Limestone reaction in calcium aluminate cement–calcium sulfate systems

The effect of calcium sulfates varieties on the properties of calcium aluminate cement-based self-leveling mortar have been investigated, and the hydration kinetics, hydrated products and microstructures are characterized by isothermal calorimeter, X-ray diffraction and mercury intrusion porosimetry, respectively. The results show that the technological properties of mortars are significantly affected by calcium sulfate varieties and content. The setting times are shortened drastically with the addition of calcium sulfates. Mortars with hemihydrate show higher early strength and less drying shrinkage. In contrast, using anhydrite in mortars cause lower strength and higher drying shrinkage at early age but larger growth of strength in the late. The increasing calcium sulfates content may result in the delay of main hydration peak in the heat evolution curve. For formulation with hemihydrate, the appearance of main hydration peaks are advanced compared with formulation without addition of calcium sulfates. Moreover, mortar microstructures are optimized by addition of β-hemihydrate, the proportion of large pores are lower than that of mortars with anhydrite.

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Expansive properties of ettringite in a mixture of calcium aluminate cement, Portland cement and β-calcium sulfate hemihydrate

Cement and Concrete Research ◽

10.1016/s0008-8846(00)00495-6 ◽

2001 ◽

Vol 31 (2) ◽

pp. 257-261 ◽

Cited By ~ 35

Author(s):

Cecilie Evju ◽

Staffan Hansen

Keyword(s):

Portland Cement ◽

Calcium Aluminate ◽

Calcium Sulfate ◽

Calcium Aluminate Cement ◽

Aluminate Cement ◽

Calcium Sulfate Hemihydrate

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Influence of curing temperatures on the hydration of calcium aluminate cement/Portland cement/calcium sulfate blends

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2017.03.016 ◽

2017 ◽

Vol 80 ◽

pp. 298-306 ◽

Cited By ~ 25

Author(s):

Linglin Xu ◽

Kai Wu ◽

Christiane Rößler ◽

Peiming Wang ◽

H.M. Ludwig

Keyword(s):

Portland Cement ◽

Calcium Aluminate ◽

Calcium Sulfate ◽

Calcium Aluminate Cement ◽

Aluminate Cement

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Binder Microstructures Developed during the Hydration Process in the System Portland Cement – Calcium Aluminate Cement – Calcium Sulfate

MRS Proceedings ◽

10.1557/opl.2016.20 ◽

2016 ◽

Vol 1812 ◽

pp. 71-76 ◽

Cited By ~ 1

Author(s):

Andreea M. Moncea ◽

Ana M. Panait ◽

György Deák ◽

George Poteraș

Keyword(s):

Portland Cement ◽

Mechanical Behavior ◽

Calcium Aluminate ◽

Calcium Sulfate ◽

Calcium Aluminate Cement ◽

Processes And Reactions ◽

Curing Conditions ◽

Stage Of Development ◽

Image Position ◽

Aluminate Cement

ABSTRACTLately, the investigations of binders from ternary system Portland cement (PC), calcium aluminate cement (CAC) and calcium sulfate ($C\overline S$), have gone through a larger stage of development due to their special properties such as fast setting and rapid hardening, early strength, non-efflorescence, etc. These special properties are ensured by the binder’s microstructure, developed through hydration processes and reactions between hydrate components, which allows us to use them in special environments (aggressive environments with very low or very high level of pH, environments with high temperature, etc.). The binders from this system were simply named “dry mortars”, and provide the final user with an easy processing. In order to explain the mechanical behavior of the specimens exposed in normal curing conditions (T = 20 ± 2 °C and R.H. ≈ 95%), and with different percentages of calcium sulfate (added as hemihydrate or anhydrite), research on the microstructure of the hardened system was performed using SEM and XRD investigation techniques. The analyses have been performed on the binder pastes, hydrated for 1 and 28 days. The tests results showed that the specimen with anhydrous $C\overline S$ content had the best mechanical behavior.

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Physicochemical, Mineralogical, and Mechanical Properties of Calcium Aluminate Cement Concrete Exposed to Elevated Temperatures

Materials ◽

10.3390/ma14143855 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3855

Author(s):

Amirmohamad Abolhasani ◽

Bijan Samali ◽

Fatemeh Aslani

Keyword(s):

Temperature Rise ◽

Calcium Aluminate ◽

Elevated Temperatures ◽

Ultrasonic Pulse Velocity ◽

Pulse Velocity ◽

Calcium Aluminate Cement ◽

Cement Concrete ◽

Sem Images ◽

Strength Deterioration ◽

Aluminate Cement

One commonly used cement type for thermal applications is CAC containing 38–40% alumina, although the postheated behavior of this cement subjected to elevated temperature has not been studied yet. Here, through extensive experimentation, the postheated mineralogical and physicochemical features of calcium aluminate cement concrete (CACC) were examined via DTA/TGA, X-ray diffraction (XRD), and scanning electron microscopy (SEM) imaging and the variation in the concrete physical features and the compressive strength deterioration with temperature rise were examined through ultrasonic pulse velocity (UPV) values. In addition, other mechanical features that were addressed were the residual tensile strength and elastic modulus. According to the XRD test results, with the temperature rise, the dehydration of the C3AH6 structure occurred, which, in turn, led to the crystallization of the monocalcium dialuminate (CA2) and alumina (Al2O3) structures. The SEM images indicated specific variations in morphology that corresponded to concrete deterioration due to heat.

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