Investigating the influence of cassava starch as admixture in concrete using two brand of cement subjected to aggressive environment

Abstract

This study investigated the influence of cassava starch as an admixture in concrete produced using two brands of cement and subjected to aggressive environmental conditions. Concrete specimens were produced using a standard mix ratio of:1:2:4 with a water-cement ratio of: w/c=0.50, Cassava starch was introduced into the concrete mixes at varying percentages of: 0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%.Two different cement brands were used to determine the compatibility and performance of cassava starch with varying cement compositions. The concrete specimens were subjected to aggressive environmental conditions including sulphate, chloride, and acidic exposure in order to assess durability performance. The findings of the study indicated that cassava starch significantly influenced the properties of concrete. The workability of fresh concrete improved as the percentage of cassava starch increased due to the water-retention and thickening characteristics of starch. The compressive strength of concrete also improved with increasing starch content up to an optimum level of approximately 2% by weight of cement. At this percentage, the concrete achieved the highest strength values due to improved bonding and reduced permeability. However, excessive starch addition beyond the optimum level resulted in a slight reduction in compressive strength because excess organic material interfered with cement hydration. The durability assessment revealed that concrete containing cassava starch exhibited better resistance to sulphate, chloride, and acidic attacks compared to conventional concrete.. However, both cement brands responded positively to the addition of cassava starch at optimum dosage. The study therefore confirmed that cassava starch can serve as a useful natural admixture for improving concrete performance and durability under aggressive environmental conditions.