Effects of spheroid and fiber-like waste-tire rubbers on interrelation of strength-to-porosity in rubberized cement and mortars

• Fiber-like waste-tire rubber has affected mechanical behavior and slump flow.
• Mechanical behavior and porosity relation was compared with previous models.
• Specific strengths of mortars have revealed an inverse effect with rubber content.

The waste tire rubber represents a serious pollution and waste disposal problem. The aim of this experimental investigation is focused on the interrelation of strength/porosity in the rubberized cement and mortars as a function of distinctive rubber morphologies. Experimental results show the interrelation of flexural (FS), compressive (CS) and specific (SS) strengths with porosity (P) and water absorption (WA) of the control and four distinctive rubberized cement pastes and mortars. It is found that the fiber-like rubber particles provide distinctive both the slump flow tendency and mechanical behavior. A bimodal distribution of the pore sizing between irregular and spheroidal morphologies is observed. Models of the compressive, flexural and specific strengths as a function of both the rubber content and porosity are also proposed. When a 5% (volume) of sand is replaced with rubber particles, a number of alternative applications (e.g. flexible pavement, building facades and water purification systems) can be induced.