自密实混凝土加固碳化混凝土界面剪切性能试验
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摘要
为研究混凝土构件长期暴露大气中表面形成的碳化层对自密实混凝土加固混凝土黏结界面剪切性能的影响,为该类结构加固设计提供依据,设计不同碳化程度Z形黏结试件进行直剪试验,考察混凝土碳化深度、混凝土强度和界面处理方式等对黏结试件破坏形式和抗剪强度的影响,并在试验基础上建立碳化混凝土黏结界面抗剪强度预测模型。研究结果表明:混凝土碳化引起黏结界面剪切裂缝分布形式的改变;混凝土碳化后强度和弹性模量均有所增强,在黏结界面间形成一个局部强化区域,剪切裂缝由原来的界面裂缝逐渐向老混凝土内部转移,扩展至碳化强化区与未碳化区交界面;混凝土碳化使得黏结界面抗剪强度增强,碳化初期,黏结界面抗剪强度增长迅速,达到一定碳化深度后,其增长幅度变小;黏结界面抗剪强度与新老混凝土的强度、界面处理方式等也密切相关,对于Ⅰ类和Ⅱ类界面,一定范围内增大新混凝土强度对于提高界面抗剪强度具有积极作用;当新老混凝土强度相差超过2个标号时,继续提高新混凝土强度作用不大;Ⅲ类界面植筋能有效提高抗剪强度,且其抗剪强度由较低强度混凝土控制。
In order to investigate the effects of carbonation on the interface shear behavior between self-compacting concrete and carbonation concrete, when the concrete structures exposed to air for a long period of time will become carbonized, and help determine the reinforcement applied to carbonized concrete structures. A series of Z-type specimens with different carbonation depths were designed and tested under a direct shear force. The influence of the concrete carbonation depth, concrete strength, and interfacial treatment modes on the failure mode and ultimate shear strength of the tested specimens were clarified. Further, an analytical model was developed to predict the shear strength between the self-compacting concrete and the carbonation concrete based on the experimental. The results show that concrete carbonation leads to the change of shear crack distribution at bond interface. A local reinforced region is formed within the interface owing to the increase in the ultimate strength and elastic modulus of concrete caused by carbonization. The shear crack gradually transfers from the original interface crack to the old concrete, and extends to the interface between the carbonization strengthening area and the non-carbonization area. The carbonation also leads to an increase in the shear strength. The increase in shear strength within the interface occurs extremely quickly for the specimens during the early stage of carbonization,and then shows a slightly increase as the carbonation depth exceeds a critical value. The shear strength within the interface is also affected by the concrete strength and the interfacial treatment modes etc. For specimens with type-Ⅰ and type-Ⅱ interface modes, the increase in new concrete strength within a certain range can effectively improve the shear strength. The further increase in the new concrete strength has little influence on the increase in shear strength as it exceeds a critical value. Moreover, the type-Ⅲ interface mode with a plated reinforcement bar significantly increases the shear strength, and it is dependent on the concrete with an ultimate low strength.
In order to investigate the effects of carbonation on the interface shear behavior between self-compacting concrete and carbonation concrete, when the concrete structures exposed to air for a long period of time will become carbonized, and help determine the reinforcement applied to carbonized concrete structures. A series of Z-type specimens with different carbonation depths were designed and tested under a direct shear force. The influence of the concrete carbonation depth, concrete strength, and interfacial treatment modes on the failure mode and ultimate shear strength of the tested specimens were clarified. Further, an analytical model was developed to predict the shear strength between the self-compacting concrete and the carbonation concrete based on the experimental. The results show that concrete carbonation leads to the change of shear crack distribution at bond interface. A local reinforced region is formed within the interface owing to the increase in the ultimate strength and elastic modulus of concrete caused by carbonization. The shear crack gradually transfers from the original interface crack to the old concrete, and extends to the interface between the carbonization strengthening area and the non-carbonization area. The carbonation also leads to an increase in the shear strength. The increase in shear strength within the interface occurs extremely quickly for the specimens during the early stage of carbonization,and then shows a slightly increase as the carbonation depth exceeds a critical value. The shear strength within the interface is also affected by the concrete strength and the interfacial treatment modes etc. For specimens with type-Ⅰ and type-Ⅱ interface modes, the increase in new concrete strength within a certain range can effectively improve the shear strength. The further increase in the new concrete strength has little influence on the increase in shear strength as it exceeds a critical value. Moreover, the type-Ⅲ interface mode with a plated reinforcement bar significantly increases the shear strength, and it is dependent on the concrete with an ultimate low strength.
