@article{saleh_braswell_elwardany_rad_castorena_kim_2022, place={OXON, ENGLAND}, title={Field Calibration and Validation of a Pavement Aging Model}, volume={2}, ISSN={1477-268X}, url={https://doi.org/10.1080/10298436.2022.2027416}, DOI={10.1080/10298436.2022.2027416}, abstractNote={ABSTRACT A pavement aging model (PAM) is established by calibrating and validating the NCHRP 09–54 kinetics model's predictions against field core measurements. Field cores, laboratory-mixed loose mixtures, and binders from a wide range of pavement sections are used, including both conventional hot mix asphalt (HMA) mixtures and modern materials (i.e. reclaimed asphalt pavement (RAP), warm mix asphalt (WMA), and polymer modified asphalt (PMA)). Field aging levels are measured at different depths from binder extracted and recovered from in-service field cores. The original component materials of these pavement sections are aged in the laboratory and used to calibrate the kinetics model. The measured field aging levels are compared against those predicted from the kinetics model to inform a depth and time dependent field calibration function for the PAM. The validation of PAM using an independent set of field sections shows that, within the limited data used in this study, the calibrated PAM may be able to predict the aging of the conventional HMA, RAP, WMA, and PMA mixtures. The PAM predictions are lastly found to outmatch the predictions by the Global Aging System (GAS) model.}, journal={International Journal of Pavement Engineering}, publisher={TAYLOR & FRANCIS LTD}, author={Saleh, N.F. and Braswell, E. and Elwardany, M. and Rad, F.Y. and Castorena, C. and Kim, Y.R.}, year={2022}, month={Feb} }
 @article{braswell_saleh_elwardany_yousefi rad_castorena_underwood_kim_2021, title={Refinement of Climate-, Depth-, and Time-Based Laboratory Aging Procedure for Asphalt Mixtures}, volume={2675}, ISSN={["2169-4052"]}, DOI={10.1177/0361198120957316}, abstractNote={This paper refines the oxidation kinetics-based approach originally proposed in the NCHRP 09-54 project to determine the laboratory aging durations at 95°C that best reflect the effects of time, climate, and depth on loose asphalt mixtures. Aging durations that match the field aging at various pavement depths were determined in this study for asphalt mixtures, including warm-mix asphalt (WMA), polymer-modified asphalt (PMA), and reclaimed asphalt pavement (RAP). Here, the laboratory aging durations were used to calibrate a climatic aging index to prescribe the laboratory aging duration, given hourly pavement temperature history obtained from Enhanced Integrated Climatic Model analysis of the Modern Era Retrospective-Analysis for Research and Applications, Version 2 weather data. The recalibrated procedure determines the required laboratory aging durations with reasonable accuracy for virgin hot-mix asphalt (HMA) and WMA mixtures. From the recalibrated results, no variations were found with regard to the laboratory aging durations for WMA materials compared with HMA materials, but there were differences between the RAP and non-RAP mixtures. In some instances, the short-term aged RAP mixtures that were prepared according to AASHTO R 30 exceeded the aging level of 4-year-old field cores, suggesting that refinement of this standard short-term aging procedure may be necessary. Approximately half of the PMA sections evaluated exhibited outlier behavior that could have been caused by the unrealistically harsh thermal history of the field projects from which the cores were acquired.}, number={2}, journal={TRANSPORTATION RESEARCH RECORD}, author={Braswell, Elizabeth and Saleh, Nooralhuda F. and Elwardany, Michael and Yousefi Rad, Farhad and Castorena, Cassie and Underwood, B. Shane and Kim, Y. Richard}, year={2021}, month={Feb}, pages={207–218} }
