Abstract:
In this study, a new grouting composite, called geopolymer grout, with high compressive strength (> 107 MPa, cured at ambient conditions) was developed and injected into damaged reinforced concrete (RC) beam. This investigation was planned in two steps: (1) determination of optimum geopolymer grout composite depending on viscosity, compressive strength, and SEM findings; (2) injection of optimum geopolymer grout to damaged RC beam. Geopolymer grouts were fabricated with different NaOH concentrations (i.e., 8, 10, and 12 M) and Ca(OH)2 contents (1, 3, 5 and 7% of slag weight). A remarkable advance in fresh and hardened characteristics of geopolymer grouts was acquired with changing of NaOH concentration and Ca(OH)2 content. A reference RC beam was subjected to bending test and the load–displacement curve was obtained. The determined optimum geopolymer grout was injected into this damaged RC beam and exposed to reloading test. The strengthened RC beam specimen was compared with reference RC beam in terms of failure modes, load capacity and crack patterns. After damaged RC beam was strengthened, it showed higher mechanical performance compared to reference RC beam. The experimental findings revealed that geopolymer grouts could be a suitable alternative for repair and strengthening of damaged RC beam due to their low viscosity, eco-friendliness, good bonding and superior compressive strength. © 2022, Iran University of Science and Technology.