Study on mechanics and water transport characteristics of sea-sand concrete based on the volume analysis of each solid composition

Abstract

As potential building sand, siliceous sea-sand and coral sand had unique physical and chemical properties compared with river sand. In order to study the effect of siliceous sea-sand and coral sand on the mechanics and water transport characteristics of concrete, the mechanical properties (including compression strength and dynamic modulus), water absorption and pore distribution of seawater and siliceous sea-sand concrete (SSC), coralaggregateseawaterconcrete (CASC) and tap water and desalted siliceous sea-sand concrete (DTC) were studied. The influence of volume ratio and pore volume ratio of each solid composition in concrete on the mechanics and water transport characteristics of concrete was investigated.Coral sand had larger porosity and better pore connectivity, so CASC had smaller mechanical properties and density than SSC and DTC, and also had greater water absorption. Since SSC had more salt crystals formed in macropores, the cement paste of SSC were more compact than that of DTC, and SSC had larger mechanical properties and smaller water absorption than DTC. The chemical properties of mixing materials were the main factors influencing the phase and microstructure of cement paste, which could affect the mechanical properties and water absorption of concrete. The material properties of fine aggregate directly affected the mechanical properties of concrete. However, the water absorption of concrete was related to the pore distribution, but not directly related to other properties of fine aggregate. Coarse aggregate was the main carrier for the mechanical properties of concrete, and cement paste also had some influence on them. The main water transport channel of concrete was the pore of cement paste, and the pore of fine aggregate was the auxiliary water transport channel.