Effect of acid on strength of concrete made with coconut shell as aggregate replacement

Abstract

This paper presents the results of experimental investigation carried out to study the effect of acidic environment on concrete made with coconut shell (CS) as a partial aggregate replacement, in which the natural coarse aggregates were replaced with 0%, 10%, 20% and 30% CSby volume. To study the performance of CS concrete in acidic environment, compressive strength test at 28 days before immersion in acid, weight loss assessment after immersion in acids at interval of 3 days and compressive strength loss assessment after immersion in 3% hydrochloric acid (HCl) and sulfuric acid (H₂SO₄) mediums for 27 days were carried out. The results indicated that Coconut shells maybe viable for use as apartial replacement to aggregate in concrete. But when subjected to strength tests after immersion in both HCl and H₂SO₄ acidic environment they did not perform well, as theircompressive strength and weight decreased with increase in CS replacements. The losses are higher in the H₂SO₄ medium than in HCl medium. The use of coconut shells in concrete should be avoided in aggressive environments.