Influence of Carbon Nanotubes on the Structure Formation of Cement Matrix

2nd International Conference on Innovative Materials, Structures and Technologies

Petrunin, S.^1 ; Vaganov, V.^2 ; Reshetniak, V.^2 ; Zakrevskaya, L.^2

Limited Liability Company Macromer, Vladimir, Russia^1

Vladimir State University, Vladimir, Russia^2

关键词: CNTs based composites;    Functionalizations;    Hydration kinetics;    Hydration products;    Mechanical and electronic properties;    Oxygen-containing functional groups;    Strength improvements;    Structure formations;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/96/1/012046/pdf
DOI  :  10.1088/1757-899X/96/1/012046

来源: IOP

【 摘 要 】

The potential of application of CNTs as a reinforcing agent in cement composites is governed by their unique mechanical and electronic properties. The analysis of concrete strength changes under CNTs introduction shows non-uniformity and sometimes inconsistency of results. Due to the fact that CNTs influence the hydration kinetics, structure and phase composition of concrete, an idea concerning the importance of interaction between the surface of CNTs and hydrate ions formed by the dissolution of the clinker phases has been suggested. In this paper, the theoretical and experimental study of interaction between hydrate ions and CNTs surface is discussed. Reference nanotubes and nanotubes functionalized by carboxylic groups are used in this research. Phase composition was determined by X-Ray analysis according to the Rietveld method. It was found that the presence of oxygen-containing functional groups on CNTs surface leads to intensification of the hydration process and increase in concentration of C-S-H gel from 65.9% to 74.4%. Special attention is usually paid to interactions between Ca2+ions and CNTs, because the hardening rate and structure of cement stone are determined by principle of Ca2+localization in the solution. In this paper the possible binding mechanisms are discussed. Based on the experimental results, the hypothesis regarding the formation of cement composite structure for different CNTs surface functionalizations is considered. According to this hypothesis, the CNTs act as the centers of crystallization for hydration products contributing to the acceleration of hydration, increase of the concentration of C-S-H gel and strength improvement of CNTs based composites.