Mechanical Properties and Damage Evolution of Siliceous Concrete Subjected to Elevated Temperatures

摘要

Siliceous concrete (SC) is applied in European Pressurized Water Reactor that is a key component of the third generation nuclear power plant. This paper investigates the mechanical properties and damage evolution of SC (with and without polypropylene fibers) exposed to high temperatures. The mass loss, compressive strength, splitting tensile strength and spalling sensitivity of SC before and after being heated to 200, 400, 600, 800, and 1000 °C are investigated. The ultrasonic testing technique was used to assess the thermal damage, by evaluating the variations of the ultrasonic wave velocity (UWV) for different temperature levels. According to the available literature, a new relationship between damage and UWV was proposed to establish a damage evolution model of SC. The results indicated that: (a) specimens without polypropylene (PP) fibers suffered severe spalling in the range 380-400°C and 470-510°C, while no spalling took place in the specimens with PP fibers in the whole range 25-1000°C; (b) the damage evolution with and without polypropylene fibers was similar, and could adequately be described by means of a Weibull distribution model.