碳纳米管增强水泥基复合材料的自收缩及抗裂性能
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摘要
水泥基材料的收缩开裂已经成为其破坏的一个主要原因,受到国内外关注,碳纳米管(CNTs)作为一种纳米纤维状材料,可能可以抑制水泥基材料收缩。本文将CNTs放入水中,经过超声处理分散后,形成CNTs分散液,设置不同的CNTs掺量将其掺入到水泥基材料中,通过波纹管实验及圆环试验对该种新型复合材料的自收缩及抗裂性能进行研究。结果表明:CNTs的掺入可以很大程度上抑制水泥基材料的自收缩,最高降低率可到40%以上,且明显提高了水泥基材料的抗裂性能。水灰比的增加会提高CNTs对水泥基材料收缩的抑制效果。当CNTs的掺量为0.1wt%时,可以获得最优效果。同时,CNTs的掺入不仅对水泥基材料自收缩有抑制作用,一定程度上也会抑制水泥基材料的干燥收缩。通过将CNTs掺入到建筑结构关键部分的水泥基材料中,可以提高建筑安全系数。
Shrinkage cracking of cement-based materials has become a major cause of its destruction,which has attracted attention at home and abroad.Carbon nanotubes(CNTs),as a nano-fibrous material,may inhibit the shrinkage of cement-based materials.In this paper,CNTs were put into water and dispersed by ultrasonic treatment to form CNTs dispersion liquid.Different CNTs contents was set and added into cement-based materials.The autogenous shrinkage and anti-cracking properties of the new composite were studied through linear shrinkage test and ring test.The results show that the incorporation of CNTs can largely inhibit the self-shrinkage of cement-based materials,with the highest reduction rate reaching more than 40%,and significantly improve the crack resistance of cement-based materials.The increase of water-cement ratio will improve the inhibition effect of CNTs on the shrinkage of cement-based materials.When the content of CNTs is 0.1 wt%,the optimal effect can be obtained.Meanwhile,the incorporation of CNTs not only inhibits the self-shrinkage of cement-based materials,but also inhibits the drying shrinkage of cement-based materials to a certain extent.By adding CNTs to cement-based materials in key parts of the building structure,the building safety coefficient can be improved.
Shrinkage cracking of cement-based materials has become a major cause of its destruction,which has attracted attention at home and abroad.Carbon nanotubes(CNTs),as a nano-fibrous material,may inhibit the shrinkage of cement-based materials.In this paper,CNTs were put into water and dispersed by ultrasonic treatment to form CNTs dispersion liquid.Different CNTs contents was set and added into cement-based materials.The autogenous shrinkage and anti-cracking properties of the new composite were studied through linear shrinkage test and ring test.The results show that the incorporation of CNTs can largely inhibit the self-shrinkage of cement-based materials,with the highest reduction rate reaching more than 40%,and significantly improve the crack resistance of cement-based materials.The increase of water-cement ratio will improve the inhibition effect of CNTs on the shrinkage of cement-based materials.When the content of CNTs is 0.1 wt%,the optimal effect can be obtained.Meanwhile,the incorporation of CNTs not only inhibits the self-shrinkage of cement-based materials,but also inhibits the drying shrinkage of cement-based materials to a certain extent.By adding CNTs to cement-based materials in key parts of the building structure,the building safety coefficient can be improved.
引文
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[19]施韬,朱敏,李泽鑫,等.碳纳米管改性水泥基复合材料研究进展[J].复合材料学报,2018,35(5):1033-1049.SHI Tao,ZHU Min,LI Zexin,et al.Review of research progress on carbon nanotubes modified cementitious composites[J].Acta Materiae Composite Sinica,2018,35(5):1033-1049(in Chinese).
[20]施韬,杨泽平,郑立炜.碳纳米管改性水泥基复合材料早龄期水化反应的傅里叶红外光谱[J].复合材料学报,2017,34(3):653-660.SHI Tao,YANG Zeping,ZHENG Liwei.FTIR spectra for early age hydration of cement-based composites incorporatted with CNTs[J].Acta Materiae Compositae Sinica,2017,34(3):653-660(in Chinese).
[21]American Society for Testing Materials.Standard test method for autogenous strain of cement paste and mortar:ASTMC1698-2009[S].West Conshohocken,America:American Society for Testing Materials,2009.
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[23]American Society for Testing Materials.Standard test method for determining age at cracking and induced tensile stress characteristics of mortar and concrete under restrained shrinkage:ASTM C1581/C1581M-2009a[S].West Conshohocken,America:American Society for Testing Materials,2009.
[24]XU S L,LIU J T,LI Q H.Mechanical properties and microstructure of multi-walled carbon nanotube-reinforced cement paste[J].Construction and Building Materials,2015,76:16-23.
[25]HAWREEN A,BOGAS J A,DIAS A P S.On the mechanical and shrinkage behavior of cement mortars reinforced with carbon nanotubes[J].Construction and Building Materials,2018,168:459-70.
[2]FENG Q,CUI J,WANG Q,et al.A feasibility study on real-time evaluation of concrete surface crack repairing using embedded piezoceramic transducers[J].Measurement,2018,122:591-596.
[3]WANG H L,DAI J L,SUN X Y,et al.Characteristics of concrete cracks and their influence on chloride penetration[J].Construction and Building Materials,2016,107:216-225.
[4]ZIA A,ALI M.Behavior of fiber reinforced concrete for controlling the rate of cracking in canal-lining[J].Construction and Building Materials,2017,155:726-739.
