Análise reológica do pó de forno proveniente da indústria cimentícia para fins de aplicação como material cimentício suplementar

Abstract

The global cement industry plays a crucial role in infrastructure development. However, it is among the main emitters of carbon dioxide (CO₂), contributing significantly to climate change. In this context, research on supplementary cementitious materials (SCMs) that partially replace cement clinker especially those derived from industrial residues has emerged as a promising area of investigation. This approach not only aims to mitigate the environmental impact of cement production but also promotes the valorization of by-products and advances the fundamental principles of the circular economy. This study investigated the technical feasibility and physicochemical behavior of filter dust, a residue from cement production, as a supplementary cementitious material in CPV-ARI cement pastes. Physical, chemical, and mineralogical analyses of the residue were carried out, along with compressive strength tests, rotational rheometry, and calorimetry. The objective was to evaluate the performance of the pastes, understand the influence of the residue on their properties, as well as verify its potential for reducing CO₂ emissions. Specific surface area results indicated an increase with the incorporation of the residue, which evidenced a filler effect and improved particle packing. This behavior was reflected in the mechanical performance: the reference paste reached 46.4 MPa at 28 days, whereas the mixture containing 5% filter dust achieved 50.7 MPa, representing an increase of approximately 9%. In contrast, the mixture with 7% addition reached 45.5 MPa, corresponding to a reduction of about 2% compared with the reference. In the rheological tests, the sample with 5% addition showed a better balance among shear stress, viscosity, and hysteresis area, which indicates a more stable behavior and better suitability for mixing, transport, and application stages. Therefore, the mixture with 7% addition exhibited increased viscosity and reduced workability. In isothermal calorimetry, an anticipation of the hydration peak and a reduction in accumulated heat were observed with the addition of the residue, indicating changes in hydration kinetics and a nucleation effect. The environmental analysis confirmed that the use of filter dust contributes to a significant reduction in the carbon footprint of cement production. Overall, the 5% filter dust content showed the best overall performance, combining increased strength, adequate rheological behavior, and reduced heat of hydration, in addition to contributing to the reduction of clinker consumption and CO₂ emissions. The results confirm the potential for reusing residues from the cement production process itself as a technically and environmentally viable strategy. As a limitation, the restricted number of samples is highlighted, and further rheological studies and larger-scale investigations are recommended for future research.