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Four cellulose ethers(CEs) were compared for their effects on the pore structure of cement paste using mercury intrusion porosimetry. The experimental results show that the total pore volume and porosity of cement pastes containing the four cellulose ethers are significantly higher than that of the pure cement pastes and the total pore volume and porosity of cement pastes containing HEC(hydroxyethyl cellulose ether) or low viscosity cellulose ethers are low in four CEs. By changing the surface tension and viscosity of liquid phase and the strengthening of liquid film between air voids in cement pastes, CEs affect the formation, diameter evolution and upward movement of air voids and the pore structure of hardening cement paste. For the four CEs, the pore volume of cement pastes containing HEC or low viscosity cellulose ethers is higher with the diameter of 30-70 nm while lower with the diameter larger than 70 nm. CEs affect the pore structure of cement paste mainly through their effects on the evolvement of the small air voids into bigger ones when the pore diameter is below 70 nm and their effects on the entrainment and stabilization of air voids when the pore diameter is above 70 nm. 相似文献
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酸激发地质聚合物(ASP-GP)是由铝硅酸盐与酸性溶液反应生成的具有三维立体网络结构的铝硅酸盐无机聚合物。它具有制备工艺简单、机械强度高(最大抗压强度达146 MPa)、耐火耐高温性能好、固封性能及介电性能优异等优点,可作为传统建筑材料、隔热耐火耐高温材料、固封材料、电子封装材料等。此外,低碳节能的制造过程恰好满足绿色环保和节能减排需求,因此,ASP-GP在土木工程、机械工程、航空航天、冶金、核废固封等领域均具有广阔的应用前景。本文依据国内外现有的ASP-GP研究成果,综述了ASP-GP反应机理及力学性能的研究进展,总结了影响ASP-GP力学性能的因素,包括铝硅酸盐活性、激发剂、原材料配合比、养护制度等,以期为ASP-GP的后续研究提供一定的指导。 相似文献
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钢筋套筒灌浆连接技术是装配式建筑中的一项关键技术,钢筋连接用套筒灌浆料(以下称灌浆料)则是其中的一种重要材料。灌浆料中需要摻入塑性膨胀剂才能保证灌浆饱满。研究一种塑性膨胀剂在灌浆料中的摻量对灌浆料性能的影响。结果表明,塑性膨胀剂掺量≤0.02%时,灌浆料初始流动度和30 min流动度损失增加。塑性膨胀剂摻量0.02%时,灌浆料初始流动度和30 min流动度损失降低;塑性膨胀剂对灌浆料的湿表观密度影响不大;当塑性膨胀剂掺量由0增加到0.03%时,灌浆料所有龄期的抗折强度和抗压强度都呈先增加,后降低的趋势。 相似文献
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Cellulose ethers are widely used to mortar formulations,and it is significant to understand the interaction between cellulose ethers and cement pastes.FT-IR spectra,thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article.The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste,but the major hydration products,such as CH(calcium hydroxide),ettringite and C-... 相似文献
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干混砂浆用纤维素醚溶液的黏度测试方法探讨 总被引:1,自引:0,他引:1
黏度是干混砂浆行业选择纤维素醚的最基本指标,测试纤维素醚溶液的黏度时,存在纤维素醚溶液不均匀、溶液内存在气泡和溶液内温度不一致等问题。通过配制MC、HEMC、HPMC和HEC 4种常见的非离子纤维素醚溶液,分析了影响纤维素醚溶液黏度测量结果的因素,包括分散、冷却、搅拌、补水、恒温和黏度测试6个方面,进而提出了测试纤维素醚溶液黏度时需要注意的环节,包括选择容器的尺寸大小、纤维素醚粉末的分散方式、搅拌速度、停止搅拌的时间和恒温时间等,以保证纤维素醚溶液黏度测试结果的可靠性。 相似文献