Experimental Study On The Mechanism Of The Promoting Technique Of The Bonding Performance Of The FRP To Concrete Surface

In the construction process of concrete structures, erosion of environment, changes of service load and other factors can lead to reduction in concrete’s structural performance and decline of its service life. Reinforcement of concrete Structure is an economic and effective method to improve various properties of concrete’s structure. Among numerous kinds of reinforcement technologies, fiber reinforced polymer (referred to as FRP in English) has been widely used in the reinforcement of structure due to its excellent physical properties (lightweight, high-strength, corrosion resistance). Externally bonded FRP reinforcement method is a commonly used FRP reinforcement method for concrete, which is mainly to paste the FRP sheets on the external surface of concrete component with epoxy resin glue. Therefore, the performance between FRP and the interface of concrete will directly affect the reinforcement effect. Existing researches show that treatment on the surface of concrete’s substrate can significantly improve the adhesive performance of FRP-concrete interface, but the existing norms and technical standards did not consider this effect. Therefore, this paper will carry out groove processing on the surface of concrete’s substrate and systematically study the effects of groove width, groove depth, groove spacing and other parameters on FRP concrete’s interface. The following studies are carried out:(1) This paper widely collected available data of FRP-concrete bonding tests in the literature at home and abroad, and analyzed the reliability of the data, carried out data selection and established the database; it made use of the database to analyze the precision of the bearing capacity model of the existing interface and carried out evaluations.(2) Established BP neural network, trained and studied the test database, analyzed the main factors affecting the interface’s bonding capacity as well as its influence rule, and finally built the interface bearing capacity model based on BP neural network.(3) This paper adopted C50 concrete in the single shear experiment, carried out groove processing on the surface of concrete’s substrate, quantized the roughness of concrete’s surface with groove width, groove spacing, groove depth as well as the ratio of groove width and groove spacing to study the effect of groove processing on the interface’s bonding properties. Based on the test results, this paper would conduct analysis and research from the aspects of failure mode, load-slip curve, stress distribution, strain distribution, local bonding and shearing stress-slip curve, etc. And this paper would fit out a bearing capacity model with groove width, groove depth, groove spacing and other parameters according to test data regression based on the existing bearing capacity model so as to provide reference for its application in the practical reinforcement projects.