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以贝壳、高岭土、石膏为原料制备白水泥,并利用XRD,SEM等检测方法对熟料性能、水泥物理性能和水化性能进行了分析.结果表明:质量分数为78%的贝壳与22%的高岭土,经过1 350℃的煅烧,并保温40min、喷水漂白1min,可制成贝壳基生态白水泥,其28d的抗压强度为33.2MPa,白度为79度,其熟料的主要矿物为A矿、B矿,还有少量的C11A7.CaCl2和Ca(OH)2;在熟料中掺入85%(质量分数)的自制活性混合材后,贝壳基生态复合白水泥的白度为87度,软化系数为0.94,28d的抗压强度可达53.3MPa;贝壳基生态复合白水泥的水泥石结构以AFt为骨架,C-S-H凝胶填充骨架孔隙,Ca(OH)2晶体穿插其间,呈致密网状体系. 相似文献
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宋远明 《武汉理工大学学报(材料科学英文版)》2014,29(5):945-949
Circulating fluidized bed combustion (CFBC) ash exhibits the desirable pozzolanic activity which makes it a potential supplementary cementitious material to replace cement for concrete production. However, the high unburnt carbon content and porous surface structure of CFBC ash may adsorb water reducer and thereby significantly reduce the efficiency of water-reducing agents. The adsorption mechanism of polycarboxylate superplasticizer in CFBC ash-Portland cement paste was investigated by ultraviolet-visible spectrophotometer, and the conception of "invalid adsorption site" of CFBC ash was presented. The results show that the adsorption behavior of polycarboxylate superplasticizer in coal ash-Portland cement paste can be described by Langmuir isothermal adsorption equation. The adsorption capacity of CFBC ash-Portland cement paste is higher than that of pulverized coal combustion (PCC) fly ash-Portland cement paste. Moreover, the adsorption amount of polycarboxylate superplasticizer increases with the ratio of ash-to-cement in the paste. At last, the fluidity of CFBC ash-Portland cement paste is lower than that of the PCC fly ash paste. This work suggests that when CFBC ash is used as concrete admixture, the poor flowability of the cementitious system due to the high adsorption of water and water-reducing agent should be taken into consideration. 相似文献
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