Multi-scale evaluation of sodium dodecyl sulfate intercalated LDHs on the ageing resistance of SBS modified bitumen

Sodium dodecyl sulfate (SDS) intercalated layered double hydroxides (LDHs) were prepared to enhance the ageing resistance of SBS modified bitumen (SMB). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that SDS has been intercalated into the interlayers of LDHs. Compared to LDHs, the interaction between SDS intercalated LDHs (OLDHs) and SMB was obviously stronger, and OLDHs exhibited better dispersity and stability in SMB. After ageing, the viscoelastic properties of SMB were deteriorated. LDHs and OLDHs could obviously alleviate the deterioration of ageing on the properties of SMB, which could improve the ageing resistance of SMB, especially OLDHs. Additionally, the enhancement mechanisms of OLDHs and LDHs for the ageing resistance of SMB at the microscopic scale were investigated by molecular dynamics. The incor-poration of LDHs could obstruct the invasion of oxygen into the interior of SMB and inhibit the diffusion rate of oxygen in SMB, which reduced the oxidation reaction probability of SMB during ageing, and eventually achieved the improvement on ageing resistance of SMB. The effectiveness of LDHs was further improved after SDS intercalated modification, that was, SDS intercalated modification was beneficial to enhance the ageing resis-tance of LDHs for SMB.