| 摘要: |
| 通过对直接挤压得到的孔溶液进行化学分析，研究了水灰比、龄期、氯盐掺量、碳化暴露等因素对水泥基材料孔溶液的氯离子存在状态以及碱度的影响规律.结果表明：孔溶液中的自由氯离子浓度与水灰比及氯盐掺量有关；随着龄期延长，水化产物对氯离子的结合率上升.在自由氯离子浓度较高的情况下，孔溶液中的氯离子结合率降低；完全碳化条件下孔溶液中的自由氯离子浓度表现出明显增大的趋势，提高幅度为1~11倍；碳化后孔溶液中的氯离子结合率比未碳化试块的孔溶液降低了27%~54%；碳化使得孔溶液的碱度由13.19~13.47降至7.67~8.10.碳化反应降低了水泥浆体的pH值，释放了自由氯离子，极大地改变了混凝土内部的化学环境. |
| 关键词: 孔溶液 水泥基材料 氯离子 碳化 碱度 |
| DOI：10.3969/j.issn.1007 9629.2012.05.024 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划（973计划）项目（2009CB623230）；国家自然科学基金重点资助项目(50739001)；山东省自然科学基金资助项目（ZR2011EEQ031） |
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| Experimental Research on Chloride Form and pH Value of Pore Solution Expressed from Cementitious Materials |
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WAN Xiao mei1, FENG Yu kun2, ZHAO Tie jun1, LIU Chao1
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1.School of Civil Engineering, Qingdao Technological University, Qingdao 266033, China;2.Logistics Department, Qingdao Technological University, Qingdao 266033, China
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| Abstract: |
| Chloride and alkalinity in pore solution expressed directly from cementitious materials under various influencing factors including mw/mc, age, chloride addition and carbonation exposure were investigated by ion chromatography and pH meter.It is found that the content of free chloride decreases with increase of mw/mc and decrease of chloride addition. The rate of combination of chloride increases with time and decreases with free chloride content in pore solution. The effect of carbonation on the dissolved chloride content in pore solution is great. For cement mortar or paste with different mw/mc(0.5 and 0.7) and chloride addition(0, 0.5% and 1.0%), complete carbonation can increase the amount of free chloride in pore solution 2 to 12 times. Furthermore, the amount of chemically combined chloride is lowered by 27% to 54%, and the pH value decreases from values in the range between 13.19 and 13.47 to values in the range between 7.67 and 8.10. It can be concluded that, in addition to lower the pH value of the pore solution, carbonation will release more free chloride from the hydration products into pore solution and the internal chemical environment of concrete is changed considerably. |
| Key words: pore solution cementitious material chloride carbonation alkalinity |
