Effect of Used Cooking Oil on the Characteristics of Concrete including Gap-graded Aggregate

Abstract

Due to large amounts, more than one billion gallons, of used cooking oil which are produced yearly, there is a need to carry out the sustainability for construction materials. This study aims to investigate the effect of Used Cooking Oil (UCO) on the fresh and hardened properties of concrete using different percentages from this oil with gap-graded aggregate. Ten concrete mixes were conducted in the laboratory for two mixing proportion (1:1.5:3) and (1:2:4) with a constant W/C equal to 0.5. This study is concentrated on the influence of UCO on the compressive strength, splitting tensile strength, flexural strength, density, and absorption. The results demonstrate that noticeable increments in the recorded slump values as the ratio of UCO used in this work raised gradually. Based on the results of compressive strength test, the existence of UCO as an admixture in concrete leads to a reduction in the compressive strength and this reduction increases with the increase of UCO ratio. Other concrete properties including splitting strength and flexural strength, indicated trends are similar to that observed in compressive strength for all proportions of UCO. Regarding to the density and absorption, the presence of UCO as an admixture in concrete leads to slightly decrease in the density for both series of mixes and this reduction increases with the increment in the percentage of UCO. While for absorption, displays increment due to the increase in the UCO proportion.

Keywords: Used cooking oil, slump test, compressive strength, gap-graded aggregate, concrete mix