Effect of seawater on compressive strength of concrete cylinders reinforced by non-adhesive wound hybrid polymer composites

Seawater absorption in concrete structures can be a serious problem in humid and marine environments. It was demonstrated that non-adhesive (separated by aluminum foil) filament wound tubes could better reinforce concrete cylinders. Furthermore, composites have ever proved to be resistant to detrimental environment. Therefore, in this study four kinds of non-adhesive composite materials are used to reinforce concrete cylinders, and then composite/concrete systems are subjected to six environmental conditions. The composites include hand-wrapped woven cloth glass/epoxy, filament wound glass/epoxy, glass-kevlar-glass hybrid, and glass-carbon-glass hybrid. These allow comparing reinforcement effect from various processing methods, fibers, and interface. The six environmental conditions consist of soaking in live or dead seawater, soaking before or after winding, and air aging before or after winding. The first and second conditions can verify the accuracy of the experiment in laboratory (dead seawater) without bothering to test near coast (live seawater). The third to sixth conditions can provide a good designing criterion regarding what the best sequence is for reinforcing seawater or air attacked concrete structure by composites.