冻融循环作用后BFRC宏微观性能的灰熵法分析
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摘要
通过玄武岩纤维混凝土(BFRC)的快速冻融试验和微观孔结构试验,研究了2种冻融介质(水和质量分数为3.5%NaCl溶液)条件下BFRC相对动弹性模量、冻融损伤度以及强度的变化规律,分析了孔结构参数(含气量、孔比表面积、气泡间距系数和气泡平均弦长)与BFRC抗压强度、抗折强度和冻融损伤度的关系,采用灰熵法探讨了BFRC孔结构参数对其抗压强度、抗折强度以及冻融损伤度的影响规律.结果表明:BFRC强度随其含气量、气泡间距系数、气泡平均弦长的增加而减小,而冻融损伤度随上述3个孔结构参数的增加而增加;BFRC强度随其孔比表面积的增加而增加,而冻融损伤度随孔比表面积的增加而减小;对BFRC抗压强度、抗折强度影响最大的因素均为孔比表面积;影响BFRC冻融损伤度的主要因素为气泡间距系数和气泡平均弦长,这2个因素随冻融循环次数、玄武岩纤维掺量的变化而变化.
Through the rapid freeze-thaw test and micro-pore structure test, the relative dynamic elastic modulus, freeze-thaw damage degree and strength of basalt fiber reinforced concrete(BFRC) after freezing and thawing cycles in water and NaCl solution with concentration of 3.5%(by mass) were studied. The relationships of the pore structure parameters(air content, specific surface area, spacing factor, average chord length) with the compressive strength, flexural strength and freeze-thaw damage degree of BFRC were investigated. Finally, the influences of pore structure parameters on compressive strength, flexural strength and freeze-thaw damage degree were studied by means of grey entropy analysis. The results show that the strength of BFRC decreases with the increase of air content, spacing factor and average chord length, and the freeze-thaw damage degree of BFRC increases with the increase of the above three pore structure parameters. The strength of BFRC increases with the increase of specific surface area, and the freeze-thaw damage degree of BFRC decreases with the increase of specific surface area. The most important influential factor on the compressive and flexural strength of BFRC is specific surface area, and the main influencing factors of the freeze-thaw damage degree of BFRC are spacing factor and average chord length with different freez-thaw cycles and different basalt fiber contents.
Through the rapid freeze-thaw test and micro-pore structure test, the relative dynamic elastic modulus, freeze-thaw damage degree and strength of basalt fiber reinforced concrete(BFRC) after freezing and thawing cycles in water and NaCl solution with concentration of 3.5%(by mass) were studied. The relationships of the pore structure parameters(air content, specific surface area, spacing factor, average chord length) with the compressive strength, flexural strength and freeze-thaw damage degree of BFRC were investigated. Finally, the influences of pore structure parameters on compressive strength, flexural strength and freeze-thaw damage degree were studied by means of grey entropy analysis. The results show that the strength of BFRC decreases with the increase of air content, spacing factor and average chord length, and the freeze-thaw damage degree of BFRC increases with the increase of the above three pore structure parameters. The strength of BFRC increases with the increase of specific surface area, and the freeze-thaw damage degree of BFRC decreases with the increase of specific surface area. The most important influential factor on the compressive and flexural strength of BFRC is specific surface area, and the main influencing factors of the freeze-thaw damage degree of BFRC are spacing factor and average chord length with different freez-thaw cycles and different basalt fiber contents.
