Interfacial Fracture Toughness of Concrete Repair Materials

Application of any repair material results in between the repair material and the existing material the repaired structure. Due to defects on the interface, and shrinkage and/or thermal loading, interface failure can limit the performance the repaired system. Such failure can take the form of delamination or spalling of the repair material. Several tests are currently used to quantify the performance of concrete repair material, all of which tensile or shear bond strength of the interface. These tests cannot be expected to have predictive capability in durability of repair systems field. Recent development of the theory interface fracture bimaterial interfaces suggests techniques for proper characterization of interface properties in repair systems. In this paper, experimental results of interface toughness substrate concrete with several repair materials are reported. Interfacial fracture toughness is presented as a function a ratio of opening versus shear mode of loading. studied include ordinary concrete, fiber reinforced concrete, quick-setting highway patch material. 1329 1 As infrastructure around the world ages, the rehabilitation of existing structures to extend the service life of the facilities becomes more important (Mailvaganam, 1992; Allen et al, 1993). Many repair materials and techniques have been specifically developed for concrete repair aimed at providing strong, longer-lasting repair at low cost. evolving innovative materials and techniques, many outstanding repair problems remain (Warner, 1994). In many cases, the repaired structure still fails in the repair part, around the repair part, or at the interface between newly applied and existing material (Emmons, 1994). In particular, failure as a result of cracks initiated at interface could be found in many repaired structures.