Experimental Research Of Influence About Freeze-thaw Splitting Performance Of Asphalt Mixture By Salt

Under the rapid development of China’s economy, transport undertakings has been rapid development. Asphalt concrete pavement has been widely used in the high-grade highways for its smooth surface, ride comfort and noise. There is great different between southern climate and northern climate in our country. In order to ensure the traffic safety in winter, we need a lot of de-icing salt to melt the ice and snow of the road. The salinasoil has some impact on the asphhalt pavement in the northwest of our country. Therefore, there is certain significant on the study of salt in the winter to asphalt concrete.Based on the analysis on the basis of asphalt concrete to freeze-thaw damage mechanism,this paper argues damaged law under the combined effect of freeze-thaw cycles and erosion by laboratory experiments. Asphalt mixture is AC-16gradation. According to the design of orthogonal test,there are three kinds of solution:0%,13%, and saturated sodium chloride solution. Simulating the eastern and northwestern regions diurnal temperature range, there are two kinds of freeze-thaw temperature:-15℃to5℃and-5℃to15℃. Also, there are four kinds of freeze-thaw cycles:2、4、6and8times of freeze-thaw cycles. Firstly, make specimens according to the requirements and then do the freeze-thaw cycle test under a variety of conditions Then, the specimens will be done the ultrasonic detection. At last, it draws the strength law after splitting test.The study shows Freeze-thaw splitting strength of asphalt concrete specimens appear overall downward trend with the increase of the number of freeze-thaw times; Asphalt concrete specimens under the temperature of-5℃to15℃have little higher freeze-thaw splitting strength than those under the temperature of-15℃to5℃; Under the temperature of-5℃to15℃,the freeze-thaw splitting strength of the specimens soaking in the saturated sodium chloride solution is the least; Under the temperature of-15℃to5℃, the freeze-thaw splitting strength of the specimens soaking in the13%sodium chloride solution is the least. Freeze-thaw splitting strength has a relatively good correlation between the intensity and the wave velocity under appropriate correction to the ultrasonic results.through the function fitting, the regression equation for the velocity and intensity is:f=0.2914e0.00093v,R2=0.91482. This research will provide a certain theoretical guidance for the design and construction of asphalt pavement under the salt corrosion.