高氧化铁粉煤灰影响聚羧酸减水剂吸附特性的机理  

Influence mechanism of high iron fly ash on the adsorption characteristics of polycarboxylate superplasticizers

作　　者：刘娟红[1] 高霞[1] 纪洪广[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083

出　　处：《北京科技大学学报》2013年第7期929-934,共6页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(51174015)

摘　　要：采用净浆流动度、ζ电位、总有机碳(TOC)、红外光谱等实验,研究粉煤灰中氧化铁含量对不同结构聚羧酸减水剂吸附性能的影响,探讨氧化铁影响聚羧酸减水剂对水泥分散性能的机理,并提出了相应改进方法.结果表明:粉煤灰中氧化铁含量对掺不同结构聚羧酸减水剂的水泥净浆流动度均有很大影响,当氧化铁质量为粉煤灰总质量的18%时相应浆体基本失去流动性;加入硫化钠能使氧化铁与聚羧酸减水剂的吸附性能降低,浆体流动度有所改善.高氧化铁粉煤灰对聚羧酸减水剂的吸附性很强,与普通Ⅱ级粉煤灰相比,外加剂溶液中有机碳的含量要减少1/3.电泳实验表明:氧化铁的含量越多,体系ζ电位绝对值越小,分散稳定性越差.红外光谱表明:硫化钠的加入降低了高氧化铁粉煤灰对聚羧酸减水剂的吸附.The effect of iron oxide content in fly ash on the adsorption characteristics of polycarboxylate super- plasticizers with different structures was studied by the experiments of fluidity of paste, ~ potential, total organic carbon （TOC） and infrared spectra. The influence mechanism of iron oxides on the cement dispersion properties of polycar- boxylate superplasticizers was discussed and the improved method was put forward. It is found that iron oxide content in fly ash has a significant impact on the fluidity of cement paste mixed with polycarboxylate superplasticizers. When iron oxides are 18% of the total fly ash by mass, the corresponding slurry fluidity will be nearly lost; adding sodium sulfide can reduce the adsorption characteristics of iron oxides onto polycarboxylate superplasticizers, and the slurry fluidity is improved. Compared with common fly ash, high iron oxide fly ash has stronger adsorption characteristics onto polycarboxylate superplasticizers, with organic carbon content in the additive solution decreasing by one-third. Electrophoresis experiments indicate that the more the iron oxide content, the smaller the absolute value of ~ potential and the poorer the dispersion stability. Infrared spectra show that the adding of sodium sulfide reduces the adsorption characteristics of high iron oxide fly ash onto polycarboxylate superplasticizers.

关 键 词：水泥 粉煤灰 氧化铁 聚羧酸酯 吸附 

分 类 号：TU528[建筑科学—建筑技术科学]