Full-Field Displacement and Strain Measurements for Debonding Test of SMPM Laminates Using ESPI

This paper presents the full-field displacement and strain measurements in the debonding tests of steel stranded wire mesh and polymer mortar (SMPM) laminates bonded to concrete, in which the electronic speckle pattern interferometry (ESPI) with four-phase shifting technique is used. The in-plane displacements of SMPM laminates are obtained by measuring the changes in phase patterns due to deformation. Derivation of displacements resulted in strains. The propagation of interference fringes and the characteristic of strain distributions are recorded and analyzed. It is concluded that the ESPI, being a whole-field non-contacting optical method, is suitable for the study of debonding mechanism of composites. However, the rigid body motions of test specimens should be strictly restrained. The strain distribution on the surface of SMPM laminates is different from that of the well-used fiber reinforced polymer (FRP) laminates, and the position of transversal stranded wires has a significant influence on the strain distribution and the debonding load. Results of this study can be used for developing the interfacial bond-slip relationship of SMPM laminates bonded to concrete.