粗合成纤维活性粉末混凝土抗弯韧性试验
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摘要
为研究不同粗合成纤维用量下活性粉末混凝土的抗弯韧性,采用四点弯曲试验对粗合成纤维用量分别为4.75,9.5,14.25,19kg·m-3的纤维活性粉末混凝土试件进行了研究,同时与不掺入纤维的素活性粉末混凝土进行了对比分析。结果表明:不掺入纤维的素活性粉末混凝土弯拉试件发生脆性破坏,试件一裂即断,未得到荷载-挠度曲线的下降段;而粗合成纤维掺入后能够提高活性粉末混凝土的韧性,使弯拉试件转变为明显的延性破坏,荷载-挠度曲线都可得到稳定的下降段,同时曲线还出现了二次强化现象,有2个峰值;随着粗合成纤维掺量的增加,弯拉试件荷载-挠度曲线的下降段愈加平缓,韧性指数增大;粗合成纤维掺量(体积分数)为1.0%~2.0%时,剩余强度在抗折强度的85%以上,此时粗合成纤维对裂后基体具有较强的阻裂能力,能够大大提高弯拉试件开裂后的韧性。
In order to evaluate the flexural toughness of synthetic macro-fiber reinforced reactive powder concrete,beam specimens were tested under four points flexural method.The contents of synthetic macro-fiber were 4.75,9.5,14.25,19kg·m-3,respectively,and plain reactive powder concrete specimens without fiber were analyzed in contrast.The results show that plain reactive powder concrete specimens without fiber are brittleness,specimens breakdown when the crack is appeared,and the descending branch of load-deflection curves cannot be collected.While the failure mode of specimens with synthetic macro-fiber is ductility and a steady descending branch of load-deflection curves is collected.At the same time,the curves all have two peaks,presenting the phenomenon of secondary reinforcement.This means that synthetic macro-fiber can improve the flexural toughness of reactive powder concrete.Descending branch of load-deflection curves isflatter and toughness index with the increasing of fiber content.The residual intensity is above85%of flexural strength when the fiber content(volume fraction)is 1.0%-2.0%,which indicates that synthetic macro-fiber has excellent crack resistance,and can improve the ductility of bending-tension specimens after cracking.
In order to evaluate the flexural toughness of synthetic macro-fiber reinforced reactive powder concrete,beam specimens were tested under four points flexural method.The contents of synthetic macro-fiber were 4.75,9.5,14.25,19kg·m-3,respectively,and plain reactive powder concrete specimens without fiber were analyzed in contrast.The results show that plain reactive powder concrete specimens without fiber are brittleness,specimens breakdown when the crack is appeared,and the descending branch of load-deflection curves cannot be collected.While the failure mode of specimens with synthetic macro-fiber is ductility and a steady descending branch of load-deflection curves is collected.At the same time,the curves all have two peaks,presenting the phenomenon of secondary reinforcement.This means that synthetic macro-fiber can improve the flexural toughness of reactive powder concrete.Descending branch of load-deflection curves isflatter and toughness index with the increasing of fiber content.The residual intensity is above85%of flexural strength when the fiber content(volume fraction)is 1.0%-2.0%,which indicates that synthetic macro-fiber has excellent crack resistance,and can improve the ductility of bending-tension specimens after cracking.
引文
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[14]邓宗才,师亚军,曹炜.聚烯烃粗合成纤维混凝土抗弯韧性试验[J].建筑科学与工程学报,2013,30(1):19-24.DENG Zong-cai,SHI Ya-jun,CAO Wei.Experiment on Flexural Toughness of Polyolefin Macro-fiber Reinforced Concrete[J].Journal of Architecture and Civil Engineering,2013,30(1):19-24.
[15]张明波,阎贵平,闫光杰,等.200MPa级活性粉末混凝土抗弯性能试验研究[J].北京交通大学学报,2007,31(2):81-84.ZHANG Ming-bo,YAN Gui-ping,YAN Guang-jie,et al.Experimental Research on the Flexing Resistance of 200MPa Reactive Powder Concrete[J].Journal of Beijing Jiaotong University,2007,31(2):81-84.
[2]BAYARD O,PLE O.Fracture Mechanics of Reactive Powder Concrete:Material Modeling and Experimental Investigations[J].Engineering Fracture Mechanics,2003,70(7/8):839-851.
