Calculation derivation and test verification of indirect tensile strength of asphalt pavement interlayers at low temperatures

Abstract

When the direct tensile test is adopted to determine the interlayer tensile strength of the asphalt pavements, specimen separation or internal cracking often occurs at the bonding area of the loading head, rather than at the interlaminar bonding interface. In view of this phenomenon, this paper attempts to introduce the indirect tensile test to determine the interlaminar bonding strength of the asphalt pavement at low temperatures when the materials are considered to work in the elastic state. In accordance with the two-dimensional elastic theory and the Flamant solution, an analytical solution of tensile stress in the indirect tensile test is proposed through the stress superposition. On this ground, the calculation formula for the indirect tensile strength of the interlaminar bonding is derived according to the Tresca law. A low temperature indirect tensile test was designed and conducted to verify the correctness of the formula. Compared with the results of the direct tensile test, it is found that the magnitudes of the interlaminar tensile strength measured with the two methods are similar. The dispersion of indirect tensile test results is smaller, indicating that the indirect tensile test can replace the direct tensile test for interlaminar tensile strength evaluation at low temperatures, and hence reduce the workload and waste of resources.