Abstract Unilateral Nuclear Magnetic Resonance is used to characterize the carbonation depth in 0.60 w/c ratio unsaturated/saturated Portland cement mortars. A three-magnet array combined with a surface elliptical coil was utilized to obtain the Nuclear Magnetic Resonance signal at different positions along mortar samples. The T2 lifetime and signal intensity behaviors in the carbonated and non-carbonated zones were analyzed. Scanning Electron Microscopy images were used to identify the macro-porosity and micro-cracking in the samples. Results confirmed that the crossover point between profiles of T2 lifetime and signal intensity agree with the carbonation depth obtained by the phenolphthalein test. The carbonation depth at the position where the T2 lifetime begins to behave nearly constant is about 1.44 times the depth indicated by the phenolphthalein test. The spatial resolution was improved four times in comparison with previous research. Scanning Electron Microscopy images analysis confirmed a significant decrease in local porosity and crack area in the carbonated zone.

中文翻译：

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不饱和和饱和硅酸盐水泥砂浆碳化深度的单边低场磁共振测量

摘要 单边核磁共振用于表征0.60 w/c 比率的不饱和/饱和波特兰水泥砂浆的碳化深度。利用三磁体阵列结合表面椭圆线圈来获得沿砂浆样品不同位置的核磁共振信号。分析了碳化区和非碳化区的 T2 寿命和信号强度行为。扫描电子显微镜图像用于识别样品中的大孔隙率和微裂纹。结果证实，T2 寿命和信号强度曲线之间的交叉点与酚酞测试获得的碳化深度一致。T2 寿命开始表现出几乎恒定的位置处的碳化深度约为 1。酚酞试验指示深度的44倍。与之前的研究相比，空间分辨率提高了四倍。扫描电子显微镜图像分析证实了碳化带中局部孔隙度和裂缝面积的显着减少。