Facile preparation and properties of foamed fly‐ash/slag‐based hollow glass microspheres/geopolymer composites.

In order to reuse the multiple solid waste and improve the porosity of geopolymer composites, a unique foaming process was developed to fabricate novel green foamed fly‐ash/slag‐based hollow glass microspheres/geopolymer (HGMs/FSGP) composites. A thorough investigation was carried out on the synergic effects of cetyltrimethylammonium bromide (CTAB), hydrogen peroxide (H2O2) and HGMs on the microstructure, strength and thermal conductivity. Results showed that the foamed HGMs/FSGP composites with the amorphous structure could be fabricated by foaming combined with HGMs at room temperature. The density of the samples changed from 1.16 to 0.47 g/cm3 with 1–5 wt.% H2O2. The acceptable compressive strength (0.71–15.05 MPa) of the HGMs/FSGP composites was attributed to the fractured HGMs, the good bond between HGMs and geopolymer matrix, and crack deflection across the HGMs. With proper H2O2 and HGMs, the composites obtained their lowest thermal conductivity of 0.116 W/(m⋅K), which could find use in insulation fields. [ABSTRACT FROM AUTHOR]