Investigation on aging resistance performance of asphalt modified with organic layered double hydroxides and antioxidants
Song Xu, Xiangjie Niu, Jia-Zhu Wang, Shaoxu Cai, Hongyan Ma, Lei Fang, Shishui Liulin, Canlin Zhang
Abstract
Asphalt undergoes thermal-oxidative and ultraviolet (UV) aging in its lifespan, yet current research tends to emphasize the enhancement of asphalt’s resistance to only one type of aging, which hinders the improvement of its overall durability. In order to improve the resistance of asphalt to thermal-oxidative and ultraviolet aging, LDHs and antioxidants were utilized to modify asphalt based on the concept of physical shielding and chemical blocking. Moreover, to boost the compatibility between LDHs and asphalt, LDHs were organically modified using salicylic acid (SA) and sodium sodium dodecyl benzene sulfonate (SDBS). The composite effect of organic LDHs and antioxidants (Irganox 1076 and Irganox 1010) was investigated through physical and rheological tests. Also, thermal-oxidative and UV aging tests were utilized to evaluate the effectiveness of organic LDHs and antioxidants. Results show that SDBS and SA can be effectively intercalated into the LDHs, which improves the compatibility between LDHs and asphalt. LDHs, as a rigid component, increases the shear resistance of asphalt, which contributes to improved high-temperature performance but diminishes its flexibility. Organic modification can mitigate this drawback. In contrast, antioxidants exhibit a softening effect on asphalt. Organic LDHs and antioxidants can simultaneously boost the resistance of asphalt to UV and thermal-oxidative aging, with no interference observed between the two. Besides, the composite effect between SDBS-LDHs and Irganox 1076 is limited, whereas the composite effect of SA-LDHs and Irganox 1010 shows the most notable improvement. This can be attributed to the composite mechanism in which SA-LDHs provides physical shielding and Irganox 1010 chemically blocks the chain aging process of asphalt. These findings provide novel insights into the improvement of asphalt and asphalt pavement durability through a combined physical and chemical strategy.