Adsorption effect on particle surfaces and complexation effect with free Ca2+ mostly determine the retarding performance of organic admixtures on cement hydration. However, it is difficult to identify which effect plays a more important role in retarding hydration by experimental methods. Here, a theoretical model was developed to investigate the retarding mechanisms of sodium gluconate (SG) on hydration of tricalcium silicate (C3S). Based on obstruction theory and complexation reaction kinetics, effects of adsorption and complexation were simulated to examine the retarding performance of C3S hydration with addition of SG. The proposed model well predicted the effect of additional dosing of SG on the retarding performance of C3S hydration. Theoretical parameter studies demonstrated that adsorption ratio contributed much largely to the delays in C3S hydration, compared with rate constant of complex generation. Therefore, it is confirmed that adsorption plays a more important role in regulating the retarding mechanism of C3S hydration.

中文翻译：

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吸附与络合相比，通过添加葡萄糖酸钠延缓 C3S 水合作用的重要性


颗粒表面的吸附效应和与游离 Ca2+ 的络合效应主要决定了有机外加剂对水泥水化的延迟性能。然而，很难通过实验方法确定哪种效应在延缓水合作用中起更重要的作用。在此，开发了一个理论模型来研究葡萄糖酸钠 （SG） 对硅酸三钙 （C3S） 水合的延迟机制。基于阻塞理论和络合反应动力学，模拟吸附和络合的影响，以检验添加 SG 后 C3S 水合的延迟性能。所提出的模型很好地预测了额外剂量 SG 对 C3S 水合作用延迟性能的影响。理论参数研究表明，与复合物生成的速率常数相比，吸附比对 C3S 水合延迟的贡献很大。因此，证实了吸附在调节 C3S 水化的延迟机制中起着更重要的作用。