高温后混凝土气体渗透性及力学性能研究
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摘要
火灾高温不仅会降低混凝土结构的力学性能,还会对混凝土的耐久性产生重大的影响。通过高温电阻炉模拟火灾试验,研究高温下混凝土的气体渗透性、弹性模量和轴心抗压强度的变化特征,以及气体渗透性和力学性能的相互关系。试验结果表明:混凝土气体渗透性随火灾温度的升高而逐渐增大,且在500℃时气体渗透性增长72.6倍;在200℃高温下,混凝土的弹性模量和轴心抗压强度略有提高,而在350℃及以上高温下,其力学性能大幅降低。
High temperature of fire hazard not only reduces the mechanical properties of concrete structure,but also has significant impact on the durability of concrete.The gas permeability,elastic modulus and axial compressive strength of concrete under high temperature were studied by simulating fire test at high temperature resistance furnace,and the relationship between gas permeability and mechanical properties was studied.The results show that the concrete gas permeability gradually increases with the fire temperature and increased by 72.6 times at 500 ℃.The elastic modulus and compressive strength of the concrete were slightly improved at 200 ℃,and the mechanical properties of the concrete were greatly reduced at 350 ℃ and above.
High temperature of fire hazard not only reduces the mechanical properties of concrete structure,but also has significant impact on the durability of concrete.The gas permeability,elastic modulus and axial compressive strength of concrete under high temperature were studied by simulating fire test at high temperature resistance furnace,and the relationship between gas permeability and mechanical properties was studied.The results show that the concrete gas permeability gradually increases with the fire temperature and increased by 72.6 times at 500 ℃.The elastic modulus and compressive strength of the concrete were slightly improved at 200 ℃,and the mechanical properties of the concrete were greatly reduced at 350 ℃ and above.
引文
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[2]闫治国,杨其新,朱合华.长大公路隧道火灾温度场分布试验研究[J].东南大学学报自然科学版,2005,35(s1):84-8.
[3]王海龙,俞秋佳,孙晓燕,等.高温作用后混凝土损伤与耐久性能评价[J].江苏大学学报(自然科学版),2014,35(2):238-42.
[4]李敏,钱春香,王珩,等.高强混凝土受火后力学性能变化规律的研究[J].硅酸盐学报,2003,31(11):1116-20.
[5]中冶建筑研究总院有限公司.火灾后建筑结构鉴定标准:Standard for building structural assessment after fire:CECS 252:2009[M].北京:中国计划出版社,2009.
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[8]刘庆,赵铁军,刘志强,等.高温作用下混凝土耐久性劣化性能研究[J].硅酸盐通报,2016,35(3):897-902.
[9]张国荣,韩依璇,Skoczylas F,et al.混凝土气体渗透性测试技术研究[J].硅酸盐通报,2015,34(s1):116-22.
[10]柳献,袁勇,叶光,等.高性能混凝土高温微观结构演化研究[J].同济大学学报自然科学版,2008,36(11):1473-8.
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