Bond behaviour of smooth surface GFRP pultruded profiles with cement grout

The advantages of glass fibre reinforced polymer (GFRP) pultruded composite profiles, such as their high strength-to-weight ratio, corrosion resistance, and low maintenance costs, have attracted the attention of researchers and end users in structural applications. In spite of this, one of the challenges associated with using GFRP pultruded profiles is their smooth surfaces when bonded with concrete. To address this challenge, this study investigated four different approaches that can be used to improve the bond performance between GFRP pultruded profiles and concrete surfaces. These approaches are the incorporation of glass sand into cement grout, the variation in the size of the sand particles in the grout, the surface preparation of GFRP profiles, and the use of various cement characteristics. The experimental results show that the surface preparation of the GFRP profiles is the most effective method of improving the bond strength between the GFRP profiles and the concrete surface. Additionally, a theoretical model is developed to predict the bond behaviour, and it is observed that the linear elastic theory with the inclusion of the bond surface roughness coefficient is capable of predicting bond behaviour. The overall outcome of the study will assist design engineers and end users in the application of smooth surface GFRP profiles in concrete structures.