Browsing by Author "Eugenin Soto, Claudia Andrea"

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    A Study on Copper Mine Tailings to Be Used as Precursor of Alkali-Activated Materials for Construction Applications
    (2025) Morales Castro, Luis Felipe; Loyola Fernández, Estefanía Francisca; Castro Quijada, Matías Daniel; Vargas, Felipe; Navarrete Leschot, Iván Ignacio; Eugenin Soto, Claudia Andrea; Marquardt Román, Carlos Jorge; Videla Leiva, Álvaro Rodrigo
    This research presents a novel methodology to classify copper tailings according to their potential as alkali-activated materials (AAMs) for construction applications. The methodology includes geochemical and mineralogical characterization via QEMSCAN and X-ray fluorescence, with mechanical performance evaluation through compressive strength test (UCS). A three-phase diagram based on Al2O3, Fe2O3, and CaO-MgO-K2O is proposed for a fast screening of copper tailing potential to be used as a construction material. In this paper, three copper tailings were chosen to test the methodology, and a set of five samples for each tailing have been geopolymerized for testing. Copper tailing samples were mixed with 0, 2.5, 5, 7.5 and 10% by mass of Ordinary Portland Cement (OPC) to evaluate the effect on performance when a chemical co-activator is used to improve material reactivity. Compressive strength testing was applied on 2 cm3 cubes after 28 days of curing at 60 °C, yielding values from 6 to 26.1 MPa. The best performing sample featured a Si/Al ≅ 3 ratio and a mineralogy with significant presence of reactive species such as plagioclase and K-feldspar (≅42%). In contrast, high levels of Fe2O3 (≥12%), clay (≥7%), and pyrite (≥4%) were associated with reduced mechanical performance.
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    Impact of mixture design and production parameters on the crushing strength of cold-bonded alkali activated aggregates made from iron tailings
    (2026) Loyola Fernández, Estefanía Francisca; Eugenin Soto, Claudia Andrea; Vargas, Felipe; Videla Leiva, Álvaro Rodrigo; Navarrete Leschot, Iván Ignacio
    This study explores the production and performance of cold-bonded alkali-activated artificial aggregates (CB- AAA) made from highly crystalline iron tailings, a low-reactivity mining by-product. A factorial experimental design was used to assess the influence of five key parameters on crushing strength: aggregate particle size, alkaline activator molarity, co-activator dosage, curing temperature, and curing time. The resulting aggregates exhibited bulk densities from 824 to 1002 kg/m³ , water absorption between 14.78 % and 25.68 %, and crushing strengths ranging from 0.18 to 3.24 MPa. A second-order polynomial regression model was developed and validated, identifying curing temperature as the most significant factor. To evaluate structural applicability, concrete specimens were prepared with 30 % and 100 % replacement of natural coarse aggregates. Higher- quality CB-AAA mitigated compressive strength losses, with partial replacement mixtures retaining up to 60 % of the reference strength. These results demonstrate the feasibility of using iron tailings in low-carbon construction materials despite the low reactivity of these waste materials, and they offer new insights into the role of mixture design and processing conditions in optimizing the performance of CB-AAA for concrete applications.