CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractThe durability of asphalt mixtures and flexible pavements are closely related to the properties of the asphalt fine aggregate matrix (FAM) with aging. However, there are still no uniform aging procedures specified for laboratory-prepared FAM. In this study, the intermediate-temperature behavior of FAM under various accelerated aging procedures was investigated at the binder scale to reveal the influence of the FAM aging. Three different long-term aging procedures were considered, including loose mixes aging (95°C and 135°C) and pressure aging vessel (PAV) protocols. Frequency sweep test and linear amplitude sweep (LAS) test were carried out on binders extracted from aged FAMs. Rheological tests were also performed on corresponding binders with standard PAV procedure to show the impact of FAM during the aging process. Moreover, an aging kinetics model was put forward to qualify the linear rheological property evolutions for fast and constant aging reaction stages under various aging conditions. The results show that 135°C loose FAM mixes aging significantly reduces the fatigue performance of styrene-butadiene-styrene (SBS) modified binder, and employing 95°C loose mixes aging and PAV aging procedures can avoid this adverse effect. Moreover, to match the aging degree of asphalt and FAM, an aging duration more than 40 h is recommended.



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