Rheological properties and storage stability of bitumen/SBS/montmorillonite composites

Styrene–Butadiene–Styrene triblock copolymer is commonly used for modifying physical, mechanical and rheological properties of bitumen. Because of the poor compatibility between SBS and bitumen, SBS modified bitumen is not storage stable at high temperature. To obtain more compatibility between SBS and bitumen, several methods have been suggested. In this study, organophilic montmorillonite/SBS modified bitumen mixtures were prepared by melt intercalated blending. Physical and rheological properties of polymer modified bitumen were compared before and after adding nanoclay to the bitumen. Results showed that the presence of nanoclay improves the storage stability of PMB significantly without adverse effect on other properties of it. The structure of OMMT/SBS/bitumen blend was characterized by XRD. The spectra indicated that proper dispersion of OMMT in SBS led to a homogenous blend which is named exfoliated structure. The result of storage stability test showed that the difference in softening point was in good accordance with ASTM standard limitation which means that OMMT can improve the storage stability of PMB. Also morphological analysis confirmed storage stability results.