Manufacture of low density geopolymer based composites with incorporation of expanded polystyrene spheres.

Reference	Presenter	Authors (Institution)	Abstract
04-091	Kurt Strecker	Strecker, K.(Universidade Federal de São João del-Rei); Lombardi, C.T.(Universidade Federal de São João del-Rei); Azevedo, A.G.(Universidade Federal de São João del-Rei);	Geopolymers are considered to be eco-friendly materials, much more than ordinary Portland cement, in terms of reduced production and lower CO2 emissions. These binders also show faster curing settings when compared to ordinary Portland cement. In the civil industry, there is a constant search for light weight materials, of high specific strength. Among the materials of low specific gravity which can be used as aggregates in this type of concrete is expanded polystyrene (EPS), which is an artificial aggregate widely used for the production of lightweight concrete. The current work studies the fabrication a light weight composite material of a geopolymer matrix using expanded polystyrene beads as aggregate. Composites were prepared varying the amount (20%, 40%, and 60% in volume) and size (0.710 to 1mm, 1.325 to 3mm, and from 4 to 8mm) of the polystyrene beads added. The results obtained show that with increasing amount of poystyrene beads added, the density of the composite materials decreases. Furthermore, density decrease has been more pronounced using larger beads. The density of the geoplomer matrix has been 1.43 g/cm3. Adding 60% of beads with a diameter range between 0.710 to 1mm density decreased to 0.86 g/cm3, while the density of composites with the same amount of larger beads, 4 to 8mm, was 0.76 g/cm3. At the same time the composite strength also decreases significantly from initially 47 MPa to 9.5 MPa and 1.56 MPa, when using 60% of smaller or larger beads, respectively. However, the composite materials developed may still be interesting for non-structural applications and may provide better thermal and acoustic isolation properties.
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