Mechanical Properties of Fly Ash Concrete Composite Reinforced with Nano-SiO2 and Steel Fibre

A parametric experimental study has been conducted to study the effect of nano-SiO₂ particles and steel fibres on the mechanical properties of the concrete composite containing fly ash. Five different nano-SiO₂ contents (1%, 3%, 5%, 7% and 9%) and five different steel fibre contents (0.5%, 1%, 1.5%, 2% and 2.5%) were used. The results indicate that addition of nano- SiO₂ and steel fibres decreases the slump and slump flow of the fresh concrete composite containing fly ash, and both the slump and slump flow decrease gradually with the increase in nano-SiO₂ and steel fibre content. The addition of nano-SiO₂ improves the mechanical properties of concrete composites containing fly ash. There is an increase in the compressive strength and compressive modulus of elasticity with increase of nano-SiO₂ content when it is below 5%, while they begin to decrease after the nano-SiO₂ content is beyond 5%. Steel fibres help improve the mechanical properties of concrete composite containing fly ash and nano-particles. With the appropriate fibre content, the reinforcement of steel fibres on the compressive strength and compressive modulus of elasticity of the concrete composite becomes more obvious as the fibre content increases.