Durability aspects and mechanical strength of mortars containing glass powder and slag

The combination of glass powder (GP) with pozzolanic additions to replace clinker can develop new types of binders (ternary cement) with improved physical and mechanical properties, thereby enabling a reduction in consumption of clinker and natural resources, and the minimisation of the carbon dioxide emissions. In this context, the present work is an attempt to study the influence of GP with two different specific surface areas (Blaine) GP30 = 300 m²/kg and GP45 = 450 m²/kg, combined with slag, on the mechanical behaviour and durability of mortars. The mechanical properties were investigated using compressive and flexural strength tests. Aspects related to durability were examined as well by water-accessible porosity, capillary absorption and sorptivity tests. The replacement rate of cement by GP varied from 10 to 20% and the proportion of slag was fixed at 10%. The results showed that a binary mortar made with 20% GP45 replacement showed increases in 90 day compressive strength, while ternary mortar with 20% GP45 + 10% slag replacement gave the best result. The same trend is also valid for durability properties examined in this study. The combined use of GP and slag at 30% replacement levels seemed to perform better compared with using GP alone.