Characterization and performance evaluation of geopolymer prepared with thermal-mechanical activated aluminum sulfate residue

Abstract

In this study, geopolymer prepared from thermal-mechanical activated aluminum sulfate residue (TMASR) and alkali activator was studied. This work aims to investigate the effects of different design factors on the workability, compressive strength, and efflorescence of TMASR-based geopolymer. The reaction products and structures of the geopolymer binders made from TMASR were tested by FTIR, XRD, and SEM. The results showed that the type, dosage, silicate modulus of the activator, and the water to binder ratio can significantly affect the fresh and hardened properties of TMASR-based geopolymer. A mixture with optimal compressive strength, workability, and efflorescence characteristics can be obtained by using Na2SiO3 solid content of 30%, the water to binder ratios of 0.6–0.65, and the modules of sodium silicate of 1.2–1.6. The main hydration products of TMASR-based geopolymer were amorphous geopolymeric materials. The efflorescence product compositions in TMASR-based geopolymer were Na2SO4, Na2SO4·10H2O, Na2CO3, and Na2CO3·nH2O. The results obtained in this study can promote the utilization of waste acidic aluminum sulfate residue for the production of sustainable construction materials.