عنوان مقاله [English]
Fibre or recycled material used in the concrete improves resistance, ductility, and durability of concrete. Concrete has fire-resistant properties but the most worrying thing about reinforced concrete structures during the fire is related to rebars. Therefore, there is a suggestion about use of alternative materials such as recycled metal spring in order to reduce above mentioned risks. In this paper, we conduct laboratory study to assess performance of concrete containing recycled metal spring while using volumetric amounts of 0.2, 0.4 and 0.6% at temperatures of 25, 100, 250, 500, 700 and 900 degrees Celsius. Furthermore, compressive strength and tensile strength of the most optimal combination of spring in the concrete are compared with concrete containing steel fibre and polypropylene. The results show that spring used in the concrete improves compressive strength and tensile strength. But the more the spring is used in the concrete, the more the resistance is reduced. Therefore, if the spring with 0.2 volume percent that is considered as the most optimal combination percentage is increased by 3 times, it increases compressive strength and tensile strength. Furthermore, the optimal compressive strength of spring in different temperatures is about 2 – 3 times of steel fibre and polypropylene and its tensile strength is close to strength of steel fibre. Fibre used in concrete reduces width of the cracks created after the test by 3 times.