Study on strengthening and toughening mechanism of fiber modified fly ash based geopolymer

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Jan.2023, Vol.46 No.1: 104-110

DOI: 10.3969/j.issn.1003-5060.2023.01.016

Authors

ZHOU Xinxing $ ^{1} $, WU Tianjun $ ^{2} $

(1. Key Laboratory of Highway Construction and Maintenance Technology in Loess Region, Shanxi Transportation Technology Research & Development Co., Ltd., Taiyuan 030032, China; 2. Shanxi Jiaoke Geotechnical Engineering Co., Ltd., Taiyuan 030006, China)

Abstract and Keywords

Abstract: In order to clarify the strengthening and toughening mechanism of lignin fiber in circulating fluidized bed fly ash based geopolymer (CFBG), by adding metakaolin and a small amount of calcium carbide slag, with the help of electronic universal material testing machine, X-ray diffractometer, field emission scanning electron microscopy, energy dispersive spectroscopy, infrared spectroscopy, industrial computed tomography (CT) and molecular simulation, mechanical properties, structure and microscopic morphology of geopolymers with different lignin fiber content (0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) were tested. The influence of different lignin fiber content on the strengthening and toughening mechanism of CFBG was analyzed. It indicates that the flexural strength and fracture toughness of CFBG reach the maximum value when the lignin fiber content is 0.3%, which are 18.6 MPa and 9.6 MPa·m $ ^{1/2} $, respectively. The compressive strength and fracture toughness of geopolymers show an upward trend with the increase of lignin fiber content. The incorporation of lignin fiber can promote the formation of mullite crystal phase, zeolite crystal phase and C-S-H gel in geopolymers, and significantly change the structure of geopolymers; and the incorporation of lignin fiber can

Keywords: geopolymer; fly ash; lignin fiber; metakaolin; strengthening and toughening mechanism

作者信息

周新星 $ ^{1} $，吴天军 $ ^{2} $

(1. 山西省交通科技研发有限公司黄土地区公路建设与养护技术交通行业重点实验室，山西太原 030032；2. 山西交科岩土工程有限公司，山西太原 030006)

摘要和关键词

摘要: 为明确木质素纤维在循环流化床粉煤灰基地聚物(circulating fluidized bed fly ash based geopolymer, CFBG)中的强韧化机理,文章通过添加偏高岭土和少量的电石渣,借助电子式万能材料试验机、X射线衍射仪、场发射扫描电子显微镜、能谱仪、红外光谱、工业CT及分子模拟,对不同木质素纤维掺量(质量分数分别为0、0.1%、0.2%、0.3%、0.4%、0.5%)的地聚物进行力学特性、结构及微观形貌测试,分析不同木质素纤维掺量对CFBG强韧化机理的影响。结果表明:当木质素纤维掺量为0.3%时,CFBG抗折强度和断裂韧性达到最大值,分别为18.6 MPa、9.6 MPa·m $ ^{1/2} $;随着木质素纤维掺量增加,地聚物抗压强度和断裂韧性呈上升趋势;掺入木质素纤维可促进地聚物中莫来石晶相、类沸石晶相及C-S-H凝胶的生成,显著改变地聚物的结构;木质素纤维的掺入可降低地聚物表面孔隙,改变地聚物破坏形式,延长裂缝的扩展路径。研究结果可为促进工业固废高附加值资源化利用提供理论依据。

关键词: 地聚物；粉煤灰；木质素纤维；偏高岭土；强韧化机理

Funding

国家自然科学基金资助项目（52008235）；山西省科技成果转化引导专项基金资助项目（201804D131034）；山西交通控股集团有限公司科技资助项目（19-JKKJ-55；20-JKKJ-43）和山西交通科学研究院集团有限公司科技创新发展资助项目（20JKCF-10；22-JKCF-10）

合肥工业大学学报(自然科学版)

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