Polyphosphate-modified calcium aluminate cement under normal and elevated temperatures: Phase evolution, microstructure, and mechanical properties

2017 ◽  
Vol 43 (17) ◽  
pp. 15525-15536 ◽  
Author(s):  
Weiting Xu ◽  
Jian-Guo Dai ◽  
Zhu Ding ◽  
Yanshuai Wang
Keyword(s):  
Mechanical Properties ◽  
Calcium Aluminate ◽  
Elevated Temperatures ◽  
Phase Evolution ◽  
Calcium Aluminate Cement ◽  
Microstructure And Mechanical Properties ◽  
Aluminate Cement

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.

Influence of Mixing Liquid on the Properties of Calcium Aluminate Cement

2008 ◽  
Vol 396-398 ◽  
pp. 241-244 ◽  
Author(s):  
L. Morejón-Alonso ◽  
Luis Alberto Santos ◽  
R. García Carrodeguas
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Calcium Phosphate ◽  
Calcium Aluminate ◽  
Calcium Aluminate Cement ◽  
Hydration Reaction ◽  
Potential Toxicity ◽  
Ca Ions ◽  
Aluminate Cement ◽  
Hydrated Calcium

The effect of using Na2HPO4 solution as mixing liquid in the physicochemical and mechanical properties of calcium aluminate cement (CAC), with a view to a possible reinforcement additive of conventional α-TCP-based CPC was studied. The results showed that the degree of the hydration reaction of CaAl2O4 (CA) increased when Na2HPO4 solution was used as mixing liquid. The porosity of cement was also lower (37.9 ± 1.3 %) than for H2O (33.2 ± 3.6 %). The values of compressive strength for cements prepared with both mixing liquids were lower than 3 MPa due to the excessive L/P ratio employed and large porosity. After immersion in SBF, only the Al(OH)3 hydrate is observed and no other crystalline hydrated calcium aluminate nor calcium phosphate was formed in any of the cements. Both cements released Ca ions to, and removed P ions from SBF, being this effect more remarkable when Na2HPO4 was used. As for other CAC, no Al was released to the SBF and no potential toxicity due to this ion should be expected.

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