Solid waste silica fume was used to replace fly ash by different ratios to study the early-age hydration reaction and strength formation mechanism of concrete. The change pattern of moisture content in different phases and micro morphological characteristics of concrete at early age were analyzed by low field nuclear magnetic resonance (LF-NMR) and scanning electron microscope (SEM). The results showed that the compressive strength of concrete was enhanced optimally when the replacement ratio of solid waste silica fume was 50%. The results of LF-NMR analysis showed that the water content of modified concrete increased with the increase of solid waste silica fume content. The compressive strength of concrete grew faster within the curing age of 7 d, which means the hydration process of concrete was also faster. The micro morphological characteristics obtained by SEM revealed that the concrete was densest internally when 50% fly ash was replaced by the solid waste silica fume, which was better than the other contents.

中文翻译：

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固废硅粉改性混凝土早期水化反应及强度形成机理

用固废硅粉按不同比例替代粉煤灰，研究混凝土早期水化反应及强度形成机理。采用低场核磁共振(LF-NMR)和扫描电镜(SEM)分析了混凝土早期不同相含水率的变化规律和微观形貌特征。结果表明，当固体废弃硅粉替代率为50%时，混凝土的抗压强度得到最佳提高。LF-NMR分析结果表明，随着固废硅粉含量的增加，改性混凝土的含水量增加。混凝土的抗压强度在养护 7 d 内增长较快，这意味着混凝土的水化过程也较快。