水泥-矿渣复合胶凝材料硬化浆体的微观结构(英文)

Microstructure of Hardened Complex Binder Pastes Blended with Slag

利用压汞法、扫描电子显微镜和透射电子显微镜研究了两种不同养护条件下水泥-矿渣复合胶凝材料硬化浆体的微观结构。结果表明:常温养护3 d龄期时,随着矿渣的掺入和掺量的增加,硬化浆体的孔隙率越大,大孔含量越多;硬化浆体微观形貌显示,掺矿渣试样的反应程度比纯水泥试样更低,密实程度较差。水化后期,复合胶凝材料的水化程度虽然比纯水泥试样低,但复合试样的孔隙率更低,孔径细化。纯水泥试样中水化硅酸钙(C-S-H)凝胶的微观形貌呈单向分布的纤维状,而复合胶凝材料试样中矿渣反应生成的C-S-H凝胶呈三维分布的箔片状,能更有效的隔断和填充连通的孔隙。在高温养护条件下,掺矿渣复合胶凝材料硬化浆体早期和后期孔隙率均较低,高温激发了矿渣早期的活性。

The microstructure of hardened Portland cement-slag complex binder pastes cured under two different curing conditions was investigated by mercury intrusion porosimetry, scanning electron microscopy and transmission electron microscopy, respectively. The results show that the porosity and volume of coarse pores of hardened binder pastes at early age(3 d) increase due to the replacement of slag when cured at room temperature. The morphology of hardened binder pastes reveals that the addition of slag into cement paste causes the reduction of hydration degree. At later age, the porosity becomes lower and the pore size refines, resulting in the denser hardened complex binder pastes, compared to those of pure Portland cement paste. Unlike fibrillar hydrated calcium silicate(C-S-H) gel in cement paste, the C-S-H gel produced by slag in the complex binder pastes exhibits a three-dimensional foil-like structure, which can more effectively block and fill interconnected pores. When cured at high temperature(i.e., 65 ℃), the complex binder pastes show a low porosity at both early and later ages.