Experimental study on the bond behavior of GFRP bars in normal and self-consolidating concrete

The bond behavior of reinforcing bars is one of the critical issues in the design of reinforced-concrete (RC) structures. This paper sheds light on the effect of various parameters on the bond behavior of spliced glass-fiber-reinforced-polymer (GFRP) bars in self-consolidating concrete (SCC) and normal concrete (NC). A total of 11 full-scale RC beams measuring 4300 mm in length, 250 mm in width, and 400 or 600 mm in height were constructed and tested under four-point bending up to failure. The test parameters included (1) concrete type; (2) splice length (20 db and 40 db, where db is the bar diameter); (3) beam height (400 or 600 mm); and (4) longitudinal-reinforcement type (GFRP or steel). The test results are reported and discussed. In addition, the splice-length predictions using JSCE-97, CSA S806-12, CSA S6-14, and ACI 440.1R-15 were assessed. Furthermore, a recommendation was made to improve the design equation suggested in CSA S6-14. The test results show that the SCC beams exhibited load capacity, crack pattern, failure mode, and load-deflection response similar to their NC counterparts. The bond strength of the reinforcing bars in the SCC beams was similar or slightly lower than that of the NC beams. Moreover, the JSCE-97 provisions gave the highest safety margin.