Experimental research on compressive strength and deformation of self-compacting concrete at high temperature

The main research focus on the residual properties of self-compacting concrete at high temperature, the results about the compressive strength and stress-strain curve is less. The total strain of concrete at high temperature consists of four strain components that are, instantaneous stress-induced strain, free thermal strain, transient strain and creep. The instantaneous stress-induced strain can be obtained by the compressive stress-strain curve under stabilized temperature field. It is very important to research the stress-strain relationship at high temperature for establishing the constitutive model and stress analysis of self-compacting concrete structure. The compressive strength and deformation properties of self-compacting concrete, self-compacting concrete with addition of polypropylene fiber, high strength concrete under different temperature were studied in this paper. The relationship between the compressive strength and temperature of self-compacting concrete was obtained, and the comparisons with the normal concrete, high-strength concrete, high-performance concrete was done. It showed that the compressive strength occurr a recover and regaining phase about 400 degrees C, the strain at peak stress increased with temperature. The relationship between stress-strain curve and temperature were studied in this paper. The functions of compressive strength, strain at peak stress, elastic modulus and strain-stress relationship were brought forward. The instantaneous stress-induced strain can be obtained by the strain-stress function, which offers a basis for the establishment of constitutive model at high temperature