Assessing Standard Tests for Admixtured Chlorides in Calcium Aluminate Cement and Calcium Sulfoaluminate Cement Systems

2020 ◽  
Vol 117 (1) ◽  
Author(s):  
Ahmed Abdulhaq Ahmed ◽  
David Trejo
Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7333
Author(s):  
Solmoi Park ◽  
Namkon Lee ◽  
Gi-Hong An ◽  
Kyeong-Taek Koh ◽  
Gum-Sung Ryu

The use of alternative cementitious binders is necessary for producing sustainable concrete. Herein, we study the effect of using alternative cementitious binders in ultra-high-performance concrete (UPHC) by calculating the phase assemblages of UHPC in which Portland cement is replaced with calcium aluminate cement, calcium sulfoaluminate cement, metakaolin or blast furnace slag. The calculation result shows that replacing Portland cement with calcium aluminate cement or calcium sulfoaluminate cement reduces the volume of C-S-H but increases the overall solid volume due to the formation of other phases, such as strätlingite or ettringite. The modeling result predicts that using calcium aluminate cement or calcium sulfoaluminate cement may require more water than it would for plain UHPC, while a similar or lower amount of water is needed for chemical reactions when using blast furnace slag or metakaolin.


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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