Study on the Sulfate Attack Resistance and High-Temperature Resistance of Phosphoric Acid-Based Geopolymer
In order to obtain a sealing/reinforcement material with high durability,low pH and effectively supporting function to fissures and fractured rock,phosphate-based geopolymers were prepared using metakaolin as the precursor raw material,phosphoric acid and aluminum dihydrogen phosphate as the activators.The sulfate attack resistance of geopolymer samples was analyzed,and the compressive strength,corresponding phase and microstructural changes of the samples under different temperatures were measured to evaluate their high-temperature resistance.The results showed that phosphate-based geopolymers exhibited good attack sulfate resistance,with the compressive strength erosion resistance coefficients of geopolymer samples soaked in 10%sodium sulfate solution both higher than 1.0.Additionally,they demonstrated excellent high-temperature resistance,the compressive strength of A100 sample after calcination at 150℃for 1 h increased by 30.4%compared with that before calcination,while the compressive strength of different groups of samples remained above 15 MPa after calcination at 1 050℃for 1 h.