Abstract The intensive use of cement as a building material causes significant pollution. The majority of CO2 emissions come from the manufacturing process and not from the product itself. Indeed, the decarbonation of limestone and the use of fuels during clinkerisation are very polluting. One of the main solutions to reduce the environmental footprint of the cement industry is the use of Supplementary Cementitious Materials (SCMs) in substitution of clinker. Among them are glass powders, fly ashes, blast-furnace slags or calcined clays. This article focuses on the thermal reactivity of an argillaceous‑carbonate sample containing palygorskite, smectite and dolomite. The sample was calcined at different temperatures and investigated using Solid State Nuclear Magnetic Resonance (NMR), X-ray diffraction (XRD), and Scanning Electron Microscope (SEM). The increase in calcination temperature leads to an amorphisation of the clay fraction of the sample, resulting in a change in the coordination of the octahedral aluminium atoms. The progressive transformation of 6-fold aluminium atoms to 5-fold and 4-fold was quantified as a function of the calcination temperature. Furthermore, calcium issued from the decarbonation of dolomite reacts with silicon from the amorphisation of clay phases to form poorly-crystallized belite (C2S). This dual system (pozzolanic and hydraulic) makes this sample a promising candidate as SCM in blended cements. The multi-technique analysis applied in this study allows to highlight a direct correlation between the calcination temperature and the induced structural modification.

中文翻译：

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含坡缕石泥质碳酸盐的煅烧潜力

摘要 水泥作为建筑材料的大量使用造成了严重的污染。大部分二氧化碳排放来自制造过程，而不是产品本身。事实上，石灰石的脱碳和熟料过程中燃料的使用是非常污染的。减少水泥行业环境足迹的主要解决方案之一是使用补充胶凝材料 (SCM) 代替熟料。其中包括玻璃粉、粉煤灰、高炉矿渣或煅烧粘土。本文重点介绍含有坡缕石、蒙脱石和白云石的泥质碳酸盐样品的热反应性。样品在不同温度下煅烧，并使用固态核磁共振 (NMR)、X 射线衍射 (XRD) 和扫描电子显微镜 (SEM) 进行研究。煅烧温度的增加导致样品的粘土部分的非晶化，导致八面体铝原子的配位发生变化。6 倍铝原子逐渐转变为 5 倍和 4 倍被量化为煅烧温度的函数。此外，白云石脱碳产生的钙与粘土相非晶化产生的硅反应，形成结晶不良的贝利特 (C2S)。这种双重系统（火山灰和水硬）使该样品成为混合水泥中作为 SCM 的有希望的候选者。本研究中应用的多技术分析可以强调煅烧温度与诱导结构改性之间的直接相关性。