减水剂在粉煤灰水泥浆体中的吸附及其流变性能影响  

Adsorption of superplasticizers in fly ash blended cement paste and its effects on the rheology

作　　者：陈伟[1] 田亚坡[2] 水中和[1] 

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070 [2]华南理工大学材料科学与工程学院,广东广州510640

出　　处：《混凝土》2012年第4期36-40,共5页Concrete

基　　金：国家自然科学基金资助课题(50802067);教育部回国留学人员科研启动基金资助课题;武汉市青年科技晨光计划资助课题(201150431086)

摘　　要：针对减水剂—粉煤灰体系的相互作用与分散特性开展研究,通过采用不同性质的粉煤灰和减水剂,研究了减水剂在水泥等胶凝颗粒上的吸附量、zeta电位等界面化学性质,并且测定了不同系统的屈服应力和塑性黏度等流变特性,建立了减水剂吸附量、zeta电位和水泥浆体流变参数之间的关系。试验结果表明:高效减水剂在粉煤灰颗粒表面的吸附规律与水泥颗粒完全不同。由于粉煤灰颗粒较为光滑并且表面动电位为负值,因此对高效减水剂的吸附能力较弱,其吸附能力随粉煤灰密度和颗粒大小差异较大。对于粉煤灰水泥浆体,其流变参数变化与减水剂吸附量关系较小,主要受粉煤灰技术性质的影响。由于粉煤灰表面动电位绝对值远高于掺入减水剂的硅酸盐水泥颗粒表面动电位绝对值,因此其自身具有颗粒分散趋势,及粉煤灰颗粒自身具有增加水泥浆体流动能力的能力。硅酸盐水泥和粉煤灰颗粒吸附萘系减水剂的能力大于吸附聚羧酸盐减水剂的能力。The interaction between superplasticizers and fly ash particles is invesgitated together with the dispersion behavior of the pastes.Fly ashes and supertplasticizers of different types and properties are used and the adsorption of suplasticizer,the zeta potential are tested.The rheological parameters containing the fly ash,portland cement and superplasticizers are measured.Correlation among the amount of adsorbed superplasticizer,the zeta potential and rehological parameters are established.It was found that the adsorption of superplasticizers on the particles surfaces of fly ash is quite different from that of Portland cement particles.The zeta potential of fly ash particles dispersed in water is negative and the surface of which is smooth,so that the adsorption capacity to superplasticizers is weaker than that of Portland cement particle.The capacity depends highly on the density and particle size of the fly ash as well.Due to the negative charge of fly ash particles,they have a self-dispersion tendency,owning to which adding fly ash partilces into cement pastes enhances the fluidity of the paste.In all cases,the adsorption of poly naphthalene sulfonate type superplasticizer is stronger on Portland cement and fly ash partilces is stronger than that of the polycarboxylate ether type superplasticizer.

关 键 词：减水剂 粉煤灰 吸附 ZETA电位 流变性能 

分 类 号：TU528.042.1[建筑科学—建筑技术科学]