International Concrete Abstracts Portal

This paper presents the construction of a bridge deck and jersey barriers with the newly developed polyolefin fiber reinforced concrete. This is the first time this synthetic fiber-reinforced concrete was used in the construction of reinforced concrete structural elements such as bridge deck and jersey barriers. The mixture proportions used, the procedure used for mixing, transporting, placing, consolidating, finishing and curing are described. This new polyolefin fiber-reinforced concrete with enhanced fatigue, impact resistance, modulus of construction of durable highway structures.

This paper deals with the application of fibre-reinforced concrete to enhance structural fire resistance. Materials, such as fibre-reinforced concrete, have good fire resistance properties and by properly designing the building elements, fire resistance, in the practical range, can be obtained. The properties of steel fibre-reinforce concrete are discussed. Examples of some fire resistance applications of steel fibre-reinforced concrete in buildings are illustrated. Results from studies on the fire resistance of concrete-filled steel columns show that the addition of steel fibres in concrete filling improves the fire resistance of steel columns and eliminates the need for external fire protection. The application of fibre-reinforced concrete in enhancing the fire resistance of high strength concrete columns is also discussed.

A simple analytical model is presented to predict the ultimate punching shear strength of slab-column connections made with steel fiber concrete. The model is based on the physical behavior of the connection under load, and is therefore applicable to both lightweight and normal weight concrete as well as to concrete without fibers. The model assumes that punching is a form of shearing without concrete crushing, and occurs when the tensile splitting strength of the concrete is exceeded. The theory is applied to predict the ultimate punching shear strength of forty seven slab-column connections tested by the authors and other researchers over a period of several years and designed to fail in shear, involving a wide range of fiber show very good agreement between the predicted and experimental values. The uniqueness of the model is that it incorporates many physical characteristics of the slabs and their failure behavior.-

It is known that Steel Fiber Reinforced Concrete (SFRC) has advantages over plain concrete. In particular, fiber reinforcement makes concrete tougher and more ductile. Although these attributes are appealing for earthquake resisting structures, design codes do not yet incorporate specifications relative to the use of SFRC for structural applications. Recent developments have indicated a good potential for SFRC in structural and seismic applications. In the first part of this paper, the beneficial effects of SFRC in the seismic design of columns are briefly reviewed. The paper then presents an overview of an ongoing research project on compression. The variables considered were the fiber content of 0%, .5% and 1.0% per volume, the amount of transverse reinforcement for confining the column core, and the confinement provided by the fibers in the cover. It is shown that SFRC improves significantly the post-peak behavior of columns for all hoop spacing and the same seismic design philosophy. Although SFRC in the cover delay its spalling confine concrete, but rather change the failure mode by limiting the progression of cracks and enhancing the aggregate interlock along failure planes.

Steel, polyolefin and carbon fiber reinforced concretes were combined with traditional transverse steel reinforcement in the form of steel spirals. The complete stress-strain relationship and the ductility of the concrete in compression in both the unconfined and confined states was evaluated. The compressive toughness was evaluated both according to the Japanese Standard JSCE-SF5 and according to a new method proposed in the present work. The experimental program consisted of testing concrete cylinders under compression at two different strength levels: Normal (48 Mpa) and high strength (70 Mpa), polyolefin and carbon fibers. These tests were then repeated with different volume percentages Vf (1.5, 2.0 and 3.0) of steel, polyolefin and carbon fibers. These tests were then repeated with different pitches (25 and 50 mm). It was found that by combining fibers and steel spirals it is possible: (1) to obtain a high level of fracture energy dissipation, which could previously be obtained only by using a high volume percentage of spiral steel: and (2) to improve the maximum strain of the concrete, corresponding to the first failure of the spiral steel.