火灾环境下桥梁混凝土动、静弹性模量试验研究  

Experimental Research on Dynamic and Static Elastic Modulus of Bridge Concrete Under Fire Environment

作　　者：申雁鹏 SHEN Yanpeng(Shanxi Transportation Technology Research&Development Co.,Ltd.,Shanxi Key Laboratory of Bridge Engineering Disaster Prevention and Mitigation,Laboratory of Highway Construction and Maintenance Technology in Loess Regin,Taiyuan,Shanxi 030006,China)

机构地区：[1]山西省交通科技研发有限公司桥梁工程防灾减灾山西省重点实验室黄土地区公路建设与养护技术交通行业重点实验室,山西太原030006

出　　处：《公路工程》2021年第2期228-233,共6页Highway Engineering

基　　金：山西省交通运输厅科技项目(2017-1-22);山西省自然科学基金项目(201801D121165)。

摘　　要：为研究桥梁在火灾环境下混凝土损伤程度及其动、静弹性模量的变化规律,开展了8组不同温度等级下(20℃~700℃)C50混凝土棱柱体试块烧蚀试验,运用冲击回波单面反射法,测试混凝土试块冲击弹性波波速,根据动弹性模量与波速的关系,计算混凝土试块的动弹性模量。结果表明:混凝土烧蚀温度升高时,试块颜色、表面裂缝、锤激声响及角隅剥落现象均有明显变化;混凝土动、静弹性模量均减小,但动弹性模量减小速率大于静弹性模量,具体表现为,20℃时C50混凝土动弹性模量>静弹性模量;300℃时动弹性模量接近静弹性模量;≥400℃后,C50混凝土动弹性模量<静弹性模量,烧蚀试验后混凝土试块的动静弹性模量比值整体呈上升趋势;烧蚀温度20℃~200℃时,典型的Lydon和Balendran式较适用;烧蚀温度≥300℃时,给出了参考公式。In order to study the damage degree of concrete,the variation of dynamic and static elastic modulus of bridge concrete under fire environment,8 groups of C50 concrete prism specimens under different temperature levels between 20℃and 700℃were tested,the impact elastic wave velocity of concrete block is measured by Impact echo single side reflection method,and the dynamic elastic modulus of concrete block is calculated according to the relationship between dynamic elastic modulus and wave velocity.The results show that when the temperature of ablation test increases,the color,surface crack,hammering sound and corner spalling phenomenon of concrete block change obviously;the dynamic and static elastic modulus of concrete decrease,and the decreasing rate of dynamic elastic modulus is greater than that of static elastic modulus,the dynamic elastic modulus of C50 concrete at 20℃is higher than that of static elastic modulus,the dynamic elastic modulus is close to static elastic modulus at 300℃,and the dynamic elastic modulus of C50 concrete is less than the static elastic modulus when the temperature is higher than or equal to 400℃;after ablation test,the ratio of dynamic and static elastic modulus of concrete test block is on the rise as a whole.When the ablation temperature is 20℃to 200℃,the typical lydon and balendran formula are more suitable;when the ablation temperature is higher than or equal to 300℃,the reference formula is given in this paper.

关 键 词：火灾环境 混凝土 弹性模量 试验研究 

分 类 号：TU528[建筑科学—建筑技术科学]