Cl~-渗透和碱集料反应作用下纳米混凝土的耐久性
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摘要
海洋环境下,氯离子(Cl~-)渗透和碱集料反应是影响混凝土耐久性的重要因素.为此,在普通海工混凝土中掺加适量纳米SiO_2或纳米Al_2O_3,研究纳米混凝土在Cl~-渗透和碱集料反应共同作用下的耐久性.结果表明:Cl~-渗透和碱集料反应两种因素对混凝土耐久性的影响是相互促进的.不同掺量的纳米SiO_2或纳米Al_2O_3可以不同程度地抑制混凝土的Cl~-渗透和碱集料反应,提高混凝土在两种因素共同作用下的耐久性,纳米SiO_2和纳米Al_2O_3在混凝土中的最优掺量均为2. 0%. Cl~-总质量分数趋于平衡时,纳米SiO_2混凝土和纳米Al_2O_3混凝土的Cl~-总质量分数分别降低18. 04%和11. 60%;在第39周时,纳米SiO_2混凝土和纳米Al_2O_3混凝土的膨胀率分别降低28. 75%和16. 87%.纳米颗粒的加入能够改善混凝土的孔结构,提高混凝土的抗Cl~-渗透性,抑制Friedels盐的产生,从而减少混凝土的膨胀;此外,纳米颗粒能够促进水泥二次水化,降低过渡区Ca(OH)2晶体的富集程度,阻碍CaCl_2的络合物产生和碱集料反应所需碱环境的形成.
In marine environment,chloride-ion( Cl~-) penetration and alkali aggregate reaction are important factors affecting the durability of concrete. In this paper,an appropriate amount of nano-SiO_2 or nano-Al_2O_3 was added to ordinary marine concrete to study the durability of concrete with nano-particles under the combined influence of Cl~-penetration and alkali aggregate reaction. The experimental results showed that Cl~-penetration and alkali aggregate reaction promoted the durability of the concrete mutually. Nano-SiO_2 or nano-Al_2O_3 of different amounts could inhibit the Cl~-penetration and alkali aggregate reaction of concrete to different degrees so that the durability of the concrete under the interaction of the two factors was improved. The optimum amount of nano-SiO_2 and nano-Al_2O_3 in concrete was both 2. 0%. When the total content of Cl~-in concrete was basically stable,the total amount of Cl~-in concrete with nano-SiO_2 or nano-Al_2O_3 was decreased by 18. 04% and 11. 60%,respectively. In the 39 th week,the expansion rate of concrete with nano-SiO_2 or nano-Al_2O_3 was reduced by28. 75% and 16. 87%,respectively. The addition of nano-particles could improve the pore structure of concrete,enhance the Cl~-penetration resistance of concrete,inhibit the generation of Friedel's salt,thereby mitigating the expansion of concrete. Additionally, nano-particles can promote secondary hydration of cement, reduce the aggregation degree of Ca( OH)2crystal in the transition zone,and restrain the formation of CaCl_2 complex compound and alkaline environment required for alkali aggregate reaction.
In marine environment,chloride-ion( Cl~-) penetration and alkali aggregate reaction are important factors affecting the durability of concrete. In this paper,an appropriate amount of nano-SiO_2 or nano-Al_2O_3 was added to ordinary marine concrete to study the durability of concrete with nano-particles under the combined influence of Cl~-penetration and alkali aggregate reaction. The experimental results showed that Cl~-penetration and alkali aggregate reaction promoted the durability of the concrete mutually. Nano-SiO_2 or nano-Al_2O_3 of different amounts could inhibit the Cl~-penetration and alkali aggregate reaction of concrete to different degrees so that the durability of the concrete under the interaction of the two factors was improved. The optimum amount of nano-SiO_2 and nano-Al_2O_3 in concrete was both 2. 0%. When the total content of Cl~-in concrete was basically stable,the total amount of Cl~-in concrete with nano-SiO_2 or nano-Al_2O_3 was decreased by 18. 04% and 11. 60%,respectively. In the 39 th week,the expansion rate of concrete with nano-SiO_2 or nano-Al_2O_3 was reduced by28. 75% and 16. 87%,respectively. The addition of nano-particles could improve the pore structure of concrete,enhance the Cl~-penetration resistance of concrete,inhibit the generation of Friedel's salt,thereby mitigating the expansion of concrete. Additionally, nano-particles can promote secondary hydration of cement, reduce the aggregation degree of Ca( OH)2crystal in the transition zone,and restrain the formation of CaCl_2 complex compound and alkaline environment required for alkali aggregate reaction.
