Pore properties, inner chemical environment, and microstructure of nano-modified CFA-WBP (class C fly ash-waste brick powder) based geopolymers

In order to study the influence of waste brick powder (WBP) and nano-modification on class C fly ash (CFA) based geopolymer, pore properties (i.e. bulk density, apparent porosity, and true porosity, and closed porosity) were tested according to the related Chinese National Standard, and the pore structure was also explored by mercury intrusion porosimetry (MIP); Water leaching procedure were performed to study the inner chemical environment; X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) were measured to the microstructure and modification mechanism. The results show that WBP as additive results in a denser structure of geopolymer; nano-modification improves the pore structure, ameliorates the anti-leaching ability of geopolymer by constraining the soluble ions in gels, makes the geopolymerization more complete, and results in a denser paste structure by filling gaps between the particles with amounts of reaction products.