高温后聚丙烯纤维混凝土抗压强度与气渗系数试验研究  

Experimental study on compressive strength and air permeability of polypropylene fiber reinforced concrete after elevated temperature

作　　者：姚秀鹏 韩阳[1] 沈雷 朱德 曹茂森[2] YAO Xiupeng;HAN Yang;SHEN Lei;ZHU De;CAO Maosen(School of Civil Engineering,Henan University of Technology,Zhengzhou 450001,China;Department of Engineering Mechanics,Hohai University,Nanjing 210098,China)

机构地区：[1]河南工业大学土木工程学院,河南郑州450001 [2]河海大学工程力学系,江苏南京210098

出　　处：《混凝土》2022年第2期85-89,共5页Concrete

基　　金：国家自然科学基金“包裹体爆裂法测定混凝土火灾温度场的研究”(50678060);国家自然科学基金“混凝土介观热-湿-力耦合离散模型与高温爆裂机理研究”(51908195);中国博士后科学基金资助项目(2020T130170)。

摘　　要：高温后聚丙烯纤维混凝土的残余抗压强度和气渗性能的研究对于火灾后建筑结构的安全评估和修复至关重要,通过试验研究了火灾高温、纤维长度以及纤维掺量对混凝土抗压强度和空气渗透系数的影响。试验结果表明:(a)经历温度不超过300℃时添加聚丙烯纤维改善混凝土抗压强度。短聚丙烯纤维(6 mm)对于混凝土抗压强度改善效果最佳;(b)常温下掺加聚丙烯纤维能够减小混凝土空气渗透系数,渗透性能改善,高温后其空气渗透系数增大,渗透性能变差,对混凝土空气渗透系数而言聚丙烯纤维长度影响大于掺量;(c)当经历温度超过300℃时,掺加聚丙烯纤维导致混凝土空气渗透系数增大,混凝土内部孔隙压力无法积聚,这与高温爆裂机理的孔隙压力学说相一致。The comprehensive understanding on compressive strength and air permeability of polypropylene fiber reinforced concrete(PFRC)after elevated temperature is of vital importance to post-fire safety assessment and restoration.Polypropylene fiber reinforced con crete with various heating treatments,fiber contents and fiber lengths are studied experimentally.The results show that(a)When the heating temperature lower than 300℃,the addition of polypropylene fiber can improve the compressive strengths.The shortest polypropylene fiber(6 mm)shows a better improvement on compressive strength of concrete.(b)At ambient temperature,the addition of polypropylene fiber results in decreases of air permeability coefficient.After high temperature treatment,the air permeability coefficient of polypropylene fiber reinforced concrete shows a faster increase compare to that of the plain concrete groups.Moreover,with the longest polypropylene fiber has a greatest increase in air permeability coefficient while the fiber content shows a relative slight impact on permeability.(c)When the heating temperatures exceed 300℃,the air permeability coefficient increases with the volume fraction of polypropylene fiber.As a result,the pore pressure inside concrete induced during heating cannot accumulate,which is consistent with the pore pressure mechanism on thermal spalling.

关 键 词：高温 聚丙烯纤维混凝土 抗压强度 气渗系数 

分 类 号：TU528.041[建筑科学—建筑技术科学]