With the ongoing sustainability movement, the incorporation of limestone powder in cementitious binders for concrete in the U.S. has become a subject of renewed interest. In addition to accelerating the early age hydration reactions of cementitious systems by providing additional surfaces for nucleation and growth of products, limestone powder is also intriguing based on its influence on low-temperature curing. For example, previous results have indicated that the utilization of limestone powder to replace one quarter of the fly ash in a high volume fly ash mixture (40–60% cement replacement) produces a reduction in the apparent activation energy for setting for temperatures below 25 °C. In the present study, the relationship between heat release and compressive strength of mortars at batching/curing temperatures of 10 and 23 °C is investigated. For Portland-limestone cements (PLC) with limestone additions on the order of 10%, a higher strength per unit heat release is obtained after only 7 d of curing in lime water. Surprisingly, in some cases, the absolute strength of these mortar cubes measured at 7 d is higher when cured at 10 °C than at 23 °C. Solubilities vs. temperature, reaction stoichiometries and enthalpies, and projected phase distributions based on thermodynamic modeling for the cementitious phases are examined to provide some theoretical insight into this strength enhancement. For a subset of the investigated cements, thermogravimetric analysis, quantitative X-ray diffraction, and scanning electron microscopy are conducted on 7-d paste specimens produced at the two temperatures to examine differences in their reaction rates and the phases produced. The strength enhancement observed in the PLC cements is related to the cement hydration products formed in the presence of carbonates as a function of temperature.

中文翻译：

---

含石灰石粉水泥基材料的低温固化强度增强

随着可持续发展运动的持续进行，在美国将石灰石粉末掺入混凝土的水泥粘合剂已成为重新引起人们关注的主题。除了通过为产品的成核和生长提供额外的表面来加速胶凝体系的早期水化反应外，石灰石粉还因其对低温固化的影响而引人注目。例如，先前的结果表明，在大量粉煤灰混合物（40-60% 的水泥替代品）中，使用石灰石粉代替四分之一的粉煤灰会降低温度低于 25 度的表观活化能。 ℃。在本研究中，研究了在 10 和 23 °C 的配料/固化温度下砂浆的热释放和抗压强度之间的关系。对于添加了 10% 左右石灰石的波特兰-石灰石水泥 (PLC)，在石灰水中仅固化 7 天后，单位热释放的强度就会更高。令人惊讶的是，在某些情况下，这些砂浆立方体在 7 天时测量的绝对强度在 10 °C 固化时高于 23 °C。检查溶解度与温度、反应化学计量和焓以及基于热力学模型的水泥相分布的预测相分布，以提供对这种强度增强的一些理论见解。对于一部分研究的水泥，热重分析、定量 X 射线衍射和扫描电子显微镜在两种温度下生产的 7 天糊状试样上进行，以检查它们的反应速率和产生的相的差异。