Efeito de nanofolhas de MXenes (Ti3C2Tx) nas resistências à compressão e ao desgaste de um concreto estrutural

Abstract

Characteristics such as versatility, durability, and performance make concrete the leading product for structural use. More studies have been conducted on concrete reinforcement with the addition of new materials to its composition. In this work, we investigated wear by abrasion and fretting of reinforced concrete. MXene is very promising new two-dimensional (2D) materials due to their layered nanostructure. Aiming to increase durability of concrete structures against the action of wear, this work developed a model to analyze the effect of reinforcing concrete with a small amount (0.02% by weight) of MXenes nanosheets on abrasive wear and fretting wear. To this end, mechanical properties of compressive strength of conventional concrete and concrete reinforced with MXenes were initially evaluated at 3 and 28 days. Subsequently, its wear by abrasion (conventional concrete and with MXenes) and the tribological behavior in wear by fretting were investigated. In addition, porosity and water absorption tests were carried out using the Archimedes Principle, the analysis by scanning electron microscopy, energy-dispersion X-ray spectroscopy, and Raman spectroscopy. From the mechanical compressive strength tests, the samples with MXenes at 3 days showed an increase in compressive strength of 15.0% in relation to the control. MXenes additions showed no significant changes in terms of porosity and water absorption in relation to the control. From the abrasion wear tests, a reduction in the average wear rate of concrete with MXenes was obtained only when using abrasive 100. In the fretting tests, we evaluated MXenes addition to concrete as well as its surface deposition by dropcasting (1 application and 5 applications). For all speed and time conditions investigated, there was no significant difference in friction when using MXenes. Regarding wear, the dropcasting deposition tests led to less wear and smoother wear tracks, particularly for one application. Thus, although the effects of using MXenes were small, the promising results obtained by increasing the amount of MXenes could represent more significant gains in their use in concretes.