Fracture of Plain and Fiber-Reinforced Concrete Slabs under Monotonic Loading

Monotonic load tests have been conducted on plain and fiber-reinforced concrete slabs on ground to monitor the effect of fiber type and dosage on the strength properties of concrete slabs. The results revealed that simple material tests do not always successfully predict the contribution of fibers in cases where structural geometry and boundary considerations control redistribution of load. The tensile cracking loads of plain and fibrous slabs were found to be similar, which had previously been reported for small- scale fiber specimens, but, there was a significant increase in the flexural strength of fiber-reinforced concrete slabs, relative to plain concrete slabs. Companion beam flexural strength tests also significantly underestimated the concrete slab flexural strength for both the plain and fibrous concrete slabs. The addition of fibers increased the collapse load of slabs, with the key factors affecting the magnitude of the collapse load being fiber type and quantity. Strain and deflection profile measurements showed that fibers assisted in crack propagation resistance, crack bridging, and load redistribution. The shape of the load deflection curves indicated that the synthetic and the steel-fiber-reinforced concrete slabs behaved similarly at different stages of cracking.