[5]郭丽萍,陈波,孙伟,等.膨胀剂对高延性水泥基复合材料力学及变形性能的影响[J].硅酸盐学报,2016,44(11):1609-13.GUO Liping,CHEN Bo,SUN Wei,et al.Effect of expansive agent on mechanical properties and deformation behavior of high ductility cementitious composites[J].Journal of the Chinese Ceramic Society,2016,44(11):1609-1613(in Chinese).
[6]YOO D Y,BANTHIA N,YOON Y S.Effectiveness of shrinkage-reducing admixture in reducing autogenous shrinkage stress of ultra-high-performance fiber-reinforced concrete[J].Cement and Concrete Composites,2015,64:27-36.
[7]LEE S J,WON J P.Shrinkage characteristics of structural nano-synthetic fibre-reinforced cementitious composites[J].Composite Structures,2016,157:236-243.
[8]爦AHMARAN M,LACHEMI M,HOSSAIN K M A,et al.Internal curing of engineered cementitious composites for prevention of early age autogenous shrinkage cracking[J].Cement and Concrete Research,2009,39(10):893-901.
[9]AL-ANSARI M,ABU-TAQA A G,HASSAN M M,et al.Performance of modified self-healing concrete with calcium nitrate microencapsulation[J].Construction and Building Materials,2017,149:525-534.
[10]IIJIMA S.Helical microtubules of graphitic carbon[J].Nature,1991,354(6348):56-58.
[11]TREACY M M J,EBBESEN T W,GIBSON J M.Exceptionally high Young’s modulus observed for individual carbon nanotubes[J].Nature,1996,381(6584):678-680.
[12]WONG E W,SHEEHAN P E,LIEBER C M.Nanobeam mechanics:Elasticity,strength,and toughness of nanorods and nanotubes[J].Science,1997,277(5334):1971-1975.
[13]LEKAWA RAUS A,GIZEWSKI T,PATMORE J,et al.Electrical transport in carbon nanotube fibres[J].Scripta Materialia,2017,131:112-118.
[14]LI G Y,WANG P M,ZHAO X.Mechanical behavior and microstructure of cement composites incorporating surfacetreated multi-walled carbon nanotubes[J].Carbon,2004,43(6):1239-1245.
[15]WANG B,HAN Y,LIU S.Effect of highly dispersed carbon nanotubes on the flexural toughness of cement-based composites[J].Construction and Building Materials,2013,46(46):8-12.
[16]李庚英,杨晶,曾令波,等.丁苯橡胶乳液改性碳纳米管水泥砂浆机敏性能[J].建筑材料学报,2013,16(01):65-69.LI Gengying,YANG Jing,ZENG Lingbo,et al.Piezoresisivity of carbon nanotubes cement mortars modified by styrene butadiene rubber emulsion[J].Journal of Building Materials,2013,16(01):65-69(in Chinese).
[17]WANG B,GUO Z,HAN Y,et al.Electromagnetic wave absorbing properties of multi-walled carbon nanotube/cement composites[J].Construction and Building Materials,2013,46(46):98-103.
[18]崔宏志,杨嘉明,林炅增.碳纳米管分散技术及碳纳米管-水泥基复合材料研究进展[J].材料导报,2016,30(03):91-95.CUI Hongzhi,YANG Jiaming,LIN Jiongzeng.Research progress on carbon nanotubes dispersion techniques and CNTs-reinforced cement-based materials[J].Materials Review,2016,30(03):91-95(in Chinese).
[19]施韬,朱敏,李泽鑫,等.碳纳米管改性水泥基复合材料研究进展[J].复合材料学报,2018,35(5):1033-1049.SHI Tao,ZHU Min,LI Zexin,et al.Review of research progress on carbon nanotubes modified cementitious composites[J].Acta Materiae Composite Sinica,2018,35(5):1033-1049(in Chinese).
[20]施韬,杨泽平,郑立炜.碳纳米管改性水泥基复合材料早龄期水化反应的傅里叶红外光谱[J].复合材料学报,2017,34(3):653-660.SHI Tao,YANG Zeping,ZHENG Liwei.FTIR spectra for early age hydration of cement-based composites incorporatted with CNTs[J].Acta Materiae Compositae Sinica,2017,34(3):653-660(in Chinese).
[21]American Society for Testing Materials.Standard test method for autogenous strain of cement paste and mortar:ASTMC1698-2009[S].West Conshohocken,America:American Society for Testing Materials,2009.
[22]中国建筑材料科学研究总院.水泥标准稠度用水量、凝结时间、安定性检验方法:GB/T 1346-2011[S].北京:中国标准出版社,2011.China Building Materlals Academy.Test methods for water requirement of normal consistency,setting time and soundness of the portland cement:GB/T 1346-2011[S].Beijing:China Standards Press,2011(in Chinese).
[23]American Society for Testing Materials.Standard test method for determining age at cracking and induced tensile stress characteristics of mortar and concrete under restrained shrinkage:ASTM C1581/C1581M-2009a[S].West Conshohocken,America:American Society for Testing Materials,2009.
[24]XU S L,LIU J T,LI Q H.Mechanical properties and microstructure of multi-walled carbon nanotube-reinforced cement paste[J].Construction and Building Materials,2015,76:16-23.
[25]HAWREEN A,BOGAS J A,DIAS A P S.On the mechanical and shrinkage behavior of cement mortars reinforced with carbon nanotubes[J].Construction and Building Materials,2018,168:459-70.