Evaluation of cracking and deflection of GFRP bar reinforced recycled concrete beams with seawater and sea sand

In this paper, the feasibility of glass fiber reinforced polymer (GFRP) bar reinforced recycled concrete beams with seawater sea sand was investigated. A four-point flexural test was carried out, and the Digital Image Correlation (DIC) technique was applied to measure strain and deflection of beam at the same time. The cracking load was calculated and compared with the test data, and the deformability and instantaneous stiffness were also calculated as a further supplement to the evaluation of the service performance of the beams. The test results showed that the crack development and failure pattern of the GFRP bar reinforced recycled concrete beams with seawater and sea sand (SSRAC beams) did not change significantly compared with the steel reinforced concrete beams, but became more ductile due to sea sand. The overall deflection of the beam reinforced with GFRP bars increased but was still within the allowable range of the current code (ACI 318-05 and GB 50010-2010), but the cracking load decreased significantly. There was no significant difference in the performance of beams using various fine aggregates in most cases. However, the excessive amount of shell particles had the potential to change the failure patterns and deformability factors of the beams. Overall, there was no significant degradation in the serviceability of SSRAC beams reinforced by GFRP bars.