Aggressive effect of vegetable oils and organic fatty acids on cement-sand mortar and concrete

Vegetable oils have a destructive effect on the strength properties of cement-sand mortar and hardened concrete, even with relatively short-term exposure. The degree of exposure depends on the type of oil, the viscosity of the oil, the quantitative ratio of fatty acids and their position on the triacylglycerin radical, the duration of exposure, and other factors. The aim of the study is to identify the intensity of the aggressive effect of vegetable oils (corn, olive and palm) on the strength of axial compression of cement-sand mortar and concrete. Concrete and cement-sand samples were tested for axial compression strength after being kept in vegetable oil for 10, 20, 30, 40, 50, 60, 70 days. Based on the factor analysis of statistical data, empirical mathematical models have been developed for predicting changes in the axial compressive strength of cement-sand mortar and concrete. Mathematical models of the strength of hardened cement-sand mortar and concrete oiled with vegetable oil link their strength with the viscosity of the oil, the duration of oiling and the comprehensive characteristics of the porosity of the sand. These mathematical models are valid in the range of the duration of oil exposure to cement-sand mortar and concrete 0 < τ ≤ 70 days. Mathematical models for predicting changes in the axial compressive strength of cement-sand mortar and concrete are proposed for the first time and are heuristic. The results obtained are of scientific importance for predicting changes in the state of concrete structures under the influence of vegetable oil and ensuring their comprehensive protection from its negative effects. The results of the study are of practical interest for the design, erection and operation of industrial buildings. © 2022