Influence of heat and ultraviolet aging on the structure and properties of high dosage SBS modified bitumen for waterproof.

• The aging behavior of HSMB and LSMB under heat and UV were investigated. • The microstructure and chemical structure of HSMB and LSMB were analyzed. • The aging reaction rate and activation energy of LSMB and HSMB were studied. In this paper, the aging behavior of high dosage styrene–butadienestyrene (SBS) modified bitumen (HSMB) for waterproof materials and low dosage SBS modified bitumen (LSMB) for pavement were investigated. The effects of heat as well as ultraviolet-heat synergism on properties and chemical structure of HSMB and LSMB were evaluated by physical properties, fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the change of softening point and low temperature flexibility of HSMB was much less than that of LSMB after heat aging, which indicated that the aging resistance of HSMB was better than that of LSMB. The physical properties changes of HSMB and LSMB after UV-heat synergism aging were much serious than that of HSMB and LSMB after heat aging. FM indicated that HSMB showed the network structure, and its structure was only partially destroyed after heat aging and completely destroyed after UV-heat synergism aging, while LSMB presented the sea-island structure, and the sea-island structure almost disappeared after aging. FTIR also showed that the change of carbonyl index (I C = O ), sulfoxide index (I S = O ) and butadiene double bonds index (I C = C ) of HSMB was smaller than that of LSMB after aging. The aging kinetic models of HSMB and LSMB were established by viscosity, the aging kinetic models showed that HSMB had lower aging reaction rate and larger activation energy than LSMB under the same aging condition, which meant that HSMB had better aging resistance. [ABSTRACT FROM AUTHOR]