Detection of slip for CFRP-concrete interface using stereovision method corrected by epipolar constraint

The bond-slip relationship for the interface between concrete and carbon fiber reinforced polymer (CFRP) has become a hot research topic. Aimed at the disadvantage of traditional measurement approaches, a stereovision method corrected by epipolar constraint is proposed to measure slip curves of CFRP-concrete interface in the present paper. The proposed stereovision measurement method employs the epipolar constraint to correct digital image correlation (DIC) matching result. The nearest point located on the right epipolar line to DIC matching result is chosen as the new matching point on the right image. Furthermore, this correction method is extended to the sequential matching of right images. The precision comparison test and the detection test of slip for CFRP-concrete interface are performed on the universal testing machine. Results of the precision comparison test show that the proposed stereovision method can improve the measurement accuracy. Experimental results of slip detection of CFRP-concrete interface show that the displacement curves obtained by the proposed stereovision method are in good agreement with that of the linear variable differential transformer (LVDT); this manifests the effectiveness and reliability of the proposed stereovision method, indicating that the proposed stereovision method can be used to measure the entire slip curves of CFRP-concrete interface.