The Effect of Multi-Walled Carbon Nanotube Additives on the Aging Process of Cement Stone

The effect of additives of multi-walled carbon nanotubes (MWCNTs) with an average diameter of 9 nm and the aspect ratio of 38 on the structure, phase composition, and the ultimate flexural and compressive strength of cement stone is studied depending on the aging time for 3-28 days. The structure of MWCNTs used are characterized by transmission electron microscopy, and the cement stone structure was analyzed by scanning electron microscopy and powder X-ray diffraction. MWCNT additives to cement stone are found to affect its strength gain process. The nanotubes act as the crystallization centers of calcium silicate hydrates at the initial time after the preparation of cement stone samples (up to 14 days). It is shown that the occurrence of these crystals in the cement stone structure increases the ultimate flexural and compressive strength.