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.
Download or read book Progress of Superpave superior Performing Asphalt Pavement written by Robert N. Jester and published by ASTM International. This book was released on 1997 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major result of the research conducted under the Strategic Highway Research Program from 1987 to 1993 was the development of the Superpave (Superior Performing Asphalt Pavement) system for the comprehensive design of asphalt pavements. These 14 contributions describe the experience to date in the
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1997 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Summary Report on Aging of Asphalt aggregate Systems written by Chris A. Bell and published by . This book was released on 1989 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a report on the state of the art of research on the phenomenon of the aging of asphalt-aggregate mixtures. Compared to research on the aging of asphalt cement, there has been little research on the aging of asphalt mixtures. Binder studies are considered as well as mixture sutdies, the relationship between laboratory aging tests and field performance, and the relationship between chemical composition and field performance. Recommendations are made for aging procedures which show promise for laboratory investigation. Test methods to evaluate aging are also considered. It is noted that extended heating procedures show the most promise for short-term aging and pressure oxidation and/or extended heating the most promise for long-term aging.
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 2021 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Research Report 973: Long-Term Aging of Asphalt Mixtures for Performance Testing and Prediction: Phase III Results refines the aging procedure developed in the original NCHRP Research Report 871: Long-Term Aging of Asphalt Mixtures for Performance Testing and Prediction. The updates field calibrate the original project aging model (PAM), develop procedures to estimate the PAM inputs, and develop a framework by which the predicted changes in asphalt binder properties that are due to oxidative aging can be related to corresponding changes in asphalt mixture performance.
Download or read book Aging Characterization of Foamed Warm Mix Asphalt written by Mir Shahnewaz Arefin and published by . This book was released on 2015 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluated the aging characteristic of foamed warm mix asphalt (WMA) produced by water injection in comparison to traditional hot mix asphalt (HMA). Four types of asphalt binders (PG 64-22, PG 64-28, PG 70-22, PG 76-22) were used in the preparation of the foamed WMA and HMA mixtures. All mixtures were prepared using limestone aggregates with a nominal maximum aggregate size (NMAS) of 12.5 mm that met the Ohio Department of Transportation (ODOT) Construction and Material Specifications (C&MS) for Item 442 (Superpave Asphalt Concrete).The short-term and long-term aging of the asphalt binders were simulated using the rolling thin film oven (RTFO) and the pressure aging vessel (PAV), respectively, while the short-term and long-term aging of the laboratory-prepared asphalt mixtures were simulated according to AASHTO R 30 (Mixture Conditioning of Hot Mix Asphalt).The dynamic shear rheometer (DSR) was used to characterize the viscoelastic behavior of the unaged, RTFO-aged, and PAV-aged asphalt binders, while the dynamic modulus (lE*l) test was used to characterize the viscoelastic behavior of the short-term and long-term aged foamed WMA and HMA mixtures.In addition, the mechanistic-empirical pavement design guide (MEPDG) global aging model was used to predict the effect of aging on the dynamic modulus (lE*l) of foamed WMA and HMA mixtures, and the MEPDG global aging model predictions were compared to dynamic modulus (lE*l) test results obtained in the laboratory for both asphalt mixtures. By comparing the DSR test results following RTFO and PAV to those obtained for the unaged asphalt binders, it was observed that PG 64-22 was the least susceptible to aging followed by PG 70-22, PG 76-22, and PG 64-28. Similar trends were also observed from the dynamic modulus test, where little difference was noticed between the short-term and long-term aged specimens prepared using PG 64-22 for both foamed WMA and HMA mixtures.The dynamic modulus test results also revealed slightly lower lE*l values for foamed WMA mixtures in comparison to traditional HMA mixtures. This indicates that foamed WMA mixtures are slightly more susceptible to rutting than HMA mixtures. However, by comparing the dynamic modulus of the long-term aged specimens to the short-term aged specimens, it was observed that the increase in stiffness for the foamed WMA mixtures was less than that for the traditional HMA mixtures. This indicates that foamed WMA mixtures are less susceptible to aging and subsequently fatigue cracking than HMA mixtures.Finally, by the comparing the MEPDG global aging model predictions to the dynamic modulus test results for both foamed WMA and HMA mixtures, it was observed that the MEPDG global aging model provided more reasonable predictions, especially at higher frequencies, but overestimated or underestimated the dynamic modulus at lower frequencies. This was observed for both foamed WMA and HMA mixtures, which suggests that this model can be used for both types of mixtures.
Download or read book Selection of Laboratory Aging Procedures for Asphalt aggregate Mixtures written by C. A. Bell and published by Strategic Highway Research Program (Shrp). This book was released on 1994 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two major effects dominate aging of asphalt-aggregate mixtures: 1) loss of volatile components and oxidation in the construction phase (short-term aging) and 2) progressive oxidation of the in-place mixture in the field (long-term aging). Aging results in hardening (stiffening) of a mixture, which alters its performance both positively and negatively. This report presents the results of a preliminary investigation to evaluate aging methods for asphalt-aggregate mixtures. Short-term methods included oven aging and extended mixing, while long-term methods included oven aging and oxygen enrichment. The effects of temperature and aging duration are presented. The effects of aging were determined using the diametral resilient modulus test. Recommendations for short- and long-term aging are provided.
