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Journal of Nanomaterials
Volume 2012, Article ID 169262, 6 pages
http://dx.doi.org/10.1155/2012/169262
Research Article

Effect of Carbon Nanotube Aqueous Dispersion Quality on Mechanical Properties of Cement Composite

1Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
2Department of Civil and Structural Engineering, Aalto University School of Engineering, Rakentajanaukio 4 A, 02150 Espoo, Finland

Received 24 November 2011; Accepted 6 January 2012

Academic Editor: Donglu Shi

Copyright © 2012 Larisa I. Nasibulina et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An effect of the quality of carbon nanotube (CNT) dispersions added to cement on paste mechanical properties has been studied. High-quality dispersions of few-walled CNT (FWCNTs) were produced in two steps. First, FWCNTs were functionalized in a mixture of nitric and sulfuric acids (70 wt.% and 96 wt.%, resp.) at 80C. Second, functionalized FWCNTs were washed out by acetone to remove carboxylated carbonaceous fragments (CCFs) formed during CNT oxidation. Mechanical test results showed 2-fold increase in the compressive strength of the cement paste prepared from the dispersion of acetone-washed functionalized FWCNTs, which is believed to occur due to the chemical interaction between cement matrix and functional groups (–COOH and –OH). Utilisation of unwashed FWCNTs led to a marginal improvement of mechanical properties of the cement pastes, whereas surfactant-treated functionalized FWCNT dispersions only worsened the mechanical properties.