2026-05-27T21:29:20Zhttps://riuma.uma.es/rest/oai/request

oai:riuma.uma.es:10630/231992026-02-03T10:50:05Zcom_10630_2254col_10630_37953

Neto, José da Silva Andrade Gómez-de-la-Torre, María de los Ángeles Campos, Carlos E. M. Gleize, Philippe J. P. Monteiro, Paulo J. M. Kirchheim, Ana Paula Martos, Paulo R. de 2021-11-11T12:30:08Z 2021-11-11T12:30:08Z 2022 Cement and Concrete Research, Volume 151, January 2022, 106639 https://hdl.handle.net/10630/23199 10.1016/j.cemconres.2021.106639 The higher reactivity of orthorhombic C3A (ort-C3A) in sulfate-containing solutions, compared with cubic C3A (cb-C3A), was previously related to the differences in crystal structure or the sodium in the ort-C3A pore solution. We analyzed the hydration of cb-C3A (in water and NaOH solution) and Na-doped ort-C3A in the presence of gypsum and hemihydrate. Calorimetry, in-situ XRD, TGA, and rheological tests were conducted. NaOH accelerated the hydration of cb-C3A, but ort-C3A still presented higher ettringite formation rate and earlier sulfate depletion. Ort-C3A pastes showed 10-20 times higher viscosities and yield stresses. Replacing gypsum by hemihydrate increased the ettringite precipitation rate and anticipated the sulfate depletion of ort-C3A but did not significantly influence cb-C3A hydration. The crystallization of hemihydrate into gypsum resulted in early (<10 min) stiffing of all C3A-hemihydrate pastes. Overall, the higher reactivity of ort-C3A is related to differences in crystal structure rather than the sodium in the pore solution. eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Reología Hidratación Cemento The role of sodium and sulfate sources on the rheology and hydration of C3A polymorphs journal article