Abstract

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.

摘要

以建筑垃圾再生细骨料替代天然砂为基础，研究了氧化石墨烯（GO）改性再生水泥基复合材料（RCBC）的综合物理性能和水化机理。通过超声分散GO和振动搅拌制备RCBC。结果表明，0.03%GO改性的RCBC在7d时抗弯强度和抗压强度分别提高了16%和21%，0.02%GO改性的RCBC在28d时抗弯强度和抗压强度分别提高了13.7%和21%。分别为 13.6%。良好的耐候性和老化冻融性能，Cl ^-含量小于0.06%。GO/RCBC的放射性检测结果为I _Ra = 0.08，I _r= 0.15，属于A级建筑材料。通过XRD、TG-DTA、SEM等手段研究了制备的GO/RCBC的水合机理。结果表明，GO促进钙矾石(AFt)、水合硅酸钙(CSH)的形成以及AFt和氢氧化钙(CH)晶型的转变，从而提高了RCBC的综合性能。