Examination of mechanical behaviors of SIFCON based on different fiber and matrix phases

SIFCON (Slurry Infiltrated Fiber Concrete) is a cement-based composite material obtained by using various fibers. SIFCON contains 5 to 20% fiber in volume. Due to its high percentage of fiber, SIFCON displays a high performance in mechanical properties such as compressive strength, bending strength, tensile strength and toughness. This new generation special concrete is recommended for use in blast proof military structures, industrial floors and bridge legs, particularly for its high toughness and bending strength. SIFCON consists of three phases; mortar phase, fiber phase and interface. In this study, steel and woolen polypropylene fibers are used in order to observe the effects of changing the fiber phase on the mechanical properties. Furthermore, effects of mineral additives mixed into the mortar phase on the mechanical properties of SIFCON were analyzed by adding silica fume in amounts of 5, 10 and 15% of cement weight and fly ash in amounts of 20, 40 and 60% of cement weight. Compression, flexural and toughness experiments were conducted on SIFCON specimens to determine the mechanical properties. Additionally, SEM images were taken to observe the changes in the internal structure caused by the mineral additives. As a result of the data obtained, it was found that the steel fibers yield higher experimental outputs compared to woolen polypropylene fibers. Positive impact of using mineral additives on the mechanical properties of the concrete was clarified with the experiments conducted. The SEM images taken in the study prove that the mineral additives improve the internal structure of the concrete.