High-pressure uniaxial confined compression tests of mortars

The paper presents the development of an experimental setup to perform confined compression tests of cementitious paste, mortar, and concrete specimens at high pressures up to 1 GPa as well as the validation of the multi-scale model for the equation of state (EOS) of mortars. The test results for the EOS show that the secant bulk modulus of the loading branch monotonically increases with the content of fine aggregate. The comparison of the loading branches of the EOS for unsaturated specimens of two different specimen sizes indicates that there is negligible size effect for all types of the mixture compositions. Validation of the multi-scale model proposed previously for the EOS of a cement paste shows good agreement with the test results at the high-stress range with slight deviation at the lower stresses. It was demonstrated on mortars with a water to cement ratio of 0.50 that the Hirsch mixture model shows a good agreement with the test results for all levels of fine aggregate content in mortars.