Performance Evaluation Of Steel Slag SMA-13 Asphalt Mixture And Research On Anti-expansion Technology

With the gradual reduction of basalt stone required by road engineering construction,the national laws prohibiting mining and using have been promulgated one after another,so it is increasingly urgent to find alternatives to basalt.Steel slag is one of the products of steel-making.After aging,it can be mixed into SMA-13 asphalt mixture as coarse aggregate,so as to reduce the cost of road construction and improve the quality of pavement service.However,the problems of large area and long time of steel slag aging increase difficulties for engineering practice.In this paper,it is determined that the steel slag from Rizhao,Shandong Province can be mixed into SMA-13 as coarse aggregate,and the method of preparing anti expansion steel slag SMA-13 based on unaged steel slag is proposed,which shortens the engineering application cycle of steel slag and improves the utilization rate of steel slag.In this paper,the slag forming process,physical and mechanical properties,f-Ca O content and volume stability of steel slag aggregate were studied by using converter hot stewed steel slag from Rizhao,Shandong Province.The microstructure of steel slag was analyzed by X-ray CT;Because of its porous material characteristics,the effective relative density of steel slag was measured by SBS modified asphalt impregnation method to obtain the maximum theoretical relative density;Five kinds of SMA-13 with different steel slag contents were prepared by replacing limestone gravel with 5 ? 10 mm and 10 ? 15 mm aged steel slag in the same volume,and their properties were compared with basalt SMA-13;The preparation technology of anti expansion steel slag SMA-13 was studied based on the coarse aggregate of unaged steel slag;Finally,the steel slag SMA-13 is applied in the upper layer of lanluo Expressway in Shandong Province.The results show that the f-Ca O content and volume expansion rate of steel slag from Rizhao,Shandong Province meet the specification requirements after 8 months aging,and the crushing value,polishing value and adhesion effect with asphalt are better than those of basalt and limestone aggregate;Adding steel slag into SMA-13 asphalt mixture can improve its high temperature stability,water stability,shear performance and dynamic modulus,and reduce its low temperature crack resistance.Based on the consideration of high temperature and water stability,the optimal volume content of aging steel slag coarse aggregate is 75%;The volume expansion prediction model of non aged steel slag SMA-13 was established.Based on the consideration of volume expansion meeting the specification requirements and maximizing economic benefits,the optimal volume content of non aged steel slag was determined as 50%,so that the non aged steel slag can be directly applied;The performance indexes of steel slag pavement section of lanluo Expressway meet the specification requirements,and the anti sliding performance is better than that of basalt pavement.