Beach Sand: Alternative Filler In Metakaolin-Based Geopolymers

The efforts toward sustainability of natural resources promote the use unexploited natural resources and raw materials. Beach sand, unsuitable as filler in concrete due to its salinity and generally uniform grain size, was tested as an alternative filler in geopolymer composites. The processability of the mixture determined the minimum and maximum amounts of beach sand (70 and 75 wt%, respectively). Geopolymer solids with the limit of sand content were studied in terms of stability and mechanical properties. Laboratory results corroborated the tendency of flexural and compressive strength to increase over time, with the maxima being 9.95 MPa for flexural and 64.1 MPa for compressive. Infrared analysis showed formation of geopolymer bonds even after the addition of beach sand. These findings offer a new potential for the use of beach sand in coastal areas as a local source of material for less demanding construction, such as seawalls.