Compressive Strength of Composite/Concrete Cylinders after Low Energy Impact

Abstract

This paper deals with the repair of the concrete cylinder by fiber reinforced composites fabricated through the filament winding method. Composites fabricated by the method can reinforce concrete cylinders efficiently because they provide comprehensive and multi-axial reinforcing effects. In this work, three winding angles were adopted to wind six layers of glass/epoxy composite jacket onto the concrete cylinder. These three winding angles combined with different lay-up sequence form seven types of composite/concrete cylinders. The compression after impact (CAI) test was conducted on the seven composite/concrete cylinders. These experiments were designed to investigate the influence of winding angles and lay-up sequence of the composite on the CAI strength. It is found that the highest CAI strength among the composite wound concrete cylinder is 4.81 times higher than that of the concrete cylinder without the reinforced composite. In addition, the former has higher failure strain than the latter. The impact resistance can be evaluated by a compression after impact/compression before impact (CAI/CBI) strength ratio. It is also detected that although impact damage has been introduced, the fracture of composite/concrete cylinder under compression may not be initiated from the impact site. Moreover, the failure strengths are influenced by damage mechanisms of the cylinders, and the damage modes for the concrete cylinder and wound composites are related. In this paper, the damage mechanisms of different wound concrete cylinders under CAI test were discussed.