Effect of fibre type and content on performance of bio-based concrete containing heat-treated apricot shell

The heat-treated apricot shell can be utilized as coarse aggregates for producing sustainable bio-based lightweight concrete with good compressive strength but poor tensile strength. In order to improve the tensile properties of apricot shell concrete (ASC), the effects of polypropylene (PP) fibre, glass (G) fibre and basalt (B) fibre at various volume fractions (Vf) (0.25%, 0.5% and 0.75%) on the performance of ASC were investigated. The results indicated that the fibre type had no significant effect on the physical properties of ASC such as slump, density, water absorption and permeable porosity. However, the slump of ASC decreases with an increase in fibre content. The B fibre has a better improvement in mechanical properties than the PP fibre and G fibre thanks to the better elastic modulus and tensile strength. When the Vf was 0.5%, the compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of ASC reinforced with B fibre were increased by 16.7%, 29.1%, 29.2%, and 18.1%, respectively, compared to ASC without any fibres. The magnesium sulfate attack results showed that the incorporation of the B fibre decreased the mass loss and compressive strength of ASC exposed to a MgSO4 solution for 6 months because the fibre arrested the microcracks caused by the expansive stress. It is concluded that the mechanical properties of bio-based ASC and its resistance to magnesium sulfate attack can be significantly improved by incorporating 0.5% B fibre.