Performance of Fiber Reinforced Lightweight and Normal Weight in Simulated Marine Environment

Results of an experimental investigation on the performance of cracked fiber reinforced concrete in a simulated marine environment are presented. A total of 111 prismatic specimens (150x150x510 mm) comprising both lightweight and normal weight concretes were used in this investigation. Cracked specimens with crack sizes of "hairline", 0.25 mm, 1.0 mm, and uncracked specimens were exposed in either simulated seawater for up to a period of 7 years or 5300 alternate wetting and drying cycles. It was found, for both lightweight and normal weight concrete, that the strength development of uncracked specimens is not hampered by alternate wetting and drying. At the end of 7 years exposure, compressive strength gain of 90% was observed over the seven day moist cured strength for both types of concrete. Corresponding uncracked prismatic specimens showed approximately 25% flexural strength gain; however their post-cracking strength decreased under a prolonged period of alternate wetting and drying. Precracked specimens with cracks of up to 0.25 mm showed improvement in load carying capacity up to 1440 wetting and drying cycles. However, specimens with cracks of 1.0 mm showed a reduction in load carrying capacity.