Study on Properties of Graphene Oxide Modified Recycled Cement-Based Composites

Based on the replacement of natural sand by recycled fine aggregate of construction waste, the comprehensive physical properties and hydration mechanism of graphene oxide (GO) modified recycled cement-based composites (RCBC) were studied. The RCBC was prepared by ultrasonic dispersion GO and vibration stirring. The results show that the flexural and compressive strength of the RCBC modified by 0.03%GO at 7d age increase by 16% and 21% respectively, the flexural strength and compressive strength of RCBC modified by 0.02% GO at 28d age increase by 13.7% and 13.6% respectively. Good weather resistance and the freeze-thaw performance at age, Cl- contents is less than 0.06%. The radioactive detection results of GO/RCBC is I-Ra = 0.08 and I-r = 0.15, which belongs to Class A building materials. The hydration mechanism of the prepared GO/RCBC was studied by XRD, TG-DTA, SEM, and other means. The results show that GO promotes the formation of ettringite (AFt), calcium silicate hydrate (C-S-H) and the transformation of AFt and calcium hydroxide (CH) crystal form, thus improving the comprehensive properties of RCBC.