Utilization of Nanofibers in Sintered Ceramic Body Based on Calcium Aluminous Cement

2016 ◽  
Vol 865 ◽  
pp. 62-66
Author(s):  
Radomír Sokolař ◽  
Mikuláš Šveda
Keyword(s):  
Calcium Aluminate ◽  
Raw Materials ◽  
Ceramic Body ◽  
Drying Shrinkage ◽  
Porcelain Body ◽  
Calcium Aluminate Cement ◽  
Sintered Ceramic ◽  
Different Temperatures ◽  
Aluminous Cement ◽  
Aluminate Cement

The aim of the article is to determine the possibility of domestic inorganic nanofibers utilization (Pardam, Ltd.) for experimentally developed porcelain body based on calcium aluminate cement. Two types of nanofibers based on pure SiO2 and Al2O3 were mixed with the casting slip prepared in the system calcium aluminate cement – quartz – feldspar. The properties of the raw materials mixture (mixing water content, drying shrinkage, strength of green body) and fired body at different temperatures (strength, porosity) were tested.

Sodium Hexametaphosphate as Deflocculation Agent for Calcium Aluminate Cements in Porcelain Body

2014 ◽  
Vol 897 ◽  
pp. 30-33 ◽  
Author(s):  
Radomír Sokolař ◽  
Lucie Vodová
Keyword(s):  
Calcium Aluminate ◽  
Raw Materials ◽  
Slip Casting ◽  
Porcelain Body ◽  
Sodium Hexametaphosphate ◽  
Modulus Of Rupture ◽  
Constant Viscosity ◽  
Casting Slip ◽  
Different Content ◽  
Aluminate Cement

Influence of typical ceramic deflocculant – sodium hexametaphosphate – on the rheological properties (viscosity) of calcium aluminate cement paste, porcelain raw materials mixture (casting slip), and fired porcelain body respectively, was determined. It was used two different typed of calcium aluminate cements (from two sources – producers - Istra, Almatis) with different content of Al2O3 (40 % and 70 %). Sodium hexametaphosphate decreases of water content needed to prepare slip casting with constant viscosity. Deflocculant increases the modulus of rupture MOR of dried green body and its bulk density. Sodium hexametaphosphate admixture is very suitable for the creation of porcelain body with low porosity after firing.

Different Chlorides Attack on the Hydration of Calcium Aluminate Cement at 5~40°C

2021 ◽  
Vol 1036 ◽  
pp. 247-254
Author(s):  
Zhong Ping Wang ◽  
Yu Ting Chen ◽  
Xiang Peng ◽  
Ling Lin Xu
Keyword(s):  
Compressive Strength ◽  
Calcium Aluminate ◽  
Physical Adsorption ◽  
Calcium Aluminate Cement ◽  
Binding Ability ◽  
Cement Pastes ◽  
Thermal Analyzer ◽  
Chloride Attack ◽  
Different Temperatures ◽  
Aluminate Cement

Calcium aluminate cement (CAC) has excellent resistance to seawater erosion, but the mechanism remains to be explored. Effects of NaCl and CaCl2 on the hydration of CAC at 5, 20 and 40°C were investigated in this paper by X-ray diffraction(XRD), thermal analyzer(TG-DSC), scanning electron microscopy(SEM), acoustic and electroacoustic spectrometer. Results show that the varieties of chlorides have great impacts on the chloride binding ability, mechanical properties and microstructure of cement pastes at different temperatures. At 5°C and 20°C, the formation of C2AH8 is suppressed by chloride attack. Though the addition of NaCl promotes the formation of CAH10, CaCl2 leads to a denser microstructure and the improvement in compressive strength. At 40°C, C2AH8 disappears by chloride attack, while C3AH6 and Friedel’s salt increase. Comparing with the attack of CaCl2, NaCl contributes to the formation of C3AH6. Therefore, it results in a the retraction in compressive strength, ascribing to a coarser structure. In addition, although NaCl is superior in chemical binding ability, CaCl2 has better physical adsorption ability which dominants the binding process, and thus leading to greater amount of bonded chloride than that with NaCl. This research provides the oretical basis for the application of CAC in marine environment.

Influence of Calcium Sulfate Varieties on Properties of Calcium Aluminate Cement-Based Self-Leveling Mortars

2016 ◽  
Vol 680 ◽  
pp. 455-461 ◽  
Author(s):  
Hao Dai ◽  
Shu Peng Zhang ◽  
Cheng Lan Ju ◽  
Dong Xu Li
Keyword(s):  
Calcium Aluminate ◽  
Calcium Sulfate ◽  
Drying Shrinkage ◽  
Heat Evolution ◽  
Calcium Aluminate Cement ◽  
X Ray Diffraction ◽  
Hydration Kinetics ◽  
Setting Times ◽  
Isothermal Calorimeter ◽  
Aluminate Cement

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.

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.

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