Determination of low-temperature crack control parameter of binding asphalt materials based on gray correlation analysis

Abstract

Convenient evaluation indexes for the low-temperature cracking of matrix asphalt, asphalt mastic, and asphalt-fine aggregate combination under different low-temperature conditions are determined. On the basis of bending failure test, the stress–strain curves of the three asphalt materials under different low-temperature conditions are ascertained to obtain the critical value of the bending strain energy density, which can effectively characterize the low-temperature crack resistance. On the basis of gray relational analysis, the correlation between the critical value of the bending strain energy density of the above-mentioned materials and their ultimate bending failure strength and strain under low-temperature conditions is determined, and the reasonable strength or strain index of different materials at dissimilar temperatures is acquired. Experimental results show that the three asphalt materials exhibit different low-temperature performance changes due to dissimilar material ratios. The changes of asphalt mastic and matrix asphalt are similar, whereas the change of the asphalt-fine aggregate combination differs from those of the two. Gray correlation analysis results show that, for the matrix asphalt and asphalt mastic, the critical fitting effect of ultimate bending failure strength with the bending strain energy density is better at 0 °C to −10 °C. Thus, the ultimate bending failure strength can be reasonably used as the low-temperature cracking control index. Under the condition of −10 °C to −30 °C, the ultimate bending failure strain can be considered the evaluation index of low-temperature cracking. For the asphalt-fine aggregate combination, the deformation capacity can be suitably used as the evaluation method of low-temperature cracking in the entire low-temperature range of 0 °C to −30 °C. These results simplify the evaluation method of low-temperature cracking performance of asphalt materials, which is important for improving the low-temperature performance of these materials.