Download or read book The Use of DMA to Characterize the Aging of Asphalt Binders written by Ioan I. Negulescu and published by . This book was released on 2010 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents issues associated with long-term aging of polymer modified asphalt cements (PMACs) as reflected by dynamic mechanical analysis (DMA) data. In this study a standard SBS (styrene-butadiene-styrene block copolymer) polymer modified asphalt cement containing 3% copolymer (PMAC) meeting LADOTD specifications for PAC-40HG and PG 76-22M was selected and subjected to accelerated laboratory aging. Procedures were developed for simulation of long term aging of asphalt binders using multiple pressure aging vessel (PAV) operations in the absence and in the presence of water. Three, five and seven year old field aged asphalt samples originally of similar PMAC composition as that of PG 76-22 listed above were recovered from a wearing course mixture located on interstate I-55 near Granada, MS. All binders were characterized with respect to their composition and rheological properties.

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 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 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 Dynamic Torsion Test for the Mechanical Characterization of Soft Biological Tissues written by Davide Valtorta and published by Cuvillier Verlag. This book was released on 2007 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 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 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 Evaluation of Warm Mix Asphalt Technologies with Respect to Binder Aging and Emissions written by Faramarz Farshidi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years Warm Mix Asphalt (WMA) technologies have been used to modify asphalt binders, with the following objectives: to decrease production and construction temperatures, reduce fumes and emissions, increase haul distance, and improve the workability of the mix. Reduced temperatures at the plant and during laydown and compaction are hypothesized to positively impact long-term oxidative aging behavior due to less oxidation/aging and result in less emissions during production and construction due to reduced production and construction temperatures. The purpose of this investigation was to quantify these improvements with respect to long-term oxidative aging in the field and environmental benefits with respect to volatile organic compounds, semi-volatile organic compounds and poly cyclic aromatic hydrocarbons in order to confirm or deny this hypothesis. This research evaluated the potential durability of WMA and Rubberized Warm Mix Asphalt (R-WMA) binders with respect to long-term aging through characterization of field-aged binders extracted and recovered from field cores. The results were compared to the control conventional Hot Mix Asphalt (HMA) and Rubberized Hot Mix Asphalt (R-HMA) samples. Binders were extracted and recovered from thirteen different test sections and a total of seven different WMA technologies were evaluated in this study. The Dynamic Shear Rheometer (DSR) was used to evaluate the rheological properties of the binders at high temperatures with respect to rutting performance in the field. The Bending Beam Rheometer (BBR) was used to characterize low temperature properties of the binder samples. A new testing procedure was developed to measure and characterize the rheological properties of the R-HMA and R-WMA binders with respect to performance-related properties in the field. The rheological results indicated that depending on the WMA technology used, the addition of WMA technologies and reduced production and compaction temperatures result in increase or decrease rutting resistance performance for WMA and R-WMA binders with respect to permanent deformation at high temperatures in the field. Both WMA and R-WMA binders studied meet the established thermal cracking criteria with respect to low temperature cracking in the field. The aging kinetics curves for WMA-treated binders are parallel to the control binders and the addition of WMA technologies including organic, chemical and mechanical foaming technologies studied in this research did not result in a different aging kinetics trend with respect to long-term aging in the field. A portable "flux" chamber was designed and fabricated to capture and directly measure emissions during paving operations. Emissions were collected in activated charcoal sorbent tubes for characterizing volatile organic compounds and semi-volatile organic compounds. XAD-2 resin tubes and filters were used to capture the gaseous phase and particulate phase of the PAH compounds, respectively. A reliable analytical method was developed to identify and quantify alkane emissions using gas chromatography mass spectrometry (GC/MS) in the laboratory. A separate method was developed for identification and characterization of trace level PAH compounds of the asphalt fumes. The results demonstrated that the warm mix asphalt technology type, plant mixing temperature and level of compaction significantly influence the emission characteristics throughout paving operations. Moreover, the emissions kinetics indicated that the majority of the reactive organic gases are volatilized in the first hour after sampling initiation (immediately after production and before compaction). To better understand and identify any chemical composition changes of the binder due to WMA technologies, nuclear magnetic resonance spectroscopy (NMR) was used for understanding structural complexities of HMA and WMA binder molecules. Qualitative analysis of both carbon and hydrogen atoms with HMA and WMA binders showed that the molecular structures of the binders are not significantly changed by the effect of WMA technologies.

Download or read book Conference on SHRP Asphalt Research written by National Research Council (U.S.). Transportation Research Board and published by . This book was released on 1993 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Thermal Degradation of Liquid Amine Anti Strip Additives in Asphalt Binders Due to RTFO and PAV Aging written by Nazimuddin M. Wasiuddin and published by . This book was released on 2007 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, thermal degradation of amine-based liquid anti-strip additives was evaluated due to RTFO-aging and PAV-aging according to AASHTO T 240 and AASHTO R 28 test methods, respectively. The surface free energy (SFE) characteristics of asphalt binders before and after aging were used as a tool for this evaluation. Two asphalt binders, namely PG 64-22 and PG 70-28, and two anti-strip additives, namely AD-Here HP Plus and Redicote E-6, were evaluated. It was observed for 0.75 % AD-Here HP Plus in PG 64-22, mixing at 163°C is more effective than mixing at 145°C with respect to increase in SFE. Also, both RTFO and PAV-aging decrease the total SFE of asphalt binders; both the aging processes are more effective in PG 64-22. In addition, the beneficial effect of anti-strip additives in acid-base characteristics of asphalt binders is severely reduced by RTFO and PAV-aging. Finally, the chemical model of asphalt binder, proposed by Wasiuddin , was expanded to include the SFE characteristics of asphalt binders due to aging.

