Nano Silica Impacts the Microstructure and Mechanical Properties of Carbon Fiber-Reinforced Foam Concrete

Abstract

Foamed Concrete is a popular choice in the construction industry due to its excellent thermal and acoustic insulation properties and ability to support structures. This study investigated the effects of incorporating nanomaterials into carbon fiber-reinforced foam concrete to enhance its mechanical properties. The experimental work was conducted in two phases. First, a lightweight foam concrete mixture with varying amounts of foam agent was produced, with the optimal balance being 11 Kg/m3 to achieve the target density of 1343 Kg/m3 within the range of 1300-1350 Kg/m3 at 28 days, and the appropriate compressive strength of 17.4 MPa. Adding carbon fibers reduced the flow test by approximately 6.63% compared to the control foam concrete mix. When 1% of Nano-silica was added, the high consistency of the mixture decreased by 7.27% compared to the control foam concrete mix. Reinforcing foamed Concrete with 3% carbon fibers increased its compressive strength by approximately 19.8%, with the best percentage being 1%. However, the dry density increased by 8.33% compared to foam concrete. When Nano silica was used, the compressive strength increased by 14.39%, and the dry density increased by about 14.64% at 28 days compared to the foam concrete-reinforced carbon fibers mix. The results demonstrated that carbon fiber and Nano Silica had a synergistic effect on enhancing the mechanical properties of the foam concrete, exerting positive impacts on reducing the porosity and improving the pore distribution at 1%. Adding Nano silica with carbon fibers further transformed large voids into small ones and introduced closed pores, leading to an enhanced microstructure for foamed Concrete.