摘要
隧道施工中常采用喷射混凝土作为初期衬砌,因此要求其具备良好的韧性和抗裂性。聚酰胺(PA)纤维能够改善混凝土的压弯及拉弯性能,但其对混凝土抗弯强度及韧性的增强效果尚不明确。基于试验研究,分析了PA纤维含量对混凝土抗弯强度及韧性的影响规律,确定了PA纤维的最优掺量。同时,对比了实验室及现场制备试样的基本力学性能差异。结果表明,PA纤维的最优掺量为0.7%;当试样处于高应变状态时,其韧性在PA纤维含量为1.00%时会降低;在达到设计强度前,韧性对PA纤维含量的敏感性较低,而当试样达到极限状态时,韧性对PA纤维含量的敏感性则显著提高。
Shot-concrete is often used as the initial lining in tunnel construction.Therefore,it is required to have good toughness and crack resistance.Polyamide(PA)fibers can improve the compression bending and tensile bending properties of concrete,but the enhancement effect on the flexural strength and toughness of concrete is not yet clear.Based on experimental research,the influence of PA fiber content on the flexural strength and toughness of concrete was analyzed to determine the optimal dosage of PA fiber.Meanwhile,the basic mechanical properties differences between the samples prepared in the laboratory and on site were compared.The results showed that the optimal dosage of PA fiber was 0.7%;When the sample is in a high strain state,its toughness will decrease when the PA fiber content is 1.00%;Before reaching the design strength,the sensitivity of toughness to PA fiber content is lower.But when the specimen reaches the ultimate state,the sensitivity of toughness to PA fiber content will significantly increases.
作者
强科明
Qiang Keming(Third Engineering Limited,China Railway 18th Bureau Group Corporation Limited,Zhuozhou 072750,China)
出处
《市政技术》
2024年第12期67-74,83,共9页
Journal of Municipal Technology
基金
中铁十八局集团有限公司2022年度科研创新项目(C2022-051)
中国铁建股份有限公司2022年度科技研究开发计划及资助课题(2022-C1)。
