Effects of TLA on rheological, aging, and chemical performance of SBS modified asphalt

Abstract

The durability and stability of Styrene-Butadiene-Styrene (SBS) modified asphalt in practical applications have garnered significant attention, with resistance to aging emerging as a pivotal indicator for evaluating performance. This study focuses on the composite modification of SBS-modified asphalt (SBS-MA) using Trinidad Lake asphalt (TLA), resulting in the creation of SBS-MA and three types of SBS/TLA composite modified asphalt (with TLA content at 10 %, 20 % and 30 % of the mass of SBS-MA). To assess the aging resistance, the four modified asphalts underwent prolonged aging for 10 h, 20 h, 30 h and 40 h using the Pressurized Aging Vessel (PAV) test. The macroscopic performance and microscopic characteristics of differently aged modified asphalts were then analyzed through methods such as Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR) and Fourier Transform Infrared Spectroscopy (FTIR). From the perspective of high-temperature performance, the asphalt modified with 10 % SBS exhibits optimal performance indicators during long-term aging processes, with a correlation coefficient reaching up to 99 % in relation to aging time. When the asphalt content exceeds 30 %, it adversely affects the stress sensitivity of SBS-modified asphalt. In terms of fatigue performance analysis, under a 5 % strain condition, the fatigue life of S-30 composite modified asphalt only decreases by 8 %, and TLA mitigates fatigue damage during the aging process of SBS-modified asphalt. Regarding low-temperature performance analysis, when the TLA content surpasses 20 %, it only manifests negative effects on SBS-modified asphalt. From a microscopic perspective, TLA introduces more sulfonyl and carbonyl groups, increasing by 3.6 times and 11 times respectively at a 30 % concentration, thus retarding the oxidation aging reaction of ST-CMA. In summary, this study provides valuable insights and methods for improving the aging resistance of SBS-MA, offering guidance for the application of Trinidad Lake asphalt in road engineering.