Fire Resistance of Concrete Columns Containing Polypropylene and Steel Fibers

Abstract

One of the new techniques to reduce explosive spalling in concrete subjected to fire is to add a cocktail of polypropylene fibers and steel fibers into the concrete mixture. This method is still in the early stages of development and requires more research to investigate the efficiency of introducing such a combination of fibers in reducing explosive spalling in fire. The purpose of this paper is to present the results of an experimental study conducted to investigate the performance of reinforced concrete columns containing steel and polypropylene fibers under different loadings and subjected to severe fire conditions. Two loading levels were investigated representing 0.6 and 0.76 of the ultimate strength limits of ACI 318. Columns containing polypropylene (1 kg/m3) and steel fibers (80kg/m3) showed a higher fire resistance by an average factor of 1.76 compared to columns containing PP fibers (1 kg/m3) only. The paper also assesses the effect of adding steel and polypropylene fibers on the severity of concrete explosion under fire. Measurements of axial displacements and concrete temperatures are presented in this paper. The paper compares the obtained experimental values of the axial displacements with theoretical values calculated using a previously developed simple approach. (13 refs.)