Recycling Egyptian rice straw for the production of low-cost building materials for energy conservation

Abstract

One form of solid agricultural waste that is produced in significant quantities in Egypt is rice straw, which is burned by farmers causing harm to the environment and human health. The goal of the work is to create an effective sustainable insulation option to replace conventional materials using Egyptian rice straw (ERS) as a renewable, biodegradable material in buildings as a means of protecting the natural environment. Experimental results show that chemical composition of ERS includes high portions of silica, fiber, and ash which assessed ERS’s thermal insulation capabilities and feasibility when added to mortar and concrete. The ERS was added to the concrete and studied the effect of compressive strength. The results show that adding only 1% ERS by weight decreased the concrete compressive strength by 30.76%, indicating poor binding. However, the investigation of adding ERS in mortar from 0 to 20% shows that the optimum conditions for using ERS are the percentage of 20% ERS. The mortar thermal conductivity decreased by 70% with 20% ERS addition compared with standard mortar without ERS. Smaller ERS particle sizes (5e10 mm) provided enhanced insulation properties versus larger sizes (10e15 mm). General empirical equations were developed to relate thermal conductivity to the ERS ratio and temperature.