Preparation And Properties Of Flame Retarded SBS Modified Asphalt

The asphalt pavement has been in a dominant position of the highway for its low noise, comfortable oriented, good anti-smooth property, easy repairing etc advantages, but asphalt has the disadvantage of easy burning, so most tunnel pavement are cements concrete. How to improve flame retardancy of asphalt and apply it to the tunnel pavement, which were emphasized and studied at home and abroad road material field.In this paper, a series of flame retarded modified asphalt were prepared by different types of flame retardants and SBS modified asphalt, the flame retardancy was evaluated by lomited oxygen index(LOI) through oxygen index method test and the flame retarded effects of various flame retardants on SBS modified asphalt were investigated. Results show that: the flame retarded effect of unitary flame retardant on SBS modified asphalt was unconspicuous, while the flame retardancy of SBS modified asphalt was improved significantly by multiplex flame retardant for synergism effect of flame retardant, the optimum flame retardant mix ratio of decabromodiphenyl ether, zinc borate and antimony trioxide is 3:1:1. LOI reached to 26.0% when 8% multiplex flame retardants was added. DSC-TGA indicated that: accelerating decomposition temperature, thermal degradation temperature and ignition temperature increased remarkably, initial lose weight temperature decreased, which indicated the extent of burning was restrained significantlyThe physical performances of flame retarded SBS modified asphalt indicated that: after SBS modified asphalt was deal with flame retardants, softening point, viscosity increased and ductility decreased appreciably, thermal storage stability was improved and temperature susceptibility reduced. Fluorescence microscopy showed the particles diameter of SBS in flame retarded SBS modified asphalt reduced which indicated SBS particles were evenly distributed in asphalt. The rheology properties of flame retarded modified asphalt were investigated by dynamic shear rheometer (DSR), Brookfield viscometer, the result showed: phase-angle minished and itsplatform area lengthened. Viscidity improved at low temperature and elasticity increased at high temperature, rut factor increased too and so flame retarded SBS modified asphalt has better anti rut property than SBS modified asphalt.The rolling thin film oven test (RTFOT) and fluorescence ultraviolet aging test (QUV) were adopted to evaluate aging property of flame retarded SBS modified asphalt. Results show that: After RTFOT aging, LOI increased, flame retardancy was improved. Before and after aging, the difference of soft point and ductility reduced, the influence of temperature on tan 6 was weaken, which improved elasticity of flame retarded SBS modified asphalt at high temperature, and rut factor increased greatly, that indicated anti aging property of flame retarded modified asphalt was improved. With the increase of UV aging time, LOI and soft point increased appreciably as well rut factor improved. After aged for 45d and 60d, the difference of flame retarded SBS modified asphalt property was less than SBS modified asphalt's.