Mechanical, Durability and Electrical Properties of Steel Fibers Reinforced Concrete

Abstract

Concrete is a constantly evolving building material whose demand is increasing due to population growth and urban development. This calls for more research on this composite material to improve its performance. However, concrete has some disadvantages, including that it is a brittle material and cannot withstand tensile stress. Therefore, rebars and fibers are incorporated into concrete to improve this property. Although previous works investigated the properties of concrete containing steel fibers, most of them were concerned with mechanical properties, while the durability properties still require further investigation to understand them. Thus, the purpose of this study is to ascertain how adding steel fibers to concrete in varying proportions (0.5, 1 and 1.5%) affects its mechanical and durability properties, including compressive strength, flexural strength, tensile strength, bulk density, water absorption, mode of failure, ultrasonic pulse velocity, dynamic modulus of elasticity and electrical resistance. Statistical relationships between the compressive strength and other characteristics were also established. The results indicated that all mechanical and durability characteristics significantly improved after adding steel fibers for all addition ratios, except for electrical resistivity, which showed lower values than the reference mixture for the 0.5 and 1% steel fiber proportions. Moreover, it was found that the best addition rate of steel fibers was 1.5%. At this percentage, the recorded increasing rates over the control sample were 29.3% in compressive strength, 83.7% in tensile strength, 27.9% in flexural strength, 50.1 in water absorption resistance, and 11.2% in electrical resistivity.

Keywords

• compressive strength
• water absorption
• electrical resistivity
• steel fibers
• ultrasonic pulse velocity