Abstract:Geopolymer is a kind of three-dimensional network structure from non-crystalline to half-crystalline inorganic polymer, synthesized by using aluminosilicate minerals or solid wastes and alkali-activate agent at 20~200℃. This paper has mainly studied the rapidly synthetic condition of geopolymer and its resistance to acid and alkali. Orthogonal experiments L9(34) of the raw material proportion of geopolymer were carried out, with the calcination temperature of kaolin, added content of kaolin, water glass and sodium hydroxide as the variable quantity. The optimum raw material proportion is that kaolin is calcined at 600℃ for 4 h, with the mass proportion of kaolin, water glass and sodium hydroxide being 7∶4.5∶1, and the early compressive strength is the highest: 62.25 MPa. On the basis of the optimal raw material proportion, the orthogonal experiments L9(34) for the preparation condition of geopolymer were conducted, with solidification temperature, curing temperature and curing time as the variables. The optimal condition was that the mixture was solidified at 60℃ and then cured at 60℃ for 1 h, in which the early compressive strength of geopolymer was 85 MPa. Geopolymer in 0.5 mol/L HCl, H2SO4 and NaOH solution was soaked for 60 h, mass changes were -2.03%, -5.33% and 2.90%,respectively, the compressive strength changes were -12.68% and 17.07%; When geopolymer in 0.25~1.0 mol/L acid and alkali solution was soaked for 24 h, with the increasing concentration, its mass and compressive strength increased in NaOH solution, changed insignificantly in HCl solution, and were significantly reduced in H2SO4 solution. The results show that the geopolymer can well resist HCl but its resistance to H2SO4 is poor, while NaOH can promote the compressive strength development of geopolymer.