Compressive and tensile stress–strain-strength behavior of asphalt concrete at different temperatures and strain rates

Abstract

Hydraulic asphalt concrete is widely used as impervious linings and facings for canals and reservoirs and as impervious cores in embankment dams. The asphalt concrete is subjected to compressive and tensile loading at different temperatures and strain rates during operation and occasional earthquake loading. A comprehensive series of compression and tension tests on asphalt concrete specimens was carried out in the temperature range −30 °C to 30 °C and in the strain rate range 10−5 1/s to 10−2 1/s. The test results show that the time–temperature superposition principle is applicable for the modulus and strength values. The shift function of the principle is almost linear with temperature, with a coefficient of about −0.11, for the compression-shear tests. A relationship between compressive strength and compression modulus is established. The coefficient is about −0.22 for the shift function for the tension tests when temperature is higher than −10 °C. The tensile behavior of asphalt concrete is much more sensitive to temperature than the compressive behavior. Mohr-Coulomb shear strength parameters were back-calculated by combining the strength values obtained by the compression and tension tests. Typical stress–strain-strength parameters for the asphalt concrete used in the experimental investigation are presented for the temperature range −30 °C to 30 °C and the strain rate range 10−5 1/s to 10−2 1/s and may be used as preliminary estimates for the design of hydraulic asphalt linings, facings and cores in dams. A simplified method is proposed to establish the corresponding parameters for other asphalt concrete mixes with different bitumen types (grades) and bitumen contents than that used in the present experimental investigation.