Effect of additions of multiwall carbon nanotubes (MWCNT, MWCNT-COOH and MWCNT-Thiazol) in mechanical compression properties of a cement-based material

This study focuses on determining the mechanical compression properties of Guatemalan cement-based materials as a function of the carbon nanotubes chemical composition and loading. Multiwall Carbon Nanotubes oxidized (MWCNT-COOH) and Multiwall Carbon Nanotubes functionalized with thiazol (MWCNT-Thiazol) were synthesized in an environmentally friendly reaction with urea, instead of the traditional acid reaction. The samples were characterized by FT-IR, RAMAN, X-Ray Diffraction (XRD) and TGA. Different weight ratios of the MWCNTs were added to a cement mortar to provide mechanical properties (0.01%, 0.03%, 0.05% w/w); additionally, a super plasticizer was employed. By adding 0.01% of MWCNT, the mechanical compression of Portland-type cement marketed in Guatemala was improved to 26.7 MPa and 35.9 MPa, representing an improvement of 5.26% and 2.02% in comparison to the control sample at 7 and 28 days, respectively. The UV-Vis of the super plasticizer and MWCNT (16:1, 20:1, and 40:1) was done to understand the optimal dispersion. The performance of the mechanical compression of MWCNT in comparison to the MWCNT-COOH and MWCNT-Thiazol is analyzed according to the non-covalent interaction with the polycarboxylate superplasticizer and the matrix cement. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Acta Materialia Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)