Defects detection in CFRP reinforced concrete structures by digital shearography

Carbon fiber reinforced polymer (CFRP) has gradually become a commonly used repair and reinforcement material in construction and bridges. Due to its excellent mechanical properties, detecting its internal defects is essential. This paper proposes a non-destructive testing system for CFRP reinforced concrete structures based on digital shearography. Thermal loading is selected to test CFRP-reinforced concrete structures. The displacement gradient of deformation is calculated according to the phase image, and the strain variation detects the internal defects of concrete structures strengthened with CFRP. The experimental results show that under the appropriate shear and loading amount, the digital shearography can successfully detect the bonding defects; good results have been achieved with different sizes, depths, and distribution positions, which has excellent theoretical and practical significance for defect detection and control of CFRP strengthened structures.