Abstract This study aims to clarify the role of micro silica in hydration of UHPC. The behavior of two different types of micro silica in UHPC was investigated with regard to their filler effect and pozzolanic reaction by using analytical techniques; XRD, TG, 29 Si and 27 Al NMR spectroscopy, and MIP. The micro silica with high pozzolanic activity led to the higher level of Al-substitution for Si in C-S-H and the denser structure, thus increasing compressive strength, whereas that facilitating filler effect limited the consumption of Ca(OH) 2 even after high temperature curing and led to the higher amount of AFm phase. In the UHPC showing high filler effect, additional hydration of C 3 S and C 2 S occurred at later ages, increasing the fraction of Q 1 site in C-S-H and decreasing the porosity in the pore diameter region below 10 nm. Consequently, a significant increase in the compressive strength of this UHPC was achieved.

中文翻译：

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揭示微硅石在超高性能混凝土 (UHPC) 水化中的作用

摘要 本研究旨在阐明微硅在UHPC 水化中的作用。使用分析技术研究了两种不同类型的微硅石在 UHPC 中的填料效应和火山灰反应；XRD、TG、29 Si 和 27 Al NMR 光谱和 MIP。具有高火山灰活性的微硅导致 CSH 中更高水平的 Al 取代 Si 和更致密的结构，从而提高了抗压强度，而促进填料作用限制了 Ca(OH) 2 的消耗，即使在高温固化和导致更高量的 AFm 相。在表现出高填料效应的 UHPC 中，C 3 S 和 C 2 S 的额外水化发生在后期，增加了 CSH 中 Q 1 位点的比例，并降低了 10 nm 以下孔径区域的孔隙率。最后，