104 / 2022-04-22 11:58:50

Hydration and mechanical properties of seawater and sea sand cement-based materials

seawater and sea sand,Hydration,mechanical properties

It is very easy for the corrosive ions in seawater to invade concrete to cause the corrosion and deterioration of reinforcement, while the fly ash (FA) and LC2 have been proved to be effective in improving the properties of concrete such as pore structure and compactness.Although the mechanical properties of cement mixtures blended with LC2 have been explored, there is still a lack of understanding of the influence mechanism of fly ash mixed with sea water and LC2 cement paste on the comprehensive properties.In this study, NMR, XRD, TGA, MIP, SEM and other advanced technologies were used to study the effects of mixing LC2/FA and seawater on hydration, mechanical properties and microstructure of cement slurry at different curing ages.The results show that seawater can promote the early hydration of cement and make the heat release of cement paste higher in the early hydration.The combined use of seawater and LC2/FA reduces the heat release from hydration.LC2 improves the compressive strength of the cement paste by refining the pore structure without changing the total porosity.Seawater can significantly improve the early compressive strength of the mixture.The combination of LC2 and sea water improves the early and late strength of cement slurry, while the combination of fly ash and sea water reduces the early strength of cement slurry, but with the growth of curing age, the late strength of cement paste is obviously improved.The hydration products of LC2-doped cement paste are C-S-H gel, calcium hydroxide, ettringite, carboaluminate and hydroaluminite.The interaction of seawater and LC2 promotes the formation of calcium aluminate hydrate.The study evaluated the feasibility of mixing LC2 and seawater into concrete designs.