▎ 摘　　要

NOVELTY - Preparing crystalline graphene comprises (i) adding the high-activity calcium hydroxide powder into the reaction furnace, heating to the preset temperature and maintaining the temperature under the protection of inert atmosphere, where the content of calcium hydroxide in the high active Calcium hydroxide powder is not less than 90% and the content of magnesium hydroxide is between 0.1-5 wt.%; (ii) introducing carbon source into the reaction furnace and performing chemical vapor deposition reaction to obtain solid phase product; and (iii) acid washing the solid phase product, filtering, drying, placing in inert atmosphere furnace containing hydrogen or carbon dioxide and etching at high temperature. USE - The crystalline graphene is useful as modifying agent in preparation of modified asphalt (claimed). ADVANTAGE - The method: produces crystalline graphene which can be highly adapted to the asphalt mixture and improve the high and low temperature performance of the asphalt. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for crystalline graphene, prepared as mentioned above.