International Concrete Abstracts Portal

SP105 Leading edge design requires leading edge technology. "Fiber Reinforced Concrete Properties and Applications," provides the knowledge you need to design and build state-of-the-art concrete structures. Fiber reinforced concrete can be used in a wide variety of applications. With fibers being made of steel, glass, or polymer they can be added to the concrete mix in a variety of ways. Added to concrete in a ready-mix truck, cast in a conventional manner, or sprayed along with mortar slurry to form thin precast panels, new fibers, methods of manufacture, fabricating, and applications are being pioneered all of the time. "Fiber Reinforced Concrete Properties and Applications," a collection of 29 papers, is divided into five main sections: fracture and mechanical properties, polymer and glass fiber reinforced concrete, steel fiber reinforced concrete, pavements, and structural behavior. Topics such as: failure mechanisms and fracture of fiber reinforced concrete, fiber reinforced soil-cement, creep of concrete containing fibers and silica fume, development of lightweight durable fiberglass-reinforced concrete, flexural fatigue strength of steel fiber reinforced concrete, steel fiber reinforced heat resistant pavement, and flexural behavior and design of reinforced fiber concrete members are presented in great detail.

Paper reviews seven test specimen geometries that have been used to determine the shear performance of fiber reinforced concrete (FRC) materials. All the geometries are modified standard quality control test specimens--modified cubes, beams, or cylinders. The performance of FRC materials can be characterized by two fracture parameters--fracture toughness, which gives the resistance to cracking, and toughness index, which quantifies the post-first-crack toughness. The shear strength results are similar for the various test geometries used in the study. The shear strength of steel FRC mixes is shown to be independent of fiber content, whereas the shear strength of polypropylene FRC decreases with increasing fiber content and the shear strength of glass FRC increases with increasing fiber content. The post-cracking toughness increases uniformly with increasing fiber content over the range of fiber contents studied. This increase in toughness is observed for all three fibers--steel, polypropylene, and glass fiber.

Paper presents the results of an experimental investigation on the behavior of slurry-infiltrated fiber concrete (SIFCON) subjected to flexure, shear, and axial tensile loading. More emphasis was placed on the flexural behavior in which the specimens were subjected to static and high-amplitude cyclic loading. Four fiber lengths, namely, 30, 40, 50, and 60 mm, and four volume contents ranging from 4 to 12 percent were used. Fibers with hooked ends were used for the entire investigation. Effect of the addition of silica fume and sand to cement slurry was investigated by using a selective group of specimens made with 8 percent fiber content. Freeze-thaw studies were also conducted using prisms that had 8 percent fibers. The behavior in shear was studied using direct shear specimens. Properties in axial tension were investigated using four fiber contents of 50 mm long fibers. The results indicate that strengths of up to 10,000 psi (68.9 MPa), 4000 psi (27.6 MPa), and 2000 psi (13.8 MPa) can be obtained in flexure, direct shear, and axial tension, respectively. The composite is extremely ductile in all three modes of loading. Based on the tests conducted in flexure, addition of silica fume increases the strength. Sand can be added to the slurry without reducing the strength up to a certain cement-sand ratio. The ductility characteristics are not affected by the addition of either sand or silica fume.

Calcium silicates (C4A3S-CS) slag-type low-alkaline cement (CGC) has recently been developed in Japan, mainly to improve the durability of glass fiber reinforced concrete (GFRC). As part of the overall evaluation testing on the performance of GFRC using CGC and AR-glass fiber (New-GFRC), various properties of New-GFRC were tested, such as durability, compressive strength, flexural fatigue, flexural strength using a plank (thick specimen), resistance to freezing and thawing (ASTM C 666), dimensional change under storage in wet and dry conditions, and the adhesive strength between paint and GFRC. As a result of these experiments, it has become clear that New-GFRC excels conventional GFRC in all the properties of durability and both mechanical and physical properties.

In recent years, a high-tenacity acrylic fiber for technical applications was developed in West Germany. Test data using these special polyacrylonitrile fibers in mortar and concrete are presented. Within a limited parameter study, the amount and geometry of the fibers and the size of the largest aggregates of the matrix were varied. The produced specimens were tested concerning the flexural and compressive behavior as well as crack development due to shrinkage. To determine the optimal length of fibers, integral pullout tests were conducted. The modulus of rupture found in the experiments was used to show the effect of the fibers in a diagram that relates the size of the "plastic zone" to the critical crack width.