The invention discloses a preparation method of a polycarboxylate
superplasticizer for small-
slump concrete. The preparation method comprises the following steps: 1, an
ethylene glycol monovinyl
polyethylene glycol
ether macromonomer,
tap water,
sodium hydroxide, unsaturated
carboxylic acid and 2-
acrylamide-2-methylpropanesulfonic acid are added into a four-necked flask one by one, and are uniformly stirred; 2, unsaturated
carboxylic acid,
tap water and other materials are uniformly mixed to obtain a solution A, and a
reducing agent and
tap water are uniformly mixed to obtain a solution B; 3,the solution A and the solution B are dropwise added into the four-necked flask at the same time and are reacted; and 4, the pH value of a
polymer prepared in step 3 to 5-7 by using an
alcohol amine
monomer. The polycarboxylate
superplasticizer synthesized by adopting the novel polyether in the preparation method improves the wrapping property and winding property of a polyether
side chain, so theconcrete has good workability and good flow retentivity, the
plasticity and cohesiveness in small-
slump concrete are improved, and
hysteresis bleeding is avoided; the polycarboxylate superplasticizerhas low sensitivity to the
water consumption of concrete, and has a good water-retaining property; and the preparation method has the advantages of simple production process, no generation of wastes,greenness, environmental friendliness, short reaction period, and easiness in realization of large-scale production.