Performance of Portland clinker produced through the incorporation of asbestos cement wast (ACW)

Desempenho do clínquer Portland produzido através da incorporação de resíduo de cimento amianto (RCA)

Abstract

The production process of Portland cement has significant environmental impacts involving the exploitation of deposits for raw materials and CO₂ emissions. In this study, the incorporation of different proportions of asbesto cement waste (ACW) was evaluated, approximately 24%, 49%, 74%, and 86% by mass, corresponding to levels of 0.43%, 0.85%, 1.27%, and 1.69% of SO₃, respectively, replacing the limestone and clay mixture in Portland clinker blends. The effects of this incorporation on the clinkering process were analyzed at different temperatures (1300 °C to 1450 °C). The phases formed in the produced clinkers were identified through X-ray diffraction (XRD), followed by the grinding process for cement production, which was subsequently characterized physically. The hydration of pastes was monitored by XRD. Additionally, the mechanical performance of pastes made with the produced cements was also assessed. From the results obtained, it was observed that ACW acts as a mineralizer at lower clinkering temperatures (1350 °C), resulting in an increase in the alite (C₃S) content in the clinkers. Consequently, cements produced with ACW showed an increase in the amount of hydrated phases and superior mechanical strengths at early ages compared to the reference cement without the addition of ACW.

Keywords
Portland cement; Asbestos cement waste; Portland clinker; Paste hydration