This work is focused on the effects of drying/re-saturation cycles on the structure and components of White Portland Cement (WPC) samples. In particular, WPC of 0.5 water-to-cement ratio was studied by ¹H Nuclear Magnetic Resonance (NMR) Relaxometry. A number of NMR sequences and different data processing methods were applied. Short (14 days of re-saturation) and long (6 months for the whole cycle) sorption cycles were investigated, using two drying methods: oven drying and drying under controlled relative humidity. The evolution during drying/re-saturation processes of interlayer space, gel pores, and bigger pores was followed by both the transverse relaxation times and the intensities of the nuclear magnetization. As a result of drying, reversible and irreversible changes in the pore structure, especially concerning the smaller porosity (interlayer and gel pores), were seen. Likewise, ¹H signals in the crystalline phases of the cement were investigated by the standard Quadrature Echo method and by a more informative analysis based and a proper acquisition and processing of the longitudinal relaxation data. This analysis allowed the signal separation of ¹H nuclei with higher and lower mobility (“solid” components). The NMR signal from this last component was analyzed on the basis of the Pake-Doublet theory in the time domain and two components were clearly detected, and assigned to ¹H nuclei of crystalline water in Ettringite and OH groups in Portlandite. Reversible changes of the solid components of the cement samples were observed. This is a new method to deeply investigate the changes of solid components during sorption cycles.

这项工作的重点是干燥/再饱和循环对白色波特兰水泥 (WPC) 样品的结构和成分的影响。特别是水灰比为 0.5 的 WPC 被¹H 核磁共振 (NMR) 弛豫测量法。应用了许多核磁共振序列和不同的数据处理方法。研究了短（14 天的再饱和）和长（整个周期为 6 个月）的吸附周期，使用两种干燥方法：烘箱干燥和在受控相对湿度下干燥。层间空间、凝胶孔和较大孔的干燥/再饱和过程中的演变伴随着横向弛豫时间和核磁化强度。由于干燥，孔结构发生了可逆和不可逆的变化，尤其是在较小的孔隙率（夹层和凝胶孔）方面。同样，¹水泥结晶相中的 H 信号通过标准正交回波方法和基于更多信息的分析以及纵向松弛数据的适当采集和处理进行研究。该分析允许具有较高和较低迁移率的¹ H 核（“固体”组分）的信号分离。根据时域中的 Pake-Doublet 理论对来自最后一个组分的 NMR 信号进行分析，清楚地检测到两个组分，并将其分配给钙矾石中结晶水的¹ H 核和硅酸盐中的 OH 基团。观察到水泥样品固体成分的可逆变化。这是一种深入研究吸附循环过程中固体组分变化的新方法。