Annually, 1 Gt of cement waste is produced, constituting one-fourth of recent cement production and surpassing the availability of most supplementary cementitious materials (SCMs). It is known that the thermoactivation of cement waste (heating to 500 °C to drive off water molecules and hydroxyl units) recovers cement reactivity. However, from literature we show that this reactivity is insufficient for adequate strength gain due to the high surface area and, hence, high water demand of thermoactivated recycled cement (RC). Instead, as proposed herein, RC used as the dominant component (>75% wt) within an optimized particle packing system (<20% wt of micronized Portland cement) yields an engineered recycled cement (eRC) with comparable early- and late-age strength gain behavior to ordinary Portland cement (OPC). Evaluation of CO₂ emissions reveals that eRC emits 198–320 kgCO₂/t, which is substantially lower than that of scalable blended Portland cements. Deploying this technology together with other strategies, such as CO₂ capture by carbonation of cement waste, can mitigate 61% of projected 2050 CO₂ emissions of the cement industry (2.31 Gt of CO₂/year).

中文翻译：

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工程混合热活化再生水泥：关于反应性、需水量、强度孔隙率和 CO2 排放的研究


每年产生 1 Gt 的水泥废料，占近期水泥产量的四分之一，超过了大多数补充胶凝材料 （SCM） 的可用性。众所周知，水泥废料的热活化（加热到 500 °C 以驱除水分子和羟基单元）可恢复水泥反应性。然而，从文献中我们表明，由于热活化再生水泥 （RC） 的高表面积和因此的高需水量，这种反应性不足以获得足够的强度增加。相反，正如本文所提议的，在优化的颗粒填充系统（<20% wt 的微粉化波特兰水泥）中用作主要成分 （>75% wt） 的 RC 可产生工程再生水泥 （eRC），其早期和晚期强度增加行为与普通波特兰水泥 （OPC） 相当。对 CO₂ 排放的评估表明，eRC 排放的二氧化碳₂/吨为 198-320 千克，大大低于可放大的混合波特兰水泥。将这项技术与其他策略一起部署，例如通过碳酸化水泥废料捕获_CO2，可以减少水泥行业预计 2050 年_CO2 排放量的 61%（每年 2.31 Gt_CO2）。