Analysis Of Interfacial Bond Characteristics Of NSM-CFRP Reinforced Concrete Under Hot And Humid Environment

Currently, carbon fiber-reinforced composites(Carbon Fiber Reinforced Polymer/Plastic, referred to as CFRP) for its excellent material properties to traditional plate, is widely used in the field of civil and structural engineering, has a very high perceived value. South cetral of China is in subtropical humid monsoon climate environment, when the CFRP strengthening concrete structures exposed to hot and humid environment for a long time, not only the physical and chemical properties of the material itself changing, interfacial residual stress caused by temperature and humidity can also lead Interfacial bond properties to decreased, thereby reducing the useful life of the structure. To study Interfacial bond properties of NSM-CFRP reinforced concrete members under hot and humid conditions, we do the following work:1) Through mechanical analysis of micro-element and in view of bilinear bond-slip constitutive relation, do the analytic calculation of bond-slip process divided into four phases, and get the expression of interfacial shear stress, slip and CFRP slab axial force. Temperature and humidity separately evaluated residual stress analysis of structures under the action of. Calculate and analyze residual stress analysis of reinforced structures under the separate action of temperature and humidity2) Use finite element software to take simulation and study on the Interfacial bond properties of NSM-CFRP reinforced concrete, establish finite element model of reinforced specimen, analyze the distribution of interface bond stress and slip; and get the load-slip relationships of the bond interface end and the ultimate bearing capacity of reinforced specimen.3) Use thermal analysis software module to seperately analyze changes and distribution along the bonding surface of interface residual stress of the reinforced specimens under the temperature and humidity, and analyze changes of ultimate bearing capacity of the specimens with time under hot and humid environment. Given the hot and humid conditions, analyze the influences of CFRP Strip thickness, material modulus of elasticity and groove depth to width ratio on bond stress. The results showed that the groove depth to width ratio have greatest impact on the bonding properties, CFRP Strip thickness and modulus, elastic modulus of epoxy resin are second, and elastic modulus of concrete can be neglected.