Behavior Of Structural Macrosynthetic Fiber-Reinforced Precast, Prestressed Hollow-Core Slabs at Different Flexure-to-Shear Ratios

Abstract

■ ■ The paper reviews available literature related to fiber-reinforced concrete as well as provides results of full-scale testing conducted on hollow-core slabs specimens and reviews the applicability of analytical modeling. The main advantages of using precast concrete elements, such as hollow-core slabs, are high quality control and reduced construction time. Hollow-core slabs have longitudinal voids running along the spans, which reduces the slab’s weight and creates a more efficient cross section for prestressing. Hollow-core slabs are usually designed as uncracked elements under service loads. However, if a structure is overloaded due to change in use, architectural modifications, or material degradation, these elements can crack and may not meet the required serviceability design criteria. Because hollow-core slabs are produced via an extrusion process, the provision of additional reinforcement is not feasible. In such scenarios, the addition of structural synthetic fibers to the concrete during casting can enhance the performance of the slabs after cracking. Current American Concrete Institute (ACI) codes require at least 60 kg (130 lb) of deformed steel fibers per cubic meter of concrete for shear reinforcement. However, in prestressed hollow-core slabs, the beneficial effect of prestressing forces could relax the minimum fiber volume requirement.