Name: LAYLLA VIDOTTO DE MELLO
Publication date: 26/02/2025
Examining board:
Name |
Role |
|---|---|
| AFONSO RANGEL GARCEZ DE AZEVEDO | Examinador Externo |
| PATRICIO JOSE MOREIRA PIRES | Examinador Interno |
| RAFAEL DORS SAKATA | Coorientador |
| RONALDO PILAR | Presidente |
Summary: DE MELLO, Laylla Vidotto. Evaluation of pastes and mortars incorporating KR slag dedusting powder as a supplementary cementitious material. 2025. Dissertation (Masters degree in Civil Engineering). Postgraduate Program in Civil Engineering, Federal University of Espírito Santo, Vitória, 2025.
Steel mills produce considerable amounts of solid waste, among which is KR slag, which is one of the desulfurization slags generated in the preliminary treatment of pig iron. Considering that the production of clinker and cement constitutes a significant source of anthropogenic CO2 emissions worldwide, and knowing that it is not possible to halt the production of these materials, one option would be to focus on the recycling of industrial waste, which is another environmental problem, as an alternative solution to the current issue. In this way, knowing the availability of the residue and the increasing search for alternative binders, this study aimed to analyze the feasibility of using KR slag tilting dust (KRP), as a substitute for granulated blast furnace slag in cementitious materials, in order to verify the effects caused on the cementitious matrix regarding the physical-mechanical and microstructural properties. Mortars and pastes were produced with CP V Portland cement, granulated blast furnace slag, and KRP contents of 0, 5, 10, and 15%, replacing the granulated slag. Mixtures containing 15% of ground KR slag were also prepared. The established water/binder ratio was 0.35 for the pastes and 0.48 for the mortars, and standard sand was also used for the mortars. The supplementary cementitious materials were then characterized under physical-chemical, mineralogical, and microstructural aspects, through the use of microstructural techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and the R3 reactivity test, in addition to tests for specific gravity, insoluble residue, and laser granulometry. The pastes were subjected to isothermal calorimetry tests and mineralogical analysis by XRD, using the Rietveld method for phase quantification at 7, 28, and 91 days. The mortars were evaluated for compressive mechanical strength at 7, 28, and 91 days. It was observed that the incorporation of KRP retarded the ettringite formation process and promoted the formation of the C-S-H product in the hydration kinetics of the pastes, besides promoting a decrease in the amount of portlandite in some pastes and increasing the compressive mechanical strength, mainly at 7 and 28 days. Based on the results, it was observed that KRP has the potential to be a viable alternative for the production of mortars, with substitutions of up to 15% of granulated blast furnace slag by KRP, showing good performance, especially in terms of mechanical strength. Keywords: Mortar. Desulfurization slag. Additional cementitious material
