PHYSICAL AND MECHANICAL BEHAVIOR OF STEEL FIBER REINFORCED REFRACTORY CONCRETE AFTER EXPOSURE TO HIGH TEMPERATURES

摘要

In the Fluid Catalytic Cracking Unit (FCCU) of a petroleum refinery, there are some elements that are made of steel and lined with steel fiber reinforced refractory concrete, which has the function of reducing the temperature in the steel. After a few years of use, it is necessary to interrupt the refinery process for replacing the concrete, due to its multiple cracking state. It is of great importance to optimize the refractory concrete composition, in order to increase its lifetime in a refinery. This work presents the results of physical and mechanical tests performed on specimens of dense refractory concretes reinforced with steel fibers, aiming to improve their resistance. Four types of refractory concrete were produced, one of them unreinforced and the other ones with different steel fiber volume contents: 0.62, 1.24 and 1.86%. Some specimens of the studied concretes were burned at 600°C (temperature that arises in the FCCU's), making it possible the evaluation of the burning effect on the performance of the concretes. Tests to determine the apparent density and porosity of the produced concretes were carried out on the unburned and the burned specimens, as well as compressive and bending tests. The results showed that, in a general manner, the higher the steel fiber content added to the concrete, the better its mechanical performance.