Browsing by Author "Navarrete, Ivan"

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    Assessing the effect of test parameters on the determination of the rheological behavior of calcium sulfoaluminate cement pastes
    (2024) Silvestro, Laura; Navarrete, Ivan; Araujo, Alamanda; Krann, Maira; Lima, Geannina; Ribeiro, Rodrigo Scoczynski; Eugenin, Claudia; Gleize, Philippe Jean Paul
    Calcium sulfoaluminate cement (CSA) is renowned for its application in technologies that require rapid setting and high initial strengths, such as 3D concrete printing and repairs. However, their rheological behavior needs to be more adequately explored. This study assesses the impact of rotational rheometer test conditions on CSA pastes with different water-to-cement ratios. For the determination of static yield stress (tau s0), stress growth test with shear rates between 0.01 and 0.05 s- 1 were employed. The results revealed that higher shear rates anticipated the occurrence of the material's peak destructuring and resulted in lower values of tau s0. In addition, the effects of geometry and testing routine on the flow curve were analyzed. The results showed that the use of vane geometry provides more consistent results of the measured dynamic yield stress, viscosity, and hysteresis area of CSA pastes than parallel plate geometry.
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    Comparison of the electrochemical decarbonation of different-grade limestones used in cement manufacturing
    (2023) Ramirez-Amaya, Dario; Dreyse, Paulina; Martinez, Natalia P.; Troncoso, Felipe; Navarrete, Ivan; Noel, Martin; Canales, Roberto I.; Gonzalez, Marcelo
    Electrochemical decarbonation (ED) of CaCO3 is a promising method to reduce CO2 emissions from limestone calcination for cement manufacturing. Most cement plants are located near accessible deposits of limestone; therefore, the feasibility of ED deployment depends on the efficiency of natural limestone decarbonation, which has variable CaCO3 content. Accordingly, this research compares the ED efficiency of different limestones (CaCO3 content between 84 % and 68 %) and the chemical and physical characteristics of precipitate materials (PM) obtained from this process. The obtained PMs were comprised mainly of Ca(OH)(2) (similar to 59 %) and had similar particle size distributions. At the same time, the efficiency of Ca(OH)(2) precipitation, energy consumption, and CaO recovery were comparable to the ED of a pure CaCO3 reagent (>99 %). The PMs were found to have higher CaO content and lower loss on ignition than the feedstock material, independent of the type of limestone, facilitating the future ED implementation in cement manufacturing.
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    Flexural behavior of stratified reinforced concrete: construction, testing, analysis, and design
    (2017) Navarrete, Ivan; Hube Ginestar, Matías Andrés; Kurama, Yayah; López Casanova, Mauricio Alejandro; CEDEUS (Chile)
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    Predicting the evolution of static yield stress with time of blended cement paste through a machine learning approach
    (2023) Navarrete, Ivan; La Fe-Perdomo, Ivan; Ramos Grez, Jorge; Lopez, Mauricio
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    Replacement of pozzolanic blended cement by supplementary cementitious materials: Mechanical and environmental approach
    (2023) Navarrete, Ivan; Valdes, Juan; Lopez, Mauricio; Vargas, Felipe
    Pozzolanic blended cements, used in several markets, can be mixed with supplementary cementitious materials (SCMs) to improve environmental performance keeping a similar compressive strength. Many SCMs are industrial byproducts that do not require intensive processing. Six industrial byproducts were studied as replacement of pozzolanic blended cement. Reactivity, compressive strength, and environmental performance were measured. Results showed that the use of SCMs as partial replacement for pozzolanic blended cement increases the reactivity of cement and, therefore, the compressive strength of cementitious pastes. Furthermore, environmental results showed beneficial or detrimental effects depending on replacement level, compressive strength, and CO2 footprint of each SCM.