Self-curing strategy of granite waste powder by calcined and alkaline activation: Mechanical and durability properties

Abstract

To explore the durability of granite waste powder (GWP) based cementing materials and expand the application potential in engineering, this paper applied alkali-activated calcined GWP (AACG) as a cementitious material to achieve GWP-AACG self-curing (GAC). The response surface methodology was used to investigate the effects of the calcined-GWP proportion, calcination temperature, alkali activator modulus, and thermal curing temperature on the strength, water resistance, and long-term durability of GAC. The results show that the four variables have a roughly linear effect on strength, while an optimal interval for water resistance and long-term durability exists. Moreover, increasing the curing temperature could improve the polymerization process, fill the capillary gap, and reduce water absorption. However, the high calcined-GWP proportion and low alkali activator modulus would increase harmful porosity in GAC. Compared to the cracking and disintegration observed in previous studies, GAC within the optimal interval not only maintains structural integrity, but also has a residual strength coefficient of nearly 50 % after-saturation. Its 28 days unconfined compressive strength can reach around 5 MPa and withstand at least 12 wetting-drying cycles. These findings significantly advance the large-scale recycling and utilization of GWP as a geopolymer precursor, demonstrating the material's potential for sustainable construction applications.