复合材料科学与工程 ›› 2024, Vol. 0 ›› Issue (10): 32-39.DOI: 10.19936/j.cnki.2096-8000.20241028.005

• 基础研究 • 上一篇    下一篇

复合盐冻融循环后PE-ECC拉伸性能及劣化机理研究

郑怡1, 陈中书1, 张晋1*, 张耀庭2   

  1. 1.湖北工业大学 土木建筑与环境学院, 武汉 430068;
    2.华中科技大学 土木与水利工程学院, 武汉 430074
  • 收稿日期:2023-07-20 出版日期:2024-10-28 发布日期:2024-12-10
  • 通讯作者: 张晋(1985—),男,博士,讲师,主要从事高性能混凝土材料方面的研究,zhangjinzjbst@126.com。
  • 作者简介:郑怡(1987—),女,博士,讲师,主要从事高性能混凝土材料方面的研究。
  • 基金资助:
    国家自然科学基金(52178140)

Study on tensile properties and deterioration mechanism of PE-ECC under coupling attack of freeze-thaw cycle and sulfate-chloride

ZHENG Yi1, CHEN Zhongshu1, ZHANG Jin1*, ZHANG Yaoting2   

  1. 1. School of Civil Engineering, Architecture and the Environment, Hubei University of Technology, Wuhan 430068, China;
    2. School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2023-07-20 Online:2024-10-28 Published:2024-12-10

摘要: 为研究聚乙烯纤维水泥基复合材料(PE-ECC)复合盐冻后的拉伸性能,设置了纯水和复合盐侵蚀(5% Na2SO4+3.5% NaCl)两种冻融环境,分别进行了0,50,100,150,200次冻融循环后的轴向拉伸试验。试验结果表明:两种冻融环境下试件的损伤程度均随着冻融次数的增加而增大;相同冻融次数下,复合盐冻条件下试件表面剥蚀程度更严重,变形性能更低,但极限应变均能保持在2%以上。在此基础上,通过XRD、SEM、EDS能谱分析、核磁共振等技术研究复合盐冻后PE-ECC拉伸性能劣化的微观机理。结果表明,复合盐侵蚀产生的膨胀性水化产物如水镁石、石膏、钙矾石等大量堆积,使孔隙和微裂缝开展,与孔中水结冰共同作用,加剧了内部结构的损伤。

关键词: 复合盐冻, 聚乙烯纤维水泥基复合材料(PE-ECC), 拉伸性能, 微观机理

Abstract: In order to study the tensile properties of polyethylene fiber engineered cementitious composites(PE-ECC) under coupling attack of freeze-thaw cycle and sulfate-chloride, two kinds of environments, pure water and sulfate-chloridesolution (5% Na2SO4+3.5% NaCl), were set up, and the axial tensile tests were carried out after 0, 50, 100, 150, and 200 freeze-thaw cycles, respectively. The test results showed that the damage degree of the specimens in both environments increased with the freeze-thaw cycles, but the degree of surface spalling was more serious and the deformation performance was lower in the sulfate-chloride environment under the same freeze-thaw cycles, but the ultimate strains could all achieve above 2%. On this basis, the micro-mechanism of deterioration of PE-ECC tensile property was investigated by XRD, SEM, EDS energy spectrum analysis, NMR and other techniques. The results show that swelling hydration products such as brucite, gypsum and ettringite produced by sulfate-chloride erosion cause pores and micro-cracks to develop, which work together with the freezing of water in the pores, aggravates the damage of the internal structure.

Key words: compound salt freeze, polyethylene fiber engineered cementitious composites (PE-ECC), tensile properties, microscopic mechanism

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