Experimental study on the durability and microstructure of marine concrete covered with barnacles

This paper characterizes the effect of barnacle settlement on the durability and microstructure of concrete. Twenty-seven concrete samples with different coverage areas of barnacles were extracted from a breakwater in the tidal zone of Huangdao district in the Yellow Sea. Durability properties, including the water absorption, chloride ion resistance, chloride ion content, and pH profiles of the concrete were determined, and the micro-structure and pore structure of the concrete were explored to elucidate these durability properties. Results confirm that the settlement of the barnacles could enhance the resistance of the concrete to water absorption, chloride ion penetration and neutralization, and this positive effect is increased as the coverage area of the barnacles expands. The barnacle adhesive at the interface between the concrete and the barnacles has a dense structure and significantly improves the pore structure of the concrete. The shells of the barnacles, barnacle adhesive, and the penetration of the adhesive collectively act as three lines of defense, aid in enhancing the durability of the concrete and then protecting the concrete from the severe marine environment.