Investigation of Bond between Concrete and Composites: Use of a Peel Test

Composites present considerable potential for use in civil infrastructure applications. One such application is that related to the strengthening of concrete structural elements through the external bonding of composite plates or wraps. Two major concerns in the use of the plating technique are the debonding or peeling of the plate from the concrete surface and the effect of environmental factors on the durability of the compositeconcrete bond. Interfacial crack propagation could actually proceed due to a number of reasons including imperfect bonding between the composite and concrete, debonding initiating due to flexural cracking in concrete, peel stresses due to non-uniformities on the concrete surface and fatigue initiated debonding. Further investigations into mechanisms of peel and the characteristics of the composite-concrete interface during debonding/peel are thus critical to understanding both design requirements and long-term use potential of composite plates as a means of rehabilitation of concrete-based infrastructure elements. The focus of this paper is on the development of an appropriate peel test for the investigation of bond between composites and the concrete surface. It also develops a methodology for the understanding of the different mechanisms and modes of interfacial fracture.