干湿循环作用下聚丙烯纤维混凝土抗拉强度试验研究  

Experimental study on tensile strength of polypropylene fiber concrete under dry-wet cycle

作　　者：杨海燕 何刚 李登峰 赵海林 陈向红 YANG Haiyan;HE Gang;LI Dengfeng;ZHAO Hailin;CHEN Xianghong(Beijing Jiaotong Vocational Technical College,Beijing 102200,China;China Mcc5 Group Corp.Ltd.,Chengdu 610063,China;Beijing Kangshuntong Engineering Project Management Co.,Ltd.,Beijing 100160,China;China Coal Construction Engineering Group Construction Co.,Ltd.,Beijing 100161,China)

机构地区：[1]北京交通职业技术学院,北京102200 [2]中国五冶集团有限公司,成都610010 [3]北京康顺通工程项目管理有限公司,北京100160 [4]中煤建工集团有限公司,北京100161

出　　处：《建筑结构》2025年第2期126-131,共6页Building Structure

基　　金：国家自然科学基金项目(41877218)。

摘　　要：混凝土中掺入聚丙烯纤维可有效提升其抗拉强度特性,但目前缺乏干湿循环作用下聚丙烯纤维混凝土抗拉强度及其微观机制的研究。通过考虑聚丙烯纤维掺量(0、0.2%、0.4%、0.6%、0.8%)及干湿循环次数(0~100次),对哑铃形试样开展单轴拉伸试验。分析干湿循环作用对聚丙烯纤维混凝土抗拉强度的影响,并结合干湿循环后试样质量损失率及微观孔隙结构,讨论上述影响的微观机制。结果表明,当聚丙烯纤维掺量小于0.6%时,聚丙烯纤维混凝土抗拉强度基本随聚丙烯纤维掺量的增大而增大;而当聚丙烯纤维掺量继续增加到0.8%时,抗拉强度出现下降;随着干湿循环次数的增加,抗拉强度逐渐降低;聚丙烯纤维掺量为0、0.2%、0.4%、0.6%、0.8%的试样经100次干湿循环后其抗拉强度分别下降了29.6%、22.8%、17.5%、11.7%、12.4%;干湿循环导致混凝土质量损失率上升,内部孔隙增大,进而导致抗裂强度显著降低。The incorporation of polypropylene fibers into concrete effectively enhances its tensile strength properties.However,there is a lack of research on the tensile strength and microscopic mechanism of polypropylene fiber reinforced concrete under dry-wet cycles.The uniaxial tensile test of dumbbell-shaped samples was carried out by considering the polypropylene fiber content(0,0.2%,0.4%,0.6%,0.8%)and the number of dry-wet cycles(0~100 times).The effect of dry-wet cycle on the tensile strength of polypropylene fiber reinforced concrete was analyzed,and the microscopic mechanism of the above effects was discussed in combination with the mass loss rate and microscopic pore structure of the samples after dry-wet cycle.The results show that when the content of polypropylene fiber is less than 0.6%,the tensile strength of polypropylene fiber concrete increases with the increase of polypropylene fiber content.When the content of polypropylene fiber continues to increase to 0.8%,the tensile strength decreases.With the increase of the number of drywet cycles,the tensile strength decreases gradually.The tensile strength of the samples with polypropylene fiber content of 0,0.2%,0.4%,0.6% and 0.8% decrease by 29.6%,22.8%,17.5%,11.7% and 12.4% respectively after 100 drywet cycles.The dry-wet cycle leads to the increase of the mass loss rate of concrete and the increase of internal pores,which leads to the significant decrease of crack resistance strength.

关 键 词：干湿循环 聚丙烯纤维混凝土 抗拉强度 微观机制 

分 类 号：TU528.57[建筑科学—建筑技术科学]