DAMAGE CHARACTERISTICS OF RECYCLED ASPHALT MIXTURES UNDER THE EROSION EFFECT OF SNOW-MELTING SALT

Abstract

The erosion effect of snow-melting salt will degrade the durability of recycled asphalt pavement, but the damage characteristics of recycled asphalt mixture triggered by the erosion effect of snow-melting salt remain unclear. To solve the snow-melting salt-induced durability degradation of asphalt pavement, two commonly used snow-melting salts, NaCl and CaCl2, were selected to carry out the saline water immersion, salt-drying and -wetting cyclic and salt-freezing and -thawing cyclic splitting tests on recycled asphalt mixture, and the attenuation laws of splitting strengths and its damage characteristics under the erosion effect of snow-melting salts were analyzed. Results demonstrate that with the increase in soaking time, salt-drying and -wetting cycles and salt-freezing and -thawing cycles, the splitting strength of the recycled asphalt mixture maintain a declining trend, and the attenuation rate of splitting strength is elevated. The damage degree of the recycled asphalt mixture presents a nonlinear growth trend during saline water immersion, salt-drying and -wetting cycles, and salt-freezing and -thawing cycles. Under the same conditions, the damage degree after the action of NaCl solution is higher than that after the action of CaCl2 solution, and meanwhile, within the range of test concentration, the damage degree after the action of low-concentration saline solution is higher than that after the action of high-concentration saline solution. Conclusions provide a significant reference for the composition design and maintenance decisions of recycled asphalt pavement materials in cold regions. Keywords: road engineering; salt erosion; recycled asphalt mixture; damage characteristics; splitting strength