This paper presents basic information on the mechanical properties of steel fiber-reinforced, high-strength, lightweight concrete with compressive and flexural strengths up to 85.4 MPa and 11.8 MPa, respectively. The influence of steel fiber on modulus of elasticity and Poisson's ratio of concrete are investigated, and flexural fracture toughness is calculated. Test results show that the effect of fiber volume fraction (Vf) and aspect ratio (lfdf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly improved, and tensile/compressive strength ratio is obviously enhanced. It is observed that the flexural deflection corresponded to ultimate load increased with the increase of Vf and lfdf, and due to fiber arresting cracking, the shape of the descending branch of load-deflection tends towards gently.

Mechanical properties of steel fiber-reinforced, high-strength, lightweight concrete

This paper investigates the behavior of steel fiber-reinforced concrete (SFRC) beams in shear, as well as the possibility of using steel fibers as minimum shear reinforcement. In the study, 28 simply supported beams with a shear span-to-effective depth ratio of approximately 3.5 were subjected to a monotonically increased, concentrated load. The target concrete compressive strength for all of the beams was 41 MPa (6000 psi). The studied parameters included beam depth, fiber length, fiber aspect ratio, fiber strength, and fiber volume fraction. Three types of steel fibers were considered, all with hooks at their ends. The behavior of beams failing in shear prior to or after flexural yielding was also investigated by varying the longitudinal reinforcement ratio. Compared to reinforced concrete (RC) beams without stirrup reinforcement, the use of hooked steel fibers in a volume fraction greater than or equal to 0.75% led to an enhanced inclined cracking pattern and a substantial increase in shear strength.

Shear Behavior of Steel Fiber-Reinforced Concrete Beams without Stirrup Reinforcement

Test data are presented on the shear strength of a series of longitudinally reinforced fibrous concrete beams in which the shear span‐to‐effective depth ratio, volume fraction of fibers, percentage of reinforcement, and strength of the concrete were varied. Test results indicate that the fibers have significant influence on the mode of failure and ultimate shear strength of a longitudinally reinforced concrete beam. Conventional reinforced concrete analyses with some modification, as suggested in this paper, to account for the effect of fibers give good predictions of the ultimate strength and the mode of failure for rectangular beams with no shear reinforcement.

P.S. Mangat

Papers

A theory for the flexural strength of steel fiber reinforced concrete

Influence of fiber geometry on the properties of steel fiber reinforced concrete