Long term performance of fly ash concrete under marine water

Abstract

The objective of this study is to ensure the suitability of marine water for mixing and curing of concrete in place of potable water to meet challenge of potable water scarcity on planet Earth. Four concrete grades viz., M20, M25, M30 and M35 using ordinary portland cement (OPC) of 53 grade of 75% and class - F fly ash of 25% with a slump of 100 mm to 150 mm were considered. The design mixes prepared were categorized as “potable water mixing and potable water curing (PP)”, “potable water mixing and sea water curing (PS)” and “sea water mixing and sea water curing (SS)”. The specimens were cured for 7, 28, 90 and 180 days of curing to study the compressive strength behavior, modulus of rupture and flexural tensile strength. The reference concrete as normal concrete was prepared without blending fly ash but with corresponding mix proportions and curing conditions. The study reveals that the compressive strength of normal and fly ash concretes up to 180 days of curing under sea water for M20, M25 and M30 grades of concretes were more than the respective target strengths. The splitting tensile strength of M20 grade fly ash concrete in all curing conditions were higher than the M20 grade normal concrete while the flexural strengths of M20, M25, M30 and M35 grades of fly ash concrete in all curing conditions were higher than those of normal concrete.