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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2022, Vol. 41 ›› Issue (1): 3-12.

Special Issue: 水泥混凝土

• Cement and Concrete • Previous Articles     Next Articles

Effect of CoFeMgAl-LDHs/CNTs Composite Material on Hydration and Microstructure of Cement

LIAO Muqing1,2,3, XIONG Zhiwen1,2,3, KE Guojun1,2,3, ZOU Pinyu1,2,3, SONG Baixing1,2,3, JIN Dan1,2,3   

  1. 1. School of Civil Engineering, University of South China, Hengyang 421001, China;
    2. China Nuclear Construction Key Laboratory of High Performance Concrete, Hengyang 421001, China;
    3. Hunan Provincial Key Laboratory of High Performance Special Concrete, Hengyang 421001, China
  • Received:2021-09-04 Revised:2021-11-10 Online:2022-01-15 Published:2022-02-10

Abstract: Heat of hydration test, non-evaporating water content test, X-ray diffraction analysis, scanning electron microscope analysis, mercury intrusion test and compressive strength tests were used to investigate the effect of the Co-Fe-Mg-Al hydrotalcite carbon nanotubes (CoFeMgAl-LDHs/CNTs) composite material on the hydration process, pore structure and strength of hardened cement paste. The results show that CoFeMgAl-LDHs/CNTs composite material significantly improves the hydration degree of cement within 3 d through nucleation, and thereby significantly enhances the compressive strength of the cement paste in the age of 3 d, the effect of improving the strength gradually reduces after 3 d and become unobvious after 7 d. Compare with blank cement paste, the content of gel pore and capillary pore in hardened cement paste increase obviously, while the macro pore decreases. At the same time, bridging effect of composite material optimizes microstructure of cement paste, and increase the stress bearing capacity of weak parts of cement matrix. Therefore, at the same age, the strength of hardened cement paste is increased. Because the change of composite content has no obvious effect on the change of pore size distribution, the change of composite content has little effect on the strength improvement of hardened cement paste at the same age.

Key words: Co-Fe-Mg-Al hydrotalcite carbon nanotubes, cement paste, hydration, pore structure, strength, nucleation, bridging effect

CLC Number: