Investigation of sodium stearate organically modified LDHs effect on the anti aging properties of asphalt binder

Abstract

The layered double hydroxides (LDHs) has been widely used as the anti-aging modifier to improve the anti aging performance of an asphalt binder, but for the different chemical and physical properties of LDHs with asphalt binder, the compatibility of them is not very well, therefore the best modification effect can not be obtained. The sodium stearate was designated to organically modify the LDHs to enhance its improvement effect on the anti aging performance of asphalt binder. The modern test instruments such as Fourier transform infrared spectroscopy, X-ray diffractometer, scanning electron microscopy, ultraviolet visible spectrophotometer were used to investigate the sodium stearate effect on the characteristics of LDHs. In addition, the LDHs modified styrene–butadienestyrene modified asphalt (LDHs/SBS MA) and sodium stearate organically modified LDHs (SS-LDHs) modified styrene–butadienestyrene modified asphalt (SS-LDHs/SBS MA) were prepared by the melt blending method, the thin film oven test and UV aging test were conducted to simulate the short term thermo-oxidative aging and UV aging of asphalt binder respectively. Finally, the chemical structure, viscosity, and complex modulus of LDHs/SBS MA and SS-LDHs/SBS MA before and after aging were tested respectively. The results show that the sodium stearate can improve the compatibility of LDHs with styrene–butadienestyrene modified asphalt binder (SBS MA). Both LDHs and SS-LDHs can improve the anti thermo-oxidative aging and anti UV aging performance of SBS MA. Notably, the improvement effect of SS-LDHs on the anti aging performance of SBS MA is much better than that of LDHs.