Studies on Durability Performance of Concrete Under Marine Environment Incorporating Metallic Slags as Sand Replacement

Abstract

An investigation was carried out to examine the aggressive effects of seawater on concrete specimens. The concrete specimens were prepared by partially replacing fine aggregates (0% to 50%) from copper slag (CS) and processed granulated blast furnace slag (PGBS) and subjected for 7, 28, 56, 90, 180, 270 and 365 days of curing. Compressive and splitting tensile strength tests were conducted at different ages after immersion in both fresh and seawater. Durability tests for chloride attack, sulphate attack, and sodium were conducted using the toxicity characteristic leaching procedure (TCLP) method. Test results revealed that the compressive and splitting tensile strength of CS and PGBS concrete cured in seawater was higher than that of cured in freshwater. Also, the concentration of chloride and sulphate ions of CS and PGBS concrete were lesser when compared to the control mix. Scanning electron microscope (SEM) analysis of specimens showed that the PGBS and CS concrete showed a denser ITZ at latter ages which may be due to the additional C-S-H formed from the hydraulic reaction of the slag aggregates. Present study shows that more durable and sustainable concrete can be designed for marine applications by partial incorporation of suitable low-cost and eco- friendly alternatives in contrast to natural fine aggregate (NFA- river sand).