Comparison of the Corrosion Resistance of Fiber-Reinforced Concrete with Steel and Polypropylene Fibers in an Acidic Environment

Rigid road pavements and industrial floors are not only subjected to moving traffic loads, but can also be exposed to environmental influences such as acid attack. The strength and corrosion resistance of fiber-reinforced concrete with steel fibers (15–25 kg/m3) and polypropylene fibers (2–3 kg/m3) in an acidic environment were compared. The influence of the amount and type of dispersed reinforcement on water absorption and the volume of permeable voids, which in turn characterizes the durability of fiber-reinforced concrete under the action of acids, was determined. The change in the compressive strength of the studied fiber-reinforced concrete after 12 months of exposure in an acidic environment was studied. At low dosages of fibers (15 kg/m3 for steel and 2 kg/m3 for polypropylene fibers), dispersed reinforcement has little effect on the corrosion resistance of concrete. In turn, the decrease in the compressive strength of concrete without fibers after 12 months of aging in acid medium led to a reduction in the design class of the concrete from C25/30 to C20/25. At a higher consumption of dispersed reinforcement (25–30 kg/m3 of steel fiber and 2.5–3.0 kg/m3 of polypropylene fiber), fiber-reinforced concrete had a higher corrosion resistance while maintaining the design compressive strength class C25/30. Structural changes in fiber-reinforced concrete after aging in an acidic environment were determined by X-ray diffraction analysis and compared with samples aged in water. It has been experimentally confirmed that the efficiency of polypropylene fibers in an acidic environment is not lower than that of steel fibers. However, the use of polypropylene fibers is economically advantageous.