Effects of Using Natural Fibers on the Fresh and Mechanical Properties of Concrete: A Comprehensive Review
Sardam Salam Shkur Shkur, Azad A. Mohammed, Soran Abdrahman Ahmad, Hersh F. Mahmood
Abstract
Most of the materials used in the construction sector are concrete, which has some disadvantages and weaknesses, such as low ductility and tensile strength. Many studies have been conducted to improve these properties, including the use of natural fibers. This article reviews previous experimental work on the use of different types of natural fibers in concrete at varying rates, highlighting their effects on both the fresh and mechanical properties of concrete. Based on the reviewed experimental data, relationships between concrete properties and the rate of fiber usage have been established. The effect of natural fibers on the slump value varies depending on the water absorption ability of the fibers. The slump decreases as the rate of natural fiber usage increases. The effect of natural fibers on compressive strength depends on fiber length and the water absorption ability of the fibers. As fiber length increases, the voids in the concrete increase, leading to a decrease in compressive strength. The effect of natural fibers on the flexural strength of concrete is influenced by fiber length and the elongation ability of the fibers. In terms of tensile strength, it was found that using sisal fiber in concrete at 0.5% increases the tensile strength by up to 30% compared to the control mix. Using jute fiber in concrete at 1.5% increases the tensile strength by up to 110% compared to the control mix. Using coir fiber in concrete at 1.5% increases the tensile strength by up to 60% compared to the control mix.