Characterization of composite formed by cement and wheat straw treated with sodium hydroxide

Abstract

Cement-based composites with lignocellulosic residues (e.g. wheat straw, rice husk, and bagasse) as fillers have reduced density and cost. Pretreatments have been applied in these raw materials to improve their compatibility with cement. This work aimed to characterize composites made from cement and wheat straw particles that had been chemically treated (2% NaOH solution) at two different temperatures (30 °C and 60 °C). Values of bulk density (209 kg·m-3) and specific density (679 kg·m-3) were determined for wheat straw at 12% moisture content. Straw yield was 71.9% and the particle size distribution showed large concentrations of wheat straw particulate material between 5- to 10-mesh. Composites made with wheat straw particles, in comparison to the control treatment, showed half the density, i.e., from 1800 to 900 kg·m-3. Also, the stress x strain curve presented a higher deformation before failure. NaOH pretreatment did not affect the mechanical properties of wheat straw composites.