Effectiveness of Polypropylene and Steel Fibers in Enhancing Fire Resistance of High-Strength Concrete Columns

Abstract

Fire-induced spalling is one of the concerns with the use of high-strength concrete (HSC) in structural applications. Some recent studies have recommended addition of polypropylene and/or steel fibers to overcome such spalling. This paper presents results from fire resistance tests on the comparative fire performance of HSC columns with and without fibers. Four reinforced concrete (RC) columns made of HSC with plain (no fibers), polypropylene, steel, and hybrid fibers, as well as one RC column made of conventional normal-strength concrete (NSC), were tested under different fire conditions. Data from these tests are utilized to evaluate comparative fire behavior of RC columns made of plain and fiber-reinforced HSC. In addition, an analytical study is carried out to evaluate relative changes in porosity and temperature-induced pore pressure in NSC and HSC, and its effect on spalling behavior and fire resistance of HSC columns. Results from fire resistance experiments and numerical studies show that hybrid-fiber-reinforced HSC columns exhibit better fire performance compared to polypropylene- or steel-fiber-reinforced or plain HSC columns.