引文
[1] KARAMLOO M,MAZLOOM M,PAYGANEH G.Effects of maximum aggregate size on fracture behaviors of self-compacting lightweight concrete[J].Construction and Building Materials,2016,123:508-515.
[2] SALESA A,PEREZ-BENEDICTO J A,ESTEBAN L M,et al.Physico-mechanical properties of multi-recycled self-compacting concrete prepared with precast concrete rejects[J].Construction and Building Materials,2017,153:364-373.
[3] RAHAL K N,KHALEEFI A L,AL-SANEE A.An experimental investigation of shear-transfer strength of normal and high strength self compacting concrete[J].Engineering Structures,2016,109:16-25.
[4] CONFORTI A,MINELLI F,PLIZZARI G A.Shear behaviour of prestressed double tees in self-compacting polypropylene fibre reinforced concrete[J].Engineering Structures,2017,146:93-104.
[5] MASTALI M,DALVAND A.Use of silica fume and recycled steel fibers in self-compacting concrete (SCC)[J].Construction and Building Materials,2016,125:196-209.
[6] 白文君,何兆益,胡金玉.新老混凝土黏结强度特性研究[J].混凝土,2008(1):45-49. BAI Wen-jun,HE Zhao-yi,HU Jin-yu.Bonding strength between old and repair concrete[J].Concrete,2008(1):45-49.
[7] 赵志方,赵国藩,刘健,等.新老混凝土粘结抗拉性能的试验研究[J].建筑结构学报,2001,22(2):51-56. ZHAO Zhi-fang,ZHAO Guo-fan,LIU Jian,et al.Experimental study on adhesive tensile performance of young on old concrete[J].Journal of Building Structures,2001,22(2):51-56.
[8] 谢慧才,李庚英,熊光晶.新老混凝土界面粘结力形成机理[J].硅酸盐通报,2003,22(3):7-10,18. XIE Hui-cai,LI Geng-ying,XIONG Guang-jing.The mechanism formed the bonding force between new and old concrete[J].Bulletin of the Chinese Ceramic Society,2003,22(3):7-10,18.
[9] 王振领,林拥军,钱永久.新老混凝土结合面抗剪性能试验研究[J].西南交通大学学报,2005,40(5):600-604. WANG Zhen-ling,LIN Yong-jun,QIAN Yong-jiu.Experimental research on shear properties of new-to-old concrete interface[J].Journal of Southwest Jiaotong University,2005,40(5):600-604.
[10] 潘传银,石雪飞,周可攀.新、老混凝土粘结抗剪强度试验[J].交通科学与工程,2014,30(2):6-12. PAN Chuan-yin,SHI Xue-fei,ZHOU Ke-pan.Study on shear strength of new and old concrete bonding interface[J].Journal of Transport Science and Engineer,2014,30(2):6-12.
[11] 陈峰,郑建岚.自密实混凝土与老混凝土粘结强度的直剪试验研究[J].建筑结构学报,2007,28(1):59-63. CHEN Feng,ZHENG Jian-lan.Experimental research on direct shear behavior of adhesion of self-compacting concrete on existing concrete[J].Journal of Building Structures,2007,28(1):59-63.
[12] DIAB A,ELMOATY A,ELDIN M.Slant shear bond strength between self compacting concrete and old concrete[J].Construction and Building Materials,2017,130:73-82.
[13] 柴敏,罗素蓉.自密实混凝土与老混凝土粘结抗剪性能试验研究[J].福州大学学报:自然科学版,2013,41(5):922-927. CHAI Min,LUO Su-rong.Experimental research on shear properties of self-compacting concrete on existing concrete[J].Journal of Fuzhou University:Natural Science Edition,2013,41(5):922-927.
[14] 陈峰,郑建岚.自密实混凝土与老混凝土粘结滑移关系的有限元分析[J].武汉大学学报:工学版,2014,47(6):774-778. CHEN Feng,ZHENG Jian-lan.Finite element analysis of bonding-slip relationship between old concrete and freshly cured self-compacting concrete[J].Engineering Journal of Wuhan University,2014,47(6):774-778.
