聚羧酸减水剂的酸醚比对水化硅酸钙晶种早强作用的影响

Impact of Acid Ether Ratio of Polycarboxylate Ether on Early Strength Enhancement of Calcium Silicate Hydrate Seed

在水泥基材料中加入水化硅酸钙晶种-聚羧酸减水剂(C-S-Hs-PCE)可以有效提高早期强度。C-S-Hs-PCE能够为水化产物C-S-H凝胶提供成核位点,促进C-S-H凝胶生成,从而加快水泥水化进程。酸醚比是梳型PCE的一个重要结构参数,对C-S-Hs-PCE的合成和早强作用的影响显著。通过动态光散射分析、总有机碳分析仪、X射线衍射分析、低场时域核磁共振分析仪、扫描电子显微镜、等温量热仪和抗压强度测试研究了酸醚比对C-S-Hs-PCE的粒径及其在水泥基材料中早期效果的影响。结果表明:高酸醚比的PCE形成的C-S-Hs-PCE具有更小的粒径,更有助于促进硅酸盐相水化和氢氧化钙、C-S-H凝胶的生成,从而加速浆体水化,降低砂浆的总孔隙率,提高砂浆的早期抗压强度,尤其是24 h龄期之内的强度。

Adding calcium silicate hydrate seed-polycarboxylate ether(C-S-Hs-PCE)to cement-based materials can effectively improve the early strength.C-S-Hs-PCE can provide nucleation sites for the formation of a hydration product C-S-H gel,effectively promoting the generation of the C-S-H gel,and accelerating the process of cement hydration.The acid-ether ratio is an important structural parameter of comb-type PCE molecules,having an impact on the synthesis and early strength enhancement of C-S-Hs-PCE.This paper investigated the effect of acid-ether ratio on the particle size of C-S-Hs-PCE and the early strength of cement-based materials by using dynamic light scattering(DLS)particle size analysis,total organic carbon analysis,X-ray diffraction,low-field time-domain nuclear magnetic resonance,scanning electronic microscopy,isothermal calorimetry,and compressive strength tests,respectively.The results show that the C-S-Hs-PCE formed at a high acid-ether ratio PCE has a smaller particle size,which is more conducive to promoting the hydration of the silicate phase and the generation of calcium hydroxide and C-S-H gel,thereby accelerating the hydration of the paste,reducing the total porosity of mortar,and improving the early compressive strength of mortar,especially within 24 h.