Research On Chlorine Salt Snowmelt Agent’s Effect Of Asphalt Mixture Performance And Mechanism

In winter, road snow ice will happen in most areas in China, which affecting road safety seriously. In order to ensure road safety and to avoid great safety accidents, chlorine salt deicing snow melt agent method with a characteristics of the simple operation and low cost, become a commonly used method of our country’s road snow removal deicing. However, chlorine salts of snowmelt agent will be a substantial reduction in asphalt pavement performance as well as snow removal deicing.This article uses the water and concentration of 0.2 g/ml of Nacl, Kcl, Mgcl these three chlorine salt snowmelt agent solution on asphalt and mineral aggregate and asphalt mixture for five cycles of dry-wet circulation soak test, and remove the corresponding period specimen laboratory experiments to study the effects of chlorine salt snowmelt agent on asphalt mixture performance and mechanism.(1) Taking asphalt soaked by chlorine salt snowmelt agent from before and after into the three major indexes, Brandt viscosity, resistance to rutting factor G*/sin8, asphalt composition analysis, infrared spectroscopy and thermal gravimetric analysis and other tests. Test result are:the softening point of asphalt, brinell viscosity and rutting resistance factor G */sin the delta is on the rise; The penetration and ductility is on the decline; Component increases, hard light component; Asphalt weightlessness rate decreases. Result in a change to the mechanism of action is:After chlorine salt snowmelt agent after soaking salting out effect and condensation reaction of asphalt and asphalt and makes the colloid content increases, saturates and aromatics content reduced.(2) Taking limestone, basalt and granite coarse which soaked by deicing salts of chlorine before and after into bulk specific gravity, aggregate crushing value, Los Angeles abrasion value, scanning electron microscopy and X-rays and other tests. The test result are:the aggregate volume relative density showed a trend of decline; Crushing value and attrition value showed a trend of rising; Aggregate surface structures appear different degree of wear and joint development and creates a new composition. Result in a change to the mechanism of action is:After chlorine salt snowmelt agent after soaking the aggregate surface due to chloride ion penetration acceleration aggregate reaction, generate double salts, and the formation of double salt is the main cause of mineral aggregate chemical attack.(3) Taking three different mineral aggregate asphalt mixture soaked by chlorine salt snowmelt agent before and after into Marshall stability, splitting tensile strength, shear strength and other tests, the effect of chlorine salt snowmelt agent on physical and mechanical properties of asphalt mixture have been studied. Test result are:after chlorine salt snowmelt agent erosion effect, Marshall stability, splitting strength, shear strength showed different degrees of decline. The reasons for this change is:Mixture after chlorine salt snowmelt agent and water soaking, reduces the performance of asphalt mixture of asphalt, aggregate and asphalt and aggregate performance of the cement performance.(4) Some tests like the three major indicators, infrared spectroscopic analysis, thermogravimetric analysis have been done to extraction of recycling asphalt and some tests like scanning electron microscope have been done to recycled aggregate, and the change of the impact of the performance of asphalt and aggregate which after the affect of chlorine salt snowmelt agent has been analyzed. Test results are:Test result:recycling asphalt softening point is on the rise; The penetration and ductility is on the decline; Recycled aggregate surface structures appear different degree of wear and tear and joint development. Result in a change to the mechanism of action is:After chlorine salt snowmelt agent after soaking salting out effect and condensation reaction of asphalt and asphalt and makes the colloid content increases, saturates and aromatics content reduced. After chlorine salt snowmelt agent after soaking the aggregate surface due to chloride ion penetration acceleration aggregate reaction, generate double salts, double salt formation is the main cause of mineral aggregate chemical attack.In summary, after the impact of chlorine salt snowmelt agent, bitumen, mineral aggregates and the asphalt mixture performance were significantly affected. Therefore, by studying the performance effects and action mechanism of chlorine salt snowmelt agent on asphalt mixture performance, a new theoretical basis can be provided for asphalt pavement structure design, and by choosing a good kind of modified bitumen and controlling asphalt pavement construction quality can achieve the ability for enhanced asphalt pavement resistance to the influence of chlorine salt snowmelt agent.