掺合料混凝土早期碳化的微观分析
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摘要
为探明掺合料混凝土早期碳化过程中微观性能的变化,通过测试pH值研究了掺合料混凝土早期碳化后内部pH值沿试件深度的分布规律;对比pH值和酚酞试剂测试结果的差异,探讨了酚酞试剂测试早期碳化测试方法的适用性;通过化学成分分析研究了早期碳化过程中物质成分的变化规律。研究表明:从表面向内部方向,混凝土试块pH值不断增大并稳定于一定值;随着掺合料掺量的增加,混凝土孔隙液的pH值沿着试件的深度方向减小,掺合料混凝土的碱性减弱,砂浆试件可碳化的Ca(OH)2含量减小;混凝土孔隙液的pH值随着养护时间的延长而逐渐增大,且其增大量随着试件深度的增加而减小;随着试验龄期的延长,表层混凝土孔隙液pH值逐渐减小,而混凝土内部孔隙液的pH值随试验龄期的延长变化不大;酚酞溶液测得的碳化深度约为pH值法测得的完全未碳化深度的0.53倍;沿砂浆试件表层向内部方向,CaCO3含量逐渐减小而Ca(OH)2含量逐渐增大,二者最终都趋于定值。
In order to ascertain the change of micro-performance change of mineral admixture concrete during early carbonation,the pH value distribution along the depth of concrete specimen after early carbonation was studied through pH value test.By comparing pH value test results with phenolphthalein test results,the applicability of phenolphthalein reagent test method was discussed.The change pattern of material composition during early carbonation was analyzed by chemical composition analysis.Results show that along the direction from surface to inner part,pH value of concrete specimen increases and gradually tends to be a certain value.With the increase of admixture content,pH value of concrete pore solution decreases,the alkalinity of mineral admixture concrete weakens,the Ca(OH)2 content of mortar specimen which can be carbonized decreases.pH value of concrete pore solution increases with the increase of curing time,and its increment deceases with the increase of specimen′s depth.As the concrete age increases,the pH value of specimen′s surface decreases gradually while the pH value of specimen′s deep doesn′t change obviously.The carbonation depth by phenolphthalein solution test is about 0.53 times of the non-carbonated depth by pH value test.Along the side surface to inner direction of mortar specimen,the CaCO3 content decreases gradually and tends to be a constant value while the Ca(OH)2 content increases gradually and tends to be a constant value.
In order to ascertain the change of micro-performance change of mineral admixture concrete during early carbonation,the pH value distribution along the depth of concrete specimen after early carbonation was studied through pH value test.By comparing pH value test results with phenolphthalein test results,the applicability of phenolphthalein reagent test method was discussed.The change pattern of material composition during early carbonation was analyzed by chemical composition analysis.Results show that along the direction from surface to inner part,pH value of concrete specimen increases and gradually tends to be a certain value.With the increase of admixture content,pH value of concrete pore solution decreases,the alkalinity of mineral admixture concrete weakens,the Ca(OH)2 content of mortar specimen which can be carbonized decreases.pH value of concrete pore solution increases with the increase of curing time,and its increment deceases with the increase of specimen′s depth.As the concrete age increases,the pH value of specimen′s surface decreases gradually while the pH value of specimen′s deep doesn′t change obviously.The carbonation depth by phenolphthalein solution test is about 0.53 times of the non-carbonated depth by pH value test.Along the side surface to inner direction of mortar specimen,the CaCO3 content decreases gradually and tends to be a constant value while the Ca(OH)2 content increases gradually and tends to be a constant value.
引文
[1]张令茂,江文辉.混凝土自然碳化及其与人工加速碳化的相关性研究[J].西安冶金建筑学院学报,1990(3):207-221(ZHANG Lingmao,JIANG Wenhui.Study on carbonation of concrete in natural condition and its correlation with artificial accelerated carbonation[J].Journal of Xi′an University of Architecture and Technology,1990(3):207-221(in Chinese))
[2]胡晓鹏,牛荻涛,张永利.粉煤灰混凝土早期碳化规律研究[J].西安建筑科技大学学报(自然科学版),2012,44(6):805-810(HU Xiaopeng,NIU Ditao,ZHANG Yongli.Experimental analysis on early carbonization rule of fly ash concrete[J].Journal of Xi′an University of Architecture and Technology(Natural Science Edition),2012,44(6):805-810(in Chinese))
[3] Houst Y.Depth profiles of carbonates formed during natural carbonation[J].Cement and Concrete Research,2002,32(12):1923-1930.
