Effect of Silane Coupling Agent Surface Modified Layered Double Hydroxides on Properties of Bitumen

Abstract

Layered double hydroxides (LDHs) surface modified by silane coupling agent KH550 were prepared to modify bitumen, the surface modified LDHs (KH550-LDHs) were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD). The effect of KH550-LDHs and LDHs on physical and anti-ageing properties of bitumen was evaluated by means of physical test. The results of FTIR showed that KH550 had successfully grafts onto the surface of LDHs, and XRD result showed that KH550 had little effect on the crystal structure of LDHs. The storage stability test showed that KH550-LDHs dispersed better homogeneously and existed more stable than LDHs in bitumen. The physical properties tests indicated that high and low temperature properties of bitumen were improved compared with LDHs. After UV aging with the addition of KH550-LDHs, the increase rate of softening point slowed remarkably, the reduction rate of ductility declined evidently compared with LDHs. Aging indices (softening point increment and ductility retention rate) show that KH550-LDHs exhibited better improvement than LDHs in UV aging resistance of bitumen, implying more effective modification of KH550-LDHs which is due to the enhanced compatibility between KH550-LDHs and bitumen.