A Detailed Investigation of the Bond Performance of Basalt Fiber-Reinforced Polymer Bars in Geopolymer Concrete

This comprehensive experimental study aimed to determine the bond performance of basalt fiber reinforced polymer (BFRP) bars in geopolymer concrete (GC). The study examined the bond performance of BFRP bars and GC by considering several parameters, including bar diameters of 8, 10, and 12 mm, embedment lengths of 4, 8, and 12 db mm (where db is the diameter of the bar), concrete covers of 20, 40, and 70 mm and compressive strengths of 21.7 and 34.4 MPa. The study also compared the effect of the bar surface and bar type on GC bond performance. Eventually, the results were compared with ordinary concrete (OC). The obtained results indicated that an increase in the BFRP bar diameter results in a decrease in the average bond stress. Similarly, an increase in the length of the bond leads to a reduction in the bond stress. The specimen possessing a short embedment length failed due to bar pullout, while the specimens with a longer embedment length failed as a result of concrete splitting. The outcomes also showed that the strength of bond increases with an increase in compressive strength and cover thickness. Furthermore, the results also indicated that BFRP-reinforced GC has comparable bond performance to steel-reinforced GC and BFRP-reinforced OC and performed better than OC. Last, Comparisons between the existing bond-slip models were offered to demonstrate the best bond stress-slip model for FRP bars and GC for ascending branch up to ultimate bond stress of the bond slip curves and for whole curves