 @article{saleh_keshavarzi_rad_mocelin_elwardany_castorena_underwood_kim_2020, title={Effects of aging on asphalt mixture and pavement performance}, volume={258}, ISSN={["1879-0526"]}, DOI={10.1016/j.conbuildmat.2020.120309}, abstractNote={This study investigates the effects of long-term aging on pavement performance under realistic traffic and thermal conditions. Using the NCHRP 09-54 aging procedure, a systematic study of the effects of aging on asphalt mixture linear viscoelastic and fatigue properties was conducted. The computational engine of FlexPAVE™ V1.1was modified to run more realistic pavement performance simulations. Results suggest that the effect of aging on pavement performance is evident only when simulations employ more realistic traffic and climatic conditions. In the absence of thermal conditions, the effect of changes in mixture properties on pavement performance is not significant.}, journal={CONSTRUCTION AND BUILDING MATERIALS}, author={Saleh, Nooralhuda F. and Keshavarzi, Behrooz and Rad, Farhad Yousefi and Mocelin, Douglas and Elwardany, Michael and Castorena, Cassie and Underwood, B. Shane and Kim, Y. Richard}, year={2020}, month={Oct} }
 @article{rad_elwardany_castorena_kim_2018, title={Evaluation of Chemical and Rheological Aging Indices to Track Oxidative Aging of Asphalt Mixtures}, volume={2672}, ISSN={["2169-4052"]}, DOI={10.1177/0361198118784138}, abstractNote={ Oxidative age hardening in asphalt binder leads to embrittlement. Embrittled asphalt is prone to fatigue and thermal cracking. Therefore, the ability to predict asphalt binder oxidative age hardening within a pavement throughout its service life could inform improved pavement material selection, design, and maintenance practices. Studying the evolution of oxidative aging requires the use of key properties to track oxidation levels, termed aging index properties (AIPs) here. The objective of this study is to identify suitable rheological and chemical AIPs to track oxidation levels in asphalt materials. A wide range of laboratory and field aged materials were evaluated in this study. A range of chemical AIPs determined by Fourier transform infrared spectroscopy (FTIR) absorbance peaks and areas were evaluated based on their correlation with laboratory aging duration. Rheological AIPs were evaluated based on the strength of their relationship to the chemical changes induced by oxidation. The rheological AIPs evaluated included the dynamic shear modulus, zero shear viscosity, Glover-Rowe parameter, and crossover modulus. The chemical AIP evaluation that most strongly correlated with laboratory aging duration is the carbonyl plus the sulfoxide absorbance peaks. The results indicate that both the dynamic shear modulus and Glover-Rowe parameter constitute rheological AIPs that relate directly to the chemical changes induced by oxidation. }, number={28}, journal={TRANSPORTATION RESEARCH RECORD}, author={Rad, Farhad Yousefi and Elwardany, Michael D. and Castorena, Cassie and Kim, Y. Richard}, year={2018}, month={Dec}, pages={349–358} }
 @article{rad_elwardany_castorena_kim_2017, title={Investigation of proper long-term laboratory aging temperature for performance testing of asphalt concrete}, volume={147}, ISSN={["1879-0526"]}, DOI={10.1016/j.conbuildmat.2017.04.197}, abstractNote={The performance implications of laboratory asphalt loose mixture aging at 135 °C were evaluated by comparing the performance of mixtures subjected to long-term aging at 95 °C and 135 °C to yield the same rheology. Although the rheology of the mixtures aged at 135 °C and 95 °C matched, their chemistry differed. Performance test results suggest that the chemical changes induced by aging at 135 °C can negatively impact performance. The relationship between binder chemistry and rheology was unaffected by aging temperatures at or below 95 °C. The rate of oxidation increased with an increase in temperature, and thus, the optimal loose mixture aging temperature is 95 °C.}, journal={CONSTRUCTION AND BUILDING MATERIALS}, author={Rad, Farhad Yousefi and Elwardany, Michael D. and Castorena, Cassie and Kim, Y. Richard}, year={2017}, month={Aug}, pages={616–629} }
 @article{mensching_daniel_bennert_medeiros_elwardany_mogawer_hajj_alavi_2014, title={Low-temperature properties of plant-produced RAP mixtures in the Northeast}, volume={15}, journal={Road Materials and Pavement Design}, author={Mensching, D. J. and Daniel, J. S. and Bennert, T. and Medeiros, M. S. and Elwardany, M. D. and Mogawer, W. and Hajj, E. Y. and Alavi, M. Z.}, year={2014}, pages={1–27} }