Effect of Polyethylene Glycol Addition on Metakaolin-based Geopolymer

Polyethylene glycol is a non-toxic water soluble polymer often used in many industrial applications. The aim of this paper is to study the effect of polyethylene glycol with relative molecular weight ranging between 400–20000 on the properties of geopolymer mortars composed of metakaolin and sodium silicate. Polyethylene glycol was added in the amount of 0.5 to 10% by mass of metakaolin. After 28 days of curing at ambient conditions, different tests were carried out: physico-chemical (density, porosity), mechanical (flexural and compressive strength) and structural (SEM). The results showed that a maximum compressive strength of 23.9 MPa and a maximum flexural strength of 2.9 MPa were achieved by adding 10% PEG 400.