| 陈益民,张洪涛,林震.三峡大坝粉煤灰的水化反应速率与大坝混凝土贫钙问题[J].水利学报,2002,33(8):0007-0012 |
| 三峡大坝粉煤灰的水化反应速率与大坝混凝土贫钙问题 |
| Hydration rate of fly ash and probability of poor lime phenomena in concrete of the Three Gorges Project |
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| DOI： |
| 中文关键词: 大坝混凝土 粉煤灰 水化速率 水化产物 贫钙问题 |
| 英文关键词: concrete fly ash hydration rate hydration product, poor lime phenomena |
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| 中文摘要: |
| 用选择溶解、化学分析、X射线衍射分析(XRD)、热重分析(TG)等方法研究了三峡大坝混凝土所用的中热水泥-一级粉煤灰体系中粉煤灰的反应速率、反应程度、水化反应产物与其掺加量的关系. 结果指出, 随粉煤灰对水泥取代数量的增加, 粉煤灰反应的程度降低, 但水化物的绝对数量增加. 粉煤灰中CaO、MgO、Fe2O3优先进入水化产物中, 反应率较高; SiO2和Al2O3反应率较低, 但是由于它们含量大, 因而进入水化产物中的数量较多, 其中SiO2反应较慢但水化物数量持续增长. 该体系中粉煤灰数量每增加10%, 水化产物中Ca(OH)2数量减少约1/3. 据此判断出为预防三峡大坝混凝土发生贫钙现象, 粉煤灰掺加量应小于50%. |
| 英文摘要: |
| The relationships between hydration rate, hydration extent, hydration product of the fly ash adopted in the Three Gorges Project and its replaced amount in the concretet are studied by means of selective solution method, wet chemical analysis, X-ray diffraction and Thermal gravity method. The cement to be used is a kind of medium heat Portland cement. The result shows that the hydration extent reduces as the amount of fly ash increases, but the amount of the hydration product will increase. In the process of hydration, CaO, MgO and Fe2O3 in fly ash enter the hydration products more quickly than SiO2 and Al2O3. But the amounts of SiO3 and Al2O3 entering the products are much more than CaO, MgO and Fe2O3, since their contents in the cement-fly ash system are great. It is noticed that the amount of SiO2 entering the hydration products increases steadily. The amount of Ca(OH)2 will decrease 1/3 if the amount of fly ash increases by 10%. It is suggested that, the replaced amount of fly ash must not exceed the limit of 50%, to prevent from the happening o fpoor lime phenomena. |
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