COMPOSITE MODIFIED PILLARED MATERIAL AND PREPARATION METHOD THEREFOR, AND FLUORIDE-FREE AND ALKALI-FREE ACCELERATOR BASED THEREON AND PREPARATION METHOD THEREFOR

The present invention belongs to the technical field of concrete admixtures. Disclosed are a composite modified pillared material modified with a hyperbranched quaternary ammonium salt, and a preparation method therefor. According to the composite modified pillared material, a hyperbranched quaternary ammonium salt having a specific structure is used as a modified material, and differs from a common modified material having a long-chain structure since the material itself contains a branched structure, thereby ensuring that after an orthorhombic pillared material is intercalated, the interlayer spacing is larger, and the CEC capacity is higher. Further disclosed in the present invention are a fluoride-free and alkali-free accelerator comprising the composite modified pillared material as a stabilizer, and a preparation method therefor. Compared with a traditional alkali-free accelerator, the fluorine-free and alkali-free accelerator increases the use amount of aluminum sulfate therein to 10% or above, such th