Thermal behavior of flexural specimens strengthened with various adhesives and FRPs

The use of fiber reinforced polymer (FRP) composites is ever growing in the construction industry. High strength- weight ratio, corrosion resistance and suitable durability are the main criteria for FRP selection and design. However, in case of high temperature exposure, change in the material properties affects the overall structure performance. The aim of this study is to evaluation the effect of cement and epoxy adhesives on the thermal performance of concrete flexural specimens strengthened with basalt (BFRP) and glass (GFRP) fabrics. Therefore, 105 flexural specimens (100 × 100 × 500 mm) were made by a constant water-cement ratio; and were kept under the 50°, 100° and 200°, for a period of one and three hours, respectively. The results show that increasing the temperature led to decreased flexural strength of unreinforced specimens by 48%. Also, flexural strength of cement and epoxy adhesives impregnated specimens decreased up to 47% and 60% respectively. Results from the presented model shows at temperatures lower than 100 0C, flexural strength of cement adhesive impregnated specimens was lower than epoxy adhesive impregnated specimens; but at 200 0C, flexural strength of specimens strengthened with basalt and glass fabrics increases 1.3 and 1.15, respectively. Also, curve for flexural strength of specimens strengthened with basalt fabrics compared to glass fabrics had an ascending trend, while it had a descending trend for epoxy adhesive impregnated specimens.