[4]阿茹罕,阎培渝.不同粉煤灰掺量混凝土的碳化特性[J].硅酸盐学报,2011,39(1):7-12(Aruhan,YAN Peiyu.Carbonation characteristics of concrete with different fly-ash contents[J].Journal of the Chinese Ceramic Society,2011,39(1):7-12(in Chinese))
[5]胡建军.掺粉煤灰和矿渣粉混凝土的碳化行为及其影响因素的研究[D].北京:清华大学,2010(HU Jianjun.Studies on carbonation behavior of concrete mixed with fly ash and granulated blast furnace slag and its influencing factors[D].Beijing:Tsinghua University,2010(in Chinese))
[6]贾耀东.大掺量矿物掺合料混凝土的碳化特性研究[D].北京:清华大学,2010(JIA Yaodong.Research on carbonation characteristics of high volume mineral admixtures concrete[D].Beijing:Tsinghua University,2010(in Chinese))
[7] Krajci L,Janotka I.Measurement techniques for rapid assessment of carbonation in concrete[J].ACI Material Journal,2000,97(2):168-171.
[8] Sanjuán M A,Andrade C,Cheyrezy M.Concrete carbonation tests in natural and accelerated conditions[J].Advance Cement Research,2003,15(4):171-180.
[9]胡晓鹏,孙广帅,张成中,等.混凝土早期碳化性能的试验研究[J].西安建筑科技大学学报(自然科学版),2017,49(4):34-38(HU Xiaopeng,SUN Guangshuai,ZHANG Chengzhong,et al.Experimental study on early carbonation of concrete[J].Journal of Xi′an University of Architecture and Technology(Natural Science Edition),2017,49(4):34-38(in Chinese))
[10]张成中,孙广帅,胡晓鹏,等.掺合料对混凝土早期碳化深度影响的试验研究[J].硅酸盐通报,2017,36(1):282-287(ZHANG Chengzhong,SUN Guangshuai,HU Xiaopeng,et al.Experimental research on influence of concrete early carbonation depth by admixture[J].Bulletin of the Chinese Ceramic Society,2017,36(1):282-287(in Chinese))
[11] GB/T 50082-2009,普通混凝土长期性能和耐久性能试验方法标准[S].北京:中国建筑工业出版社,2009(GB/T 50082-2009,Standard for test method of long-term performance and durability of ordinary concrete[S].Beijing:China Architecture&Building Press,2009(in Chinese))
[12]黄利频,郑建岚.测试混凝土孔溶液的pH值研究混凝土的碳化性能[J].福州大学学报,2012,40(6):794-799(HUANG Lipin,ZHENG Jianlan.Study on the carbonation performance of concrete by testing the pH value of concrete pore solution[J].Journal of Fuzhou University(Natural Science Edition),2012,40(6):794-799(in Chinese))
[13] Rasanen V,Penttala V.The pH measurement of concrete and smoothing mortar using a concrete powder suspension[J].Cement and Concrete Research,2004,34(5):813-820.
[14]姬永生.钢筋混凝土的全寿命过程与预计[M].中国铁道出版社,2011(JI Yongsheng.Performance and prediction of reinforced concrete in full service life due to corrosion damage[M].China Railway Publishing House,2011(in Chinese))
[15]杨南如.无机非金属材料测试方法[M].武汉工业出版社,1990(YANG Nanru.Test method for inorganic nonmetallic materials[M].Wuhan Industry Press,1990(in Chinese))
[16]徐飞,陈正,莫林.混凝土碳化试验与碳化深度测定方法的对比分析[J].工程与试验,2013,53(4):27-31(XU Fei,CHEN Zheng,MO Lin.Comparative analysis of experimental methods for concrete carbonation and measuring methods for carbonation depth[J].Engineering and Test,2013,53(4):27-31(in Chinese))
[2]胡晓鹏,牛荻涛,张永利.粉煤灰混凝土早期碳化规律研究[J].西安建筑科技大学学报(自然科学版),2012,44(6):805-810(HU Xiaopeng,NIU Ditao,ZHANG Yongli.Experimental analysis on early carbonization rule of fly ash concrete[J].Journal of Xi′an University of Architecture and Technology(Natural Science Edition),2012,44(6):805-810(in Chinese))
[3] Houst Y.Depth profiles of carbonates formed during natural carbonation[J].Cement and Concrete Research,2002,32(12):1923-1930.
