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

Abstract

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.