X射线透射成像技术原位追踪混凝土吸水过程

为了表征二维混凝土的传输过程，制备厚度为1 mm的混凝土薄片. 采用X射线透射成像（TXR）技术，联合扫描电镜、背散射和能谱分析技术（SEM/BSE/EDS）原位追踪水在2维混凝土薄片中的毛细自吸过程. 测试不同质量分数CsCl溶液对X射线透射图像的增强效果. 结果表明，CsCl能够提高吸水过程中混凝土薄片的TXR图像对比度，使得水在混凝土中的渗流路径更清晰、可辨. 水泥浆体在吸收CsCl后，扫描电子背散射图像的对比度显著增强. 不同位置铯原子的EDS能谱结果验证了TXR技术确定吸水前锋位置的准确性.

Water imbibition in concrete in-situ traced by transmission X-ray radiography

Concrete slices with the thickness of 1 mm were fabricated in order to characterize the two-dimensional (2D) water transport process. Transmission X-ray radiography (TXR) was combined with scanning electron microscopy/back-scattered electron/energy-dispersive X-ray spectroscopy (SEM/BSE/EDS) to in-situ trace water imbibitions in the two-dimensional concrete slices. CsCl solutions at different mass fractions were tested to explore the enhancements in contrast of the TXR images. Results show that CsCl can improve the contrast of the TXR images when the concrete slices were partially saturated with the CsCl solutions, which makes the imbibition paths and fronts in the concrete clearly visible. The contrast of the BSE images was enhanced due to the absorption of CsCl in the cement paste. The EDS results of the Cs distributions at different sites of the concrete testified the accuracy of the imbibition fronts detected by TXR.