Experimental research on compressive strength-size effect and mechanical properties of cement-based grout

Abstract

The shapes and sizes of grout blocks used to test the material properties vary in the codes and regulations of different countries. This paper investigated the relationship between the compressive strength of grout with 60 blocks of different shapes and sizes, including 40 × 40 × 160 mm prisms specified in the codes of China, Japan and Europe, 50 mm cubes in American code, 70.7 mm cubes in RILEM, ø100 × 200 mm cylinders in the codes of Australia and New Zealand. In addition, another 60 grout blocks were used to investigate the relationship between the cubic compressive strength and the axial compressive strength, elastic modulus and splitting tensile strength. The test results showed that, in the range of the compressive strength from 65 MPa to 110 MPa, the cubic compressive strength of grout had the phenomena of size effect, but the compressive strength increased with the increase of block sizes, which was different from concrete. Significant deviations were observed in the calculation of grout's axial compressive strength, elastic modulus, and splitting tensile strength by using the concrete conversion equations. Formulas proposed in this study can determine the compressive strength between test blocks with multiple shapes and sizes and calculate material properties of the grout.