MULTIAXIAL TENSILE-COMPRESSIVE MECHANICAL BEHAVIOUR OF PLAIN HIGH-STRENGTH HIGH-PERFORMANCE CONCRETE

Multiaxial tensile-compressive tests were performed on 100mm×100mm×100mm cubic specimens of plain high-strength high-performace concrete (HSHPC) at variable stress ratios using a large static-dynamic true triaxial machine. Friction-reducing pads were composed of three layers of plastic membrane with glycerine in-between for the compressive loading plane; the tensile loading planes of concrete samples were processed by attrition machine, and then the samples were glued-up with the loading plate using structural glue. The failure characteristics of specimens and the crack directions were recorded and described respectively. The three principal strengths and strains in the corresponding stress state were measured. The influence of stress states and stress ratios on the triaxial strengths and peak strains of HSHPC was also analyzed respectively. The experimental results show that the changing of the multiaxial tensile-compressive strength and deformation depends on stress states and stress ratios. The multiaxial tensile-compressive strengths (1f ,3f ) of HSHPC at all stress ratios are less than the corresponding uniaxial tensile and compressive strength (ft, fc). The tensile and compressive peak strains reach the least and greatest values under uniaxial tensile and compressive stress state respectively. The formula of a failure criterion under multiaxial tensile-compressive stress states for plain HSHPC was proposed.