Utilization of used-engine oil (UEO) resulted in a significant alteration in the
performance of OPC concrete during its fresh state. UEO decreases the initial
setting time and increases the consistency, air content and rate of fluidity loss of
OPC concrete. These effects increase with increasing the dosage of UEO in OPC
mixes. Therefore, UEO behaved as a chemical admixture and its impacts would
provide the dual action of both plasticizer and air-entraining admixtures.