Vol 6, No 3 (2015) > Metalurgy and Material Engineering >

Thermal Effect on Flexural Strength of Geopolymer Matrix Composite with Alumina and Wollastonite as Fillers

Dwi Marta Nurjaya, Sotya Astutiningsih, Anne Zulfia



The addition of
alumina and wollastonite in geopolymer resin is expected
to increase the thermal behavior of the geopolymer matrix composite. In this work, fine granules of
solid alumina and acicular wollastonite used as filler were mixed with a fly
ash-based geopolymer resin paste to form a composite matrix.
The filler additions were 2.5% to 10.0% of the total weight with sodium
silicates and sodium hydroxide used as activators.
The results showed that the addition of alumina and wollastonite as filler
did not have much effect on the flexural and compressive
strength of the geopolymer matrix composite at room temperature. Wollastonite
fiber, which was added in the form of a short-sized fiber, only produced a very small bridging effect. Nevertheless, alumina
filler composite showed a good result after being exposed
to a temperature at 200°C, although the strength was reduced
as the temperature increased. Moreover, wollastonite fibers only managed to
maintain 50% of their flexural strength after 2 hours
exposure at a temperature of 200°C due to the damage of the
wollastonite fiber.

Keywords: Alumina; Composite; Flexural strength; Fly ash; Geopolymer; Wollastonite

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