[15] 郑建岚,陈峰.自密实混凝土与老混凝土粘结剪切强度的塑性极限分析[J].工程力学,2008,25(8):164-168. ZHENG Jian-lan,CHEN Feng.The plastic limit analysis of adhesive shear strength between self-compacting concrete and old concrete[J].Engineering Mechanics,2008,25(8):164-168.
[16] 陈艾荣,冯师蓉,马如进.基于退化机理的混凝土桥梁耐久性环境区划[J].同济大学学报:自然科学版,2014,42(3):331-337. CHEN Ai-rong,FENG Shi-rong,MA Ru-jin.Environmental zoning for durability performance of concrete bridges based on deterioration mechanism[J].Journal of Tongji University:Natural Science,2014,42(3):331-337.
[17] JIANG C,HUANG Q,GU X,et al.Experimental investigation on carbonation in fatigue-damaged concrete[J].Cement and Concrete Research,2017,99:38-52.
[18] LO T Y,LIAO W,WONG C,et al.Evaluation of carbonation resistance of paint coated concrete for buildings[J].Construction and Building Materials,2016,107:299-306.
[19] LI G,DONG L,BAI Z A,et al.Predicting carbonation depth for concrete with organic film coatings combined with ageing effects[J].Construction and Building Materials,2017,142:59-65.
[20] 邓华锋,肖瑶,胥焘,等.碳纤维水泥基复合材料加固节理岩体试验[J].中国公路学报,2018,31(2):242-251. DENG Hua-feng,XIAO Yao,XU Tao,et al.Experiment on reinforcement of jointed rock mass by carbon fiber cement-based composite material[J].China Journal of Highway and Transport,2018,31(2):242-251.
[21] 刘人太,郑卓,李术才,等.破碎岩体注浆加固后的力学特性研究[J].中国公路学报,2018,31(10):284-291. LIU Ren-tai,ZHENG Zhuo,LI Shu-cai,et al.Mechanical properties of fractured rock mass with consideration of grouting reinforcement[J].China Journal of Highway and Transport,2018,31(10):284-291.
[22] 何薇.混凝土碳化及其对地下结构力学性能的影响研究[D].成都:西南交通大学,2013. HE Wei.Research on concrete carbonization and its influence on the mechanical behavior of underground structures[D].Chengdu:Southwest Jiaotong University,2013.
[23] ACI 318-08,Building code requirements for structural concrete and commentary[S].
[2] SALESA A,PEREZ-BENEDICTO J A,ESTEBAN L M,et al.Physico-mechanical properties of multi-recycled self-compacting concrete prepared with precast concrete rejects[J].Construction and Building Materials,2017,153:364-373.
[3] RAHAL K N,KHALEEFI A L,AL-SANEE A.An experimental investigation of shear-transfer strength of normal and high strength self compacting concrete[J].Engineering Structures,2016,109:16-25.
[4] CONFORTI A,MINELLI F,PLIZZARI G A.Shear behaviour of prestressed double tees in self-compacting polypropylene fibre reinforced concrete[J].Engineering Structures,2017,146:93-104.
[5] MASTALI M,DALVAND A.Use of silica fume and recycled steel fibers in self-compacting concrete (SCC)[J].Construction and Building Materials,2016,125:196-209.
[6] 白文君,何兆益,胡金玉.新老混凝土黏结强度特性研究[J].混凝土,2008(1):45-49. BAI Wen-jun,HE Zhao-yi,HU Jin-yu.Bonding strength between old and repair concrete[J].Concrete,2008(1):45-49.
[7] 赵志方,赵国藩,刘健,等.新老混凝土粘结抗拉性能的试验研究[J].建筑结构学报,2001,22(2):51-56. ZHAO Zhi-fang,ZHAO Guo-fan,LIU Jian,et al.Experimental study on adhesive tensile performance of young on old concrete[J].Journal of Building Structures,2001,22(2):51-56.
[8] 谢慧才,李庚英,熊光晶.新老混凝土界面粘结力形成机理[J].硅酸盐通报,2003,22(3):7-10,18. XIE Hui-cai,LI Geng-ying,XIONG Guang-jing.The mechanism formed the bonding force between new and old concrete[J].Bulletin of the Chinese Ceramic Society,2003,22(3):7-10,18.
