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101.
高岭土应用研究的新进展 总被引:19,自引:1,他引:19
高岭土经过脱水后,转变成为具有高火山灰活性的偏高岭土。本文主要介绍了利用高活性偏高岭土通过碱激活制备的土聚水泥和直接作为混凝土矿物掺合料在水泥基材料中的应用途径。土聚水泥在工艺、性能、用途等方面集有机高聚物、陶瓷、水泥等材料的特征,是同时具有独特优点的新材料。偏高岭参合料具有提高混凝土的早期强度,改善硬化混凝土的工作性和耐久性,减少水泥石的自收缩等方面的作用。高岭土在水泥基材料中广阔的应用领域和优异的性能向人们展示了其诱人的开发前景。 相似文献
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The present research deals with strength, porosity and hydric behavior of metakaolin cement admixtured with different types of water. The hydration of ordinary Portland cement in the presence of 0%, 10%, 20% and 30% metakaolin treated with distilled, ground and sea water with the water to cement ratio of 0.4 was studied. The experimental results on setting time, strength, porosity and hydric parameters are reported. The results show that, metakaolin percentage increases in strength with a decrease in porosity. The observed results are discussed with SEM micrographs. Further, sea water accelerates the cement hydration at the early stages but retards it in the latter stages of hydration. 相似文献
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Liu Ye Yu Xianbo Qin Lei Wang Jingdai Yang Yongrong 《中国炼油与石油化工》2010,12(1):23-28
ZSM-5 zeolite was in-situ synthesized from metakaolin or spinel by incorporating additional silica and alumina sources, respectively. The ZSM-5 zeolite was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and N2 adsorption measurement. This supported zeolite was tested on the methanol to propylene (MTP) processes. Experimental results showed that the ZSM-5 zeolite exhibited high selectivity for propylene. The yield of propylene on ZSM-5 zeolite made from metakaolin was increased by 17.73%, while that on ZSM-5 zeolite made from spinel was raised by 9.90%, compared to that achieved with the commercial ZSM-5 zeolite. The significant increase in propylene production is probably due to the distinctive morphology of the ZSM-5 zeolite, which possessed a rough external surface covered with sphere-like particles and distribution of small crystals sized at around 400-500 nm. This morphology could help to generate more crystal defects so that more active centers could be exposed to the reaction mixture. In addition, the zeolite product had a gradient pore distribution and many medium Bronsted acid sites, both of which might also contribute to the increased propylene production. 相似文献
105.
WEI Xiaosheng ZHU Hongping LI Guowei ZHANG Changqing XIAO Lianzhen 《武汉理工大学学报(材料科学英文版)》2007,22(4):728-732
The compressive strength and dynamic modulus of high volume fly ash concrete with incorporation of either metakaolin or silica fume were investigated. The water to cementitious materials ratio was kept at 0.4 for all mixtures. The use of high volume fly ash in concrete greatly reduces the strength and dynamic modulus during the first 28 days. The decreased properties during the short term of high volume fly ash concrete is effectively compensated by the incorporation of metakaolin or silica fume. The DTA results confirmed that metakaolin or silica fume increase the amount of the hydration products. An empirical relationship between dynamic modulus and compressive strength of concrete has been obtained. This relation provides a nondestructive evaluation for estimating the strength of concrete by use of the dynamic modulus. 相似文献
106.
掺偏高岭土活性粉末混凝土的试验研究 总被引:1,自引:0,他引:1
针对我国自然资源的现状,探讨采用化学组成与硅灰相似的偏高岭土配置活性粉末混凝土(RPC),进行了约150组掺偏高岭土活性粉末混凝土的立方抗压强度试验。结果表明:偏高岭土性能与硅灰相近,能较明显提高混凝土的抗压强度,同时偏高岭土与其它活性矿物掺合料能产生良好的复合效应,可以部分或全部替代硅灰配制活性粉末混凝土;通过调整配合比,用细砂亦可配制出强度较高的活性粉末混凝土。 相似文献
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偏高岭土、矿渣和赤泥对高性能混合水泥性能影响的研究 总被引:1,自引:0,他引:1
通过用硅酸盐水泥、偏高岭土等混合材、膨胀剂及减水剂等制备混合水泥的研究发现:偏高岭土和赤泥的加入使水泥的凝结时间缩短,矿渣的加入延长了水泥的凝结时间;偏高岭土和矿渣对水泥的胶砂流动性影响较小,赤泥的加入使得水泥胶砂流动性显著降低;适量偏高岭土的加入对水泥的3d和28d强度均有增强作用,适量矿渣的加入使水泥抗折强度降低,抗压强度增大;少量的赤泥对水泥强度特别是早期强度有一定的增强作用,但掺量超过20%后水泥强度迅速降低;偏高岭土对水泥微膨胀的产生有促进作用,矿渣和赤泥对水泥微膨胀有抑制作用。用80%~90%的硅酸盐水泥、10%~20%的偏高岭土以及少量的膨胀剂和减水剂能够制备出具有较优流动性、较高的强度以及微膨胀的高性能混合水泥。 相似文献