Short-Term Effect on Mechanical Strength and Water Absorption of Concrete Containing Palm Oil Fuel Ash Exposed to Chloride Solution

Abstract

This study emphasises the short-term effects of mechanical strength and water absorption of concrete containing palm oil fuel ash (POFA) that is exposed to chloride solution compared to concrete exposed to normal water. The replacement of cement by POFA in concrete is one of the efforts to produce green concrete as well as to maintain environmental sustainability as the POFA always disposed of without any positive benefits. The POFA obtained from the mill was dried and sieved using 300 µm sieve. The volume of 10%, 20% and 30% of cement were replaced by POFA with the same level of replacement. Hardened concretes were cured under normal water and 3.5% chloride solution until 28 days, respectively. Fresh concretes were tested by slump test while hardened concrete underwent compressive strength test, flexural strength test and water absorption test at the age of 7 and 28 days. By using the same w/b ratio, it was found that concrete workability and performances decreased with the increases of POFA replacement for both types of exposure. For short term effects, control concrete that exposed to chloride solution was found to have the highest chloride exposure with no deterioration as it achieved the highest compressive and flexural strength than control concrete exposed to normal water. The lowest percentage of water absorption also recorded by control concrete exposed to chloride solution. The overall results of the study found that increment of the percentage of POFA replacement with cement in concrete resulted in consistently decreased of compressive and flexural strength within 7 and 28 days. However, concrete containing 10% replacement of POFA was observed as having the potential as it achieved more than 80% compressive and flexural strength compared to control concrete exposed to water and chloride solution. Furthermore, it had a good percentage of water absorption.