scholarly journals The Influence of Sodium Hexametaphosphate (Na6P6O18) on Hydration of Calcium Aluminate Cement Under Hydrothermal Condition

2016 ◽  
Vol 151 ◽  
pp. 119-126 ◽  
Author(s):  
Martin Palou ◽  
Eva Kuzielová ◽  
Matúš Žemlička ◽  
Vladimír Živica
Keyword(s):  
Calcium Aluminate ◽  
Hydrothermal Condition ◽  
Calcium Aluminate Cement ◽  
Sodium Hexametaphosphate ◽  
Aluminate Cement

Dispersants for Dual Binding System Kaolin - Calcium Aluminate Cement

2015 ◽  
Vol 1124 ◽  
pp. 10-15
Author(s):  
Radomír Sokolář
Keyword(s):  
Rheological Properties ◽  
Sodium Silicate ◽  
Sodium Carbonate ◽  
Calcium Aluminate ◽  
Water Glass ◽  
Calcium Aluminate Cement ◽  
Sodium Hexametaphosphate ◽  
Green Body ◽  
Rotational Viscometer ◽  
Aluminate Cement

Calcium aluminate cement CAC is able to increase strength of green body distintly. Influence of typical ceramic dispersants – sodium hexametaphosphate SHMP, sodium carbonate SC and sodium silicate (water glass) SWG – on the rheological properties (viscosity) of calcium aluminate cement – kaolin slurries with different ratio between CAC and kaolin was determined. In all cases sodium carbonate is the most effective dispersant but deflocculation is not very intensive – decrease of torque during the rotational viscometer test was not higher than 15 % (from 68,8 N.mm to 58.3 N.mm for ratio 1:1 of CAC:kaolin suspension when 0,06 %-wt of sodium carbonate was used).

scholarly journals Effects of Sodium Hexametaphosphate Addition on the Dispersion and Hydration of Pure Calcium Aluminate Cement

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5229
Author(s):  
Benjun Cheng ◽  
Can Yao ◽  
Jian Xiong ◽  
Xueyin Liu ◽  
Haijun Zhang ◽  
...  
Keyword(s):  
Calcium Aluminate ◽  
Coaxial Cylinder ◽  
Calcium Aluminate Cement ◽  
Sodium Hexametaphosphate ◽  
Hydration Reaction ◽  
Residual Concentration ◽  
Ζ Potential ◽  
Concentration Method ◽  
Reduced Viscosity ◽  
Aluminate Cement

The effects of sodium hexametaphosphate (SHMP) addition on the dispersion and hydration of calcium aluminate cement were investigated, and the relevant mechanisms discussed. The content of SHMP and the adsorption capacity of SHMP on the surface of cement particles were estimated using plasma adsorption spectroscopy and the residual concentration method. The rheological behavior of hydrate, ζ-potential value of cement particles, phase transformation and the microstructure of the samples were determined by coaxial cylinder rheometer, zeta probe, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that SHMP readily reacted with Ca2+, forming complexes [Ca2(PO3)6]2− ions which were subsequently adsorbed onto the surfaces of cement particles. When the content of SHMP was 0.05%, the adsorption ratio reached 99%. However, it decreased to 89% upon further increasing the addition of SHMP to 0.4%. The complexes [Ca2(PO3)6]2− adsorbed onto the surfaces of cement particles inhibited the concentration of Ca2+ and changed ζ-potential, resulting in enhanced electrostatic repulsive force between the cement particles and reduced viscosity of cement-water slurry. The experimental results indicate that the complexes [Ca2(PO3)6]2− covering the surfaces of cement particles led to a delayed hydration reaction, i.e., they extended the hydration time of the cement particles, and that the optimal addition of SHMP was found to be about 0.2%.

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

Materials ◽  
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.

High temperature properties of MDF composite based on calcium aluminate cement and polyvinyl alcohol

2013 ◽  
Vol 115 (2) ◽  
pp. 1245-1252 ◽  
Author(s):  
František Šoukal ◽  
Petr Ptáček ◽  
Jiří Másilko ◽  
Tomáš Opravil ◽  
Jaromír Havlica ◽  
...  
Keyword(s):  
High Temperature ◽  
Polyvinyl Alcohol ◽  
Calcium Aluminate ◽  
Calcium Aluminate Cement ◽  
High Temperature Properties ◽  
Aluminate Cement
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