1.Northwest Research Institute Co. Ltd. of C.R.E.C.;2.School of Civil Engineering and Mechanics，Lanzhou University;3.Leshan Giant Buddha Management Committee
Sichuan Science and Technology Program (No. 2020YFS0391); Key Research Project of China Railway Academy Co. Ltd. (No. 2019-KJ011-Z010-A2, No. 2020-KJ009-Z009-A2).
More than 8000 grottoes and cliff statues located in Sichuan and Chongqing areas, and most of them are made from sandstone. The properties of sandstone are deteriorated due to long-term environmental effects, which pose threats to the cultural relics. Graphene sheets are added to the traditional sandstone cultural relics mortarto enhance the properties, which is defined as “CH@G mortars”. The mechanical properties and volume stability of CH@G mortars are enhanced by Graphene sheets. The specimen with the highest strength is obtained by addition of 0.07 wt% Graphene sheets,and its values (increase proportion compared with CH mortar) of compressive strength, flexural strength and tensile strength at 56 days are 4.21 MPa (7.36 %), 2.21 MPa (19.46 %) and 0.47 MPa (51.61 %), respectively. The results of FT-IR and Raman spectra show that Graphene sheets have little influence on the composition of products, and Graphene sheets could accelerate the hydration in early age according to the XRD results. SEM images exhibit that Graphene sheets could act as a regulate phase to form uniform and compacted microstructure.