Study On Performance Of Warm Mix Recycled SBS Modified Asphalt Mixture

The highway in China has transformed from the high-speed development stage of construction into the high-quality development stage of the integration of construction and maintenance.A lot of Reclaimed Asphalt Pavement(RAP)have been produced in the maintenance and reconstruction project,among which most of the high-grade pavement used SBS modified asphalt,and the efficient recycling of waste modified asphalt pavement materials has become one of the goals of sustainable development of highway construction.Meanwhile,in the context of global warming and energy shortage,higher requirement has been posed to the highway construction of energy conservation and environment protection in China.The warm-mixed recycled asphalt mixture that combines warm-mixed technology and renewable technology together can both reduces the emission of noxious gas and realizes the effective utilization of waste and scrap,which has good social and economic benefits.In the production process of reclaimed asphalt mixture,the heating temperature of the recycled asphalt mixture is limited.When mixed in high amount,it is difficult to reach the compaction temperature when mixed with new materials.Warm-mixed recycled asphalt mixture enables effective compaction in the low temperature for high amount added reclaimed asphalt mixture and realizes the high added quantity of RAP.The study aims to evaluate the performance of warm mixed and reclaimed asphalt mixtures.selecting the evotherm as surface active and warming agent and comparing the performance of warm-mixed reclaimed asphalt(WMRA)and hot-mixed reclaimed mix(HMRA)mixtures.discussing the problem of lower water stability on warm mixed and recycled asphalt mixtures,and analyzing the comprehensive benefits brought by the warm mixing and recycling technology.The mix design of WMRA and HMRA recycled mixtures with SBS modified asphalt was carried out,comparing the pavement performance of WMRA with HMRA.The test results indicate that HMRA has better high-temperature stability than WMRA,but lower lowtemperature stability and fatigue pproperties.The effect of surface active and warming agent on the properties of SBS modified asphalt was investigated.The results indicate that the certain amount of warming agent has no effect on the basic properties and rheological properties of SBS modified asphalt,the adhesion to asphalt and aggregate,and the anti-aging properties of asphalt have been improved.A single variable was controlled to study the factors and mechanisms of water stability of WMRA recycled mixtures.The t results indicate that the warming agent can improve the adhesion of asphalt and aggregates and improve the water stability of the mixtures by reducing the surface energy of the modified asphalt.Mixed and synthetic temperature,the way of adding additive,the content of different RAP,warming agent dosage and the short-term oven aging have effects of different degrees on water stability of the mixtures.WMRA with suitable amount of RAP can meet the technical requirements of HMRA recycled mixtures and the warm mixing and recycling technology saves production costs,reduces energy consumption and harmful gas emissions.