Investigating measurement variations of flexural behavior in preloaded specimens of pozzolanic concrete reinforced with steel and glass fibers

Flexural behavior investigation of concrete materials is one of the most important issues in evaluating its mechanical behavior and is one of the main criteria for the design of concrete structures. The flexural behavior analysis of concrete specimens in a laboratory can simulate the behavior of concrete in a real scale with acceptable accuracy. Flexural strength, failure energy, bending coefficient and toughness are parameters that can be extracted from concrete bending results. Each of these parameters is important in the complex and sensitive design of high-rise or non-structural structures. In this research, two pozzolans of zeolite and silica ash, as well as two types of steel and glass fibers are used to improve the concrete specificationsThe effect of individual behavior of these materials and their effects simultaneously has been highlighted. The materials used in this project have a significant research background. However, in the combination of materials mentioned, little research has been done; and there are still more studying points. The results of pre-loading concrete fibers represented new aspects of concrete behavior in structural performance. It was observed that in the non-pozzolan specimens, increasing the amount of steel fibers increased flexural strength while increasing the amount of glass fibers did not have a significant effect on increasing flexural strength. Also, in the specimens with mixed pre-loading, with the decrease of the percentage of silica soot, the difference of results is reduced. This trend indicates that zeolite has a more important role in repairing cracks for shorter time intervals. Examination of fracture energy showed that specimens containing 1% steel fiber had the highest fracture energy due to fiber performance. After the specimens are damaged, this process is maintained and it seems that cracking in the fiber specimens does not necessarily lead to disruption of fracture energy changes.