利用超声、显微硬度检测、汞压力测孔等综合手段,对高温后高强混凝土单轴受压疲劳过程中的细微观结构进行了试验研究。通过测定声时和波幅、显微硬度、孔径分布、累积进汞量等参数,对比分析了高温后高强混凝土疲劳过程中细微观结构的变化规律。建立了高温后高强混凝土疲劳残余应变与声时、显微硬度之间的关系模型,并进一步揭示了高温作用与疲劳循环荷载综合工况下高强混凝土内部细微观结构的动态演化过程及损伤机理。研究表明,随着疲劳循环次数的增加,高温后高强混凝土的声时整体呈不断增大的趋势,而波幅与显微硬度呈减小的趋势;最可几孔径与总孔隙体积显著增大,孔径大于50nm的有害孔和多害孔的数量明显增多,各参数的变化幅度整体呈快-慢-快的三阶段变化规律;在相同温度工况下,高强混凝土单轴受压疲劳过程中低应力水平在达到相同寿命比时造成的疲劳损伤要较高应力水平造成的损伤大。研究结果为遭受火灾或经其他高温历程的混凝土结构的无损检测、疲劳损伤分析及结构评估提供参考。
Abstract
The microstructure of highstrength concrete (HSC) after high temperature and uniaxial compression fatigue was studied by using ultrasonic, microhardness test and mercury intrusion porosimetry (MIP). The variation law of microstructure during uniaxial compressive fatigue was compared and analyzed by measuring sonic time and amplitude, microhardness, pore size distribution and cumulative pore volume. The relationship between fatigue residual strain and sonic time, microhardness was established. Both the dynamic evolution process and damage mechanism of microstructure of HSC during uniaxial compressive fatigue after high temperature were further investiaged. The results show that the sonic time tends to increase, while the amplitude and microhardness decrease with the relative fatigue cycles. The most probable pore size,the total pore volume and the harmful pores (pore diameter>50 nm) tend to increase significantly. The variations of the parameters show almost fastslowfast trend and also show obvious threestage variation. At the same life ratio, the fatigue damage caused by the lower stress level is greater than the higher stress level during uniaxial compressive fatigue of HSC after high temperature. The research results provide reference for nondestructive testing, fatigue damage analysis, structure assessment suffered from fire or other high temperature process.
关键词
高强混凝土 /
高温 /
单轴受压疲劳 /
细微观结构
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Key words
high-strength concrete(HSC) /
hightemperature /
uniaxial compression fatigue;microstructure
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参考文献
[1] 柳献,袁勇,叶光,Geert De Schutte.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): 1474-1478.
LIU Xian,YUAN Yong,YE Guang,Geert De Schutter.Study on pore structure evolution of high performance concrete with elevated temperatures [J].Journal of Tongji University (Natural Science),2008,36(11):1474-1478.
[2] 赵东拂,刘梅.高强混凝土高温后剩余强度及无损检测试验研究[J].建筑结构学报,2015,36(增刊2):365-371.
ZHAO Dongfu, LIU Mei. Experimental study on residual strength and nondestructive testing of high strength concrete after high temperature[J].Journal of Building Structures,2015,36 (Suppl 2):365-371.
[3] Michael Henry, Ivan Sandi Darma, Takafumi Sugiyama. Analysis of the effect of heating and re-curing on the microstructureof high-strength concrete using X-ray CT [J].Construction and Building Materials,2014,67:37-46.
[4] M. Saridemir, M.H. Severcan, M. Ciflikli, et al. The influence of elevated temperature on strength and microstructureof high strength concrete containing ground pumice and metakaolin[J]. Construction and Building Materials,2016, 124:244-257.
[5] Georgali. B.,Tsakiridis.P.E. Microstructure offire-damagedconcrete. A case study [J].Cement andConcreteComposites, 2005,v27(2):255-259.
[6] Chiara Rossino, Francesco Lo Monte, Stefano Cangiano, et al. HPC Subjected to High Temperature: A Study on Intrinsic and Mechanical Damage[J].Key Engineering Materials Vols.629-630 (2014)pp239-244.
[7] 周新刚,吴江龙.高温后混凝土轴压疲劳性能初探[J].工业建筑,1996,26(5):33-36.
ZHOU Xingang, WU Jianglong. Preliminary research on fatigue behavior of concrete after exposed to high temperature [J].Industrial Construction,1996,26(5):33-36.
[8] 高海静.经不同高温历程后高强混凝土的受压疲劳性能研究[D].北京:北京建筑大学,2017,6:25-57.
GAO Haijing. Research on the compressive fatigue properties of HSC after different high temperature process[D].Beijing: Beijing University of Civil Engineering and Architecture,2017,6:25-57.
[9] 朱劲松,宋玉普.混凝土双轴抗压疲劳损伤特性的超声波速法研究[J].岩石力学与工程学报,2004,23(13):2230-2234.
ZHU Jinsong,SONGYupu.Research on fatigue damage of concrete under biaxial compressive loading using ultrasonic velocity method [J].Chinese Journal of Rock Mechanics and Engineering,2004,23(13):2230-2234.
[10] 吴中伟,廉慧珍.高性能混凝土[M].北京:中国铁道出版社,1999.
WU Zhongwei,LIAN Huizhen.Highperformance concrete [M].Beijing: China Railway Publishing House,1999.
[11] 侯景鹏.混凝土材料疲劳破坏准则研究[D].大连:大连理工大学,2001,6:43-65.
HOU Jingpeng.Research on fatigue failure criterion of plain concrete material [D].Dalian: Dalian University of Technology,2001,6:43-65.
[12] 宫俊,吴昊,方秦等.刚玉骨料超高性能水泥基材料抗侵彻试验和细观数值模拟[J].振动与冲击,2017,36(1):55-68.
GONG Jun, WU Hao, FANG Qin, et al.Test and mesoscale numerical simulation for corundum-aggregate ultra-high performance cementitious composites against projectile penetration[J].Journal of Vibration and Shock,2017,36(1): 55-68.
[13] Fares,Hanaa1Remond,Sébastien1;Noumowe,Albert1;Cousture,Annelise1.Hightemperature behaviour of self-consolidating concrete. Microstructure and physicochemical properties,Cement and Concrete Research,2010v40,n3:488-496.
[14] P. Vargas, Oscar Restrepo-Baena, Jorge I. Tobón.Microstructural analysis of interfacial transition zone (ITZ) and itsimpact on the compressive strength of lightweight concretes [J].Construction and Building Materials,2017,137: 381-389.
[15] Nadja Oneschkow.Fatigue behaviour of high-strength concrete with respect to strain and stiffness [J].International Journal of Fatigue,2016,8:38-49.
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