The effect of polyamide, polyester and jute fibers of different sizes on the mechanical behaviour of concrete

Concrete is a brittle material with very low tensile strength and low tensile deformation capacity. In order to improve these weak properties of concrete, fibers produced from different materials and with high technical properties were added to the concrete. In this study, it is aimed to investigate the physical and mechanical properties of concretes obtained by using polyester, polyamide and jute fibers at % 0.5, % 1, % 1.5 ratios by keeping amount of cement constant in the concrete mixtures. Standard cubic samples of 10×10×10 cm were produced for concrete compressive strengths and beam samples of 10×10×40 cm were produced for flexural-tensile strengths. The fibers used were cut as 3 cm, 4.5 cm and 6 cm. The cut fibers were grouped in pairs with the same fiber length and added into the concrete at the specified rates. In this study, compressive strength, triaxial bending strength, schmidt hardness hammer test, ultrasound test, thermal conductivity coefficient measurement, water absorption test and slump test were performed. It is thought that these three fibers contribute to improving the mechanical properties of concrete. It was determined that as the fiber ratio increased, Schmidt hardness and flexural strength values increased, while the amount of slump, thermal conductivity coefficient and compressive strength values decreased. It is thought that the increase in fiber ratio will contribute to thermal insulation by decreasing the thermal conductivity value and fiber length should not be used more than 4.5 cm. However, it is seen that the fiber concrete samples produced do not make a clear difference among themselves, and generally all results give close values.