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

SGER：通过核共振反应分析对水泥水化进行纳米级研究

• 批准号: 0236977
• 负责人: Jeffrey Schweitzer
• 金额: $ 8.09万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2003-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0236977&HistoricalAwards=false
• 关键词: SGER; Nanoscale; Investigation; Cement; Hydration

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.

水泥水化过程的纳米核共振分析 首次将核共振反应分析（NRRA）应用于水泥水化研究。通过使用这种技术，在几个纳米尺度上（对应于几个单元电池）的氢浓度的变化可以研究作为诱导期期间的时间的函数。初步结果表明，在诱导期内形成的表面层上的硅酸三钙颗粒（用于本初步研究）是一致的托贝莫来石状材料，根据观察到的氢浓度的绝对值和测量的表面层的厚度。 最佳束能量分辨率是关键参数，因为测量的空间分辨率主要由入射离子束的能量分辨率限定。因此，德国波鸿鲁尔大学的Dynamitron串列加速器被用于实验研究，因为该机器在过去15年中进行了大量工作，以产生最佳的离子束能量分辨率。氢浓度在晶粒表面几纳米的深度上获得，并且可以连续测量到晶粒中约2微米的深度。对硅酸三钙在20 oC下的水化过程的初步研究确定了4.25小时的诱导时间，统计精度为0.07小时。 该建议将支持通过应用NRRA技术对水泥水化的详细调查。一系列的实验将研究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）影响水合过程的方式提供清晰的见解。这些信息最终将用于改进建筑和其他用途的水泥配方。