The effect of quantity and type of fibers and recycled metal springs on concrete properties

The use of fibers or recycled materials in concrete will results in improving the strength, plasticity and durability of concrete. Therefore, one of the suggestions to improve the mechanical properties of concrete is the use of fibers as well as alternative materials such as recycled steel springs. In this paper, we investigate the performance of concretes containing steel and polypropylene fibers and recycled metal springs using 0.2, 0.4, 0.6 and 0.8 percent volumetric percentages. For this purpose, a number of cylindrical and prismatic samples at the age of 28 days were tested for compressive, tensile and flexural strength tests. It should be noted that the steel fibers used have a length and diameter of 50 and 0.8 mm, polypropylene fiber has 12 mm length, as well as a metal spring with a wire diameter of 0.8 mm, a length of 25 mm and a hole diameter of 8 mm. The results indicate that the use of recycled metal springs in concrete has a better performance than other fibers in the control of cracks caused by tension. Also, in low percentages, the use of springs has improved the mechanical properties of concrete. Also, polypropylene fibers and metal springs increase the flexural strength of concrete up to 2 times, which for the use of steel fibers this amounts to 13 times. So, with better recognition and changes in the type and characteristics of the spring, better resistance can be achieved.