Belonging to the technical field of concrete additive preparation, the invention relates to a preparation method of a stable alkali-free setting accelerator. The method includes: firstly conducting gelatinization treatment on black
fungus chaff powder, them performing mixing heating with an acrylic
monomer,
ammonium persulfate and other substances to obtain
fungus chaff water-absorbent resin, then subjecting the
fungus chaff water-absorbent resin and a self-made
gelatin gel solution to mixing
grinding so as to obtain mixed water-absorbent resin
powder, then subjecting the mixed water-absorbent resin
powder and
calcium carbonate powder to mixing pressing, and performing ball milling to obtain
calcium carbonate resin composite powder, then using aluminum
sulfate and
benzylamine as the raw materials to prepare an organic amine dispersion solution, and finally heating the organic amine dispersion solution,
calcium carbonate resin composite powder and other substances, and then performing cooling. The stable alkali-free setting accelerator prepared by the method provided by the invention has good stability, does not hydrolyze easily, enhances the
setting time to a initial
setting time of less than 2min and a final
setting time of less than 4min, is free of alkali component, does not cause harm to
human body, also is environment-friendly, and improves the concrete strength, thus being widely applicable to bridges, underground
engineering and other fields.