▎ 摘　　要

NOVELTY - A graphene mortar composition comprises 30-50 wt.% cement, 30-60 wt.% sand, 1-5 wt.% calcium sulfoaluminate, 1-5 wt.% vinyl acetate copolymer, 0.1-2 wt.% trimethylolpropane, 1-5 wt.% silica fume, 0.1-3 wt.% silane compound, and 0.2-1.2 wt.% graphene oxide. The calcium sulfoaluminate comprises alumina quicklime and anhydrite. Trimethylolpropane is mixed with diethylene glycol, triethylene glycol and/or ethylene glycol. The silane compound is silane, octadecyltrimethoxysilane, octadecyltrichlorosilane, dimethoxydimethylsilane and/or tetramethyl orthosilicate. USE - Graphene mortar composition is used for repairing damaged portions of concrete (claimed). ADVANTAGE - The method enables repairing the damaged part of the concrete of the expansion joint of the bridge structure by using the mortar composition so as to improve bondability with the damaged parts of the structure, so that mechanical properties can be improved by using a paint composition to have abrasion resistance and corrosion resistance. The method enables preventing re-damage through improvement of material properties even if external factors such as impact occur on the repaired section. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for repairing damaged portions of concrete, which involves cleaning damaged portions of concrete, applying a rust inhibitor to surface of reinforcing bar to prevent oxidation of reinforcing bar when exposed, applying an adhesion strengthening agent to the surface of the damaged portions, filling the damaged portions with the mortar composition, curing the mortar composition at a constant temperature, and finishing by applying an abrasion-resistant functional paint to the cured surface.