氨基磺酸系高效减水剂保塑性能与机理研究

Plasticity-Retention Performances and Mechanism of Aminosulfonic Acid-Based Superplasticizer ASP

较系统地研究了氨基磺酸系高效减水剂(ASP)对水泥体系的保塑性能、在水泥表面的吸附层厚度、ξ-电位及对Ca2+的络合能力,并与萘系减水剂(FDN)进行了对比.结果表明:ASP具有使水泥净浆流动度和坍落度损失小、延缓水泥凝结时间等性能.由于ASP在水泥颗粒表面的吸附层较厚、空间位阻较大、溶剂化层较厚及ξ-电位较稳定等原因,阻碍了水泥颗粒间的凝聚;同时由于ASP含有的—OH,—NH2等官能团与水化产生的Ca2+形成不稳定的络合物,抑制了水化产物C-S-H,Ca(OH)2和钙矾石等结晶体的形成,从而抑制了水泥的早期水化,故ASP具有良好的保塑性能.

Plasticity-retention, adsorption layer thickness and ξ-potential after adsorbed on surface of cement, and the complexation with Ca^2＋ using aminosulfonic acid-based superplasticizer （ASP） were systematically investigated comparing with β-naphthalenesulfonic acid-based superplasticizer （FDN）. The plasticity-retention mechanism of ASP on cement was represented. The results show that ASP can decrease the fluidity loss of cement paste, retard the setting time of cement paste and decrease the slump loss of concrete. All the thick adsorption layer, large space steric hindrance, thick solvate layer and stable ξ-potential of ASP adsorbed on cement particles resist the flocculation of cement particles. In addition the early stage hydration of cement is restrained because the -OH, -NH2 in ASP can suppress the formation of hydrated products such as C-S-H, Ca（OH）2 and ettringite crystals through forming unstable complex compound with Ca^2＋. So ASP has excellent plasticity-retention capability of concrete.