Use of E-Waste in Metakaolin Blended Cement Concrete for Sustainable Construction

Abstract

This paper investigates the use of non-metallic portion (NMP) reclaimed from e-waste (i.e., waste printed circuit board—PCB) as replacement of natural sand in the blended cement concrete by using Metakaolin (MK) as supplementary cementitious material for its effect on the mechanical, durability, microstructural, and mineralogical properties of concrete. It was found that the blended mixes containing NMP and MK outperformed the control mix. With the addition of 10% NMP and 10% MK, the maximum compressive strength was obtained, with the splitting tensile and flexural strength following the same trend. The performance of the mixes was lowered above 10% replacement levels, although it was still better than the control mixture. When compared to other mixes, 10% NMP and 10% MK concrete had the lowest sorptivity and water absorption values, as well as the highest resistance to chloride-ion penetration. FESEM was used to confirm the results, and then XRD was used to determine the elemental classification. This study lays the groundwork for a long-term strategy for utilising NMP and MK as extremely effective concrete additives.

Eco-Friendly Sustainable Concrete and Mortar Using Coal Dust Waste

“…And the water absorption of concrete decreased by 9.7%, and for mortar it decreased by 9.3%. This is in good agreement with the works of a number of authors, in particular with the works [13][14][15][16][17][18][19] devoted to the processes of structure formation of concrete composites using coal dust and the works of the authors [20][21][22][23][24][25][26][27] devoted to the physical and mechanical characteristics of concrete modified with coal dust. Based on the results of XRD analysis of concrete of the control composition, the phases of portlandite, illite, anorite, calcite and quartz were identified.…”

“…It should be noted that, based on the results of the literature review, no studies were found on the use of coal dust with a similar chemical composition as a partial replacement for binders in the technology of cement composites. However, there are a number of studies [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] where the use of inert mineral additives, namely, clay, metakaolin, electric arc furnace dust, stone dust and finely ground sea shell powders, as a partial replacement for cement allows in rational amounts the improvement of the physical and mechanical characteristics of the composite and at the same time an increase in its environmental friendliness. The optimal percentages for replacing part of the cement with these types of additives varied from 2% to 20%, while improvements in the strength characteristics, water absorption and porosity of experimental cement composites were observed.…”

“…It should be noted that, based on the results of the literature review, no studies were found on the use of coal dust with a similar chemical composition as a partial replacement for binders in the technology of cement composites. However, there are a number of studies [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] where the use of inert mineral additives, namely, clay, metakaolin, electric arc furnace dust, stone dust and finely ground sea shell powders, as a partial replacement for cement allows in rational The use of coal dust of similar origin in the study [8] in small quantities-up to 2.5 wt.% of ordinary Portland cement-made it possible to improve the mechanical strength of cement composites by reducing open porosity and increased formation of hydration products compared to the reference ones. The prospect of the effective use of coal dust in appropriate, rationally selected quantities in the production of concrete was noted [8].…”

“…It was established that metakaolin in SCC at a rational quantity also has a positive effect on the strength, water absorption and porosity. The use of metakaolin as a partial replacement for cement in concrete technology was also studied in detail in [16][17][18][19]. It is noted that the use of this additive in rational quantities makes it possible to improve the strength characteristics and durability of composites and reduce their porosity and water absorption.…”