SGER: Nanoscale Investigation of Cement Hydration by Nuclear Resonant Reaction Analysis

核共振反应分析（Nuclear resonance Reaction Analysis， NRRA）首次应用于水泥水化研究。通过使用该技术，可以研究诱导期间几个纳米尺度（对应于几个单位电池）上氢浓度的变化作为时间的函数。根据观察到的氢浓度绝对值和测量到的表面层厚度，初步结果表明，在诱导期形成的硅酸三钙颗粒（用于本初步研究）表面层与托贝莫里石样物质一致。最佳光束能量分辨率是一个关键参数，因为测量的空间分辨率在很大程度上取决于入射离子束的能量分辨率。因此，德国鲁尔大学的Dynamitron串联加速器被用于实验研究，因为在过去的15年里，这台机器已经做了大量的工作，以产生最好的离子束能量分辨率。氢浓度可以在晶粒表面几纳米的深度上得到，并且可以连续测量到晶粒内部约2微米的深度。初步研究了硅酸三钙在20℃下的水化过程，确定了4.25 h的诱导时间，统计精度为0.07 h。该建议将支持应用NRRA技术对水泥水化的详细研究。研究了不同参数对水化过程的影响。对实验数据的分析将为不同参数（如温度、pH值和起始成分）影响水化过程的方式提供清晰的见解。这些信息最终将用于改进用于建筑和其他目的的水泥配方。

Nanoscale Investigation of Cement Hydration by Nuclear Resonant Reaction Analysis Nuclear Resonant Reaction Analysis (NRRA) has been applied for the first time to study cement hydration. Through the use of this technique, the change in hydrogen concentration on a few nanometer scale (corresponding to a few unit cells) can be studied as a function of time during the induction period. Preliminary results have demonstrated that the surface layer formed during the induction period on the tricalcium silicate grains (used in this initial study) is consistent with a tobermorite-like material, based on the absolute value of the observed hydrogen concentration and the measured thickness of the surface layer. Optimum beam energy resolution is a critical parameter as the spatial resolution of the measurement is defined largely by the energy resolution of the incident ion beam. Therefore, the Dynamitron Tandem accelerator at the Ruhr Universitat, Bochum, Germany is being used for the experimental studies as this machine has had extensive work done over the last fifteen years to generate the best possible energy resolution for ion beams. The hydrogen concentration is obtained over a depth of a few nanometers at the surface of the grains and can be measured continuously to a depth of about 2 microns into the grains. An initial study of the hydration process of tricalcium silicate at 20 oC determined an induction time of 4.25 hours with a statistical precision of 0.07 hours. This proposal will support a detailed investigation of cement hydration by applying the NRRA technique. A series of experiments will investigate the effect of different parameters on the hydration process. The analysis of the experimental data will provide clear insights into the way different parameters, such as temperature, pH, and starting composition, affect the hydration process. This information will ultimately be used to improve the formulation of cements for construction and other purposes.