[4]阿茹罕,阎培渝.不同粉煤灰掺量混凝土的碳化特性[J].硅酸盐学报,2011,39(1):7-12(Aruhan,YAN Peiyu.Carbonation characteristics of concrete with different fly-ash contents[J].Journal of the Chinese Ceramic Society,2011,39(1):7-12(in Chinese))
[5]胡建军.掺粉煤灰和矿渣粉混凝土的碳化行为及其影响因素的研究[D].北京:清华大学,2010(HU Jianjun.Studies on carbonation behavior of concrete mixed with fly ash and granulated blast furnace slag and its influencing factors[D].Beijing:Tsinghua University,2010(in Chinese))
[6]贾耀东.大掺量矿物掺合料混凝土的碳化特性研究[D].北京:清华大学,2010(JIA Yaodong.Research on carbonation characteristics of high volume mineral admixtures concrete[D].Beijing:Tsinghua University,2010(in Chinese))
[7] Krajci L,Janotka I.Measurement techniques for rapid assessment of carbonation in concrete[J].ACI Material Journal,2000,97(2):168-171.
[8] Sanjuán M A,Andrade C,Cheyrezy M.Concrete carbonation tests in natural and accelerated conditions[J].Advance Cement Research,2003,15(4):171-180.
[9]胡晓鹏,孙广帅,张成中,等.混凝土早期碳化性能的试验研究[J].西安建筑科技大学学报(自然科学版),2017,49(4):34-38(HU Xiaopeng,SUN Guangshuai,ZHANG Chengzhong,et al.Experimental study on early carbonation of concrete[J].Journal of Xi′an University of Architecture and Technology(Natural Science Edition),2017,49(4):34-38(in Chinese))
[10]张成中,孙广帅,胡晓鹏,等.掺合料对混凝土早期碳化深度影响的试验研究[J].硅酸盐通报,2017,36(1):282-287(ZHANG Chengzhong,SUN Guangshuai,HU Xiaopeng,et al.Experimental research on influence of concrete early carbonation depth by admixture[J].Bulletin of the Chinese Ceramic Society,2017,36(1):282-287(in Chinese))
[11] GB/T 50082-2009,普通混凝土长期性能和耐久性能试验方法标准[S].北京:中国建筑工业出版社,2009(GB/T 50082-2009,Standard for test method of long-term performance and durability of ordinary concrete[S].Beijing:China Architecture&Building Press,2009(in Chinese))
[12]黄利频,郑建岚.测试混凝土孔溶液的pH值研究混凝土的碳化性能[J].福州大学学报,2012,40(6):794-799(HUANG Lipin,ZHENG Jianlan.Study on the carbonation performance of concrete by testing the pH value of concrete pore solution[J].Journal of Fuzhou University(Natural Science Edition),2012,40(6):794-799(in Chinese))
[13] Rasanen V,Penttala V.The pH measurement of concrete and smoothing mortar using a concrete powder suspension[J].Cement and Concrete Research,2004,34(5):813-820.
[14]姬永生.钢筋混凝土的全寿命过程与预计[M].中国铁道出版社,2011(JI Yongsheng.Performance and prediction of reinforced concrete in full service life due to corrosion damage[M].China Railway Publishing House,2011(in Chinese))
[15]杨南如.无机非金属材料测试方法[M].武汉工业出版社,1990(YANG Nanru.Test method for inorganic nonmetallic materials[M].Wuhan Industry Press,1990(in Chinese))
[16]徐飞,陈正,莫林.混凝土碳化试验与碳化深度测定方法的对比分析[J].工程与试验,2013,53(4):27-31(XU Fei,CHEN Zheng,MO Lin.Comparative analysis of experimental methods for concrete carbonation and measuring methods for carbonation depth[J].Engineering and Test,2013,53(4):27-31(in Chinese))