Long-term durability of concrete made with slag cements under marine environment

Durability of concrete in seawater is a key concern related to the development of sustainable infrastructures in the marine environment. For verification of durability performance of concrete made with slag cement in seawater, three different series of concrete specimens were investigated at the end of 10, 15, and 30 years of marine tidal exposure. Physical appearance, compressive strength, carbonation depth, concrete resistivity, chloride ingress, microstructures, mineralogy, corrosion of steel bars in concrete, and interfaces of concrete were evaluated. Compared to ordinary portland cement (OPC), a tendency of more long-term strength gain is found for slag cement. The microstructure of concrete located at the outer region of the samples made with slag cement becomes denser after a long-term marine exposure, which prevents chloride from entering into concrete at a greater depth. Slag cement shows the best performance against chloride ingress and corrosion of steel bars in concrete.