[3]JI T,CHEN C Y,ZHUANG Y Z.Evaluation Method for Cracking Resistant Behavior of Reactive Powder Concrete[J].Construction and Building Materials,2012,28(1):45-49
[4]邓宗才.高性能合成纤维混凝土[M].北京:科学出版社,2003.DENG Zong-cai.High Performance Synthetic Fiber Reinforced Concrete[M].Beijing:Science Press,2003.
[5]常洪雷,金祖权,任鹏程.有机仿钢纤维增强混凝土断裂韧性及抗裂性能研究[J].混凝土,2013(2):46-49.CHANG Hong-lei,JIN Zu-quan,REN Peng-cheng.Study on Fracture Toughness and Crack Resistance of Steel-wire-like Organic Fiber Reinforced Concrete[J].Concrete,2013(2):46-49.
[6]邓宗才,李建辉,王现卫,等.粗合成纤维增强混凝土的冲击动载特性[J].混凝土,2006(10):27-30.DENG Zong-cai,LI Jian-hui,WANG Xian-wei,et al.Dynamic Properties of Synthetic Macro-fiber Reinforced Concrete[J].Concrete,2006(10):27-30.
[7]李建辉,张科强,邓宗才.粗合成纤维混凝土抗弯冲击强度的分布规律[J].建筑科学与工程学报,2007,24(4):54-59.LI Jian-hui,ZHANG Ke-qiang,DENG Zong-cai.Distribution Regularity of Flexural Impact Resistance of Synthetic Macro-fiber Reinforced Concrete[J].Journal of Architecture and Civil Engineering,2007,24(4):54-59.
[8]邓宗才,李建辉,王现卫,等.粗合成纤维混凝土抗弯韧性及疲劳特性试验研究[J].新型建筑材料,2006(7):8-10.DENG Zong-cai,LI Jian-hui,WANG Xian-wei,et al.Experimental Study on Flexure Resistance and Fatigue Characteristic of Coarse Synthetic Fiber Concrete[J].New Building Materials,2006(7):8-10.
[9]HSIE M,TU C,SONG P S.Mechanical Properties of Polypropylene Hybrid Fiber Reinforced Concrete[J].Materials Science and Engineering:A,2008,494(1/2):153-157.
[10]曹小霞,郑居焕.钢纤维和聚丙烯粗纤维对活性粉末混凝土强度和延性的影响[J].安徽建筑工业学院学报:自然科学版,2011,19(2):58-61.CAO Xiao-xia,ZHENG Ju-huan.The Effects of Steel Fiber and Polypropylene Coarse Fiber on the Compressive Strength and Ductility of Metakaolin RPC[J].Journal of Anhui Institute of Architecture&Industry:Natural Science,2011,19(2):58-61.
[11]尹机会.钢-合成纤维混凝土强度与韧性的试验研究[D].大连:大连理工大学,2006.YIN Ji-hui.Experimental Study on Strength and Toughness Characteristics of Steel-synthetic Fiber Reinforced Concrete[D].Dalian:Dalian University of Technology,2006.
[12]华渊,刘荣华,曾艺.纤维增韧高性能混凝土的试验研究[J].混凝土与水泥制品,1998(3):40-43.HUA Yuan,LIU Rong-hua,ZENG Yi.Experimental Study on Fiber Toughness of High Performance Concrete[J].China Concrete and Cement Products,1998(3):40-43.
[13]戴建国,宋玉普,赵国藩.低弹性模量纤维混凝土剩余弯曲强度的力学意义[J].混凝土与水泥制品,1999(1):35-38.DAI Jian-guo,SONG Yu-pu,ZHAO Guo-fan.Postpeak Flexural Strength of Low Elstic-modulus Fiber Reinforced Concrete[J].China Concrete and Cement Products,1999(1):35-38.
[14]邓宗才,师亚军,曹炜.聚烯烃粗合成纤维混凝土抗弯韧性试验[J].建筑科学与工程学报,2013,30(1):19-24.DENG Zong-cai,SHI Ya-jun,CAO Wei.Experiment on Flexural Toughness of Polyolefin Macro-fiber Reinforced Concrete[J].Journal of Architecture and Civil Engineering,2013,30(1):19-24.
[15]张明波,阎贵平,闫光杰,等.200MPa级活性粉末混凝土抗弯性能试验研究[J].北京交通大学学报,2007,31(2):81-84.ZHANG Ming-bo,YAN Gui-ping,YAN Guang-jie,et al.Experimental Research on the Flexing Resistance of 200MPa Reactive Powder Concrete[J].Journal of Beijing Jiaotong University,2007,31(2):81-84.