An Experimental Investigation of CFRP Strengthening Efficiency on the Retrofitted Damaged Geopolymer Concrete Beams

Abstract

In this study, beams produced by geopolymer concrete (GC) with different properties such as compressive strengths, stirrups ratios, and shear-span to effective depth ratio (a/d) were tested up to the failure to attain the load-deflection behaviors. Then, tested damaged beams were retrofitted using Carbon Fiber Reinforced Polymer (CFRP) in both shear and flexure to examine the CFRP strengthening efficiency. A three-point flexural test was conducted on both reference and retrofitted GC beams. According to this study, applying the CFRP strengthening to damaged GC beams increased the load-carrying capacity between 4%- 72%, depending on the compressive strength, stirrups spacing, and a/d with reference to the reference GC beams. The area calculated under the load-deflection graph of the retrofitted GC beams was lower than the reference beams in all tested series. The initial stiffness in the tested retrofitted beams was generally obtained lower compared to the reference GC beams. The deflection capability of the retrofitted beams in the tested series was between 18%-80% lower than the reference beams.