Abstract The industrial injection of carbon dioxide into ready mixed concrete during mixing and batching can produce a measurable increase in hydration and a significant compressive strength increase. Physiochemical aspects of the mechanism were investigated through the analysis of a model tricalcium silicate system activated with a carbon dioxide addition immediately after hydration started. The attendant effects were examined through isothermal calorimetry, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Carbonate reaction products around 70 nm were observed to have formed within 60 s of the CO2 gas injection. Within 10 min the carbonates have been covered by new hydration products. The initial product formed appears to be an amorphous or poorly crystalline calcium carbonate. The overall reaction over 24 h was the same for the hydrated and CO2-activated cases although the latter instance included the formation of carbonate reaction products.

中文翻译：

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原位碳酸盐晶种对硅酸三钙早期水化的影响

摘要 在搅拌和配料过程中向预拌混凝土中工业注入二氧化碳可以产生可测量的水化增加和抗压强度的显着增加。通过分析在水合开始后立即加入二氧化碳激活的模型硅酸三钙系统，研究了该机制的物理化学方面。通过等温量热法、热重分析 (TGA)、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM) 和电子能量损失光谱 (EELS) 检查伴随的影响。观察到在 CO2 气体注入后 60 秒内形成了大约 70 nm 的碳酸盐反应产物。在 10 分钟内，碳酸盐已被新的水合产物覆盖。形成的初始产物似乎是无定形或结晶性差的碳酸钙。24 小时内的总反应对于水合和 CO2 活化的情况是相同的，尽管后者包括碳酸盐反应产物的形成。