Study on the axial compressive behavior of FRP-confined seawater sea-sand concrete

The rapid industrial development has led to a global shortage of fresh water and river sand. A promising solution involves using seawater and sea-sand as alternative raw materials to produce seawater sea-sand concrete (SSC), and using fiber-reinforced polymer (FRP) owing excellent corrosion resistance as confinement material to produce FRP-confined SSC with reasonable performance. This study aims to investigate the axial compressive behavior of FRP-confined SSC experimentally and evaluate the existing predictive models. A total of 48 short columns and 48 standard cubes were tested. The studied parameters in the experiments covered the type of concrete as well as the type and thickness of FRP. The test results indicated that concretes incorporating seawater exhibited higher early-age strength but comparable 28-day strength to normal concrete; under the same FRP confinement condition, different types of concrete showed similar behavior, including dilation performance, axial stress-strain response and ultimate condition. It can be deduced that seawater and sea-sand substitutions have negligible influence on the performance of FRP-confined concrete. Moreover, a database including existing FRP-confined SSC specimens was established and used to evaluate the applicability of existing analysis-oriented models for FRP-confined SSC. The results showed that the model developed by Jiang and Teng demonstrates the highest predictive accuracy.