Near Surface Embedded Application for FRCM Strengthening of RC Beams in Flexure

Abstract

In this paper, the efficacy of a recent strengthening technique, referred to as Near Surface Embedded (NSE), has been investigated for flexural strengthening of Reinforced Concrete (RC) beams using Fabric Reinforced Cementitious Matrix (FRCM). The process of applying NSE-FRCM strengthening technique involves removing the concrete layer at the beam's soffit (being the most deteriorated), which is then replaced by the FRCM composite. In this study, seven RC beams were constructed and tested under four-point loading considering two test variables, namely, (a) FRCM material (Polyparaphenylene Benzobisoxazole (PBO)/carbon/glass), and (b) strengthening configuration (NSE/ Externally-Bonded (EB)). Amongst the three FRCM materials, the PBO-FRCM system offered the highest strengthening effectiveness (i.e., highest gain in the load carrying capacity). The average gain in the load-carrying capacity was 45% and 58% for the NSE- and EB-FRCM strengthened beams, respectively, compared to the reference (i.e., non-strengthened) specimen. Nonetheless, the results showed a clear advantage for NSE-FRCM strengthening systems over those externally bonded in terms of ductility performance. The advantage of NSE over EB strengthening was also demonstrated by the improved FRCM/concrete bond associated with NSE-FRCM application