Recycling argan nut shell and wheat straw as a porous agent in the production of clay masonry units

Abstract

The present work aims to study and compare the effect of incorporating argan nut shell (ANS) and wheat straw (WS) into clay mixtures as construction materials additives on physical, mechanical, structural, and thermal properties of fired clay bricks. Five clay mixtures were prepared, including a control sample free of waste, two clay samples containing 5 wt% and 10 w.t% of ANS (ANS5 and ANS10), two others containing 5 wt% and 10 wt% of WS (WS5 and WS10), all specimens were fired at 900 °C, and their technological properties in term of loss on ignition, firing shrinkage, water absorption, apparent porosity, bulk density, flexural strength, compressive strength, and thermal conductivity were evaluated. A reduction in bulk density and thermal conductivity has been observed with the incorporation of ANS and WS, leading to an increment in the apparent porosity and water absorption in their turn, which is typically due to the specimen’s porous structure. The thermal conductivity of clay brick samples containing 5–10 wt% of ANS or WS decreased by 5–17% and 27–46%, respectively. Thus, the thermal insulation property is improved while the mechanical properties (flexural and compressive strength) meet the requirements of the standards for clay masonry units, except for WS5 brick. Test results highlighted the potential of recycling ANS and WS in clay masonry units and thus, the production of lightweight material.