引文
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[12] 张金喜,金珊珊.水泥混凝土微观孔隙结构及其作用[M].北京:科学出版社,2014:37-38.ZHANG Jinxi,JIN Shanshan.Microscopic pore structure of cementconcrete and its effect[M].Beijing:Science Press,2014:37-38.(in Chinese)
[13] 洪锦祥,缪昌文,刘加平,等.冻融损伤混凝土力学性能衰减规律[J].建筑材料学报,2012,15(2):173-178.HONG Jinxiang,MIAO Changwen,LIU Jiaping,et al.Degradation law of mechanical properties of concrete subjected to freeze-thaw cycles[J].Journal of Building Materials,2012,15(2):173-178.(in Chinese)
[14] 杜栋,庞庆华.现代综合评价方法与案例精选[M].北京:清华大学出版社,2005:111-134.DU Dong,PANG Qinghua.Modern comprehensive evaluation method and case selection[M].Beijing:Tsinghua University Press,2005:111-134.(in Chinese)
[15] 李梦梦.混掺纤维高强自密实混凝土性能研究[D].大连:大连交通大学,2013.LI Mengmeng.Study on performance of the high strength and hybrid fiber reinforced self-compacting concrete[D].Dalian:Dalian Jiaotong University,2013.(in Chinese)
[2] 谢永亮,战仕利,王瑞,等.玄武岩纤维对机场道面混凝土抗冻性能影响研究[J].混凝土与水泥制品,2012(12):48-50.XIE Yongliang,ZHAN Shili,WANG Rui,et al.Study on influence of basalt fiber on frost resistance of airport pavement concrete[J].China Concrete and Cement Products,2012(12):48-50.(in Chinese)
[3] 金生吉,李忠良,张健,等.玄武岩纤维混凝土腐蚀条件下抗冻融性能试验研究[J].工程力学,2015,32(5):178-183.JIN Shengji,LI Zhongliang,ZHANG Jian,et al.Experimental study on anti-freezing and thawing performance of reinforced concrete of basalt fiber under corrosion condition.[J].Engineering Mechanics,2015,32(5):178-183.(in Chinese)
[4] 吴中伟,廉慧珍.高性能混凝土[M].北京:中国铁道出版社,1999:22-23.WU Zhongwei,LIAN Huizhen.High-performance concrete[M].Beijing:China Railway Publishing House,1999:22-23.(in Chinese)
[5] KUMAR R,BHATTACHARJEE B.Porosity,pore size distribution and in situ strength of concrete[J].Cement and Concrete Research,2003,33(1):155-164.
[6] SHI C J.Strength,pore structure and permeability of alkail-activated slag mortars[J].Cement and Concrete Research,1996,26(12):1789-1799.
[7] JAMBER J.Pore structure and strength development of cement composites[J].Cement and Concrete Research,1990,20(6):948-954.
[8] 王庆石,王起才,张凯,等.不同含气量混凝土的孔结构及抗冻性分析[J].硅酸盐通报,2015,34(1):30-35.WANG Qingshi,WANG Qicai,ZHANG Kai,et al.Analysis of pore structure and frost resistance of concrete with different air content[J].Bulletin of the Chinese Ceramic Society,2015,34(1):30-35.(in Chinese)
[9] POWERS T C.Void spacing as a basis for producing air-entrained concrete[J].Journal of the American Concrete Institute,1954,50(5):741-759.
[10] OKADA E,HISAKA M,KAZAMA Y,et al.Freeze-thaw resistance of superplasticizer concretes[J].Journal of the American Concrete Institute,1981,68:215-232.
[11] 张金喜,郭明洋,杨荣俊,等.引气剂对硬化混凝土结构和性能的影响[J].武汉理工大学学报,2008,30(5):38-41.ZHANG Jinxi,GUO Mingyang,YANG Rongjun,et al.Effect of air-entraining admixtures on the structure and properties of hardened concrete[J].Journal of Wuhan University of Technology,2008,30(5):38-41.(in Chinese)
[12] 张金喜,金珊珊.水泥混凝土微观孔隙结构及其作用[M].北京:科学出版社,2014:37-38.ZHANG Jinxi,JIN Shanshan.Microscopic pore structure of cementconcrete and its effect[M].Beijing:Science Press,2014:37-38.(in Chinese)
[13] 洪锦祥,缪昌文,刘加平,等.冻融损伤混凝土力学性能衰减规律[J].建筑材料学报,2012,15(2):173-178.HONG Jinxiang,MIAO Changwen,LIU Jiaping,et al.Degradation law of mechanical properties of concrete subjected to freeze-thaw cycles[J].Journal of Building Materials,2012,15(2):173-178.(in Chinese)
[14] 杜栋,庞庆华.现代综合评价方法与案例精选[M].北京:清华大学出版社,2005:111-134.DU Dong,PANG Qinghua.Modern comprehensive evaluation method and case selection[M].Beijing:Tsinghua University Press,2005:111-134.(in Chinese)
[15] 李梦梦.混掺纤维高强自密实混凝土性能研究[D].大连:大连交通大学,2013.LI Mengmeng.Study on performance of the high strength and hybrid fiber reinforced self-compacting concrete[D].Dalian:Dalian Jiaotong University,2013.(in Chinese)