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Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Silvestro, Laura ; Ruviaro, Artur ; Lima, Geannina ; de Matos, Paulo ; de Azevedo, Afonso R. G. ; Monteiro, Sérgio Neves ; Gleize, Philippe

Materials, 2021-09, Vol.14 (18), p.5248 [Periódico revisado por pares]

Basel: MDPI AG

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Título:
Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes
Autor: Silvestro, Laura ; Ruviaro, Artur ; Lima, Geannina ; de Matos, Paulo ; de Azevedo, Afonso R. G. ; Monteiro, Sérgio Neves ; Gleize, Philippe
Assuntos: Amplitudes ; Aqueous solutions ; Carbon ; carbon nanotube ; Carbon nanotubes ; Cement ; Cement paste ; Compressive strength ; Dispersions ; Energy ; Fourier transforms ; Graphene ; Hydration ; Infrared spectroscopy ; Mechanical properties ; Microscopy ; Molecular structure ; Nanomaterials ; Photon correlation spectroscopy ; Portland cements ; Rheological properties ; Rheology ; Rheometry ; Spectrum analysis ; Superplasticizers ; Thermogravimetric analysis ; Ultrasonic imaging ; ultrasonication ; Weight ; Yield stress
É parte de: Materials, 2021-09, Vol.14 (18), p.5248
Notas: ObjectType-Article-1
SourceType-Scholarly Journals-1
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Descrição: The functionalization process usually increases the localized defects of carbon nanotubes (CNT). Thus, the ultrasonication parameters used for dispersing non-functionalized CNT should be carefully evaluated to verify if they are adequate in dispersing functionalized CNT. Although ultrasonication is widely used for non-functionalized CNT, the effect of this dispersing process of functionalized CNT has not been thoroughly investigated. Thus, this work investigated the effect of ultrasonication on functionalized CNT + superplasticizer (SP) aqueous dispersions by ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Furthermore, Portland cement pastes with additions of 0.05% and 0.1% CNT by cement weight and ultrasonication amplitudes of 0%, 50% and 80% were evaluated through rheometry, isothermal calorimetry, compressive strength at 1, 7 and 28 days, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). FTIR results from CNT + SP dispersions indicated that ultrasonication may negatively affect SP molecules and CNT graphene structure. The increase in CNT content and amplitude of ultrasonication gradually increased the static and dynamic yield stress of paste but did not significantly affect its hydration kinetics. Compressive strength results indicated that the optimum CNT content was 0.05% by cement weight, which increased the strength of composite by up to 15.8% compared with the plain paste. CNT ultrasonication neither increases the degree of hydration of cement nor the mechanical performance of composite when compared with mixes containing unsonicated CNT. Overall, ultrasonication of functionalized CNT is not efficient in improving the fresh and hardened performance of cementitious composites.
Editor: Basel: MDPI AG
Idioma: Inglês

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Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Silvestro, Laura ; Ruviaro, Artur ; Lima, Geannina ; de Matos, Paulo ; de Azevedo, Afonso R. G. ; Monteiro, Sérgio Neves ; Gleize, Philippe

Basel: MDPI AG

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