Research on a novel technology of FRP bonded to concrete substrate without adhesive

Without any treatment for concrete surface, a novel technology of FRP bonded to concrete substrate without adhesive was developed, in which the porous lightweight aggregate was used as bridge material between FRP sheet and concrete. Base on that technology, a prefabricated rough FRP sheet which can be used accompanying with concrete pouring was presented with the aim to improve the durability of concrete, which has a great potential to be widely used in the area of reinforcement, surface decoration and protection for concrete construction. The durability of rough FRP sheet was preliminarily evaluated by pull-off test and chloride ion penetration test. Results indicated that bond strength between rough FRP sheet and concrete substrate was 2.17MPa, chloride ion permeability coefficient at 30 days was 8.41×10−4mg/d·cm2. Microstructure analysis showed that the bond strength was mainly determined by mechanical interlocking and interfacial structure between lightweight aggregate and cement paste, an equation based on the bond model was put forward to optimize the design of rough FRP sheet.