Physical and Mechanical Properties of the Cotton Straw Fibre and Expanded Polystyrene Cementitious Composite

This experimental work aims to develop cement-based composites with low cost and high performance using straw cotton stalk fiber (CSF) and expanded polystyrene(EPS). 5%, 10%, 15% CSF and 1%, 2%, 3% EPS were mixed into cement mortar, taking the specimens without CSF and EPS as the control group (CK), the compressive strength, splitting strength, and flexural strength of the specimens with different mix proportions for 7-day and 28-day were tested, and the mechanical properties of the materials were verified. The thermal conductivity and water absorption of the 28-day specimens were measured, and the physical properties of the materials were obtained. The results show that when the content of CSF or EPS is constant, the compressive strength and axial compressive strength of the samples at 28-day decrease with the increase of EPS or CSF content. The maximum compressive and axial compressive strengths of CSF and EPS specimens are 33% and 42.6% lower than CK. The maximum flexural and anti-splitting strengths are 33% and 42.6% more than that of CK. The water absorption of specimens increases with the content of CSF and EPS increasing. The thermal conductivity of specimens decreases with the increase of CSF and EPS content respectively. The results show that the composite made by adding 5%-10% CSF and 1%-2% EPS to cement mortar can meet the mechanical property standard of self-insulation block and meet its thermal insulation performance.