ǂThe ǂinfluence of calcium sulfate content on the hydration of belite-calcium sulfoaluminate cements with different clinker phase compositions

Maruša Borštnar (Author), Frank Winnefeld (Author), Barbara Lothenbach (Author), Sabina Kramar (Author)

Abstract

The influence of different amounts of gypsum on the hydration of a belite-rich and a yeʼelimite-rich belite-calcium sulfoaluminate clinker (BCSA) was investigated. The hydration kinetics, phase assemblages and compressive strength devel- opment of cements prepared using yeʼelimite/ calcium sulfate molar ratios of 1, 1.5 and 2 were studied. Besides ettringite and monosulfate, aluminium hydroxide, strätlingite, C-S-H, iron-containing silic- eous hydrogarnet and hydrotalcite were present as hydration products. Increasing the amount of gypsum increased the ratio of ettringite to monosulfate formed in the cement paste, lowered the amount of pore solution, delayed the dissolution of belite and ferrite, decreased the formation of strätlingite and, in the case of the yeʼelimite-rich BCSA, led to an increase in compressive strength. Increased amounts of belite in the clinker led to the formation of higher quantities of C-S-H, at the expense of straätlingite and a lower compressive strength, as belite has a lower degree of reaction than yeʼelimite and due to the formation of more C-S-H and stratlingite compared to the more space-filling ettringite. The thermodynamic model established for BCSA cement hydration agrees well with the experimental data. Compressive strength directly correlated with bound water from thermo- gravimetric analyses and inversely correlated with the porosity calculated from thermodynamic modelling.

Keywords

belitno-kalcijevo sulfoaluminatni cement;sadra;hidratacija;termodinamsko modeliranje;odprti dostop;belite-calcium sulfoaluminate cement;gypsum;hydration;thermodynamic modelling;open access;

Data

Language:	English
Year of publishing:	2021
Typology:	1.01 - Original Scientific Article
Organization:	ZAG - Slovenian National Building and Civil Engineering Institute
Publisher:	Springer Netherlands
UDC:	620.1/.2
COBISS:	84002051
ISSN:	1871-6873
Views:	6
Downloads:	1
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	belitno-kalcijevo sulfoaluminatni cement;sadra;hidratacija;termodinamsko modeliranje;
Source comment:	Article no.: 212;
Pages:	str. 1-17
Issue:	ǂVol. ǂ54
Chronology:	Nov. 2021
DOI:	10.1617/s11527-021-01811-w
ID:	19661071