To investigate the compressive dynamic properties of hydraulic asphalt concrete under various temperatures, four temperatures and four strain rates have been set to perform the uniaxial compression experiments using hydraulic servo machine in this paper. The influence of temperature and strain rate on the failure modes, stress-strain curves and mechanical characteristic parameters of hydraulic asphalt concrete is analyzed and the results reveal that the failure modes and stress-strain curves have significant temperature effect. When the temperature is between −20 °C and 0 °C, the failure mode is dominated by brittle failure of asphalt binder, and hydraulic asphalt concrete shows obvious strain softening. With the addition of temperature, the failure modes of specimens are transferred from brittle failure to ductile failure since the asphalt changes from elastic-brittleness to viscoelasticity. Influenced by temperature effect, the compressive stress-strain curves of hydraulic asphalt concrete show strain hardening while the peak stress of hydraulic asphalt concrete is obviously decreased, and the variation coefficient of peak stress has a power relation with temperature. With successive increases in strain rate, the stress-strain curves of hydraulic asphalt concrete gradually are transferred from strain hardening to strain softening. The peak stress and stiffness modulus of specimens under compression gradually increase, and the dynamic increase factor of peak stress is linearly related with the logarithm value of strain rate after dimensionless treatment. In terms of the quantitative analysis of the experimental data, two relationship models of the coupling effect between temperature and strain rate are proposed. The proposed models have good applicability to the quantitative analysis of the experimental results in the manuscript. This paper offers important insights into the application and development of hydraulic asphalt concrete in hydraulic engineering.

In this paper, experiments carried out on ordinary concrete under multiaxial compression of both full section and local section are presented and the failure modes compared under different loading conditions. According to the stress–strain curves obtained in true triaxial compression experiments, the mechanical properties of ordinary concrete were also extracted under different loading conditions, including full section loading and local loading. Because of the confining pressure, as for full section loading, the peak stresses under multiaxial compression were 1.27–2.27 times higher than those under uniaxial compression, whereas for local loading, the multiple was 1.24–2.05 times. It is obvious that the increasing coefficients under full section compression are more susceptible to confining pressures than those under local compression. The unique point of the experimental method is that ordinary concrete was subjected to full section or local uniaxial compression after full section or local triaxial compression. In this way, the failure modes of ordinary concrete were clearly revealed owing to the initial damage caused by triaxial compression. Meanwhile, the residual mechanical properties of ordinary concrete that had been subjected to full section or local triaxial compression were obtained, contributing to a comprehensive understanding of the mechanical properties of ordinary concrete under triaxial compression. Then a failure criterion of ordinary concrete under local loading was proposed based on the data of true triaxial compression experiments. The failure criterion was verified using data of both relevant scholars’ experiments and independent experiments of local triaxial loading. The results showed that the proposed failure criterion was simple but effective enough to compute the failure strength of ordinary concrete.

To examine the uniaxial behaviors of plain concrete and lightweight aggregate concrete under dynamic loadings, the plain concrete specimens and lightweight aggregate concrete specimens prepared by shale ceramsite were designed and tested under the loading strain rate range of ${10}^{-5}/{\mathrm{s}–10}^{-2}/\mathrm{s}$ . The hydraulic servo machine and shear device were applied to conduct the uniaxial compression, splitting tensile, and shear tests of both types of concretes, and the failure modes and stress-strain curves of two concrete at varying loading conditions were obtained from the test results. By comparing and analyzing the test results, the following conclusions are obtained: the failure of cementing layer occurs in plain concrete at low strain rates, while some coarse aggregates are damaged at high strain rates, but the failure of lightweight aggregate concrete is caused by the fracture of shale ceramsite at all strain rates. As the loading strain rate increases, the uniaxial compressive strength, splitting tensile strength, and shear strength of plain concrete and lightweight aggregate concrete are significantly increased, with the improved percentages of 35.63%, 43.75%, and 41.29% for plain concrete and 44.87%, 55.97%, and 49.44% for light aggregate concrete, respectively. For both types of concrete, the increase of strain rate has a more significant effect on the increase of splitting strength than compressive strength. In addition, the strain rate effect on the strength of lightweight aggregate concrete is significantly higher than that of plain concrete. The dynamic increase factor of peak stress of both concretes under uniaxial loadings is linearly related to the dimensionless logarithmic values of the strain rate. Based on the test results and analysis, two different relationship expressions between compressive strength, splitting tensile strength, and shear strength of two types of concretes are proposed, and the dynamic effects of concrete are explored from the perspective of the damage mechanism. This study is meaningful to the engineering applications and development of plain concrete and lightweight aggregate concrete.