Impact of Salt Freeze-Thaw Cycles on Low Temperature Performance of Asphalt Mixture Based on the Strain Energy Density

With the use of snow-thawing salt in the cold winter, asphalt pavement is damaged easily by salt freeze-thaw cycles. The aim of this research is to study the impact of salt freeze-thaw cycles on low temperature performance of asphalt mixture. Through low temperature bending test, the decay law of strain energy density of asphalt mixture under the conditions of salt freeze-thaw cycles was analyzed, and strain energy density was used for regression by the exponential model, what's more, the improvement of fiber, anti-stripping agent and slaked lime on the low temperature performance of the mixture were investigated. The results of low temperature bending test showed that the strain energy density of asphalt mixture decreased rapidly after salt freeze-thaw cycles, moreover, the more the times of salt freeze-thaw cycles, the higher the concentration of salt solution and lower the change of freezing temperature, the larger the influence on strain energy density of asphalt mixture. Regression analysis results revealed that the exponential model could well reflect the variation of strain energy density of the mixture with the times change of the salt freeze-thaw cycles. The improvement of basalt fiber on the low temperature performance of the asphalt mixture was very significant under the condition of salt freeze-thaw cycles.