Preparation of dodecyltrimethoxysilane surface organic LDHs and application in aging resistance of SBS modified bitumen

Abstract

Dodecyltrimethoxysilane surface organic layered double hydroxides (LDHs) was synthesized and used to improve the aging resistance of SBS modified bitumen (SMB), According to Fourier transform infrared spectroscopy, x-ray diffraction and Contact angle meter, dodecyltrimethoxysilane has been chemically grafted onto the surface of LDHs and will not affect the crystal structure of LDHs. After dodecyltrimethoxysilane surface organic modification, the -OH on the surface of LDHs was decreased, meanwhile, some organic groups were introduced into LDHs, which contributed to reducing the surface hydrophilicity of LDHs. Then, the physical, rheological properties and chemical structure of SMB containing OLDHs and LDHs before and after aging were studied thoroughly. Compared with LDHs, the compatibility of OLDHs in SMB has been significantly enhanced. Furthermore, OLDHs modified SMB exhibited more excellent high-temperature behavior. After aging, bitumen was oxidized and SBS was degraded, the physical and rheological properties of SMB were seriously deteriorated. The addition of LDHs can suppress the destruction of aging on the performance and chemical structure of SBM, and enhance the aging resistance of SBM. The enhancement of LDHs has been notably strengthened after dodecyltrimethoxysilane surface organic modification.