In-situ early-age hydration study of sulfobelite cements by synchrotron powder diffraction

Abstract

Eco-friendly belite calcium sulfoaluminate (BCSA) cement hydration behavior is not yet well understood. Here, we report an in-situ synchrotron X-ray powder diffraction study for the first hours of hydration of BCSA cements. Rietveld quantitative phase analysis has been used to establish the degree of reaction (α). The hydration of a mixture of ye'elimite and gypsum revealed that ettringite formation (α~70% at 50 h) is limited by ye'elimite dissolution. Two laboratory-prepared BCSA cements were also studied: non-active-BCSA and active-BCSA cements, with β-and α′ H -belite as main phases, respectively. Ye'elimite, in the non-active-BCSA system, dissolves at higher pace (α~25% at 1 h) than in the active-BCSA one (α~10% at 1 h), with differences in the crystallization of ettringite (α~30% and α~5%, respectively). This behavior has strongly affected subsequent belite and ferrite reactivities, yielding stratlingite and other layered phases in non-active-BCSA. The dissolution and crystallization processes are reported and discussed in detail.

Research review of cement clinker chemistry

“…Especially the high temperature chemistry of clinker production [119,120] and the hydration of the BC$A and C$A cements [121][122][123] are the focus of research. But also the possibility to include fly ash into C$A cements in order to reduce CO 2 footprint has been evaluated [124,125].…”

Recent studies of cements and concretes by synchrotron radiation crystallographic and cognate methods

“…[68] The hydration of eco-cements, including phase content evolution by Rietveld methodology, has also been analysed for aluminium-rich belite sulphoaluminate cements, [69] active sulphobelite cements [70] and active sulphobelite cements at very early ages. [71] SXRPD coupled with the Rietveld method can also be used to characterize the long-term leaching behaviour of concretes by quantifying portlandite dissolution at different hydration times. [72] These results were compared to those obtained by DTA/TGA.…”

Influence of Different Lithium Compounds on Hydration and Mechanical Properties of Calcium Sulfoaluminate Cement

“…Cement-based materials are the most used artificial materials in the world attributing to their favorable features such as low prices, reliable mechanical properties, high versatilities [ 1 , 2 , 3 ], etc. As a kind of promising cement-based material [ 4 ], calcium sulfoaluminate (CSA) cement was developed in the 1970s [ 5 ], and manufactured by calcining natural materials such as limestone, bauxite and clay together with gypsum or anhydrite at 1250–1350 °C, which is lower than Portland cement’s [ 6 ].…”