Dissertação
Uso de agregados leves à base de resíduos de poliéster e laminado de PVC extrusados com poliestireno em matrizes cimentícias
Fecha
2023-07-21Autor
Cruz, Bruna Silva da
Institución
Resumen
The generation of waste from different sectors of the Brazilian economy has
generated studies and research related to the consumption and disposal of the most
varied products. In this context, the industries of the footwear sector, traditional in the
State of Rio Grande do Sul, are inserted, which have the need to seek sustainable
actions in the reuse of leftover raw materials from the production of footwear.
Therefore, this work aimed to evaluate the use of a lightweight aggregate based on
polyester waste and PVC laminate extruded with recycled polystyrene in
cementitious matrices. Reference mortars were prepared with a mass ratio of 1:3
(cement: dry sand) and a water/cement ratio (w/c) of 0.48. Another four mortars were
prepared with levels of replacement of quartz sand, in volume, by light aggregate, at
25%, 50%, 75% and 100%. The results in the fresh state of the mortar show that the
workability reduced with the increase in the percentage of light aggregate in the
mortar. In the hardened state, increasing the percentage of lightweight aggregate led
to an inverse behavior for compressive strength and specific mass, and a direct
behavior for water absorption, porosity and void ratio. With the aid of the scanning
electron microscope (SEM) it was observed that the thickness of the microcrack
between the quartz sand and the hydrated cement paste was smaller when
compared to the thickness of the microcrack between the lightweight aggregate and
the cement paste after compressive strength tests , which indicates that the
lightweight aggregate makes this region less resistant, which corroborates the 86%
drop in compressive strength at 28 days between the reference matrix and the matrix
containing 100% lightweight aggregate. By energy dispersive spectroscopy (EDS)
the chemical elements present on the surface of the samples were verified. Fourier
Transform Infrared Spectroscopy (FTIR) identified the characteristic functional groups
of materials and cementitious matrices at 7 and 28 days. With the aid of X-ray
diffraction (XRD) it was observed that the intensity of the characteristic peaks of
quartz reduced as there was an increase in the replacement of quartz sand by light
aggregate in the cementitious matrices.