Effect of admixture on compressive fatigue properties of lightweight concrete underwater

Abstract

Using lightweight concrete, rather than ordinary concrete, for floating structures is expected to reduce costs, mainly due to the reduction of external mooring forces. However, previous studies point out that lightweight concrete has lower fatigue strength than ordinary concrete and that the fatigue strength of concrete decreases when underwater. To investigate whether the admixture helped improve fatigue performance, this study conducted compressive fatigue tests on concretes with several kinds of compositions in air and underwater. It was observed that the underwater fatigue life of lightweight concrete mixed with silica fume and reinforced with steel fiber is about 20–30 times larger than that of ordinary concrete, which has almost the same static compressive strength. Consequently, silica fume and fiber reinforcement effectively improved the underwater compressive fatigue strength of lightweight concrete.