Fiber-Type Influence on the Flexural Behavior of RC Two-Way Slabs with an Opening

Abstract

Combining fiber with concrete mixes has become essential and its widespread use improves the strength of structural concrete elements. This research conducted an experiment into the structural performance of flat slabs with and without a square opening using four types of fiber (hooked-end, straight, corrugated steel fiber and polyolefin fiber) to gain a better understanding of how the variance of fiber type and shape effects the flexural behaviors of two-way slabs. The test program involved (a) testing the properties of hardened concrete, such as compressive properties, modulus of rupture and splitting tensile strength, and (b) testing the flexural behavior of two-way slabs. Ten slabs were divided into five pairs, including two specimens used as reference specimens (with and without openings), and eight other specimens with different types of fibers. Results revealed that the existing fiber in concrete improved the mechanical properties of hardened concrete mix, and the compressive strength test showed higher improvement in specimens with hooked and straight steel fiber. The flexural behavior of reinforced concrete slab was significantly enhanced, and the flexural strength capacity was especially improved for the slabs strengthened with hooked-end and corrugated steel fiber. Polyolefin fiber showed a slight enhancement of mechanical properties and good improvement in flexural capacity. Generally, the highest increments in compressive strength and modulus of rupture were 24.8%, 20% and 11%, and the ultimate load-carrying capacity of slabs was 39%, 13% and 19% for specimens with steel hooked, steel corrugated and polyolefin fibers, respectively, compared with control specimens.