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. 2021 Aug 26;14(17):4862.
doi: 10.3390/ma14174862.

Effect of Boron and Water-to-Cement Ratio on the Performances of Laboratory Prepared Belite-Ye'elimite-Ferrite (BYF) Cements

Raquel Pérez-Bravo  1 , Alejandro Morales-Cantero  1 , Margherita Bruscolini  2 , Miguel A G Aranda  1 , Isabel Santacruz  1 , Angeles G De la Torre  1
Affiliations

Effect of Boron and Water-to-Cement Ratio on the Performances of Laboratory Prepared Belite-Ye'elimite-Ferrite (BYF) Cements

Raquel Pérez-Bravo et al. Materials (Basel). .

Abstract

The effect of superplasticiser, borax and the water-to-cement ratio on BYF hydration and mechanical strengths has been studied. Two laboratory-scale BYF cements-st-BYF (with β-C2S and orthorhombic C4A3S¯) and borax-activated B-BYF (with α'H-C2S and pseudo-cubic C4A3S¯)-have been used, and both show similar particle size distribution. The addition of superplasticiser and 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 externally added 0.25 wt % B2O3, respectively) result in low viscosities yielding homogeneous mortars. The calorimetric study revealed that st-BYF is more reactive than B-BYF, as the values of heat released are 300-370 J/g and 190-210 J/g, respectively, after 7 days of hydration; this fact is independent of the water-to-cement ratio. These findings agree with the higher degree of hydration at 28 days of β-C2S in st-BYF (from 45 to 60%) than α'H-C2S in B-BYF (~20 to 30%). The phase assemblage evolution has been determined by LXRPD coupled with the Rietveld method and MAS-NMR. The formation of stratlingite is favoured by increasing the w/c ratio in both systems. Finally, the optimisation of fresh BYF pastes jointly with the reduction of water-to-cement ratio to 0.40 have allowed the achieving of mortars with compressive strengths over 40 MPa at 7 days in all systems. Moreover, the st-BYF mortar, where borax was externally added, achieved more than 70 MPa after 28 days. The main conclusion of this work does not support Lafarge's approach of adding boron/borax to the raw meal of BYF cements. This procedure stabilises the alpha belite polymorph, but its reactivity, in these systems, is lower and the associated mechanical strengths poorer.

Keywords: Rietveld method; belite; calcium sulphoaluminate; degree of hydration; mechanical strengths; rheology; superplasticisers.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Flow curves of (a) st-BYF and (b) B-BYF pastes prepared at w/c = 0.40 and different superplasticiser (SP) contents. Inset of (b) shows the evolution of the viscosity with time of B-BYF pastes (w/c = 0.40) and different amounts of SP at a shear rate of 5 s−1. Numbers close to each curve stand for the amount of SP (wt %) of active matter referred to cement content.
Figure 2
Figure 2
Flow curves of st-BYF with 0.25 wt % of B2O3 externally added as borax with w/c = 0.40 and different superplasticiser (SP) contents.
Figure 3
Figure 3
Evolution of the viscosity with time of st-BYF_wc040_03SP, st-BYF_wc040_01SP_0.25B2O3 and B-BYF_wc040_04SP pastes at a shear rate of 5 s−1.
Figure 4
Figure 4
Calorimetric curves for (a) and (b) st-BYF and (c) and (d) B-BYF, with different w/c ratios. Vertical bars in (a) and (c) indicate the heat evolved due to the precipitation of AFt.
Figure 5
Figure 5
27Al MAS-NMR spectra for (a) st-BYF_wc040_03SP and (b) st-BYF_wc060 as a function of time. Asterisk indicates the interlayer IVAl resonance due to stratlingite. Vertical dashed lines mark the resonance due to VIAl in AH3-gel.
Figure 6
Figure 6
Degree of reaction of (a) β-C2S and α’H-C2S and (b) C4AF in all BYF pastes. Data calculated from [22] for w/c of 0.55 are also included.
Figure 7
Figure 7
(a) 27Al MAS-NMR and (b) 29Si MAS-NMR spectra for selected pastes after 120 days of hydration. Asterisk indicates the interlayer IVAl resonance due to stratlingite. # stands for Q3(2Al) and Q2(1Al) resonances of stratlingite. IVAl resonance in C-A-S-H gel is labelled as 1 in (a). Q1 and Q2 resonances due to C-S-H gel are labelled as 2 and 3 in (b).
Figure 8
Figure 8
Volume evolution with time for (a) st-BYF-wc040_03SP and (b) B-BYF-wc040_04SP. Dashed vertical lines indicate 7 and 28 days of hydration.
Figure 9
Figure 9
Compressive strengths of selected st-BYF and B-BYF mortars. Data from [22] and a type I 42.5R PC prepared as UNE-EN196-1 are also given for the sake of comparison. Percentage of mechanical strengths with respect to those with w/c of 0.55 from [22].
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References

    1. Shi C., Qu B., Provis J.L. Recent progress in low-carbon binders. Cem. Concr. Res. 2019;122:227–250. doi: 10.1016/j.cemconres.2019.05.009. - DOI
    1. Amato I. Green cement: Concrete solutions. Nature. 2013;494:300–301. doi: 10.1038/494300a. - DOI - PubMed
    1. Gartner E.M. What are BYF cements, and how do they differ from CSA cements?; Proceedings of the The Future of Cement, 200 years after Louis Vicat; Paris, France. 6–8 June 2017; pp. 1–9.
    1. Aranda M.A.G., De la Torre A.G. Sulfoaluminate cement. In: Pacheco-Torgal F., Jalali S., Labrincha J., editors. Eco-Efficient Concrete. Woodhead Publishing Limited; Cambridge, UK: 2013. pp. 488–522.
    1. Zajac M., Skocek J., Stabler C., Bullerjahn F., Ben Haha M. Hydration and performance evolution of belite-ye’elimite-ferrite cement. Adv. Cem. Res. 2019;31:124–137. doi: 10.1680/jadcr.18.00110. - DOI

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