Experimental Study on Effect of Temperature on Direct Tensile Behavior of Hydraulic Asphalt Concrete at Different Strain Rates

The tensile mechanical properties of hydraulic asphalt concrete (HAC) play a significantly important role in the safety of the impervious core in embankment dams. This paper aims to develop a direct tensile test setup with temperature control, to devise the direct tensile test method for HAC, and to investigate the direct tensile properties of HAC in a temperature range of 0 degrees C-20 degrees C and a strain rate range of 10(-5)-10-2 s(-1). Through a large number of direct tensile tests, the shape and size of the specimen and the connection mode between the clamp and the specimen were designed. The test results show that the temperature and the strain rate significantly affect the tensile stress-strain characteristics of the HAC. As the temperature decreased from 20 degrees C- 0 degrees C or the strain rate increased from 10(-5)-10(-2) s(-1), the tensile strength, the tensile modulus, and the aggregate cracking ratio increased, whereas the peak strain declined. Moreover, the empirical formulas for the tensile strength, tensile modulus, and peak strain were successfully derived by applying the time-temperature superposition principle. The coefficient of determination was more than 0.95, indicating that the modeling data well agreed with the test results. Finally, according to the Mohr-Coulomb criterion, the effect of the temperature on the cohesion and the internal friction angle was analyzed at the various strain rates. The obtained test results can provide a reference for the design of asphalt concrete cores in embankment dams. (C) 2022 American Society of Civil Engineers.