Experimental Examination of The Effect of Length and Percentage of Steel Fibers on The Tension and Compression Strengths of Concrete

Fiber-containing concretes are among the new generations of concrete that have been considered by researchers and engineers for decades.    Fibers play a very important  role in improving  the weaknesses of concrete, including the tensile and flexural strengths of concrete.   In re cent years, researchers have done  a lot  of research  on the properties of fiber  concrete and concretes with different fibers such as: steel, carbon, polypropylene, glass, as well as plant fibers such as: palm, hemp, coconut and/or even examined fibers from recycled materials such as car tyre and sacks. In order to study the effect of length and percentage of steel fibers on tensile and compressive strengths of concrete, in this study, it is intended to create three concrete models with conventional concrete mixing design and by adding steel fibers with a length of 3 and 5 cm and   Also, their combination should be tested with volume percentages of 0.5%, 1% and 1.5%.  In addition, samples of plain concrete were made to determine the effect of fibers on the strength of concrete.   Then, using the hydrulic jack machine, tension  and compression  strength tests were performed  on the concrete specimens.   Based on the obtained results, it seems that with increasing the length and percentage of steel fibers, the tensile and compressive strengths of concrete increase.  Also, based on the observations made, it can be interpreted that samples containing a combination of 3 and 5 cm steel fibers in concrete have lower strength than 5 cm samples and more resistance  than 3 cm samples, respectively.  Reports.   Based on the experiments performed and taking into account the comparisons  made,  the  use  of  5  cm  steel  fibers  is  recommended  to  increase  the  tensile  and compressive strengths of concrete with different percentages compared to 3 cm steel fibers.