2026-05-30T18:05:43Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/404712026-05-29T12:18:40Zcom_10630_2254col_10630_37953

Low-grade kaolinitic clays as SCMs for low-carbon cements and strength improvement by C-S-H gel nucleation seeding Vallina, Diego Santacruz-Cruz, María Isabel Morales-Cantero, Alejandro Rodríguez-Ruiz, María Dolores Cuesta-García, Ana María Gómez-de-la-Torre, María de los Ángeles Dalla-Libera, Alessandro Borralleras, Pere Dhers, Sébastien Schwesig, Peter Mazanec, Oliver García-Aranda, Miguel Ángel Resistencia de materiales Cemento Arcilla Artículo disponible online desde 24/09/2025 This study seeks to push the limits of LC3-50 binders by utilising low-grade kaolinite clays and C-S-H gel nucleation seeding. Four commercially-available kaolinite clays (i.e. kaolinite contents ~20 wt%) have been studied by X-ray fluorescence, X-ray powder diffraction and thermal analysis. The clays were thermally activated and milled to Dv,50 = 11 ± 2 μm. The activated clays showed low pozzolanic performances, as determined by ASTM C1897-20 standard. The heat flows ranged 200–230 J/g calcined clay and the bound waters 4.3–5.7 %. The LC3-50 pastes were characterised by calorimetry, X-ray powder diffraction and the Rietveld method, thermal analysis, and porosimetry to evaluate pozzolanic reactivity and the seeding effect. LC3 mortars, w/b = 0.40, have relatively low compressive strengths, especially at one day, but these values were increased by 64 % on average at one day by seeding. At 1 day, three LC3 mortars showed 11 MPa which increased to 18–20 MPa by seeding. A fourth mortar showed a much higher compressive strength, 16 MPa, that increased to 23 MPa, by seeding. A tested concrete, w/b = 0.50, also showed a high increase of 37 % at 1 day. The improvements at 28 days were maintained but quantitatively lower, 12 and 14 % for the mortars and the concrete, respectively. Insights into the pozzolanic reactions and C-S-H seeding are obtained from the quanti-tative study of the pastes. For instance, it is proven the pozzolanic reaction at 1 day from the portlandite con-sumption. Also shown is the enhanced formation of carboaluminates when the strength enhancing admixture is added. 2025-10-28T10:10:18Z 2025-10-28T10:10:18Z 2026-01 journal article Diego Vallina, Isabel Santacruz, Alejandro Morales-Cantero, María Dolores Rodríguez-Ruiz, Ana Cuesta, Angeles G. De la Torre, Alessandro Dalla-Libera, Pere Borralleras, Sébastien Dhers, Peter Schwesig, Oliver Mazanec, Miguel A.G. Aranda, Low-grade kaolinitic clays as SCMs for low-carbon cements and strength improvement by C-S-H gel nucleation seeding, Cement and Concrete Research, Volume 199, 2026, 108036, ISSN 0008-8846, https://doi.org/10.1016/j.cemconres.2025.108036. https://hdl.handle.net/10630/40471 10.1016/j.cemconres.2025.108036 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Elsevier