Abstract: Waste glass powder and metakaolin were used to prepare geopolymer mortar. The effects of alkali activator with different sodium silicate modulus and liquid-solid ratios on the fluidity and mechanical properties of the waste glass powder-metakaolin geopolymer mortar were investigated, and the crystal structure, thermochemistry, pore structure, and micromorphology of the geopolymer mortar were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning thermal (TG-DSC), mercury in piezoelectricity (MIP), and scanning electron microscopy (SEM). The results show that the sodium silicate modulus and liquid-solid ratio have more obvious effects on the fluidity and mechanical properties of the geopolymer mortar. With the increase of sodium silicate modulus, the fluidity and strength of geopolymer mortar increase first and then decrease. When the sodium silicate modulus is 1.25, the alkali activator has the best excitation effect on the material, which increases the degree of reaction of the geopolymer, generates more hydration products, optimizes the pore structure of the matrix, and the compressive strength of 28 d reaches 43.0 MPa. The increase of liquid-solid ratio improves the fluidity of the geopolymer mortar, but decreases the compressive strength and has a negative effect on the pore structure. Moreover, the XRD, FTIR and TG-DSC results show that the waste glass in the geopolymer participates in the hydration reaction, provides Ca²⁺, and promotes the generation of C-S-H and C-A-S-H gels.

Key words: geopolymer, waste glass powder, metakaolin, alkali-activation, fluidity, mechanical property