Continuous In-situ Monitoring the Early Hydration Process of Ultra-high Performance Cement-based Materials by a New Designed Ultrasonic Apparatus and XRD

摘要

A new specially designed ultrasonic monitoring device (UMD) for continuously in-situ studying of the early hydration process of cementitious materials is developed. Utilizing UMD, the early microstructure formation process is systematically investigated for ultra-high performance cementitious materials made with various mineral admixtures (fly ash, slag and silica fume) and different curing temperature (20°C, 40"C, 60°C, 80°C, 90°C). The results show that the silica fume addition accelerates the microstructure formation, while the reverse phenomenon is observed when fly ash and slag is incorporated. A new test platform for the XRD testing is specially designed. The sample is measured continuous and in-situ and the evolution phases of ultra-high performance cement-based materials present is studied by XRD spectra. The XRD tests results shows that it corresponding well with the UPV curves.