Effects of steel and glass fibers on mechanical and durability properties of concrete exposed to high temperatures

The behavior of a concrete structure at elevated temperatures is one of the vital areas of concern in civil engineering. Because high temperatures cause adverse effects on the mechanical and durability properties of concrete structures, finding solutions to improve these properties at various temperatures is important. This study goes to indicate the effects of steel and glass fiber addition on the behavior of normal concrete at high temperatures. The mechanical and durability specifications were tested at elevated temperatures, and after cooling, respectively. The volume fraction of fibers is 0.25%, and measurements are conducted at temperatures ranging from 28 degrees C to 800 degrees C. The results indicate that the application of steel fibers improves the compressive, tensile, and shear strength in a range of 9-27%, 8-198%, and 1-22% at high temperatures, respectively. For specimens containing glass fiber, the level of compressive and tensile strength improvement is in the range of 1-18% and 19-213%, respectively. Although the durability tests show that high temperatures can damage the durability properties of concrete, the addition of fibers has compensated for this damage. Meanwhile, it is observed that the sorptivity and penetration depth of water tests due to the capillary properties has a similar result.