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.
Download or read book Prediction of Low Temperature Cracking of Asphalt Concrete Mixtures with Thermal Stress Restrained Specimen Test Results written by Hannele K. Kanerva and published by . This book was released on 1993 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low temperature cracking is attributed to tensile stresses induced in an asphalt concrete pavement that develop when the pavement is subjected to a cold temperature. Cracking results in poor ride quality and a reduction in service life of the pavement. Low temperature cracking has been predicted by regression equations, mechanistic approaches and by simulation measurements. The purpose of the study reported herein is to (1) evaluate the Thermal Stress Restrained Specimen Test (TSRST) as an accelerated performance test to simulate low temperature cracking of asphalt concrete mixtures and (2) develop a deterministic and probabilistic model to predict low temperature cracking with TSRST results. Construction histories, cracking observations and temperature data were collected for five test roads in Alaska, Pennsylvania and Finland. A full scale and fully controlled low temperature cracking test program was conducted at the U.S. Army Cold Regions Research and Engineering Laboratory (USACRREL). Specimens were fabricated in the laboratory with original asphalt cements and aggregates from the test roads. In addition, asphalt concrete pavement specimens were cut from the test sections. The TSRST results obtained for these samples were correlated with the field observations. Based on a statistical analysis of the data, the TSRST fracture temperature is associated with the field cracking temperature and crack frequency for the test roads where mixture properties dominated low temperature cracking. It was concluded that the TSRST can be used to simulate low temperature cracking of asphalt concrete mixtures. A deterministic and a probabilistic model were developed to predict crack spacing as a function of time using the TSRST results, pavement thickness and bulk density, pavement restraint conditions and air temperature. The affect of aging on pavement properties was incorporated in the models by predicting the field aging with Long Term Oven Aging (LTOA) treatment in the laboratory. The calculation of the crack spacing is based on the theory that the pavement slab cracks when the pavement temperature reaches the cracking temperature of the mixture and the slab is fully restrained. The deterministic model predicts crack spacing with time whereas the probabilistic model predicts crack spacing and its variation with time and yields the reliability of the design with regard to a minimum acceptable crack spacing criterion defined by road authorities. The models were verified by comparing the predicted crack spacings for the five test roads to the observed crack spacings. The probabilistic model is recommended for use in predicting the low temperature cracking of asphalt concrete mixtures.
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 National Research. This book was released on 2004 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Short Term Aging Effect of Hot Mix Asphalt Due to Elevated Temperatures and Extended Aging Time written by Rubben Lolly and published by . This book was released on 2013 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heating of asphalt during production and construction causes the volatilization and oxidation of binders used in mixes. Volatilization and oxidation causes degradation of asphalt pavements by increasing the stiffness of the binders, increasing susceptibility to cracking and negatively affecting the functional and structural performance of the pavements. Degradation of asphalt binders by volatilization and oxidation due to high production temperature occur during early stages of pavement life and are known as Short Term Aging (STA). Elevated temperatures and increased exposure time to elevated temperatures causes increased STA of asphalt. The objective of this research was to investigate how elevated mixing temperatures and exposure time to elevated temperatures affect aging and stiffening of binders, thus influencing properties of the asphalt mixtures. The study was conducted in two stages. The first stage evaluated STA effect of asphalt binders. It involved aging two Performance Graded (PG) virgin asphalt binders, PG 76-16 and PG 64-22 at two different temperatures and durations, then measuring their viscosities. The second stage involved evaluating the effects of elevated STA temperature and time on properties of the asphalt mixtures. It involved STA of asphalt mixtures produced in the laboratory with the PG 64-22 binder at mixing temperatures elevated 25OF above standard practice; STA times at 2 and 4 hours longer than standard practices, and then compacted in a gyratory compactor. Dynamic modulus (E*) and Indirect Tensile Strength (IDT) were measured for the aged mixtures for each temperature and duration to determine the effect of different aging times and temperatures on the stiffness and fatigue properties of the aged asphalt mixtures. The binder test results showed that in all cases, there was increased viscosity. The results showed the highest increase in viscosity resulted from increased aging time. The results also indicated that PG 64-22 was more susceptible to elevated STA temperature and extended time than the PG 76-16 binders. The asphalt mixture test results confirmed the expected outcome that increasing the STA and mixing temperature by 25oF alters the stiffness of mixtures. Significant change in the dynamic modulus mostly occurred at four hour increase in STA time regardless of temperature.
