EXPERIMENTAL EVALUATION OF ALTERNATIVE MIX WATER FOR CONCRETE: CASE STUDY OF SEAWATER AND LABORATORY BRINE

Abstract

This paper presents a comparison of seawater and laboratory brine on concrete using experimental methods. The seawater employed was obtained from Escravos in the coast of Atlantic Ocean in Nigeria. A concrete mix of 1:2:4and water/cement ratio of 0.6 was adopted. The cube samples measured 150mmx150mmx150mm. The samples were cured in potable water for a period of 7, 14, 21 and 28 days at 24⁰C.The seawater and laboratory simulated saltwater contained an equal amount of salt ion concentration. The laboratory saltwater was prepared with an analytical grade sodium chloride salt. The concrete cubes cast with potable water had a 28 days compressive strength of 33.48 N/mm², concrete cubes cast with the seawater had a compressive strength of 31.04N/mm², while the laboratory brined concrete cubes had a compressive strength of 25.26N/mm². The results showed that the laboratory prepared salt water samples had the least compressive strength. Compared with the control samples, there was a strength reduction of 7.29% and 24.55% in the compressive strength of the seawater and laboratory saltwater samples respectively. Comparing the concrete cubes made with seawater with that of laboratory brined samples revealed a reduction of 18.62% in compressive strength of the laboratory brined concrete. Seawater therefore has a lesser reducing effect on the compressive strength of concrete than brine. Seawater is currently in use for mixing structural concrete in the Niger Delta region of Nigeria where portable water is not easily available.

http://dx.doi.org/10.4314/njt.v34i3.6