The potential use of used engine oil as a concrete admixture

Abstract

Globally, there is a continuous effort to investigate and eventually include waste materials in concrete mixes to minimise as much as possible environmental impacts. Indeed, as an attempt to reduce the negative impact of a hazardous waste, such as waste engine oil, on the environment, experimental investigations have been carried out to investigate and report the effects of engine oil on concrete mixes and establish some common conclusions which were reviewed and compared with in this study. Nevertheless, one must bear in mind that an immense range oi engine oil types exists and, moreover, most of the times various types of waste oils are mixed together prior to disposal. However, in this experimental research, a fully synthetic engine oil was used and apart from being careful to limit the variances only to two oil states (i.e. new and used), a chemical analysis was also made on both engine oils such that effects of engine oil (used and new). Due to the main objective of the research of exploring the potential use of used engine oil as a concrete admixture, the main variables in this study were the admixture type and percentage dosages based on the cement weight being used in a particular mix. The percentage dosages used vary from 2-6% as regards to used/new engine oil and 0.3- 0.5% as regards to SP. The fresh concrete property tests conducted included slump, flow table, density, bleeding and air content while the hardened concrete property tests included ultrasonic pulse velocity and compressive strength. In fact, a spectrum of results was successfully obtained. When comparing to other existing studies, this research showed similarities in some results, for instance air content volume increase with EO additions. However unlike to what was reported with almost all papers consulted, the EO used in this research did not perform as a plasticising admixture, increasing workability. However, this study set the pace for a new field of experimental research, which, despite being still at a very early stage locally, it may easily have potential benefits to future developments.