Abstract

Mixed glasses of different colors are economically difficult to reuse for the fabrication of new glass products but their use in cement-based materials is a promising way to recycle this material. This paper deals with the pouzzollanique activity of mixed glass cullet, by evaluating the pouzzollanique behavior of a large range of glass particle sizes, from less than 40 μm (540 m2/kg) up to 2.5 mm (2.2 m2/kg). Five different classes of glass are assessed separately, in terms of compressive strength tests on mortars, consumption of lime (TG), morphology (SEM) and composition of hydrates (EDX and X-ray fluorescence). The results show that the pouzzollanique activity increases with glass fineness and that, compared to a reference material without glass, equivalent or superior compressive strength can be obtained when using up to 40% of glass of 540 m2/kg fineness. Transition fineness around 30 m2/kg (140 μm) is highlighted, for which the pouzzollanique activity becomes substantial. However, a slight but significant pouzzollanique activity is detected for coarse particles (>1 mm), as confirmed by the consumption of Ca(OH)2, the formation of C-S-H-like hydrates and an increase of 10% (5 MPa) in the compressive strength compared to an inert admixture.

KEYWORDS

recycled glass; glass powder; glass aggregate; pouzzolane; pouzzollanique reaction; alkali-silica reaction