引文
[1]詹炳根,孙伟.碱硅酸反应作用下混凝土中氯离子扩散规律和结合能力[J].东南大学学报,2006,36(6):956ZHAN Binggen,SUN Wei. Diffusion law and binding ability of chloride ion in concrete under alkali-silicic acid reaction[J]. Journal of Southeast University,2006,36(6):956
[2]詹炳根,孙伟.氯离子腐蚀与碱集料反应双重破坏因素作用下混凝土膨胀行为的研究[J].工业建筑,2005,35(2):77ZHAN Binggen,SUN Wei. Study on the expansion behavior of concrete under the double failure factors of chloride-ion corrosion and alkaliaggregate reaction[J]. Industrial Construction,2005,35(2):77
[3]BERUBE M A,DORION J F,DUCHESNE J,et al. Laboratory and field investigations of the influence of sodium chloride on alkali-silica reactivity[J]. Cement and Concrete Research,2003(33):77.DOI:10. 1016/s0008-8846(02)00926-2
[4]JENSEN A D,CHATTERJI S,CHRISTENSEN P,et al. An accelerated method for detection of alkali-aggregate reactivities of aggregates[J]. Cement and Concrete Research,1978(8):647.DOI:10. 1016/0008-8846(78)90047-9
[5]SIBBICK R G,PAGE C L. Mechanisms affecting the development of alkali-silica reaction in hardened concrete exposed to saline environments[J]. Magazine of Concrete Research,1998(MC50):147. DOI:10. 1680/macr. 1998. 50. 2. 147
[6]季韬,黄与舟,郑作樵.纳米混凝土物理力学性能研究初探[J].混凝土,2003(3):13JI Tao,HUANG Yuzhou,ZHENG Zuoqiao. Study on physical and mechanical properties of nano-concrete[J]. Concrete,2003(3):13
[7]沈洋,许仲梓,唐明述.试验温度与水泥碱质量分数对硅质集料砂浆棒试样膨胀的影响[J].南京化工大学学报,1999,21(2):5SHEN Yang, XU Zhongzi, TANG Mingshu. Influence of test temperature and cement alkali content on swelling of silica aggregate mortar rod samples[J]. Journal of Nanjing University of Chemical Technology,1999,21(2):5
[8] KRIVENKO P, DROCHYTKA R, GELEVERA A, et al.Mechanism of preventing the alkali-aggregate reaction in alkali activated cement concretes[J]. Cement and Concrete Composites,2014(45):157. DOI:10. 1016/j. cemconcomp. 2013. 10. 003
[9]BIRNIN-YAURI U A,GLASSER F P. Friedel’s salt,Ca2Al(OH)6(Cl,OH)·H2O:Its solid solution and their role in chloride binding[J]. Cement and Concrete Research,1998,28(12):1713. DOI:10. 1016/s0008-8846(98)00162-8
[10]CHATTERJI S,CLAUSSON-KASS N F. Prevention of alkali-silica expansion by using slag-portland cement[J]. Cement and Concrete Research,1984(14):816. DOI:10. 1016/0008-8846(84)90006-1
[11]ZHANG Maohua. Pore structure and chloride permeability of concrete containing nano-particles for pavement[J]. Construction and Building Materials, 2011(2):608. DOI:10. 1016/j.conbuildmat. 2010. 07. 032
[12]徐庆磊.纳米二氧化硅对水泥基材料性能的影响及作用机理研究[D].杭州:浙江大学,2013:72XU Qinglei. Effect of nano-silica on properties of cement-based materials and its mechanism[D]. Hangzhou:Zhejiang University,2013:72
[13]管申.纳米材料对水泥基材料水化和性能的影响[D].哈尔滨:哈尔滨工业大学,2017:83GUAN Shen. Effect of nano-materials on hydration and properties of cement-based materials[D]. Harbin:Harbin Institute of Technology,2017:83
[14]李国新.建筑材料[M].北京:机械工业出版社,2014LI Guoxin. Building materials[M]. Beijing:Machinery Industry Press,2014
[15]KONG L J,HOU L R,WANG Y H,et al. Investigation of the interfacial transition zone between aggregate-cement paste by AC impedance spectroscopy[J]. Journal of Wuhan University of Technology(Materials Science),2016,31(4):865. DOI:10.1007/s11595-016-1460-2
