Improvement of mechanical properties of impregnated resin for carbon fibre sheet by adding nano-silica

Abstract: Carbon fibre reinforced polymer (CFRP) has been identified as a promising solution for repairing metal bridges due to its high specific strength, non-damaging nature to steel substrates, and uniform stress distribution. However, epoxy resin, commonly used as a matrix material for manufacturing CFRP and as an adhesive in joints, faces challenges in coastal environments where high temperatures and humidity can lead to plasticisation, expansion, and hydrolysis, causing degradation of its mechanical properties. The study investigates nano-silica at varying proportions was used to modify the epoxy resin, followed by tensile tests. The results showed that as the nano-silica content increased, the tensile strength of the modified resin initially increased and then decreased. The tensile strength was maximized with a 2 wt% addition of nano-silica, yielding a 30% improvement. After deterioration of the neat and modified resin specimens in distilled water at 50°C for 60 days, the aged modified resin showed a remarkable enhancement in tensile strength compared to the aged neat resin, with an increase ranging from 39% to 52%.