Lightweight Geopolymer Concrete with EPS Beads

Activation of class F fly ash with the 10 M sodium hydroxide and sodium silicate and its geopolymeric products were analysed under quasi-isothermal mode of DSC, FTIR and TG/DTA techniques. Before adding in concrete, expanded polystyrene beads were prewetted with the styrenebutadienestyrene latex aimed at to improve their bonding with geopolymer. Lightweight mortars/concretes were made from geopolymeric binder, hardener and expanded polystyrene beads as part replacement of normal aggregates to various densities (800 -1840 kg/m). The expanded polystyrene beads were added in the mix in the range of 1 -3% by wt. (40 91% by vol.). It was observed that increasing concentration of expanded polystyrene beads reduces compressive strength, split tensile strength and ovendry density of the resulting mortars/concretes. Fire performance of expanded polystyrene/geopolymer concrete assessed by a cone calorimeter and reaction to fire characteristics methods was below the limits prescribed in the BS EN: 476 and ISO: 56601: 2002 and exhibiting no support to growth of the fire. However, it was noted that heat release rate and effective heat of combustion of expanded polystyrene concrete were higher than the control due to inclusion of expanded polystyrene bead aggregates in the mix. The thermal conductivity was reduced by 27-50% when expanded polystyrene beads were added in the geopolymer mixes to a level of 0.5-3% by wt. The properties of expanded polystyrene/geopolymer concrete were also compared with the existing guidelines (ASTM C 90).