Concerns about high-strength concrete (HSC) have increasingly grown in tandem with the building industry's rapid development. However, the high CO emissions, high hydration heat, and high autogenous shrinkage of HSCs considered key issues that limit their wide application. In this study, various proportions of dry ice (solid CO) were added to concrete to optimize HSC. The test results indicated that adding solid CO decreased the hydration heat and autogenous shrinkage and increased the mechanical properties and surface electrical resistivity of HSC. This is primarily attributed to the physical and chemical effects of solid CO in HSC curing. At 28 d of curing, the sample containing 3 wt% solid CO exhibited the most significant optimization effect. This is attributed to the fact that, at lower solid CO content (3%), the production of carbonation products compensates for the loss of strength caused by the reduction of hydration products. In addition, the addition of solid CO caused a decrease in the initial temperature, which delayed the hydration reaction and reduced the autogenous shrinkage. Adding solid CO led to an increase in acidity and promoted the formation of AFt, further reducing the autogenous shrinkage. And the more solid CO added, the greater the reduction in CO emissions for the mixture. Therefore, adding solid CO can play a role in optimizing the performance and promoting the sustainability of HSC and can contribute to the objectives of low CO emissions, low hydration heat, and low autogenous shrinkage of HSC.

中文翻译：

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使用干冰（固体二氧化碳）作为二氧化碳利用外加剂生产低二氧化碳硅粉混合高强度混凝土

随着建筑业的快速发展，对高强度混凝土（HSC）的担忧也日益增长。然而，HSC 的高 CO 排放量、高水化热和高自收缩性被认为是限制其广泛应用的关键问题。在本研究中，将不同比例的干冰（固体 CO）添加到混凝土中以优化 HSC。测试结果表明，添加固体CO降低了HSC的水化热和自收缩，提高了HSC的机械性能和表面电阻率。这主要归因于 HSC 固化中固体 CO 的物理和化学效应。固化28 d时，含有3 wt%固体CO的样品表现出最显着的优化效果。这是因为，在较低的固体CO含量（3%）下，碳酸化产物的产生补偿了因水化产物减少而造成的强度损失。此外，固体CO的添加导致初始温度降低，从而延迟了水化反应并减少了自收缩。添加固体CO导致酸度增加并促进AFt的形成，进一步减少自收缩。添加的固体二氧化碳越多，混合物中二氧化碳排放量的减少量就越大。因此，添加固体CO可以起到优化HSC性能和促进其可持续性的作用，有助于实现HSC低CO排放、低水化热和低自收缩的目标。