[9] 王振领,林拥军,钱永久.新老混凝土结合面抗剪性能试验研究[J].西南交通大学学报,2005,40(5):600-604. WANG Zhen-ling,LIN Yong-jun,QIAN Yong-jiu.Experimental research on shear properties of new-to-old concrete interface[J].Journal of Southwest Jiaotong University,2005,40(5):600-604.
[10] 潘传银,石雪飞,周可攀.新、老混凝土粘结抗剪强度试验[J].交通科学与工程,2014,30(2):6-12. PAN Chuan-yin,SHI Xue-fei,ZHOU Ke-pan.Study on shear strength of new and old concrete bonding interface[J].Journal of Transport Science and Engineer,2014,30(2):6-12.
[11] 陈峰,郑建岚.自密实混凝土与老混凝土粘结强度的直剪试验研究[J].建筑结构学报,2007,28(1):59-63. CHEN Feng,ZHENG Jian-lan.Experimental research on direct shear behavior of adhesion of self-compacting concrete on existing concrete[J].Journal of Building Structures,2007,28(1):59-63.
[12] DIAB A,ELMOATY A,ELDIN M.Slant shear bond strength between self compacting concrete and old concrete[J].Construction and Building Materials,2017,130:73-82.
[13] 柴敏,罗素蓉.自密实混凝土与老混凝土粘结抗剪性能试验研究[J].福州大学学报:自然科学版,2013,41(5):922-927. CHAI Min,LUO Su-rong.Experimental research on shear properties of self-compacting concrete on existing concrete[J].Journal of Fuzhou University:Natural Science Edition,2013,41(5):922-927.
[14] 陈峰,郑建岚.自密实混凝土与老混凝土粘结滑移关系的有限元分析[J].武汉大学学报:工学版,2014,47(6):774-778. CHEN Feng,ZHENG Jian-lan.Finite element analysis of bonding-slip relationship between old concrete and freshly cured self-compacting concrete[J].Engineering Journal of Wuhan University,2014,47(6):774-778.
[15] 郑建岚,陈峰.自密实混凝土与老混凝土粘结剪切强度的塑性极限分析[J].工程力学,2008,25(8):164-168. ZHENG Jian-lan,CHEN Feng.The plastic limit analysis of adhesive shear strength between self-compacting concrete and old concrete[J].Engineering Mechanics,2008,25(8):164-168.
[16] 陈艾荣,冯师蓉,马如进.基于退化机理的混凝土桥梁耐久性环境区划[J].同济大学学报:自然科学版,2014,42(3):331-337. CHEN Ai-rong,FENG Shi-rong,MA Ru-jin.Environmental zoning for durability performance of concrete bridges based on deterioration mechanism[J].Journal of Tongji University:Natural Science,2014,42(3):331-337.
[17] JIANG C,HUANG Q,GU X,et al.Experimental investigation on carbonation in fatigue-damaged concrete[J].Cement and Concrete Research,2017,99:38-52.
[18] LO T Y,LIAO W,WONG C,et al.Evaluation of carbonation resistance of paint coated concrete for buildings[J].Construction and Building Materials,2016,107:299-306.
[19] LI G,DONG L,BAI Z A,et al.Predicting carbonation depth for concrete with organic film coatings combined with ageing effects[J].Construction and Building Materials,2017,142:59-65.
[20] 邓华锋,肖瑶,胥焘,等.碳纤维水泥基复合材料加固节理岩体试验[J].中国公路学报,2018,31(2):242-251. DENG Hua-feng,XIAO Yao,XU Tao,et al.Experiment on reinforcement of jointed rock mass by carbon fiber cement-based composite material[J].China Journal of Highway and Transport,2018,31(2):242-251.
[21] 刘人太,郑卓,李术才,等.破碎岩体注浆加固后的力学特性研究[J].中国公路学报,2018,31(10):284-291. LIU Ren-tai,ZHENG Zhuo,LI Shu-cai,et al.Mechanical properties of fractured rock mass with consideration of grouting reinforcement[J].China Journal of Highway and Transport,2018,31(10):284-291.
[22] 何薇.混凝土碳化及其对地下结构力学性能的影响研究[D].成都:西南交通大学,2013. HE Wei.Research on concrete carbonization and its influence on the mechanical behavior of underground structures[D].Chengdu:Southwest Jiaotong University,2013.
[23] ACI 318-08,Building code requirements for structural concrete and commentary[S].