Online SEM investigation of microcrack characteristics of concretes at various temperatures

Detecting and quantifying microcracking damage in microscopy has become an integral aspect of concrete technology. Better methods that have emerged over the last decade have led to improved understanding of the failure mechanisms and consequent effect on mechanical properties of concretes. This paper focuses on the applications of the scanning electron microscope (SEM) in situ observations of concrete and the description of their microcrack characteristics at different temperatures. For the sake of brevity, nondestructive evaluations of large-scale cracking, such as delaminations and spalling, have not been addressed here. The microcracks propagation is a critical factor at high temperatures. These results indicated that the thermal energy plays an important role in microcracking and propagation of these concretes and reflected that there are different fracture types with changing the microstructure of concretes. The thermal mismatch of mixed materials play a significant role in the microcracking damage of concrete.