Synthesis of industrial solid wastes based geopolymer foams for building energy conservation: Effects of metallic aluminium and reclaimed materials

Abstract

Thermal insulation materials with less energy consumption and low CO2 emissions have been paid great attention. This study was devoted to assessing the feasibility of utilizing industrial solid wastes for the preparation of sustainable geopolymer foams to make up for the weak link of using industrial solid waste in green low-carbon building energy-saving materials research. Efforts were made to investigate the effects of aluminium powder content and substitution ratio of reclaimed materials on slurry performance, physic-mechanical properties and formation of gel species by a series of characterization methods. Results revealed that the geopolymer foams characterized by compressive strength of 2.83 MPa, bulk density of 507 kg/m3 and thermal conductivity of 0.167 W/(m·K) were successfully produced by external incorporation of 0.17 % dosage of Al powder. 10 % substitution ratio of reclaimed materials presented no obvious negative effect on fluidity, initial setting time, bulk density, compressive strength, thermal conductivity, pore structure and microstructure of the specimens. The pore structure, morphology and polymeric gels of pore partition matrix co-determined the macroscopic properties of geopolymer foams. The existence of semi-crystalline zeolite precursors in reclaimed materials may induce the formation of zeolite-like grains on the inner surface of pores. The present work was in agreement with the strategic objective of resources recycling, solid waste utilization, lower carbon emission and building energy saving, which was conducive to the development of the circular and green economy.