Abstract
Different modification methods, such as adding modifiers and pretreating crumb rubber, have been developed to achieve decent engineering properties and reduce the viscosity of rubberized bitumen. This study evaluated the influence of the modification methods on the aging resistance for rubberized bitumen. Two types of crumb rubber—a 40-mesh crumb rubber and a microwave-pretreated crumb rubber—and two kinds of modifiers—Sasobit and Trans-polyoctenamer—were selected to prepare rubberized bitumen. The samples were subjected to a Thin-Film Oven Test for the simulation of the short-term aging condition, while a Pressure-Aging-Vessel test was used to simulate the long-term aging condition. The indexes of rubberized bitumen, including softening point, elastic recovery ratio, maximum load, ductility, fracture energy, phase angle, and dynamic modulus, were tested before and after aging. The result showed that trans-polyoctenamer displayed the best resistance to short-term aging, while Sasobit significantly improved the fracture energy of rubberized bitumen after short-term aging. Microwave pretreated partially destroyed the internal structure of crumb rubber, leading to a decrease of short-term aging resistance for rubberized bitumen. Compared with short-term aging, the changing trends of various indexes were basically same, except the discrepancy of properties indexes was reduced after long-term aging.
Highlights
Rubberized bitumen was extensively used in the bitumen pavement because of its excellent performance [1,2]
Warm mix additives (WMA) and pre-degradation crumb rubber (CR) were two effect methods to decrease the high viscosity of rubberized bitumen
Wang et al [13] investigated the effects of laboratory STA and LTA on the chemistry and rheology of rubberized bitumen, and the results showed that CR improved the aging resistance of rubberized, which reflected by the decreased carbonyl and sulfoxide indices
Summary
Rubberized bitumen was extensively used in the bitumen pavement because of its excellent performance [1,2]. Warm mix additives (WMA) and pre-degradation CR were two effect methods to decrease the high viscosity of rubberized bitumen Another method is to add reactive modifiers such as trans-polyoctenamer (TOR), the purpose of which is to improve the compatibility between CR and bitumen [11]. It has been noted that the properties of rubberized bitumen such as elastic recovery, high-temperature stability, and modulus were improved by the use of TOR [4] It improved aging resistance effectively [27,31]. The main objective of this study is to evaluate the influence of different modification methods test were used used to simulate simulate aging conditions.
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