Anti-aging performance and mechanism analysis of styrene–butadiene–styrene modified bitumen containing antioxidant/cinnamic acid intercalated layered double hydroxides

To improve the aging resistance of bitumen for the construction of durable flexible pavement, the composite of antioxidants and cinnamic acid intercalated layered double hydroxides (CA-LDHs) were applied to modify-four styrene–butadienestyrene (SBS) modified bitumens (SMBs) aiming at revealing the anti-aging mechanism of different modifiers according to the aging behaviors of SMBs which were evaluated by the physical and rheological properties, characteristic functional groups and chemical compositions of SMBs before and after thermal-oxidative and ultraviolet (UV) aging. The results show that antioxidants/CA-LDHs can simultaneously improve the thermal-oxidative and UV aging resistance of four kinds of SMBs. Compared with the composite of pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) (1010), tris (2,4-di-tert-butylphenyl) phosphite (168) and CA-LDHs, the composite of octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (1076), tris (2,4-di-tert-butylphenyl) phosphite (168) and CA-LDHs shows a better improvement effect on the anti-aging performance of SMB. LDHs can shield UV light and prevent oxygen from penetrating into SMB, and antioxidants can capture and decompose intermediate products generated during aging, these effects would restrain the oxidative aging. It is concluded that there is a synergistic effect between antioxidants and LDHs in improving the thermal-oxidative and UV aging resistance of SMBs.