C-S-H纳米晶核对矿物掺合料复合胶凝材料水化性能的影响研究

水泥中掺入大量矿物掺合料易造成其早期强度低、施工周期长等问题。本文研究了C-S-H晶核对含矿物掺合料的复合胶凝材料体系水化性能的影响规律;通过热力学计算阐述了C-S-H晶核降低水化产物成核势垒的机理,并通过离子溶出与沉积探讨大掺量矿物掺合料胶凝体系水化机理。结果表明:矿物掺合料复合胶凝材料体系水化能力较弱,这是由于Ca²⁺溶出受到制约,C₃S的水化反应缓慢;当加入晶核后,水泥中硅酸盐相溶解-结晶能力得到大幅提升,使得矿物掺合料水泥体系的水化反应活性接近纯水泥体系。研究表明,C-S-H晶核可解决大掺量矿物掺合料胶凝体系所带来的水化能力严重不足问题。

Effect of C-S-H Nanocrystalline Nucleus on Hydration Properties of Mineral Admixture Composite Cementitious Materials

A high-volume replacement of mineral admixtures to cement usually causes low early strength, inducing a long construction period. In this study, the effects of C-S-H nanocrystalline nucleus on the hydration properties of cementitious materials mixed with high-volume mineral admixtures were studied. Through thermodynamic calculation, the mechanism of reduction of nucleation barrier for adding C-S-H nanocrystalline nucleus was explained. The ions dissolution and precipitation behavior were tested. The results show that the hydration depth of mineral admixtures mixed cementitious materials is low because the dissolution of Ca²⁺ is restricted, inducing the slow hydration of C₃S. The dissolution-precipitation of silicate phases is greatly enhanced when the C-S-H nanocrystalline nucleus is added. Furthermore, the addition of C-S-H nanocrystalline nucleus promote the hydration activity of mineral admixtures mixed cementitious materials, reaching a similar hydration activity as pure cement. The results indicate that the C-S-H nanocrystalline nucleus significantly solve the insufficient hydration problem for a high-volume mineral admixtures replacement of cementitious materials.