Preparation And Pavement Performance Of Micro-surfacing Mixture Of Steel-slag Based On Traffic Safety

Road traffic accident is one of the social hazards that threaten the security of people's life and property.In order to improve the safety of road traffic,a kind of safety function material for pavement maintenance is developed based on the concept of the intrinsic safety of road traffic,which is named micro-surfacing mixture of steel-slag.It is necessary to analyze the influence of steel slag mixing ratio on the performance of micro-surfacing mixture and determine the optimum steel slag mixing ratio in order to prepare excellent micro-surfacing mixture of steel-slag.According to the specification of micro-surfacing and dilute slurry seal technology guide,16 groups of mix proportion are drafted.The gradation type of MS-? intermediate gradation and the target mix proportion of basalt: water: cement: SBR modified emulsion asphalt =100:8:2:10 are obtained by comparing the slurry state and the early strength of the mixtures under various mix proportions.Based on the target mix proportion,7 groups of asphalt mixture with the steel slag mixing ratio of 0%,20%,35%,80%,50%,65%,100% respectively are prepared by compound method.The performance tests of the 7 groups of asphalt mixture are carried out.It is found that the optimum mixing ratio of steel slag is 50% which means the optimum mix proportion is basalt: steel slag: water: cement: SBR modified emulsion asphalt=50:50:8:2:10.Under this condition,the asphalt mixture is in a good slurry condition during the mixing process,and the 1 hour wet wheel wear value is 237.2g/m2,the load wheel sand is 80g/m2,the unit width deformation rate is 2%,the unit thickness rut depth rate is 12.9%.In order to further realize the utilization of steel slag with high added value and further reduce the cost of the micro-surfacing mixture,the steel slag powder is used instead of the cement as the filler on the basis of the optimum mix proportion.Two groups of steel slag asphalt mixture are prepared with the steel slag powder mixing ratio of 50% and 100% respectively,which are compared with the mixture prepared by the optimum mix proportion with the steel slag powder mixing ratio of 0%.The results indicate that the cement can be completely replaced by the steel slag powder as the filler in the micro-surfacing technology.All the pavement performance indexes of the asphalt mixture meet the specification requirements when the mix proportion is basalt: steel slag: water: steel slag powder: SBR modified emulsion asphalt =50:50:8:2:10.The technical indexes including 1 hour wet wheel wear value,unit width deformation rate,unit thickness rut depth and other core indicators of the micro-surfacing mixture of steel-slag developed in this paper are superior to the relevant technical specification requirements in China,which can improve the safety of the road effectively.