Study the Effect of Adding Waste Tire Rubber on Permeation and Thermal Properties of Fiber-Reinforced Foam Concrete

This work presents an experimental investigation of the effect of optimum quantities of waste tire rubber (WTR) on the characteristics of fiber-reinforced foamed concrete modified with a superplasticizer (SP), including its thermal conductivity, water absorption, total porosity, and sorptivity. This research produced four types of foamed concrete with a density of 1100 kg/m³: conventional foamed concrete, SP-modified foamed concrete, SP-PP fiber-reinforced foamed concrete, and SPWTR-PP fiber-reinforced foamed concrete. To examine the impact of density, two more mixtures were created as fibre-reinforced rubberized foamed concrete with densities of 800 and 1400 kg/m³. In all examined mixtures, a fraction of sand (≤ 2.36 mm) in foamed concrete was substituted with WTR at optimal proportions of 50% for coarse WTR (4.75–10 mm) and 34% for fine WTR (≤ 2.36 mm). The findings indicated that, at a density of 1100 kg/m³, a fiber-reinforced rubberized foamed concrete mix modified by SP, in comparison to the mix including SP and PP, resulted in reduced thermal conductivity, water absorption, porosity, and sorptivity. In comparison to the conventional foamed concrete mix without SP and PP, it demonstrated a 36.5% reduction in thermal conductivity, a 17.2% drop in water absorption, an 11.7% reduction in porosity, and a 77.6% lower sorptivity. Aside from water absorption and porosity, a rise in the density of rubberized foamed concrete led to heightened thermal conductivity and sorptivity.