Zhang Xia, He Jun-Xi, Huang Gang, Zhou Chao, Feng Man-Man, Li Yan
National and Local Joint Engineering Laboratory of Traffic Civil Engineering Materials, Chongqing Jiaotong University, Chongqing 400074, China.
Chongqing Tongli Expressway Maintenance Engineering Co., Ltd., Chongqing 400074, China.
Materials (Basel). 2019 Mar 5;12(5):757. doi: 10.3390/ma12050757.
In this study, graphene-modified asphalt (GMA) was prepared from SK-70# matrix asphalt and ethylene bis(stearamide) (EBS). Based on the uniform design method, a model was created using Data Processing System (DPS) software and First Optimization (1stOpt) software using the graphene mixing amount, EBS mixing amount, shear rate, shear time, and shear temperature as factors and using the asphalt penetration, softening point, force ductility, SHRP-PG test, and multistress creep recovery data as indices. Calculations and analysis showed that the optimal composition and preparation parameters of GMA are as follows: the graphene proportion is 20‰, the EBS proportion is 1%, the shear rate is 6000 r.p.m., the shear time is 180 min, and the shear temperature is 140 °C. The prepared GMA had a significantly improved softening point, low-temperature fracture energy, antirutting factor, and creep recovery rate, indicating that adding graphene can improve the high- and low-temperature performance of asphalt. The prepared GMA was characterized by X-ray diffraction (XRD). The dispersibility of graphene in asphalt was evaluated by fluorescence microscopy and Image-Pro Plus imaging software. The results show that graphene can exist in asphalt in a stable form, which increases the loose-layered structure of stacked asphalt or gum. The intense adsorption effect of graphene strengthens the ordered structure of asphalt. However, due to its dispersibility characteristics, some graphene exists in asphalt in clustered form. When the graphene-to-dispersant ratio approaches the optimal value, the dispersant changes the form of graphene in asphalt from irregular clusters to regular clusters and from large, distinct clusters to small, indistinct clusters. When dispersant cannot uniformly disperse graphene in asphalt, graphene clusters primarily form medium-sized grains.
在本研究中，采用SK-70#基质沥青和乙烯双硬脂酰胺（EBS）制备了石墨烯改性沥青（GMA）。基于均匀设计方法，以石墨烯掺量、EBS掺量、剪切速率、剪切时间和剪切温度为因素，以沥青针入度、软化点、延度、SHRP-PG试验和多应力蠕变恢复数据为指标，使用数据处理系统（DPS）软件和First Optimization（1stOpt）软件建立了模型。计算与分析表明，GMA的最佳组成和制备参数如下：石墨烯比例为20‰，EBS比例为1%，剪切速率为6000 r.p.m.，剪切时间为180 min，剪切温度为140℃。制备的GMA的软化点、低温断裂能、抗车辙因子和蠕变恢复率均有显著提高，表明添加石墨烯可改善沥青的高低温性能。对制备的GMA进行了X射线衍射（XRD）表征。通过荧光显微镜和Image-Pro Plus成像软件评估了石墨烯在沥青中的分散性。结果表明，石墨烯能够以稳定的形式存在于沥青中，这增加了堆积沥青或胶质的松散层状结构。石墨烯的强烈吸附作用强化了沥青的有序结构。然而，由于其分散性特点，部分石墨烯以团聚形式存在于沥青中。当石墨烯与分散剂的比例接近最佳值时，分散剂将沥青中石墨烯的形态从不规则团聚体转变为规则团聚体，从大的、明显的团聚体转变为小的、不明显的团聚体。当分散剂不能使石墨烯在沥青中均匀分散时，石墨烯团聚体主要形成中等尺寸的颗粒。
