Experimental Investigation into Lightweight High Strength Concrete with Shale and Clay Ceramsite for Offshore Structures

To develop lightweight high-strength concrete (LWHSC) for offshore structures in a harsh seawater environment, LWHSC with shale and clay ceramsites was designed. LWHSC was experimentally investigated in terms of density, compressive strength, and durability in a coastal environment. Then, its feasibility for offshore structures was also assessed. The results show that the compressive strength and oven dry density of LWHSC appropriately improve with increases in cement content, while they are reduced by the replacement of shale ceramsite with clay ceramsite. The compressive strength of LWHSC also increases first and then decreases with an increase in the pre-wetting of shale and clay ceramsites. Their optional pre-wetting time is about 0.5 h. LWHSC exhibits a higher brittleness compared with conventional concrete. LWHSC has increases in the resistances of freeze–thaw, carbonization, water penetration, and chloride penetration when the shale and clay ceramsite light aggregates decrease in the concrete. The LWHSC prepared in this paper is suitable for the harsh seawater environment of offshore oil platforms but is limited to the southern region where there is no requirement for the freeze–thaw resistance of concrete. The results of this study can provide some reference for the application of LWHSC in offshore structures and other similar aspects of engineering.