High temperature effect of foamed concrete under equal displacement increment triaxial cyclic compression

Foamed concrete (FC) has been extensively used for its lightweight, good thermal insulation, and sound insulation properties. It has gained broad investigations in the past decades, but the data of triaxial cyclic compression tests are lacking. In this study, triaxial cyclic tests were conducted under different confining pressures (0 MPa, 0.3 MPa, 0.5 MPa, 0.8 MPa) with four temperature treatments (25 °C, 100 °C, 200 °C, 300 °C) to obtain the failure modes and stress-strain curves, analyze the compressive strength, residual strength, elastic modulus and brittleness index, explain the fracture mechanism and damage evolution of FC from the perspective of energy dissipation. Furthermore, the strength prediction model of FC was proposed and its yield criterion was verified. The results show that the damage pattern of FC was significantly influenced by confining pressure and the mechanical parameters were more sensitive to temperature. The energy density and damage increased linearly with the number of cycles, and the dissipated energy accounted for a large proportion under low confining pressure or high temperature. The Crushable-foam yield criterion had good applicability to FC, and thermal damage decreased the hydrostatic yield strength of FC.