Microstructure, Hydration, and Chloride Binding Behavior of Limestone Calcined Clay Cement Prepared Using Seawater

Abstract

Limestone calcined clay cement (LC3) is rich in aluminates, which can bind many corrosive ions in seawater. The microstructure, hydration, and chloride binding behavior of LC3 prepared using seawater are investigated in this study. Seawater significantly enhances the compressive strength of LC3 paste up to 28 days and further refines the pore structure of LC3. Correspondingly, the promotion of seawater on the hydration of portland cement (PC) paste begins to decrease after 72 h, although it still promotes the hydration of LC3 paste until 200 h. When LC3 paste is prepared using seawater, about 75% of total chloride ions are chemically bound to form Friedel’s salts at 28 days and 80% of them are formed at 3 days. Moreover, the free chloride ions content in LC3 paste prepared using seawater is 45.2 mg/100 g paste at 28 days, which is only 28% of that in PC paste prepared using seawater and only 6% of total chloride ions. It shows that LC3 has strong chloride binding ability and great potential for preparing seawater concrete.