Fire resistance performance is one of the most important requirements in geological storage conditions in order to improve the resistance of storage packages to high thermal constraints (in the case of a fire for example). With the need to develop new fire-resistant materials, the aim of the present study was to develop fire-resistant geopolymer binders based on Callovo-Oxfordian (COx) argillite. Two types of kaolin with different degrees of purity were mixed with argillite in various proportions. These mixtures were calcined at 600 or 750°C. In order to assess the fire resistance of activated materials, thermal treatment at 1000°C was performed. The compressive strength and mineralogical composition of the samples were investigated before and after heat treatment. The results showed that the addition of argillite improved significantly the thermomechanical properties of kaolin-based geopolymers containing impurities, especially the mixture containing 67% argillite and calcined at 750°C. This phenomenon was not observed for the pure-kaolin geopolymer. Improvement of fire resistance was due to the formation in situ of leucite and zeolite-type phases (KAlSi 2 O 6 and KAlSiO 4 ) and of wollastonite (CaSiO 3 ) at high temperature, which is linked to the Ca available in the raw materials.

中文翻译：

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高温、抗性、基于泥土的、碱活化的材料，具有改进的热处理后机械强度

防火性能是地质储存条件中最重要的要求之一，以提高储存包装对高热限制（例如在火灾情况下）的抵抗力。由于需要开发新的耐火材料，本研究的目的是开发基于 Callovo-Oxfordian (COx) 泥质岩的耐火地质聚合物粘合剂。两种纯度不同的高岭土与泥土按不同比例混合。这些混合物在 600 或 750°C 下煅烧。为了评估活性材料的耐火性，进行了 1000°C 的热处理。在热处理前后对样品的抗压强度和矿物组成进行了研究。结果表明，泥质岩的加入显着改善了含杂质高岭土基地质聚合物的热力学性能，尤其是含67%泥质岩并在750℃煅烧的混合物。对于纯高岭土地质聚合物没有观察到这种现象。耐火性的提高是由于在高温下原位形成白榴石和沸石型相（KAlSi 2 O 6 和 KAlSiO 4 ）以及硅灰石（CaSiO 3 ），这与原材料中的钙有关。