Rheological behavior, hydration, and mechanical properties of LC³ systems with the incorporation of functionalized multi-walled carbon nanotubes

Comportamento reológico, hidratação e propriedades mecânicas de sistemas LC³ com a incorporação de nanotubos de carbono de paredes múltiplas funcionalizados

Abstract

Alternatives to conventional Portland cement with a more sustainable appeal are increasingly recurrent. Among these are the Limestone Calcined Clay (LC³) systems, characterized by high replacement percentages of Portland clinker by calcined clay and limestone, materials widely available worldwide. A complete understanding of the rheological behavior of LC³ systems is necessary for the practical application of this type of cement to be consolidated. Furthermore, although not yet investigated, the incorporation of nanomaterials stands out as a promising alternative for accelerating reactions and enhancing the mechanical performance of these systems at early ages. This study investigated the incorporation of carbon nanotubes (CNT) contents from 0.05 to 0.125% in an LC³ system through rotational rheometry, isothermal calorimetry, compressive strength at 7 and 28 days, and X-ray diffraction. Although the CNT incorporation increased the dynamic yield stress and equivalent viscosity of the LC³ pastes, the content of 0.1 wt.% slightly increased and anticipated the occurrence of the main peak of the aluminates. Increases of up to 13.5% in compressive strength at 7 and 28 days of hydration were observed for a CNT content of 0.1 wt.%.

Keywords:
LC³; carbon nanotubes; composites; rheology; hydration