NANOINDENTATION METHOD FOR STUDYING THE STRUCTURE OF MODIFIED CEMENT STONE

Preliminary results for the cement specimens under study have been obtained by the nanoindentation method. It has been found that the elastic modulus increases in the specimens that contain a complex admixture with nanosize particles. Also, the effect is observed on adding an admixture containing only one type of nanoparticles (sol of nanosilica SiO2 or the MWCNT carbon material). Parameters of the nanoindentation method have been selected that ensure obtaining final consistent results. These results are presented by the histograms of distribution of nanoindentation points by elastic moduli and hardness, and also by the distributions in these characteristics in the horizontal plane xy, which is perpendicular to the nanoindenter's motion. The obtained results suggest that there is a change in the nanostructure of the C-S-H gel, which is compared with the increment in the strength, the Young moduli, and the shear on adding SiO2 nanoparticles and MWCNT nanoparticles.