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.