Quantitative relationship between pore size distribution and compressive strength of cementitious materials

Abstract

Cementitious materials have complex pore structure, which has a significant impact on material properties. The present paper aims to determine the quantitative relationship between pore size distribution and compressive strength of cementitious materials. An influence function is proposed to describe the influence of pore size on strength, based on which an integral model of compressive strength is established. A total of 11 sets of mortar specimens with wide differences in pore size distribution were prepared with the virtual pore method to verify the influence function and the strength model. The influence function indicates that the effect of pores per unit volume on strength increases with the increase of pore size. The effect increases slowly at small pore size and increases significantly at large pore size like microscale pores. The influence of porosity on strength can be determined quantitatively with the proposed influence function when the pore size distribution is obtained, which further gives the predicted strength. It is indicated that microscale pores have a significant impact on the material strength, so the existence of these pores should be avoided to improve material strength.