Download or read book Characterizing Short and Long Term Mixture Aging of a Full scale and Non trafficked Asphalt Test Section written by Braden T. Smith and published by . This book was released on 2017 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ideally, asphalt pavements are designed to achieve sufficient stiffness prior to the application of traffic to resist rutting while also maintaining enough flexibility after years of service to minimize the amount of durability/brittleness related distresses (e.g. cracking and weathering). Multiple factors have caused an industry transition to mixes which are much more susceptible to crack, and durability related distresses are often the primary mechanism by which pavements fail. To restore a balance between rutting and durability distresses in asphalt pavements, the industry has started investigating balanced mix designs (BMDs) While mitigating only rutting or cracking behaviors is a straightforward exercise based on the collection of knowledge, simultaneously considering the two types of distresses is challenging considering that rutting is an early life distress and durability distresses are not typically observed until longer term aging has occurred. Mixture conditioning protocols to simulate field aging in conjunction with tests to fairly evaluate mixture integrity after conditioning are needed to scrutinize asphalt mixtures for durability related distresses during the mixture design phase. The current longer term conditioning protocol (R30) adopted by the American Association of State Highway and Transportation Officials (AASHTO) is not as severe as suggested when considering durability/brittleness (Isola et al. 2014; Yin et al. 2016; Cox et al. 2017). This dissertation’s primary objective is to provide guidance on asphalt mixture aging by contributing in four areas: 1) ensuring proper density measurement of field aged cores, 2) provide guidance on increased short term aging time effects in asphalt mixtures, 3) suggest improved mixture conditioning protocols to simulate longer term field aging, and 4) make suggestions for improving binder conditioning protocols to simulate longer term field aging. To these ends, a series of mixture and extracted binder tests were conducted on materials that were used to construct a full-scale test section in Columbus, MS that was monitored for aging for up to 5 after construction. The overall work presented provides simple recommendations or protocols which have the potential to improve the level of scrutiny that can be given to paving materials during the mix design phase and thus improve overall pavement performance.
Download or read book Evaluation of Low Temperature Cracking in Asphalt Pavement Mixes written by Khaled Ksaibati and published by . This book was released on 1998 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report examines the feasibility of using the thermal stress restrained specimen test to evaluate low temperature cracking in asphalt pavement mixes. Data were collected from laboratory and field evaluations. Various mixing, aging, and compaction methods were used to prepare test samples with materials obtained from two Wyoming Department of Transportation (WYDOT) highway projects. Field data were obtained from two recently built test sections and compared with laboratory test results. Pavement condition surveys quantified low temperature cracking of both test sections after one winter. Temperature data for the project sites also were collected. Pavement condition and temperature data were compared to results from the thermal stress restrained specimen test. The thermal stress restrained specimen test was effective in testing asphalt pavement mixes. However, test results indicated that lab prepared samples did not closely simulate field samples. Also, comparisons of lab results with field conditions were performed. However, it is recommended that a more comprehensive analysis be performed after test sections have been in service for a few years.
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 Influence of Warm Mix Asphalt on Aging of Asphalt Binders written by Ala R. Abbas and published by . This book was released on 2014 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Low Temperature Cracking in Asphalt Pavement Mixes and Rheological Performance of Asphalt Binders written by and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Government spends a lot of money on the reconstruction and rehabilitation of road pavements in any given year due to various distresses and eventual failure. Low temperature (thermal) cracking, one of the main types of pavement distress, contributes partly to this economic loss, and comes about as a result of accumulated tensile strains exceeding the threshold tensile strain capacity of the pavement. This pavement distress leads to a drastic reduction of the pavement's service life and performance. In this study, the severity of low temperature (thermal) cracking on road pavements selected across the Province of Ontario and its predicted time to failure was assessed using the AASTHO Mechanistic-Empirical Pavement Design Guide (MEPDG) and AASHTOWARE (TM) software, with inputs such as creep compliance and tensile strength from laboratory test. Highway 400, K1, K2, Y1, Sasobit, Rediset LQ, and Rediset WMX were predicted to have a pavement in-service life above 15 years. Additionally, the rheological performance of the recovered asphalt binders was assessed using Superpave (TM) tests such as the dynamic shear rheometer (DSR) and bending beam rheometer (BBR). Further tests using modified standard protocols such as the extended bending beam rheometer (eBBR) (LS-308) test method and double-edge notched tension (DENT) test (LS-299) were employed to evaluate the failure properties associated with in service performance. The various rheological tests showed K1 to be the least susceptible to low temperature cracking compared to the remaining samples whiles Highway 24 will be highly susceptible to low temperature cracking. X-ray fluorescence (XRF) analysis was performed on the recovered asphalt binders to determine the presence of metals such as zinc (Zn) and molybdenum (Mo) believed to originate from waste engine oil, which is often added to asphalt binders. Finally, the severity of oxidative aging (hardening) of the recovered asphalt binders was also evaluated using the Fourier transform infrared (FTIR) spectroscopy to determine the abundance of functional groups such as the carbonyl (CO) and sulfoxide (SO). Functional groups such as styrene and butadiene were also evaluated to determine the polymer modifier content in recovered asphalt binders.
