Long-term exposure of RC columns immersed in seawater or crude oil confined with CFRP fabrics under monotonic or cyclic loading

A combination of fiber reinforced polymer (FRP) and concrete subjected to seawater or crude oil is a desirable solution to reduce resource shortage and environmental issues. In current decades, numerous investigations have considered the utilization of FRP composites as a way for concrete confinement. Such composites have been typically limited to wrapping concrete columns at ambient temperatures. This raises the question of whether such composites can be utilized in some other applications. For that reason, the effectiveness of carbon fiber reinforced polymer (CFRP) wrapped concrete under seawater or crude oil exposure for 90 days and 720 days long-term impacts at ambient temperature concentrations have been tested experimentally. To accomplish this objective, 16 column specimens were prepared and tested. The impacts of exposure conditions, exposure time, loading type, and CFRP thickness were examined. Although it is evident that control columns' load-bearing capacities are reduced when immersed in seawater or crude oil, there is a noticeable improvement in load-bearing capability for columns immersed in seawater for a prolonged period of time for 720 days compared to those immersed in crude oil for the same amount of exposure. The strength of the confined control column and the columns submerged in seawater or crude oil significantly improved as compared to the unwrapped column without soaking in seawater or crude oil under monotonic or cyclic loading. The results of the experiment and the available design-oriented strength models can encourage the widespread use of FRP confined seawater or crude oil concrete in artificial islands and offshore structures. It was determined that these models are insufficient for predicting the strength of RC columns that had been submerged in seawater or crude oil and then encased in CFRP confinement.