Potencial de produção de compósitos à base de gesso reforçados com nanoestruturas

Abstract

Nanotechnology has the potential to be the key to a new world in the field of construction and building materials. Plaster has excellent properties, but its use is still limited due to its porous matrix, which absorbs water, and its low mechanical strength. Due to the increasing use of plaster in civil construction, and in order to circumvent its main limitations to increase its scope of use, this study examined the insertion of different nanomaterials in plaster matrices, which are multi-walled carbon nanotubes (MWCNT), Cellulose nanofibrils (CNFs) and nanotalc (NT). The influence of these nanomaterials on plaster matrices was studied separately. The levels of incorporated MWCNT were 0%, 0.001%, 0.002%, 0.003% and 0.004% in relation to the plaster mass. And the percentages of CNFs and NT were 0%, 0.5%, 1%, 1.5% and 2%, also in relation to the plaster mass. In the experimental process, the different percentages of the nanomaterials were sonicated with water extracted from each trace, then the plaster was sprinkled into the mixture, mixed manually and molded into 4 x 4 x 16 cm shapes. After 28 days, tests were performed to evaluate apparent density, water absorption by immersion, flexural and compression strength, and morphology. There was a decrease in water absorption and an increase in apparent density, as MWCNT was incorporated into the plaster matrix. The mechanical strengths increased up to a certain point of the curve. The flexural strength, in turn, increased up to 12.74%, and the compressive strength had an increase of 26.4%, when compared to the control. In this study, the incorporation of lower levels of CNFs (up to 0.69%) proved to be viable and ensured lower water absorption. However, it did not significantly alter the compressive strength, and there was a decrease in flexural strength. On the other hand, given that CNFs are sustainable, cheap and highly available, and can even be obtained from waste, it is possible to create an innovative, sustainable material with high added-value. Regarding the incorporation of NT, a small amount of NT filled the pores of the plaster matrix, increasing the apparent density by up to 1.8%, increasing the compressive strength by up to 24.12%, and decreasing the water absorption by up to 5, 86%. It did not significantly change the flexural strength.