediction written by Y. Richard Kim and published by . This book was released on 2018 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: