减水剂与乳液复掺对水泥浆zeta电位的影响

Influence of Mixing Procedures of Superplasticizer and Latex on Zeta Potential of Cement Pastes

采用萘系减水剂(NF)、聚羧酸系减水剂(PC),研究了减水剂与乳液不同复掺方式对水泥浆zeta(ζ)电位的影响.结果表明:随PC掺量不同,PC与乳液同掺水泥浆ζ电位或正或负;NF与乳液同掺水泥浆ζ电位介于单掺NF水泥浆与单掺乳液水泥浆ζ电位之间.NF滴加后,掺乳液水泥浆平衡ζ电位绝对值低于单掺NF水泥浆、单掺乳液水泥浆及NF与乳液同掺水泥浆平衡ζ电位绝对值;随PC的滴加,掺乳液水泥浆ζ电位值可以降至与单掺乳液水泥浆平衡ζ电位值接近.随乳液滴加量的增大,掺1.0%(质量分数)PC水泥浆的ζ电位几乎没有变化,掺0.1%PC水泥浆的ζ电位最初急剧降低,而后几乎不变;掺NF水泥浆ζ电位随乳液的滴入由-10 mV迅速升高至-6mV,而后随乳液滴加量的增大,ζ电位仅略微升高.减水剂(NF或PC)与乳液同掺或者乳液后掺,均可降低水泥粒子对聚合物颗粒的吸附量.

Because of less thorough study on the properties of cement pastes with superplasticizers and latex mixed together, the influence of different mixing procedures of superplasticizers and latex on the ζ poten- tial of cement pastes（fresh） were analyzed using the ZetaProbe instrument. The experimental results show that with adding different use level（by mass） of polycarboxylic superplasticizer（PC）, the cement pastes with both PC and latex added have negative or positive ζ＂ potential. However, the ζ potential of cement pastes with both naphthalene formaldehyde condensate superplasticizer（NF） and latex added is lower than that of cement pastes with NF added but higher than that of cement pastes with latex added. Adding NF into cement pastes with latex added, the absolute value of equilibrium ζ potential of the cement pastes is lower than that of cement pastes with NF added, cement pastes with latex added and cement pastes with both NF and latex added. Adding PC into cement pastes with latex added, the ζ potential of the cement pastes can even reach the equilibrium ζ potential of cement paste with latex added. When latex is added in, the ζ potential of cement paste with 1. 0% PC added doesn＇t change, but the ζ potential of cement paste with O. 1% PC added decreases greatly to a certain value. The ζ potential of cement paste with NF added increases from --10 mV to --6 mV when latex is added in, and then increases slowly with the increase of use level of latex. By adding superplasticizer（NF or PC） and latex into cement pastes simultaneously or adding latex into cement pastes with superplasticizer（NF or PC） added, the adsorbed proportion of poly- mer particles on cement grains can be decreased.