ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 63, (4) 356 - 364 (2019)


THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF CEMENTITIOUS MATERIALS COMPRISED OF LIMESTONE, CALCINED CLAY AND CLINKER
 
Li Qinfei, Wang Han, Hou Pengkun, Chen Heng,Wang Yang, Cheng Xin
 
Shandong Provincial Key Laboratory of Preparation and Measurements of Building Materials, University of Jinan, Jinan, 250022

Keywords: Calcined clay, Limestone, Mechanical properties, Microstructure
 

Limestone, calcined clay and cement (LC³) are one of the low carbon cement materials which are used as a partial substitution of clinker and Portland cement. In this study, the effects of limestone and calcined clay (LC²) on the mechanical properties and microstructure of mortars were studied under multi-scales. It could be concluded that the compressive strength decreased slightly with an increase in the LC² content, but the flexural strength increased significantly due to the greater formation of crystalline aluminates in the LC³. The x-ray diffraction and thermal analysis results prove the pozzolanic activity of the calcined clay in the LC³ system which is in agreement with the results of the decreasing calcium hydroxide and the increasing ettringite content, and the LC² could reduce the heat of the hydration of the LC³ significantly. Also, the formation of calcium hemicarboaluminate (3CaO.Al₂O₃.Ca[(OH)(CO₃)0.5].xH₂O) and calcium monocarboaluminate (3CaO.Al₂O₃.CaCO₃.xH₂O), as well as the pozzolanic activity of the calcined clay contributed to the development of the mechanical strength.


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doi: 10.13168/cs.2019.0031
 
 
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