Resistance to the alkali-aggregate reaction of sustainable mortars produced with scheelite tailings in replacing natural sand aggregates

Brunna Lima De Almeida Victor Medeiros,Gelmires De Araújo Neves,Fabiana Pereira Da Costa,Jucielle Veras Fernandes,Alisson Mendes Rodrigues,Sâmea Valensca Alves Barros

doi:10.33448/rsd-v10i14.22209

Abstract

This work produced coating mortars with scheelite tailings (ST) in total replacement of natural sand aggregate. The chemical and mineralogical composition of the scheelite tailings was determined by X-ray diffraction (XRD) and X-ray fluorescence (XRF). Mortar samples with a mass proportion of 1:2:9 (cement: lime: sand/scheelite tailings) were prepared with and without the scheelite tailings. The mortars were evaluated by mercury intrusion porosimetry and compressive and flexural strength tests. The resistance to the alkali-aggregate reaction was assessed from the bar expansion test and by scanning electron microscopy (SEM) in the crack and pore regions. The results indicate that until the 22nd day, the scheelite tailings were not reactive; however, in 28 days, the expansion was deleterious. SEM images did not detect the presence of amorphous alkaline gel characteristic of the alkali-aggregate reaction. Therefore, although the mortar with scheelite tailings aggregate has shown the deleterious potential to 28 days, mechanical tests indicate that it has the potential to be used as a coating mortar.

Highlights

In recent decades, the global concern with preserving natural resources has intensified due to the growing market demand and the possibility of depletion of these resources originating from non-renewable sources (Yang et al, 2020)
Sustainable mortars were produced with scheelite tailings in total replacement to natural sand aggregate
The results of the chemical characterization showed that the scheelite tailings have chemical and physical characteristics similar to those of natural sand

Summary

Introduction

The global concern with preserving natural resources has intensified due to the growing market demand and the possibility of depletion of these resources originating from non-renewable sources (Yang et al, 2020). Several researches have been focused on developing sustainable materials, using alternative raw materials from mining tailings and industrial waste. Other authors (Almeida et al, 2021; Hoppe Filho et al, 2021; Huseien et al, 2018; Pereira-De-Oliveira et al, 2012; Samadi et al, 2020; Torres et al, 2020) used red ceramic wastes to be used as a partial replacement for Portland cement or as aggregates. Other researchers (Almeida et al, 2021; Fernandes et al, 2020; Figueirêdo et al, 2020) used scheelite tailings to partially replace Portland cement or aggregate for the development of sustainable materials

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