Abstract
The strength of cementitious materials is strongly related to their microstructures. This paper aims to investigate the effect of high-pressure water on the static and dynamic tensile strength of cementitious materials and interpret the influence through the view of microstructure. Specimens were first put in different water pressure (0 MPa, 1 MPa, 3 MPa, and 5 MPa) then their strength and microstructures were measured through splitting tensile tests, SEM tests, and MIP tests. Results showed that as water pressure increased, the strength of mortar decreased with a maximum loss of 32.54 %, while strain rate sensitivity increased. The static strength of saturated specimens was higher than the dried ones under the same water pressure, whereas the opposite results were obtained for dynamic strength. The observed microstructure morphology indicated that higher water pressure would induce more microcracks around pores and around aggregate-matrix interfaces, which led to the loss of strength. The water content and total porosity increased with increasing water pressure. Predictive static and dynamic tensile strength models concerning water pressure, porosity, and saturation states are proposed. The predicted values are in good agreement with the test values.
Published Version
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