Physical and mechanical properties of cotton straw fibre and expanded polystyrene cementitious composite

This aim of this work was to develop a low-cost, high-performance cement-based composite using straw cotton straw fibre (CSF) and expanded polystyrene (EPS). To this end, cement mortar specimens with different proportions of CSF (5%, 10% and 15%) and EPS (1%, 2% and 3%) were prepared. A control group (CG), without CSF or EPS was also tested. The compressive strengths, anti-splitting and flexural strengths of the specimens with different mix proportions were tested at for 7 days and 28 days. The thermal conductivity and water absorption of the specimens at 28 days were also measured. It was found that, for a constant content of CSF or EPS, the compressive strength and axial compressive strength of the samples at 28 days decreased with an increase of EPS or CSF content. The maximum compressive and axial compressive strengths of the CSF–EPS specimens were 37% and 42.6% lower than those of the CG, respectively, whereas the maximum flexural and anti-splitting strengths were 33% and 94% more than those of the CG. With an increase in the content of CSF and EPS, the water absorption of the specimens increased, whereas the thermal conductivity decreased. The cementitious composite made with 5–10% CSF and 1–2% EPS met the requirements for the mechanical properties and thermal insulation performance of self-insulating blocks.