Shiva Shirani (1), Ana Cuesta (1), Alejandro Morales-Cantero (1), Angeles G. De la Torre (1), Margie P. Olbinado (2), Miguel A.G. Aranda (1)
Cement and Concrete Research, 147, September 2021. DOI: 10.1016/j.cemconres.2021.106499

Keywords

CO2 footprint; C-S-H gel; Microstructure; Rietveld analysis; Synchrotron X-ray microtomography

Abstract

Belite cements (BCs) could be a more sustainable binder than Portland cements (PCs) but adequate knowledge of the hydration features has still to be built. In particular, the mild curing hydration temperature effects have been extensively studied for PCs but not for BCs. This research was triggered by a previous work reporting improved mechanical strengths of BCs at higher curing temperatures. Here, we report the hydration characteristics of a BC at 20, 40 and 60 °C and compared to those of a typical PC. We have corroborated previous findings and used a multi-technique approach including Rietveld phase analysis, thermal analysis, calorimetry, silicon MAS-NMR, mercury intrusion porosimetry and chiefly synchrotron X-ray microtomography, to thoroughly understand the different behavior. In a nutshell, the improved mechanical performances at mild curing temperatures for BCs are mainly due to a much larger belite degree of reaction, with lower porosity coarsening of belite cements also playing a role.

How Our Software Was Used

Dragonfly was used to perform segmentation by manual thresholding.

Author Affiliation

(1) Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, Málaga 29071, Spain.
(2) Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.