RT Journal Article
T1 Effect of boron and water-to-cement ratio on the performances of laboratory prepared Belite-Ye'elimite-Ferrite (BYF) cements
A1 Pérez-Bravo, Raquel
A1 Morales-Cantero, Alejandro
A1 Bruscolini, Marguerita
A1 García-Aranda, Miguel Ángel
A1 Santacruz-Cruz, María Isabel
A1 Gómez-de-la-Torre, María de los  Ángeles
K1 Materiales
K1 Cemento
AB The effect of superplasticiser, borax and the water-to-cement ratio on BYF hydration andmechanical strengths has been studied. Two laboratory-scale BYF cements—st-BYF (with  -C2Sand orthorhombic C4A3 S) and borax-activated B-BYF (with a’H-C2S and pseudo-cubic C4A3s)have been used, and both show similar particle size distribution. The addition of superplasticiserand externally added borax to BYF pastes has been optimised through rheological measurements.Optimised superplasticiser contents (0.3, 0.4 and 0.1 wt%for st-BYF, B-BYF and st-BYF with externallyadded 0.25 wt % B2O3, respectively) result in low viscosities yielding homogeneous mortars. Thecalorimetric study revealed that st-BYF is more reactive than B-BYF, as the values of heat released are300–370 J/g and 190–210 J/g, respectively, after 7 days of hydration; this fact is independent of thewater-to-cement ratio. These findings agree with the higher degree of hydration at 28 days of b -C2Sin st-BYF (from 45 to 60%) than a’H-C2S in B-BYF (~20 to 30%). The phase assemblage evolution hasbeen determined by LXRPD coupled with the Rietveld method and MAS-NMR. The formation ofstratlingite is favoured by increasing the w/c ratio in both systems. Finally, the optimisation of freshBYF pastes jointly with the reduction of water-to-cement ratio to 0.40 have allowed the achievingof mortars with compressive strengths over 40 MPa at 7 days in all systems. Moreover, the st-BYFmortar, where borax was externally added, achieved more than 70 MPa after 28 days. The mainconclusion of this work does not support Lafarge’s approach of adding boron/borax to the raw mealof BYF cements. This procedure stabilises the alpha belite polymorph, but its reactivity, in thesesystems, is lower and the associated mechanical strengths poorer.
YR 2021
FD 2021
LK https://hdl.handle.net/10630/22784
UL https://hdl.handle.net/10630/22784
LA eng
NO Materials, 2021, 14, 4862
NO UMA18-FEDERJA-095 y P18-RT-720, ambos cofinanciados FEDER
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 20 ene 2026