Evaluation of organic enhancer on the mechanical properties of periwinkle shells concrete

Abstract

The utilization of green materials in engineering applications has become a necessity due to the negative environmental and health consequences of most synthetic materials. Enhancement of periwinkle shell concrete through corn starch treatment was investigated in this study. Twenty-five (25) sets of concrete were produced with various corn starch concentrations (0, 0.5, 1, 1.5 and 2%); and periwinkle shell quantities varying from 0 kg (0%) to 2 kg (20%) were used as a partial replacement for granite. All the concrete sets produced and their mechanical properties were determined in accordance with ASTM (American Society for Testing and Materials) International standards. Statistically, the results revealed that corn starch and periwinkle shells had a significant (p≤0.05) influence on the concrete mechanical properties. The slump results revealed that the periwinkle shell hindered the concrete’s workability, as the slump decreased non-linearly as the periwinkle shell substitution increased from 0% to 20% (per weight of the granite). Contrary, the corn starch enhanced the concrete workability, as the slump increased from 0.0 mm to 48.17 mm, as the corn starch concentration increased from 0% to 2%. Furthermore, it was observed that concretes incorporated with corn starch developed higher density, compared to the concrete produced without corn starch; while the concrete density declined non-linearly, as the periwinkle quantity increased from 0 to 2 kg. Regarding the compressive strength, findings revealed that the compressive strength of the concretes declined from 32.03 to 10 MPa, as the periwinkle shell substitution increased from 0 to 2 kg; though concretes treated (incorporated) with corn starch developed higher compressive strength, compared to the untreated concrete. The results indicated that the incorporation of corn starch as a workability enhancer; with smaller quantities of the periwinkle shell (5% - 15% as coarse aggregates) can be utilized to produce lightweight concrete for engineering applications.