Glass fiber-reinforced Concrete (GFRC) has now been in use worldwide for over 30 years. There are many varied applications for this composite material and this paper describes four specific applications that illustrate the benefits that GFRC offers to the construction industry.

Most maintenance problems associated with industrial concrete floors result from the joints. This paper emphasizes a method to eliminate saw-cut joints in slabs-on-grade by the use of steel fiber reinforced concrete (SFRC) only. The performance of the composite material is directly linked with the choice of a specific concrete mix design and an improved technique to uniformly mix a high dosage of steel fibers. Tests and experience have shown that high level post-cracking ductility of the SFRC can control micro-cracking caused by flexural and shear stresses combined with restrained shrinkage. The proposed design approach, based on the yield-line theory, gives an objective view of the safety factor in relation to the ultimate state. Case studies demonstrate that typical areas of 25,000 ft² (2322 m²), without saw-cut joints, are regularly achieved by experienced contractors with relevant site quality control. Practical site aspects such as armored contraction joints, slab details, aspect ratio, installation techniques etc., are an integral part of the case study as well. The second part of this paper details the use of this technique for structural applications such as suspended slabs on piles and mat foundations. To demonstrate the structural capacity of concrete solely reinforced with a high dosage of steel fibers, real scale tests and practical case studies are presented.

The ready-mixed industry makes up nearly 75 percent of the U.S. consumption of cement and this represents a significant market opportunity for the possible use of wood pulp fiber in ready-mixed concrete applications. Most research surrounding cellulose fiber-cement composites has focused on manufactured products such as flat and corrugated sheets for cladding and roofing, nonpressure pipes, and cable pits. Integration of cellulose fiber into the mainstream ready mix operation for value added benefits to the concrete mix is proven in practical applications as shown in this paper. Concrete properties enhanced by cellulose fiber addition are summarized. Properties of the fiber concrete composite discussed in this paper include fiber and cement matrix bond, alkaline stability, freeze-thaw durability, plastic shrinkage cracking resistance, combustibility, fire resistance and impact resistance. The paper also highlights selected project examples demonstrating the use of cellulose fibers in concrete, such as, overlays, slab on grade, and decorative concrete.

The effects of fresh state properties on the fiber dispersion characteristics of fiber-reinforced composites (FRCs) were studied by quantifying fiber segregation. Fresh state properties of concrete mixes were varied using different combinations of a plasticizing agent and viscosity modifier. A self-designed parallel-plate rheometer was used to obtain rheological parameters. Vibration was applied to the specimens and vibration times were varied to understand the effects of vibration on fiber segregation. An electrical characterization method, alternating current-impedance spectroscopy (AC-IS), was used to quantify fiber segregation in specimens. The relationship between fresh state properties and fiber segregation was evaluated.

The case history presented in this paper describes a small sized project for design and construction of a macro synthetic fiber reinforced concrete (SnFRC) residential driveway with an average grade of 17%. The study highlights risks and benefits of choosing this material for this project. Five almost-equal lengths of SnFRC sections were placed in two groups 11 months apart. The delay between placements allowed for some experience to better analyze and determine if this was the best solution given the customer’s performance criteria and the difficult construction conditions. The design included a high cementitious content mixture with small aggregate, synthetic macro fibers, and air-entraining admixture. The resulting driveway was constructed down hill and has performed well in spite of minimal surface preparations and no jointing or saw cuts in the overlay. Some small cracking has occurred but has been of no consequence because the concrete has been held together by the synthetic fibers. For the construction of this residential driveway utilizing synthetic fiber reinforced concrete, the performance criteria was met, the construction schedule was on time, and the construction costs were significantly lower.