Pang Shuai, Zhang Xiangdong, Zhu Kaixin, Li Jiaze, Su Lijuan
School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China.
Resource Utilization of Coal Gangue and Energy-Saving Building Materials Liaoning Provincial Key Laboratory, Liaoning Technical University, Fuxin 123000, China.
Polymers (Basel). 2023 Jan 30;15(3):700. doi: 10.3390/polym15030700.
Eco-gelled coal gangue materials (EGCGMs) are usually produced using coal gangue, slag, and fly ash in a highly alkaline environment. Herein, to improve the mechanical properties of such materials, polypropylene fibers were uniformly mixed with them. An unconfined compressive strength test and a three-point bending test of the fiber-reinforced EGCGMs under different conditions were conducted. Based on the performance degradation control technology of the fiber structure, the interface mechanism of the composite materials was analyzed from the micro level using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). In the mechanical test, the 28 d UCS and flexural properties of the fiber-reinforced EGCGMs were analyzed using the Box-Behnken design response surface design method and orthogonal design method, respectively. The order of significance was as follows: sodium hydroxide, fiber length, and fiber content. Within the scope of the experimental study, when the NaOH content is 3, the fiber content is 5 ‱, and the fiber length is 9 mm, the mechanical properties are the best. Based on the microscopic equipment, it was discovered that the amorphous ecological glue condensation product formed by the reaction of slag and fly ash in the alkaline environment was filled between the coal gangue particles and the fibers, and several polymerization products accumulated to form a honeycomb network topology. The distribution of fibers in the EGCGM matrix could be primarily divided into single embedded and network occurrences. The fiber inhibits the crack initiation and development of the matrix through the crack resistance effect, and improves the brittleness characteristics through the bridging effect during the failure process, which promotes the ductility of the ecological cementitious coal gangue matrix.The results presented herein can provide a theoretical basis for improving the mechanical properties of alkali-activated geopolymers.
生态凝胶煤矸石材料（EGCGMs）通常是在高碱性环境中使用煤矸石、矿渣和粉煤灰生产的。在此，为了提高此类材料的力学性能，将聚丙烯纤维与它们均匀混合。对不同条件下纤维增强EGCGMs进行了无侧限抗压强度试验和三点弯曲试验。基于纤维结构的性能劣化控制技术，利用扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射（XRD）从微观层面分析了复合材料的界面机理。在力学试验中，分别采用Box-Behnken设计响应面设计方法和正交设计方法分析了纤维增强EGCGMs的28天无侧限抗压强度（UCS）和弯曲性能。显著性顺序如下：氢氧化钠、纤维长度和纤维含量。在实验研究范围内，当氢氧化钠含量为3、纤维含量为5‱且纤维长度为9mm时，力学性能最佳。基于微观设备发现，矿渣和粉煤灰在碱性环境中反应形成的无定形生态胶凝产物填充在煤矸石颗粒与纤维之间，几种聚合产物堆积形成蜂窝状网络拓扑结构。EGCGM基体中纤维的分布主要可分为单根嵌入和网络状出现。纤维通过抗裂作用抑制基体裂纹的萌生和扩展，并在破坏过程中通过桥接作用改善脆性特征，从而提高生态胶凝煤矸石基体的延性。本文给出的结果可为提高碱激活地质聚合物的力学性能提供理论依据。
