Effect of particle size of hydromagnesite on properties of calcium aluminate cement bonded corundum based castables

2020 ◽  
Vol 46 (17) ◽  
pp. 27119-27125
Author(s):  
Ye Li ◽  
Liu Guo ◽  
Dafei Ding ◽  
Liugang Chen
2013 ◽  
Vol 1612 ◽  
Author(s):  
L.L Cardona-Hernández ◽  
J.I. Escalante-García

ABSTRACTAn investigation on composite geopolymeric binders, based on alkali activated fly ash (PFA) substituted with low-alumina calcium aluminate cement (CAC), was carried out using a Factorial experimental design in which the factors and levels were: %Na2O, 8-12%; modulus of the solution Ms=SiO2/Na2O =0 - 2, 10-30 wt% of CAC and fineness of PFA (D90) from 161.8 to 6.46 microns. The contribution of each factor was estimated with the 28-day compressive strength as the response variable. The curing temperature was 24h@60°C, and then at 20°C until mechanical testing. The specimens were also characterized by XRD and SEM. The results showed that the grinding modified the morphology of the PFA without changing the crystallographic or chemical characteristics as detected by XRD; and improved the mechanical properties of the geopolymers. The strength increased notably with the Ms up to 1, and reduced for Ms >1; the strength increased with the %Na2O and %CAC. Electron microscopy showed a higher densification at smaller PFA particle size, and the CAC addition promoted the formation of zeolite and Na2O-Al2O3-SiO2-H2O products.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3855
Author(s):  
Amirmohamad Abolhasani ◽  
Bijan Samali ◽  
Fatemeh Aslani

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.


2013 ◽  
Vol 115 (2) ◽  
pp. 1245-1252 ◽  
Author(s):  
František Šoukal ◽  
Petr Ptáček ◽  
Jiří Másilko ◽  
Tomáš Opravil ◽  
Jaromír Havlica ◽  
...  

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