Effects of Salt Water on the Compressive, Flexural and Split Tensile Strength on Reinforced Concrete using Seawater from Badagry Beach

This study investigated the applicability of seawater as an alternative to freshwater in concrete mixing and curing for construction, addressing the growing need for sustainable water resources. This was done by examining the impacts of seawater on the compressive, flexural, and split tensile strengths of fresh and hardened concrete. Seawater samples from Suntan Beach, Badagry, Lagos State, were characterized at Central Research Laboratory of Bells University of Technology. Cement and aggregate tests were conducted at Structures and Materials Laboratory of the same university. Casting and curing of concrete specimens using both freshwater and seawater were done in four phases such as Freshwater (FF), Freshwater/Seawater (FS), Seawater/Freshwater (SF) and Seawater/Seawater (SS), with strength measurements taken at 7, 14, and 28 days. Seawater characterization results showed significant presence of salts and oxides. Slump test results showed seawater reduced workability of concrete compared with freshwater. Results of compressive and flexural tests at 28days ranged between 19.26 and 20.74 Mpa (SS and SF), while split tensile values were 3.1 for FS and 5.1 Mpa SS respectively, at 28days. The study concludes that seawater had negative effects on compressive and flexural strengths, but positively affected flexural strength.