Experimental investigation into the flexural behaviour of basalt FRP reinforced concrete members

Abstract

The durability of reinforced concrete structures is an ongoing challenge for engineers, particularly in harsh environments. In these conditions, concrete is susceptible to excessive cracking which allows water or other aggressive agents to penetrate the structure, thereby accelerating the deterioration, mainly through corrosion, of the steel reinforcement. The deteriorated concrete structures require frequent maintenance to achieve and extend their service life and may need expensive rehabilitation measures. The use of fibre-reinforced polymer (FRP) rebars, such as carbon and glass FRPs, can be an effective, sustainable and durable solution to enhance the durability of reinforced concrete structures in aggressive environments. Another type of FRP that has gained popularity in construction in the last two decades is basalt fibre-reinforced polymer (BFRP), which is the subject of the current paper. In order to investigate their behaviour, an experimental programme comprising five reinforced concrete beams and seven one-way spanning slabs has been conducted, and is described herein in detail. Three different types of reinforcement were included in the tests, namely sand-coated BFRP bars, ribbed BFRP bars as well as regular carbon steel reinforcement, for comparison. All of the members were tested up until failure. The test results are presented and analysed, with particular focus given to the cracking moment, ultimate moment capacity, deflections and also crack opening widths. The results are compared with the guidance currently available in several international design codes. In addition, based on the results and analysis presented herein, design recommendations for reinforced concrete with BFRP rebars are proposed.