Effect of Alternate Wetting and Drying on some Properties of High Strength Concrete in Tropical Coastal Environments

Abstract

Concrete is one of the most used construction materials in the world, due to its good durability and fire resistance properties, versatility in forming various shapes, abundance of raw materials and low manufacturing and maintenance costs. High strength concrete, which is a type of concrete, finds its application in construction of high rise buildings, bridges, highways, etc. Its physical properties are greatly affected by the method of curing and the environment in which it is placed. This study investigated the effect on the compressive strength and some transport properties of high strength concrete subjected to alternate wetting and drying exposure, which may be due to intermittent rains, or rise and fall in tides of the sea, an exposure type that is commonly experienced in coastal areas. High strength concrete samples were prepared and subjected to two different curing regimes, one in which the concrete samples were cured continuously under water, and the other in which the concrete samples were subjected to 12-hr curing under water followed by 12-hr curing under ambient air. Various tests such as ultrasonic pulse velocity (UPV), compressive strength, water and chloride ingress tests were conducted on the cured concrete samples. The results obtained from the tests conducted, generally showed that the strength and transport properties of the high strength concrete was greatly affected by the alternate wetting and drying curing method. The effect was seen to be more adverse at the later ages than at the early ages.