Analysis of the mechanical and fracture behavior of heated ultra-high-performance fiber-reinforced concrete by X-ray computed tomography

Abstract

This work analyzes the effects of temperature (300 °C) on mechanical and fracture behavior of an ultra-high-performance steel-fiber-reinforced concrete. The deterioration of the pore structure due to thermal damage of the fiber-reinforced concrete and its un-reinforced matrix was analyzed by X-ray computed tomography. Complementarily, a thermogravimetric analysis was performed to relate the observed phase changes, due to dehydration and decomposition, with the deterioration of pore structure. Additionally, an analysis of their mechanical and fracture properties was also done at room temperature and 300 °C. Finally, a connection between the damage within the concrete matrix and its corresponding mechanical behavior was established. From the results, it has been ascertained that the propagation of thermal damage within the matrix affects the mechanical and fracture behavior in different ways depending on the pore-size. The presence of fibers modifies the pore structure and consequently the evolution of the thermal damage in the ultra-high-performance concrete, inferring its mechanical and fracture behavior.