Reduction in cement content of normal strength concrete with used engine oil (UEO) as chemical admixture

In this study, the coupling effects of admixing a used engine oil (UEO) and reducing the cement paste content on the properties of a normal strength concrete were investigated. Initially, various tests were performed to determine the effect of the admixed UEO on the properties (i.e. workability, air content, setting times, strengths, drying shrinkage, and freezing and thawing (F–T) durability) of the reference concrete (formed in accordance with ASTM C494). Based on the acquired knowledge regarding the aforementioned effects, the chemical-admixture type of the UEO was evaluated. The UEO largely complies with the ASTM C494 type A water-reducing admixture specifications. The admixed UEO can facilitate the production of concrete with 9.4% less cement content than that in the reference concrete, but with comparable properties. This study provides a basis for realizing a more economical and eco-friendly production of concrete by both reducing its cement content and admixing UEO.