Fiber Pullout and Bond Slip. I: Analytical Study

This is the first of a two‐part paper involving a fundamental study of bond in fiber‐reinforced cement composites. The concept of a relationship between the bond shear stress and the local slip at the interface between the reinforcement and the matrix for fiber‐reinforced, cement‐based composites is relatively new. Moreover, the difficulties involved in conducting strain measurements on short discontinuous fibers have made it impossible so far to develop experimental bond shear stress versus slip curves for fiber‐reinforced concrete. This paper involves a fundamental study of the bond‐stress‐slip relationship between steel fibers and concrete. The analysis consists of a primal problem, whereby a complete pullout curve is predicted from an assumed bond‐slip relationship, and a dual problem in which the bond‐slip relationship is obtained from an experimental pullout curve. The frictional behavior of the interface is also related to and explained by the shrink‐fit and fiber‐matrix misfit theory. The theory derived in this paper is validated in a second paper using experimental pullout load versus slip curves.