接枝聚醚型超塑化剂的合成及其在水泥硅灰体系中的应用研究

Synthesis of grafted polyether type superplasticizer and its performance on cement-silica fume paste

为满足低水胶比混凝土体系浆体流动性调节需求,以新型接枝型聚醚大单体(PgE)与甲基丙烯酰氧基乙基单磷酸酯(HEMAP)为共聚单体,合成系列不同吸附基团密度的接枝聚醚型磷酸基超塑化剂(PPAs),通过研究常规水胶比(0.29)和低水胶比(0.14~0.19)条件下PPAs在水泥-硅灰体系的减水分散性,并比较PPAs在水泥及硅灰颗粒表面的吸附性差异,揭示了PPAs提升低水胶比水泥-硅灰体系流动性的影响机制。结果表明:PPAs在水泥颗粒表面的吸附量高于市售聚羧酸超塑化剂PCEs,二者在硅灰表面吸附量接近;PPAs对低水胶比水泥-硅灰体系具有更好的分散性。

In order to meet the flo wability regulation requirements of low water binder ratio concrete systems,a novel phos phate-based superplasticizer PPAs with a grafted polyether was synthesized,using grafted polyether(PgE) and hydroxyethyl methacry late phosphate(HEMAP) as comonomers.The water reducing and dispersing properties of conventional water binder ratio(0.29) and low water binder ratio(0.14~0.19) PPAs on the cement silica fume system were studied,and the adsorption differences of PPAs on the surface of cement and silica fume particles were compared,revealing the possible influencing mechanism of PPAs on enhancing the fluidity of low water cement ratio cement silic a fume system.The experimental results exhibited that adsorption capacity of PPAs onto cement was higher than that of PCEs,while their adsorption capacity onto silicon fume was close.Therefore,PPAs had a better dispersion performance in cement-silicon fume system than PCEs at low water binder ratio.