Effect of flame retardants on long-term aging characteristics of asphalt binders

Abstract

This work investigates the effects of flame retardants on long-term aging and rheological characteristics of modified asphalt binder containing Styrene-Butadiene-Styrene triblock copolymer (SBS) and flame retardants. The flame retardants included #A (decabromodiphenyl ether, antimony trioxide, and zinc borate with the ratio of 3:1:1 by mass) and #B (tetrabromobisphenol A bis (2, 3-dibromopropyl ether), antimony trioxide with the ratio of 2:1 by mass). Modified asphalt binders were aged according to the Pressure Aging Vessel (PAV) and Fluorescent Ultraviolet aging test (UV). Aged and unaged asphalt binders were characterized using limited oxygen index (LOI), and viscosity and dynamic shear rheology (DSR), respectively. Experimental results indicated that flame resistance of asphalt binder increases after PAV and UV aging processing, and the complex modulus and viscosity also increases. The UV aging brings a plateau region of the phase angle master curves over the intermediate temperature range. This behavior is very weak in the studied PAV aging and unaged asphalt binder. These changes were mainly due to the ultraviolet crossing linked to the asphalt. Compared with #B modified asphalt binder, #A modified asphalt binder showed better flame retardancy and rheological characteristics before and after aging.