▎ 摘　　要

NOVELTY - A concrete expansion agent comprises 50-90 pts. wt. limestone, 8-30 pts. wt. anhydrite, 2-20 pts. wt. alumina, 3-5 pts. wt. graphene, 3-5 pts. wt. styrene-maleic anhydride graft copolymer, 0.2-0.3 pt. wt. alkali metal powder, 5-8 pts. wt. acidic slag, 0.2-0.3 pt. wt. tartaric acid, 1-2 pts. wt. solid nickel, 2-3 pts. wt. rosin hot polymer, and 2-3 pts. wt. polyethylene glycol fatty acid ester. The mass fraction of aluminum oxide in bauxite is 40-50 wt.%. USE - Concrete expansion agent. ADVANTAGE - The method is simple, has improved sintering condition, and improves expanding agent quality. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the expansion agent comprising mixing limestone, anhydrite, and bauxite at mass ratio of 5:2:1, grinding into powder, heating to 500-800 degrees C for 15-20 minutes, and calcining to 1000-1100 degrees C for 10-15 minutes, adding remaining raw materials, and calcining to 1200-1250 degrees C for 8-10 minutes.