Statistical analysis and Response Surface Modelling of the compressive strength inhibition of crude oil in concrete test cubes

Abstract

The use of crude oil contaminated fine aggregates in the production of concrete significantly affect the properties of such concrete, especially the compressive strength. In the present investigation, response surface methodology (RSM) of the Design-Expert software version 11.1.0.1 was used for the statistical analysis and predictive modelling of the compressive strength of concrete cubes made from crude oil contaminated fine aggregates at 7, 14, 28, and 56 days curing periods. The fine aggregates were mixed with varying concentrations of crude oil contamination (ranging from 0% to 5% by weight of the fine aggregates, at 1% interval). Concrete test cubes were produced for compressive strength determination and prediction phase of the modelling. A steady reduction in the compressive strength of the concrete cubes was recorded as the crude oil content increases, due to the inhibitive and surface shielding influence of crude oil molecules on the fine aggregates, thereby hindering physical bond formation between the cement paste and the aggregates. Statistical analysis of the output/response was carried out; a correlation coefficient of 0.9923 was obtained. The result of the modelling has shown that the use of RSM is adequate in the prediction of the compressive strength inhibition of crude oil in concrete made from crude oil-contaminated sand