Treated Used Engine Oil as a Concrete Admixture

Over the years, plenty of studies have proven that the used engine oil (UEO) can be
used as a concrete admixture to improve workability and also the air content of the
concrete, thus making UEO a potential green alternative to the traditional water
reducers and air entraimnent agents.
However, the UEO have a wide range of impurities, and some of the impurities are
ionic compounds, such as acids, sulphates, phosphates, chlorides and heavy metal
oxides which are traditionally harmful components towards the durability of
concrete.
Purpose of this project is to treat the UEO using ionic liquid (IL), determine the
effects of different types ofUEO, as well as their constituent on concrete in terms of
workability, compressive strength and porosity. A total of 5 UEO samples collected
from different sources and 5 different ILs are tested for performance of phase
separation first. ILs used in this project are: 2-hydroxy ethylanunonium formate
(HEF), bis(2-hydroxylethyl) methyl anunonium formate (BHEF), 2-hydroxyethyl
anunomum acetate (HEA), 1-n-butyl-3-methylirnidazolium thiocyanate
([bmim][SCN]), and 1-butyl-3-methylimidazolium acetate ([bmim][Ac]). Samples
of UEO are mixed with IL at I: 1 ratio for extraction, where mixture stirred at
SOOrpm for 30 minutes, and then left for settlement for 3 days. HEF is chosen to ·
produce treated UEO (TUEO) due to overall better phase separation. Impurities
removal rates by HEF are roughly estimated, where it is noted to be efficient at
extracting 803, CaO, ZnO and MgO. Unfortunately, HEF causes an increase in
acidity in two TUEO samples, which cause decreased concrete strength.