A Beam Test Study on the Bond Performance between Epoxy-Coated Reinforcement and Geopolymer Concrete

An epoxy-coated reinforcement geopolymer concrete structure with good durability and energy-saving properties can be formed by combining epoxy-coated reinforcement and geopolymer concrete. The bond strength is the precondition for the two to work together. In this paper, 13 beam specimens (11 epoxy-coated reinforcements and 2 ordinary deformed reinforcements) were designed to investigate the influence of the strength of geopolymer concrete, diameter of the reinforcement, bonding length and type of reinforcement on the bond performance between reinforcement and geopolymer concrete. The test results show that the ultimate bond strength of the epoxy-coated reinforcement (ECR) and geopolymer concrete decreased by 7.32% and 14.76%, respectively, when the rebar diameter increased from 14 mm to 16 mm and then to 20 mm. The ultimate bond strength between ordinary threaded reinforcement and geopolymer concrete was slightly higher than that between ECR and geopolymer concrete. When the length of the bond section is small or the concrete strength is low, the beam specimen is prone to the failure of the reinforcement pullout. The specimen with the larger reinforcement diameter is prone to concrete splitting failure. However, the specimens with medium bond length and small reinforcement diameter suffered from pull-out failure after concrete splitting. In this paper, based on the test data, the bond-slip constitutive model of ECR and geopolymer concrete was established, and the bond-slip curve obtained by this model was in good agreement with the measured curve. In addition, the calculation formula of the ultimate bond strength between ECR and geopolymer concrete was also proposed in this paper, which can provide theoretical reference for the engineering application of geopolymer concrete.