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高钙粉煤灰安定性若干问题的探索 总被引:2,自引:0,他引:2
上海地区有一定量的立窑水泥应用于建筑市场。众所周知,立窑水泥的安定性不太稳定,随着高钙灰的逐步推广应用,与立窑水泥混合配制混凝土,此时立窑水泥中的f-CaO与高钙灰中的f-CaO值的机械加和可能导致安定性的更复杂化,本试验采集了雷氏值接近标准极限值的立窑425号普硅水泥及f-CaO接近上海市地方标准《高钙灰混凝土应用技术规程》中限值的高钙灰,并试验水泥自身安定性对高钙灰安定性的影响,同时通过化学外加剂及矿物外加剂探索了改善高钙灰安定性的可能性。1 425号普硅水泥波动性对高钙灰的影响①以普硅42… 相似文献
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1前言高钙灰比低钙灰有较低的需水量比和较高的强度比,但是当高钙灰中f-CaO含量高时,作为水泥的掺合料会引起安定性不合格,影响高钙灰安全的应用于商品混凝土。本文通过压蒸与蒸煮安定性方法的对比,对不同f-CaO的高钙灰的不同品种水泥中的极限掺量的安定性... 相似文献
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高钙粉煤灰作为水泥活性混合材的试验研究 总被引:1,自引:0,他引:1
通过不同高钙粉煤灰掺入量的水泥净浆和水泥砂浆试验,讨论了既能保证满足水泥安定性又充分利用高钙粉煤灰活性的较佳掺量。当高钙粉煤灰f—CaO<5%时能满足GB1596—91对水泥生产活性混合材料要求,较佳掺量为15%-20%,并可提高至30%,如加入适量外加剂并作一定处理,可使掺量提高更多。 相似文献
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针对增钙粉煤灰中f-CaO高的特点,研制出了一种新型外加剂。利用这种外加剂充分激发增钙粉煤灰的水化活性,并以此材料作胶结料,以液态渣作骨料,不用水泥,生产出达到国标要求的增钙粉煤灰小型空心砌块。 相似文献
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萃取熟料中fCaO时温度对各矿物的影响游良俭中国建筑材料科学研究院水泥所(100024)水泥熟料中fCaO是生产过程中的控制指标,快速、准确测定其含量至关重要。用乙二醇作萃取剂萃取水泥熟料中的fCaO,其萃取能力强于甘油-乙醇,这一事实已为人们所接受... 相似文献
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SO3对阿利特—硫铝酸盐水泥熟料性能影响的研究 总被引:5,自引:0,他引:5
文章探讨了SO3对阿利特-硫铝酸盐水泥熟料矿物形成及性能的影响。结果表明,适量的SO3可改善生料的易烧性,促进f-CaO的吸收,保证C4A3^-S的形成并使水泥的强度提高;当SO3含量较高时,则不利于C3S的形成,熟料中f-CaO升高,水泥的强度降低;SO3含量较低时,水泥的强度低且快凝。 相似文献
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高钙粉煤灰—水泥体积安定性的研究(上) 总被引:4,自引:0,他引:4
本文对上海高钙灰的品质特征,高钙灰中f-CaO的结构特征和水化特点,做了较深入的研究。特别是采取粉磨和添加稳定剂等技术措施介决了高钙灰掺入水泥后的体积安定性。 相似文献
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高钙粉煤灰—水泥体积安定性的研究(下) 总被引:2,自引:0,他引:2
本文对上海高钙灰的品质特征,高钙灰中f-CaO的结构特征和水化特点,做了较深入的研究。特别是采取粉磨和添加稳定剂等技术措施介决了高钙灰掺入水泥后的体积安定性。 相似文献
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Hydration of fly ash cement 总被引:1,自引:0,他引:1
It is necessary to establish the material design system for the utilization of large amounts of fly ash as blended cement instead of disposing of it as a waste. Cement blended with fly ash is also required as a countermeasure to reduce the amount of CO2 generation. In this study, the influences of the glass content and the basicity of glass phase on the hydration of fly ash cement were clarified and hydration over a long curing time was characterized. Two kinds of fly ash with different glass content, one with 38.2% and another with 76.6%, were used. The hydration ratio of fly ash was increased by increasing the glass content in fly ash in the specimens cured for 270 days. When the glass content of fly ash is low, the basicity of glass phase tends to decrease. Reactivity