[16]李固华.纳米材料对混凝土耐久性的影响[D].成都:西南交通大学,2006:92LI Guhua. Nano-materials impact on durability of concrete[D].Chengdu:Southwest Jiaotong University,2006:92
[2]詹炳根,孙伟.氯离子腐蚀与碱集料反应双重破坏因素作用下混凝土膨胀行为的研究[J].工业建筑,2005,35(2):77ZHAN Binggen,SUN Wei. Study on the expansion behavior of concrete under the double failure factors of chloride-ion corrosion and alkaliaggregate reaction[J]. Industrial Construction,2005,35(2):77
[3]BERUBE M A,DORION J F,DUCHESNE J,et al. Laboratory and field investigations of the influence of sodium chloride on alkali-silica reactivity[J]. Cement and Concrete Research,2003(33):77.DOI:10. 1016/s0008-8846(02)00926-2
[4]JENSEN A D,CHATTERJI S,CHRISTENSEN P,et al. An accelerated method for detection of alkali-aggregate reactivities of aggregates[J]. Cement and Concrete Research,1978(8):647.DOI:10. 1016/0008-8846(78)90047-9
[5]SIBBICK R G,PAGE C L. Mechanisms affecting the development of alkali-silica reaction in hardened concrete exposed to saline environments[J]. Magazine of Concrete Research,1998(MC50):147. DOI:10. 1680/macr. 1998. 50. 2. 147
[6]季韬,黄与舟,郑作樵.纳米混凝土物理力学性能研究初探[J].混凝土,2003(3):13JI Tao,HUANG Yuzhou,ZHENG Zuoqiao. Study on physical and mechanical properties of nano-concrete[J]. Concrete,2003(3):13
[7]沈洋,许仲梓,唐明述.试验温度与水泥碱质量分数对硅质集料砂浆棒试样膨胀的影响[J].南京化工大学学报,1999,21(2):5SHEN Yang, XU Zhongzi, TANG Mingshu. Influence of test temperature and cement alkali content on swelling of silica aggregate mortar rod samples[J]. Journal of Nanjing University of Chemical Technology,1999,21(2):5
[8] KRIVENKO P, DROCHYTKA R, GELEVERA A, et al.Mechanism of preventing the alkali-aggregate reaction in alkali activated cement concretes[J]. Cement and Concrete Composites,2014(45):157. DOI:10. 1016/j. cemconcomp. 2013. 10. 003
[9]BIRNIN-YAURI U A,GLASSER F P. Friedel’s salt,Ca2Al(OH)6(Cl,OH)·H2O:Its solid solution and their role in chloride binding[J]. Cement and Concrete Research,1998,28(12):1713. DOI:10. 1016/s0008-8846(98)00162-8
[10]CHATTERJI S,CLAUSSON-KASS N F. Prevention of alkali-silica expansion by using slag-portland cement[J]. Cement and Concrete Research,1984(14):816. DOI:10. 1016/0008-8846(84)90006-1
[11]ZHANG Maohua. Pore structure and chloride permeability of concrete containing nano-particles for pavement[J]. Construction and Building Materials, 2011(2):608. DOI:10. 1016/j.conbuildmat. 2010. 07. 032
[12]徐庆磊.纳米二氧化硅对水泥基材料性能的影响及作用机理研究[D].杭州:浙江大学,2013:72XU Qinglei. Effect of nano-silica on properties of cement-based materials and its mechanism[D]. Hangzhou:Zhejiang University,2013:72
[13]管申.纳米材料对水泥基材料水化和性能的影响[D].哈尔滨:哈尔滨工业大学,2017:83GUAN Shen. Effect of nano-materials on hydration and properties of cement-based materials[D]. Harbin:Harbin Institute of Technology,2017:83
[14]李国新.建筑材料[M].北京:机械工业出版社,2014LI Guoxin. Building materials[M]. Beijing:Machinery Industry Press,2014
[15]KONG L J,HOU L R,WANG Y H,et al. Investigation of the interfacial transition zone between aggregate-cement paste by AC impedance spectroscopy[J]. Journal of Wuhan University of Technology(Materials Science),2016,31(4):865. DOI:10.1007/s11595-016-1460-2
[16]李固华.纳米材料对混凝土耐久性的影响[D].成都:西南交通大学,2006:92LI Guhua. Nano-materials impact on durability of concrete[D].Chengdu:Southwest Jiaotong University,2006:92