PRODUCTION AND PROPERTIES OF LOW-DENSITY ALKALI-ACTIVATED COMPOSITES BY INCORPORATION OF EXPANDED POLYSTYRENE (EPS)

The increasing consumption of Portland cement raised concerns about the large amount of CO2generated during its production, Alkali-Activated Materials (AAM) being an alternative for its replacement in some applications. This research investigated the production of lightweight Alkali-Activated Composites (AAC), based on metakaolin and expanded polystyrene (EPS) as an agglomerate. The effects of the amount and size of EPS incorporated in the matrix (18, 35and 53vol.-% and varied average sizes of 0.85, 2.16, and 6.00 mm) were evaluated. Increasing amounts of EPS reduced strength, from 42 MPa to 25 or 14 MPa for 18 or 53vol.-% of beads of size 0.85 mm. Strength decrease is more pronounced for larger EPS beads, i.e. to 12.2 and 1.5 MPa when 18 or 53vol.-% EPS beads with an average diameter of 6.0 mm were added. However, composites with a density as low as 0.8 to 1.2 g/cm3were produced with strength varying between 15 and 25 MPa, demonstrating their potential as construction materials for non-structural applications.