Effect of shrinkage‑controlled polymer‑modified binders (SC‑PMB) on the bond strength of repaired structural concrete

摘要

Concrete structures get damaged over time, due to being subjected to various environmental exposures, improper design, management, and poor material durability. Portland cement mortars have been used as a repair material; however, it is both uneconomical and not eco-friendly due to high embodied carbon. Recently, polymer-modified binders have gained interest for their application in the repair of concrete structures. This research investigated the effectiveness of shrinkage-controlled polymer-modified binders (SC-PMB) in improving the bond strength of repaired structural concrete. The efficiency of the SC-PMB was investigated by performing a splitting tensile strength test on a concrete specimen prepared at two different mix ratios, i.e., 1:2:4 and 1:1.5:3 with 0.55, 0.50, and 0.475 water-cement (w/c) ratio. The fractured concrete samples were repaired with cement mortar (CM), cement paste (CP), polymer mortar (PM), and polymer paste (PP). It was observed that structural concrete repaired with polymer binders (PM and PP) showed greater performance in improving bond strength in tension. Particularly, structural concrete repaired with PP presented 100% higher bond strength values in tension compared to CP, PM and CM.