The brittle characteristics of geopolymers during failure seriously hinder their practical engineering applications. To improve the toughness of low-energy alkali-activated geopolymer cementing coal gangue (AGCCG), the flexural performance of alkali-activated geopolymer cementing coal gangue (AGCCG) was enhanced by layering polypropylene fibers. Based on DIC digital speckle technology, the four-point flexure test of AGCCG was carried out, and the strength formation mechanism of the material was analyzed in depth by combining SEM-EDS and XRD. 3D visualization and analysis of the inside of the specimen with the help of CT scanning technology. The internal crack evolution law of the sample was illustrated by PFC numerical simulation. The results showed that the crack formation threshold, peak flexural strength and residual flexural strength of the specimens reached a local maximum at 3 % NaOH doping. With the increase of NaOH dosage, the cementitious product becomes more and more dense and homogeneous, and the area of void defects in the hydration product within the field of view becomes smaller and smaller. The peak bending strength of specimen B4-#4 is 79.43 % of that of specimen B5-#1–4, in which the cost of specimen B5-#1–4 is four times of that of specimen B4-#4, and the way of fiber assignment in specimen B4-#4 is more reasonable when considered together. The layered addition of fibers has a directional strengthening effect on the mechanical properties of geopolymer, and the overall addition of fibers can improve the overall strength and toughness of geopolymer. The numerical simulation results basically coincide with the macroscopic test results, and are consistent with the progressive damage law of the specimens obtained from the numerical scattering test. The results of the study can provide a theoretical basis for improving the bearing capacity of geopolymer and optimizing its structural performance. As well as reducing the impact of solid waste on the environment and improving the efficiency of resource use.

中文翻译：

---

分层添加纤维提高碱活化地质聚合物胶结煤矸石弯曲性能的研究


地质聚合物在破坏过程中的脆性特性严重阻碍了其实际工程应用。为了提高低能碱活化地质聚合物固井煤矸石（ACCCG）的韧性，通过分层聚丙烯纤维来增强碱活化地质聚合物固井煤矸石（ACCCG）的弯曲性能。基于DIC数字散斑技术，对AGCCG进行了四点弯曲测试，并结合SEM-EDS和XRD对材料的强度形成机理进行了深入分析。借助 CT 扫描技术对标本内部进行 3D 可视化和分析。通过PFC数值模拟阐明了样品内部裂纹的演化规律。结果表明，当NaOH掺杂量为3%时，试件的裂纹形成阈值、峰值弯曲强度和残余弯曲强度均达到局部最大值。随着NaOH用量的增加，胶凝制品越来越致密、均匀，视场内水化产物的空隙缺陷面积越来越小。试件B4-#4的峰值弯曲强度是试件B5-#1-4的79.43%，其中试件B5-#1-4的成本是试件B4-#4的4倍，并且综合考虑，标本B4-#4的纤维分配方式更为合理。纤维的分层添加对地聚合物的力学性能有定向强化作用，纤维的整体添加可以提高地聚合物的整体强度和韧性。数值模拟结果与宏观试验结果基本吻合，与数值散射试验得到的试件渐进损伤规律一致。 研究结果可为提高地聚合物的承载能力、优化其结构性能提供理论依据。以及减少固体废物对环境的影响，提高资源利用效率。