Time-Stability Dispersion of MWCNTs for the Improvement of Mechanical Properties of Portland Cement Specimens

Abstract

This study shows the energy optimization and stabilization in the time of solutions composed of H2O + TX-100 + Multi-Wall Carbon Nanotubes (MWCNTs), used to improve the mechanical properties of Portland cement pastes. For developing this research, sonication energies at 90, 190, 290, 340, 390, 440, 490 and 590 J/g are applied to a colloidal substance (MWCNTs/TX-100 + H2O) with a molarity of 10 mM. Raman spectroscopy analyses showed that, for energies greater than 440 J/g, there are ruptures and fragmentation of the MWCNTs; meanwhile at energies below 390 J/g, better dispersions are obtained. The stability of the dispersion over time was evaluated over 13 weeks using UV-vis spectroscopy and Zeta Potential. With the most relevant data collected, sonication energies of 190, 390 and 490 J/g, at 10 mM were selected at the first and the fourth week of storage to obtain Portland cement specimens. Finally, we found an improvement of the mechanical properties of the samples built with Portland cement and solutions stored for one and four weeks; it can be concluded that the MWCNTs improved the hydration period.

Low Concentrations of Gold Nanoparticles as Electric Charge Carriers in Piezoelectric Cement-Based Materials

“…This curing setup is presented in Figure 2. At the end of the curing process, the cement paste cylinders were placed into an oven at 40 °C for 24 h to remove excess water in the pores of the composite [34].…”

Effects of Molarity and Storage Time of MWCNTs on the Properties of Cement Paste

“…Some experiments have confirmed that MWCNTs can be effectively dispersed in water using ultrasound energy and commercial surfactants [11][12][13]. In the literature, it is possible to observe works focused on applying surfactants to sustain the dispersion [14]. For example, Mendoza [15] studied several dispersion concentrations of surfactants such as sodium lauryl sulfate, cetylpyridinium chloride, and Triton X-100, finding that the reinforcing effect of MWCNTs is masked by the negative effect of the surfactants.…”

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

“…The setting of favorable conditions for effective hydration can be reached by the application of ultrafine additives with high surface activity caused by their small size. Among such additives, it is possible to mention carbon-based nanomaterials such as carbon black [14][15][16][17], isostatic graphite [18][19][20], graphene oxide [21,22], graphene nanoplatelets [23,24], carbon nanotubes [25][26][27], and carbon fibers [28,29]. The listed additives possess several unique properties, such as high surface energy, mechanical strength, and electrical conductivity.…”

“…The listed additives possess several unique properties, such as high surface energy, mechanical strength, and electrical conductivity. The application of such additives for the modification of composites provides an improvement in the structure of the binding matrix and, consequently, leads to the improvement of different composite properties [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…Carbon nanotubes (CNTs) are among the most well-known and widely studied additives for the modification of cement composites. CNTs enable the obtainment of concrete with multifunctional properties [25][26][27]. However, the high price of CNTs and their contradictory results limit their application in construction practice.…”