Preliminary investigation of artificial reef concrete with sulphoaluminate cement, marine sand and sea water

To promote the extensive application of artificial reefs, developing a type of economical and low-alkaline artificial reef concrete (ARC) where marine organisms can grow quickly is necessary. A grade C30 ARC with sulphoaluminate cement (SAC), sea water and marine sand is proposed. The workability, mechanical properties, surface pH and microstructure (scanning electron microscopy (SEM), X-ray diffraction (XRD) and pore structure) of this ARC were studied. The influences of the cement type (ordinary Portland cement (OPC), SAC and a mixed SAC and OPC cement), water type (freshwater and sea water) and sand type (river sand and marine sand) on the properties of ARC are discussed. In terms of the mechanical properties and surface pH of ARC with sea water and marine sand, SAC performed better than OPC. However, a mixed SAC and OPC cement had significantly negative effects on the workability and mechanical properties of the sea water and marine sand-based ARC. Marine sand and sea water displayed positive effects on the mechanical properties but no obvious effects on the surface pH of SAC-based ARC. Compared to ARC with OPC, river sand and freshwater, the proposed ARC has superior mechanical properties, a better microstructure, a lower surface pH and a lower cost. (C) 2019 Published by Elsevier Ltd.