Abstract SRM 2686a is a NIST reference Portland clinker with reported mineralogical analysis from powder diffraction and electron microscopy. This sample is used in ASTM C1365 test method for Rietveld quantitative phase analysis validation procedure. Here, we have analysed SRM 2686a by using three state-of-the-art powder diffraction configurations: i) strictly monochromatic CuKα1 radiation in flat reflection geometry; ii) strictly monochromatic MoKα1 radiation in flat transmission geometry; and iii) synchrotron radiation in rotating capillary transmission geometry. The silicate and aluminate enriched residues have also been studied by CuKα1 powder diffraction. All the powder patterns were analysed by Rietveld method with the best available protocols. The results indicate that belite in SRM 2686a is composed of two polymorphs (β- and α'H-) that must be included in the analyses. The use of a unique phase for describing belite (β-polymorph) and improper peak shape modelling could explain the problems found for implementing ASTM C1365 in some cement manufacturing plants. Furthermore, all the patterns are deposited as open data access at Zenodo, so interested laboratories can analyse these data to verify their protocols.

中文翻译：

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SRM 2686a 的 Rietveld 定量相分析：标准波特兰熟料

摘要 SRM 2686a 是 NIST 参考波特兰熟料，已通过粉末衍射和电子显微镜报告了矿物学分析。该样品用于 Rietveld 定量相分析验证程序的 ASTM C1365 测试方法。在这里，我们使用三种最先进的粉末衍射配置分析了 SRM 2686a：i) 平面反射几何中的严格单色 CuKα1 辐射；ii) 平面透射几何中的严格单色 MoKα1 辐射；iii) 旋转毛细管传输几何中的同步辐射。还通过 CuKα1 粉末衍射研究了富含硅酸盐和铝酸盐的残留物。所有粉末图案均通过 Rietveld 方法使用最佳可用方案进行分析。结果表明 SRM 2686a 中的 belite 由两种多晶型物（β-和 α' H-) 必须包括在分析中。使用独特的相来描述贝利特（β-多晶型物）和不正确的峰形建模可以解释在某些水泥制造厂实施 ASTM C1365 时发现的问题。此外，所有模式都作为开放数据访问存放在 Zenodo，因此感兴趣的实验室可以分析这些数据以验证他们的协议。