Development of Reinforcing Bars in SRCC Matrix: Modeling and Interpretation

Abstract

Experiments on deformed reinforcing bar anchorages developed in strain-resilient cementitious composites (SRCCs) with high tensile deformation capacity illustrate that the bar-matrix assembly may respond in a ductile manner marked by pullout failure with no cover splitting—even in the absence of external confinement. This ductile bond-slip response is owing to the extremely high tensile fracture energy of the matrix, which is attributed to the reinforcing action of the dispersed microfibers in the cementitious matrix. This enhances the associated bond-slip law with higher strength and a slowly descending branch, very similar in form to the response curve of confined anchorages that demonstrate ductile, resilient response. To understand and model the structural response of an elastic bar anchorage in a SRCC matrix, the analytical solution of the field equations that govern the bond problem are established with reference to the entire range of the bond-slip law up to large levels of slip, including the postpeak descending branch, which quantifies the fracture energy of the matrix. The accuracy of the mathematical solution is verified through correlation with laboratory evidence, benchmark finite-element analysis examples, and numerical solutions of the discretized problem. The mathematical solution is used in order to conduct a parametric investigation that accounts both for the bond toughness and the anchorage geometry, to illustrate their significance as prerequisite for development of high-strength reinforcement.