石墨烯量子点对蛇纹石混凝土力学性能及微结构的影响

Effect of graphene quantum dots on mechanical properties and microstructure of serpentine concrete

  • 摘要: 为了考察石墨烯量子点(GQDs)作为外掺料改善蛇纹石混凝土性能的可行性,研究了25、150、300、450和600℃时GQDs掺量对蛇纹石混凝土强度、结晶水损失率和微结构的影响。结果表明:室温(25℃)下,蛇纹石混凝土强度随GQDs掺量的增加而提升,当掺量为0.12wt%时,改善效果最佳,其7天、28天抗压强度和28天劈裂抗拉强度分别较基准组提高了26.4%、20.9%和27.7%;加热期间,与未掺GQDs的蛇纹石混凝土相比,掺入0.12wt%的GQDs使蛇纹石混凝土结晶水损失率降低了1.8%~20.0%,抗压强度和劈裂抗拉强度分别增加了18.0%~34.0%和29.4%~39.8%;微观试验表明高温环境促使蛇纹石混凝土水化,而GQDs拥有较好的导热性和纳米填充性,在二者共同作用下显著提高了蛇纹石混凝土的微观致密度,且300℃时致密度最高。

     

    Abstract: In order to explore the feasibility of using graphene quantum dots (GQDs) as admixtures to improve the properties of serpentine concrete, effects of GQDs dosage on strength, crystal water loss rate, and microstructure of serpentine concrete were investigated at 25, 150, 300, 450, and 600℃. The results show that strength of serpentine concrete at room temperature (25℃) is enhanced with the increase in the dosage of GQDs, and the best enhancement is achieved when the dosage is 0.12wt%, and its 7 days and 28 days compressive strength and 28 days splitting tensile strength are increased by 26.4%, 20.9%, and 27.7%, respectively, compared with the baseline group. The addition of 0.12wt% GQDs reduces the crystal water loss rate of serpentine concrete by 1.8%~20.0%, and increases the compressive strength and splitting tensile strength by 18.0%~34.0% and 29.4%~39.8%, respectively, as compared to serpentine concrete without GQDs during the entire heating period. Microscopic tests show that high temperature environment promotes the hydration of serpentine concrete, as well as GQDs possess better thermal conductivity and nano-filling properties, which together significantly improve the micro-density of serpentine concrete, and the micro-density is highest at 300℃.

     

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