Water reducing agent, preparation method thereof and concrete using water reducing agent

The invention relates to the technical field of additives for concrete, and particularly discloses a water reducing agent, a preparation method of the water reducing agent and concrete using the water reducing agent. The water reducing agent is prepared from 10 to 20 parts of acrylic acid, 34 to 38 parts of modified trimethylolpropane tripolypropylene glycol ether, 3 to 9 parts of potassium persulfate, 16 to 20 parts of sodium hydroxide and 23 to 27 parts of water; the preparation method comprises the following steps: S1, uniformly mixing acrylic acid, potassium persulfate and modified trimethylolpropane tripolypropylene glycol ether to form a mixed solution; s2, dropwise adding the mixed solution into water at 80-90 DEG C, uniformly mixing, and keeping the constant temperature for 3-5 hours to prepare a polymer solution; S3, cooling to room temperature, adding an alkaline solution into the polymer solution, and neutralizing to weak acidity to prepare the polycarboxylate superplasticizer. The water reducing a