Experimental Investigation and a Predictive Model of the Strength Evolution of Rubberized Cementitious Materials Based on the Virtual Pore Method

Abstract

Mixing waste rubber in cementitious materials such as concrete is an effective way to reuse the rubber, which is important due to its environmental significance. This work predicted the strength evolution of rubberized cementitious materials based on their rubber content and porosity. Mortar specimens with rubber content ranging from 0% to 15.3% per mortar volume were prepared based on the method of making pores in cementitious materials with soft materials, i.e., the virtual pore method. Their porosity and compressive strength at 3, 7, and 28 days were measured by tests. With the increasing volume fraction of rubber particles, the porosity of the specimens increased and the strength decreased. By dividing the pores in cementitious materials into matrix pores and virtual pores, the strength of the rubber free cement mortar and the effect of rubber particles were considered separately and a predictive strength model of rubberized cementitious materials was established based on their rubber content and porosity. The proposed model is applicable to materials of different ages and hydration degrees. It was applied to the strength prediction in the available literature, and the predicted values were in good agreement with the test values.