Bond of corroded reinforcement in strain resilient cementitious composites

Abstract

Abstract In corroded steel anchorages, radial pressures generated by corrosion and bond are balanced by hoop tension provided by the concrete cover. As the concrete has negligible tension strain capacity, in the absence of confinement, anchorage failure occurs by cover splitting and consequent bond deterioration. This paper presents an experimental study of short reinforcement anchorages embedded in a strain resilient cementitious composite matrix, which were preconditioned under simulated corrosion before mechanical loading. The experiment was meant to assess the restraining effect of randomly dispersed plastic fibers on the build-up of expansive rust, by measuring the degree of rebar corrosion that led to cracking of the concrete cover, and the consequent improvements in residual anchorage capacity, by measuring the mechanical response to four-point loading. A total of eighteen short beams were tested with variables being the anchorage length extending into the shear span of the beams as well as the matrix (with and without fibers). Comparisons among artificially corroded and non-corroded coupons demonstrate the favorable effect a strain resilient matrix has in delaying metal consumption as a consequence of the fibers’ restrain against crack initiation/widening; their mechanical testing reveals even increase of local bond strength for corrosion level less than 10%.