of fly ash is controlled by the basicity of the glass phase in fly ash during a period from 28 to 270 days. However, at an age of 360 days, the reaction ratios of fly ash show almost identical values with different glass contents. Fly ash also affected the hydration of cement clinker minerals in fly ash cement. While the hydration of alite was accelerated, that of belite was retarded at a late stage. 相似文献
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通过实验室球磨机制备出比表面积分别为280m2/kg、370m2/kg和670m2/kg的3种水泥熟料,与不同掺量的粉煤灰配制成不同颗粒级配的粉煤灰水泥,并测试了粉煤灰水泥浆体的抗压强度、自收缩、孔隙率和显微结构。结果表明:提高熟料细度能在很大程度上降低粉煤灰水泥浆体的孔隙率并提高复合水泥浆体早期抗压强度;粉煤灰的掺入降低了水泥体系的自收缩,提高了粉煤灰水泥浆体的体积稳定性;粉煤灰水泥浆体背散射图像表明,提高熟料细度可显著减少粉煤灰水泥浆体中未水化的水泥颗粒含量,并在一定程度上减少未水化粉煤灰颗粒含量。 相似文献
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利用高钙粉煤灰生产膨胀水泥的初步研究 总被引:10,自引:2,他引:8
通过对掺加游离氧化钙含量不同的高钙粉煤灰水泥的研究,表明掺入合适的添加物不仅可提高该水泥的强度,而且可调节水泥硬化浆体的膨胀值,使掺高钙粉煤灰水泥的基本性能满足一些膨胀水泥的技术指标,可利用高钙粉煤灰生产膨胀水泥。 相似文献
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分别粉磨对粉煤灰水泥性能及能耗的影响 总被引:1,自引:5,他引:1
在半工业化试验球磨机中对粉煤灰水泥的组分进行了单独粉磨,然后在混合机中进行混合配制,研究了分别粉磨工艺和传统共同粉磨工艺磨制的粉煤灰水泥在颗粒分布、水泥性能及粉磨电耗等方面的差异,探讨了利用分别粉磨工艺生产粉煤灰水泥的最佳技术方案。结果表明,采用分别粉磨工艺,是解决传统共同粉磨的粉煤灰水泥需水量大、早期强度低等缺点的有效措施。选择合适的配制方案,不仅能够显著改善水泥的物理性能和与减水剂的适应性,也可适当提高水泥中粉煤灰的掺量和节约一定的粉磨电耗。 相似文献
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Fly ash coming from a circulating fluidized bed combustion (CFBC) boiler co-firing coal and petroleum coke (CFBC fly ash) is very different from coal ash from traditional pulverized fuel firing due to many differences in their combustion processes, and thus they have different effects on the properties of Portland cement. The influences of CFBC fly ash on the strength, setting time, volume stability, water requirement for normal consistency, and hydration products of Portland cement were investigated. The results showed that CFBC fly ash had a little effect on the strength of the Portland cement when its content was below 20%, but the strength decreased significantly if the ash content was over 20%. The water requirement for normal consistency of cement increased from 1.8% to 3.2% (absolute increment value) with an addition of 10% CFBC fly ash; and the free lime (f-CaO) content of CFBC fly ash affected the value of increasing. The setting time decreased with an increase of CFBC fly ash content. The volume stability of the cement was qualified even when the content of SO3 and f-CaO reached 4.48% and 3.0% in cement, respectively. The main hydration productions of cement with CFBC fly ash were C-S-H (hydrated calcium silicate), AFt (ettringite), and portlandite. 相似文献