Multiscale Experimental Investigation of the Influence of Pores on the Static and Dynamic Strength of Cementitious Materials

Abstract

This work studied the influence of pores of different scales on the strength of cementitious materials. A method to make pores in cementitious materials with particles of soft materials was developed and proved. With this method, mortar specimens with different porosity and pore-size distributions were prepared. The results of static and dynamic strength tests showed that the static and dynamic compressive strength decreases with the increase of porosity and average pore radius, whereas the strain rate sensitivity increases. Predictive models of static strength, dynamic strength, dynamic increase factor, and their respective relationships with multiscale porosity were proposed. The influence of multiscale pores on strength and strain rate sensitivity was calculated quantitatively. It indicated that when the pore radius is larger than 100 nm, at the same pore volume the effect of pores on static strength, dynamic strength, and strain rate sensitivity increases with the pore radius.