Effects after 1500 Hardening Days on the Microstructure and Durability-Related Parameters of Mortars Produced by the Incorporation of Waste Glass Powder as a Clinker Replacement

Abstract

One of the ways of lessening the CO2 emissions of cement industry consists of replacing clinkers with supplementary cementitious materials. The required service life of real construction elements is long, so it is useful to characterize the performance of these materials in the very long term. Here, the influence of incorporating waste glass powder as a supplementary cementitious material, regarding the microstructure and durability of mortars after 1500 hardening days (approximately 4 years), compared with reference mortars without additions, was studied. The percentages of clinker replacement by glass powder were 10% and 20%. The microstructure was studied using impedance spectroscopy and mercury intrusion porosimetry. Differential thermal and X-ray diffraction analyses were performed for assessing the pozzolanic activity of glass powder at the end of the time period studied. Water absorption after immersion, the steady-state diffusion coefficient, and length change were also determined. In view of the results obtained, the microstructure of mortars that incorporated waste glass powder was more refined compared with the reference specimens. The global solid fraction and pores volume were very similar for all of the studied series. The addition of waste glass powder reduced the chloride diffusion coefficient of the mortars, without worsening their behaviour regarding water absorption after immersion.

Microstructure and mechanical properties of ternary mortars with brick powder, glass powder, slag, fly ash, and limestone

“…The solid phases formed as products of these reactions, would progressively close the pores, giving as a result lower porosity values, as has been observed. The result that additions with pozzolanic activity, such as fly ash and glass powder, did not produce a noticeable reduction of total porosity of cement‐based materials, compared to reference mortars without additions, whereas they produced a significant pore refinement, would agree with the results pointed out by other authors 22,41 . However, the binder with slag and brick powder (S‐BP series) reached similar total porosity values at 250 days than reference specimens, which could be explained in relation to the hydraulic activity of slag, which would have a more notable effect in the reduction of porosity, according to other works 22,53 …”

“…The result that additions with pozzolanic activity, such as fly ash and glass powder, did not produce a noticeable reduction of total porosity of cement-based materials, compared to reference mortars without additions, whereas they produced a significant pore refinement, would agree with the results pointed out by other authors. 22,41 However, the binder with slag and brick powder (S-BP series) reached similar total porosity values at 250 days than reference specimens, which could be explained in relation to the hydraulic activity of slag, which would have a more notable effect in the reduction of porosity, according to other works. 22,53 The electrical resistivity is a useful parameter for obtaining information related to the connectivity of pores, as well as the evolution of the microstructure.…”

“…The characteristics of waste glass powder addition used in this research were reported by Letelier et al 40 . and Tremiño et al 41 . On the other hand, the additions of fly ash, ground granulated blast furnace slag, and limestone accomplished the prescriptions of the UNE‐EN 197‐1 standard 37 for being used in the manufacture of commercial cements.…”

“…The complete characterization of the brick powder used here can be consulted in the work of Letelier et al 39 The waste glass powder used as addition in the ternary binders was obtained with a process of crushing and dry grinding of the original glass residues, which came from recycled containers. The characteristics of waste glass powder addition used in this research were reported by Letelier et al 40 and Tremiño et al 41 On the other hand, the additions of fly ash, ground granulated blast furnace slag, and limestone accomplished the prescriptions of the UNE-EN 197-1 standard 37 for being used in the manufacture of commercial cements. These three standardized additions were 2.…”

Effects of a Real Exposure Class XC4 Mediterranean Climate Environment in the Behavior of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone

“…Among them, the use of eco-friendly cements with additions substituting clinker is becoming more and more common [ 6 , 7 , 8 ]. Most of these additions or supplementary cementitious materials are obtained from wastes generated in other industries [ 9 , 10 , 11 , 12 ], so the reuse of these wastes in cement manufacture would avoid other environmental impacts, also contributing to sustainability. In addition, it has been reported that the use of some of these additions produces an enhancement in the behavior of cementitious materials [ 10 , 13 , 14 ], so the study of their effects still constitutes a relevant area of investigation.…”