Influence of porosity on compressive and tensile strength of cement mortar

The compressive, flexural and splitting tensile strength of cement mortar has been measured and interpreted in terms of its porosity. The authors first reviewed the existing porosity–strength relationships (Ryshkewithch, Schiller, Balshin and Hasselman model) and assessed the suitability of existing relationships. The Zheng model for porous materials has been used to evaluate the porosity–strength relationship of cement mortar. Over the porosity ranges examined, the extended Zheng model is good representation of the experimental data on the strength of cement mortar. Based on the generality of the assumptions used in the derivation of the extended Zheng model, this model for cement mortar can be applied for other cement-based materials. The experimental data also show that the ratio between compressive strength and indirect tensile (splitting tensile and flexural) strength of cement mortar is not constant, but is porosity dependent. The ratio decreases with increase porosity values of cement mortar.