Mechanic performance of phosphoric acid-based geopolymer cured in an open environment

Phosphoric acid-based geopolymer (PGEO) belongs to acidic material and has many applications in environmental disposal. The curing method has an important impact on the mechanic performance of geopolymers, the existing research concerning PGEO synthesized from fly ash (FA) and phosphoric acid (PA) are performed on the specimens cured at sealed environment, but no related research on the PGEO cured at an open environment is found. Therefore, to investigate the mechanic performance, pH and of PGEO cured in an open environment, the unconfined compressive strength tests were conducted on PGEO specimens cured in an open environment, and its mechanism was investigated using Scanning Electron Microscope, X-Ray diffraction, and Fourier transform infrared reflection (FTIR) tests. Moreover, the thermogravimetric was measured using the thermogravimetric tests. The results showed that in the scope of this study, the compressive strength of the PGEO decreased with the PA concentration and the liquid–solid ratio (L/S) increasing. When the L/S was a fixed value, as the curing time increased, an obvious strength loss was observed for the PGEO with the content of 40 and 50