▎ 摘　　要

NOVELTY - Nano-modified graphene oxide comprises graphene oxide, and indium hydroxide crystal particles bound on the graphene oxide through functional group on the surface of the graphene oxide. USE - Nano-modified graphene oxide is used for preparing concrete anti-cracking and toughening additive used in building, road, bridge and tunnel (all claimed). ADVANTAGE - The nano-modified graphene oxide improves the surface roughness of graphene oxide, the graphene oxide and the cement substrate can be firmly combined together, improving the mechanical property of the concrete. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: 1. concrete anti-cracking and toughening additive, which comprises 10-20 %mass nano-modified graphene oxide which is dispersed in aqueous phase; 2. a nano-modified graphene oxide composition, which comprises 40-70 pts. wt. graphene oxide dispersion liquid, 0.1-5 pts. wt. indium source, 0.1-30 pts. wt. urea and 0.1-30 pts. wt. citrate; 3. preparation of the nano-modified graphene oxide; and 4. preparation of the concrete anti-cracking and toughening additive.