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通过溶液法合成钙矾石,并借助XRD、SEM、IR等分析测试术,分析比较了钙矾石对不同价态、不同存在方式铬离子(Cr~(6+)和Cr~(3+))固化机制,及其在冻融、碳化、氯盐侵蚀等不同环境条件下的稳定性。研究结果表明,钙矾石对Cr~(6+)和Cr~(3+)固化机制及其稳定性并不相同。钙矾石对Cr~(3+)有较强固化能力,固化率大于90%;但对Cr~(6+)固化能力较弱,固化率不足50%,且随养护龄期延长,钙矾石对Cr~(6+)固化能力有所减弱。在冻融、碳化、氯盐侵蚀及复合环境条件作用下,钙矾石对Cr~(3+)固化作用影响相对较小,固化率大于80%;对Cr~(6+)固化能力却显著降低,且碳化、冻融、氯盐侵蚀多因素复合对其固化稳定性有极大影响。在冻融循环作用下,钙矾石对Cr~(6+)固化率为12%;但在碳化作用下,Cr~(6+)固化率仅2.4%。
The ettringite was synthesized by solution method and analyzed by XRD, SEM and IR. The effects of ettringite on Cr (6+) and Cr (3+) ) Curing mechanism, and its stability in different environmental conditions such as freeze-thaw, carbonization, chloride corrosion. The results show that the mechanism and stability of ettringite to Cr 6+ and Cr 3+ are not the same. Eutectite has stronger curing ability to Cr 3+, the curing rate is more than 90%, but it is weak to Cr 6+, the curing rate is less than 50%, and with the increase of curing age, Stone on the Cr ~ (6 +) curing ability weakened. Under the action of freeze-thaw, carbonization, chloride attack and composite environmental conditions, ettringite has a relatively small effect on the solidification of Cr 3+, the curing rate is more than 80% and the solidification ability of Cr 6+ is significant Reduce, and carbonization, freeze-thaw, chloride salt corrosion multi-factor compound has a great influence on its curing stability. Under the action of freeze-thaw cycles, the solidification rate of ettringite to Cr 6+ is 12%, but the solidification rate of Cr 6+ is only 2.4% under carbonation.