Effect of ultraviolet absorber (UV-531) on the properties of SBS-modified asphalt with different block ratios

Abstract

SBS modified asphalt with different block ratios (40/60, 30/70, 20/80) was prepared using a high-speed shearing apparatus to study the effect of the ultraviolet absorber (UV-531) on its properties. A melt blending method was used to prepare the modified asphalt with three doses of UV-531. The ultraviolet aging of asphalt was simulated in an indoor chamber. Dynamic shear rheological test, bending beam rheological test and force ductility test were used to assess the effects of different doses of UV-531 on high and low temperature performance of asphalt material modified with SBS of different block ratios. The results showed that UV-531 has little effect on the complex shear modulus of SBS-modified asphalt, and has a great influence on the phase angle of SBS-modified asphalt. The structural characteristics of SBS modifier is an important factor affecting the rheological properties at high temperature. UV-531 affects the distribution state of SBS modified medium hard segment (S) and soft segment (B) in asphalt, and has great influence on the low temperature performance of SBS-modified asphalt with different block ratios. The degree of aging and chemical changes in the UV-SBS modified asphalt were studied according to its softening point increment (SPI), complex shear modulus aging index (G*AI), infrared spectrum and scanning electron microscope. These results suggest that the degradation reaction of SBS modifier under UV leads to a significant reduction of polybutadiene segment (B) and cracking of SBS-modified asphalt. UV-531 can effectively reduce the aging of SBS-modified asphalt and prevent the decomposition reaction of SBS modifier in asphalt.