Download or read book Influence of Mixture Characteristics on the Oxidative Aging of Asphalt Binders written by Nathaniel Evan Morian and published by . This book was released on 2014 with total page 1802 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research effort focused on the evaluation of asphalt mixtures with respect to thermal cracking. Preliminary investigations soon indicated that a fundamental evaluation of thermal cracking was highly dependent upon the more complicated understanding of asphalt binder oxidation. The oxidation of asphalt binders within an asphalt mixture were understood to potentially be influenced by the mixture characteristics (i.e. air void levels, binder content, etc.) and aggregate properties (i.e. aggregate absorption, gradation, etc.). Therefore, this study was conducted in order to investigate and quantify the effects different aggregate sources and mixture properties may have on the oxidation and thermal cracking performance of asphalt mixtures. The investigation specifically focused on quantifying the oxidation of the asphalt binder alone and as part of the asphalt mixture when subjected to isothermal oven aging. The oxidation parameters of pan-aged asphalt binders were quantified, according to the standard of practice in the industry. These parameters were then compared to extracted and recovered mixture-aged asphalt binders to examine the influence of the main aggregate and mixture factors on the binder oxidation. The study observed differences between the pan-aged and mixture-aged asphalt binders in terms of oxidation kinetics, rheological measures, and the combined effect represented as the hardening susceptibility. Further evaluation of the binder oxidation based upon the dynamic modulus measures indicated marked influences of the mixture characteristics, the individual component materials, and the interactions between the investigated factors. Differentiation of the experimental factors was further identified by the newly developed low-temperature evaluation method, Uniaxial Thermal Stress and Strain Test (UTSST). The UTSST provides a fundamental approach to characterize the thermo-viscoelastic properties of asphalt mixtures permitting the pragmatic evaluation of changes in the stiffness and overall behavior of mixtures as a function of oxidative aging. Five distinct stages in the UTSST modulus were identified as thermo-viscoelastic properties, which are identified as a function of temperature: viscous softening, viscous-glassy transition, glassy hardening, crack initiation, and fracture stages. Through consideration of the thermo-viscoelastic properties, marked differences in the binder oxidation were noted between the experimental factors. Typically, decreases in the viscous response of the mixtures as well as increases in both the stiffness and brittle behavior were observed with aging. The evaluation method provides definitive measures to monitor multiple aspects of the performance of asphalt mixtures subjected to thermal loading.

Download or read book Transportation Research Record written by and published by . This book was released on 1997 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rheological and Rutting Characterization of Asphalt Mixes with Modified Binders written by S. Anjan kumar and published by . This book was released on 2012 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of investigations on the rheological properties of modified asphalt binders and their influence on the performance of asphalt mixes. Asphalt mixes with modified binders such as styrene butadiene styrene polymer, crumb rubber, natural rubber, and waste plastics were evaluated for their rheological properties and compared to the properties of asphalt mixes with unmodified VG30 (viscosity grade) asphalt binder. The dynamic modulus values and rutting characteristics of the asphalt mixes were studied with due consideration to different levels of aging and temperature variations. Studies on the rheological properties showed that the energy dissipated by unmodified asphalt (VG30) binder is higher than that of modified asphalt binders. Long-term aged natural rubber and waste plastic modified asphalt binders showed significant increase in the properties compared to unmodified asphalt binder (VG30). Reduced temperature susceptibility of polymer modified asphalt binder showed that only polymer modification can enhance both high temperature rutting resistance and low temperature thermal cracking resistance of asphalt mixes. The transient nature of polymer modified asphalt mix from viscoelastic solid-like to viscoelastic fluid-like condition is significantly shifted to higher temperature compared to that of the mix with unmodified asphalt binder. Aging and rutting indices showed that rubber modified asphalt mixes are highly susceptible to aging. Statistical analysis of test results showed that the process of modification of asphalt binder, aging, and temperature during the test influence the rheological and rutting characteristics of asphalt mixes significantly. Correlation between the asphalt binder properties and its influence on the rutting resistance are found to be statistically significant. The analysis using least significant difference showed that polymer modified asphalt binder significantly improves the aging and rutting resistance of asphalt mixes compared to unmodified asphalt binder.

Download or read book Binder Characterization and Evaluation written by Peterson and published by Strategic Highway Research Program (Shrp). This book was released on 1994 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final report, in four volumes, of Strategic Highway Research Program (SHRP) Project A-002A describes intensive investigations of the chemical and physical properties of petroleum asphalts used in the construction of highway pavements. The model and predictive capability constitute the major portion of volume 1.

Download or read book Performance Evaluation of Warm Mix Recycled Asphalt Binders After Long Term Aging written by Qiang Li and published by . This book was released on 2019 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluates the pavement performance evolution of warm-mix recycled asphalt binders during the secondary service period. Warm-mix recycled asphalt binders with various long-term aging levels and recycling plans were produced by the laboratory simulation method. Conventional physical properties tests, the dynamic shear rheometer test, and the bending beam rheometer test were conducted to measure the performance of recycled binders. Effects of the aging level and recycling plan on the resistance to rutting, fatigue cracking, and low temperature cracking were investigated by statistical methods. It was found that after secondary long-term aging, recycled binders are more resistant to rutting, while they are less resistant to fatigue and low temperature cracking. The modified aging kinetic model can be used to accurately characterize the effect of secondary aging time on rutting or fatigue factors for recycled binders. The resistance of aged binders to fatigue and low temperature cracking is obviously improved by adding the warm mix asphalt additive. By comparison, using styrene butadiene rubber latex enhances the binder performance in almost all aspects. The aging level has a more significant effect than the recycling plan for all performance parameters.