碳化-冻融作用下钢筋混凝土梁承载力衰减分析
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摘要
为了研究碳化-冻融环境对钢筋混凝土梁承载力的影响,对钢筋混凝土试验梁进行了多重循环碳化-冻融交替作用下的加速腐蚀试验,然后对完成腐蚀试验的钢筋混凝土梁进行抗弯荷载试验。通过荷载试验获得腐蚀梁的应变变化、裂缝发展及荷载位移曲线,分析碳化-冻融耦合作用对试验梁承载力衰减的影响。结果表明:荷载试验过程中腐蚀钢筋混凝土梁的跨中截面应变基本满足平截面假定,相同荷载下受腐蚀梁的跨中应变大于未腐蚀梁的应变值;与未腐蚀钢筋混凝土梁相比受腐蚀梁的裂缝出现的较早,裂缝较宽、数量较少;从试验梁的荷载-位移曲线可知同一级别荷载作用后梁体跨中位移值随碳化-冻融腐蚀周期的增加而增大,极限荷载随腐蚀周期的增加而降低。根据试验梁荷载试验的实测数据提出了钢筋混凝土梁在全寿命周期内承载力时变衰减系数的计算公式,并通过有限元模拟分析验证了其正确性,该系数可用于我国严寒区钢筋混凝土结构的承载力衰减模拟分析和评估,成果可为实际工程参考。
In order to study the influence of load capacity of RC beam due to carbonization and freezethaw action,accelerated corrosion test of RC beam under multi-cycle of carbonization and freeze-thaw alternating action was carried out,then the bending load test of the beam was also carried out. The strain change,crack development and load-displacement curves of corroded beams were obtained during load test,the influence of carbonization and freeze-thaw coupling on the load capacity attenuation of the beam was analyzed. The results show that the strain of the mid-span section of corroded RC beam is mainly satisfied the plane-section assumption in the course of the load test,strain of the mid-span of the corroded beam is larger than that of the uncorroded beam under the same load level. The cracks of corroded RC beam appeares earlier than those of uncorroded beam,cracks are wider and less in number. According to the load-displacement curve of the beam,it can be known that mid-span displacement of the beam increases after the same load level action and the ultimate load decreases with the increase of carbonization and freeze-thaw corrosion cycle. Based on the test data of the beam,a formula for calculating time-varying attenuation coefficient of RC beam in the whole life cycle is presented,and the consistency of the coefficient is verified by finite element simulation,this coefficient can be used to simulate and evaluate the load capacity attenuation of reinforced concrete structures in cold regions of China,the results can be referred for practical engineering.
In order to study the influence of load capacity of RC beam due to carbonization and freezethaw action,accelerated corrosion test of RC beam under multi-cycle of carbonization and freeze-thaw alternating action was carried out,then the bending load test of the beam was also carried out. The strain change,crack development and load-displacement curves of corroded beams were obtained during load test,the influence of carbonization and freeze-thaw coupling on the load capacity attenuation of the beam was analyzed. The results show that the strain of the mid-span section of corroded RC beam is mainly satisfied the plane-section assumption in the course of the load test,strain of the mid-span of the corroded beam is larger than that of the uncorroded beam under the same load level. The cracks of corroded RC beam appeares earlier than those of uncorroded beam,cracks are wider and less in number. According to the load-displacement curve of the beam,it can be known that mid-span displacement of the beam increases after the same load level action and the ultimate load decreases with the increase of carbonization and freeze-thaw corrosion cycle. Based on the test data of the beam,a formula for calculating time-varying attenuation coefficient of RC beam in the whole life cycle is presented,and the consistency of the coefficient is verified by finite element simulation,this coefficient can be used to simulate and evaluate the load capacity attenuation of reinforced concrete structures in cold regions of China,the results can be referred for practical engineering.
引文
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[13]蒋林华,那彬彬,周晓明,等.冻融与碳化交替作用下的混凝土性能试验[J].水利水电科技进展,2012,32(4):33-36.
[14]杨彦克,郭晓芳.混凝土碳化对冻融破坏的促进作用试验研究.全国混凝土耐久性学术交流会[C].2012.
[15]于琦,牛荻涛,元成方,等.冻融环境下混凝土碳化深度的试验研究[J].硅酸盐通报,2012,31(4):979-983.
[16]谢晓鹏,高丹盈,赵军.钢纤维混凝土冻融和碳化后力学性能试验研究[J].西安建筑科技大学学报(自然科学版),2006,38(4):514-517.
[17]张鹏,赵铁军,杨进波,等.冻融前后混凝土碳化性能试验研究[J].混凝土,2007(5):6-8.
[18]GB/T 50082-2009,普通混凝土长期性能和耐久性能试验方法标准[S].北京:中国建筑工业出版社,2009.
[2]柯伟.中国腐蚀调查报告[M].北京:化学工业出版社,2003.
[3]邹洪波,罗小勇,汤敏捷.南方在役钢筋混凝土结构耐久性问题调查与研究[J].建筑结构,2014,2(14):39-43.
[4]肖前慧.冻融环境多因素耦合作用混凝土结构耐久性研究[D].西安:西安建筑科技大学,2010.
[5]蒋利学,张誉,刘亚芹,等.混凝土碳化深度的计算与试验研究[J].混凝土,1996(4):12-17.
[6]牛荻涛.混凝土结构耐久性与寿命预测[M].北京:科学出版社,2003.
[7]谭克锋.水灰比和掺合料对混凝土抗冻性能的影响[J].武汉理工大学学报,2006,28(3):58-60.
[8]宋玉普,冀晓东.混凝土冻融损伤可靠度分析及剩余寿命预测[J].水利学报,2006,37(3):259-263.
[9]李春生,陈胜宏,何真,等.冻融循环作用下混凝土结构寿命分析[J].武汉大学学报(工学版),2010,43(2):203-207.
[10]张向东,李庆文,李桂秀,等.冻融-碳化耦合环境下自燃煤矸石混凝土耐久性实验研究[J].环境工程学报,2016,10(5):2595-2600.
[11]赵高升,何真,杨华美.冻融循环和碳化交替作用下的混凝土耐久性[J].武汉大学学报(工学版),2013(5):604-609.
[12]周晓明,蒋林华,濮琦,等.冻融与碳化交替作用下混凝土损伤模型[J].南水北调与水利科技,2009,7(6):234-236.
[13]蒋林华,那彬彬,周晓明,等.冻融与碳化交替作用下的混凝土性能试验[J].水利水电科技进展,2012,32(4):33-36.
[14]杨彦克,郭晓芳.混凝土碳化对冻融破坏的促进作用试验研究.全国混凝土耐久性学术交流会[C].2012.
[15]于琦,牛荻涛,元成方,等.冻融环境下混凝土碳化深度的试验研究[J].硅酸盐通报,2012,31(4):979-983.
[16]谢晓鹏,高丹盈,赵军.钢纤维混凝土冻融和碳化后力学性能试验研究[J].西安建筑科技大学学报(自然科学版),2006,38(4):514-517.
[17]张鹏,赵铁军,杨进波,等.冻融前后混凝土碳化性能试验研究[J].混凝土,2007(5):6-8.
[18]GB/T 50082-2009,普通混凝土长期性能和耐久性能试验方法标准[S].北京:中国建筑工业出版社,2009.
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