This CD-ROM contains 10 papers that were presented at sessions sponsored by ACI Committee 544 at the Spring 2011 ACI Convention in Tampa, FL. The topics of the papers cover durability aspects of fiber-reinforced concrete, ranging from permeability, shrinkage cracking, long-term behavior in chloride environment and resistance to chloride penetration, as well as applications of fiber-reinforced concrete for coupling beams for highrise core-wall structures, beams for bridges, panels and suspended foundation slabs. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-280

Reinforced concrete structures exhibit frequent deterioration problems that are related to the penetration of water, air and deleterious agents into the concrete. Cracking initiated by internal and external loads applied to the structures favors a deepen penetration of gaz and fluids and accelerates deterioration processes. The impact of cracking and load application on concrete durability can be evaluated with water permeability measurement. In this project, a novel device was used to evaluate water permeability of reinforced concrete specimens made in normal strength concrete (NSC) and fiber reinforced concrete (FRC). The permeability was measured during the application of a tensile load on the specimens. Complementary tensile tests permitted to characterize the crack pattern and the crack openings in the specimens under loads. Experimental results were combined to collectively analyze measurements of permeability, crack opening and stress in reinforcement were combined to establish correlations. The permeability of the FRC was approximately 3 times smaller than the one of the NSC at an equivalent loading level in the reinforcement of the specimens. Moreover, for the same permeability, admissible stresses in the reinforcement can be at least 75 MPa higher when it is embedded in FRC rather than in NSC. It means that for an equivalent durability, an engineer can design structural members with the studied FRC with less reinforcement or to withstand higher loads at serviceability.

The paper will review durability data for glass fiber reinforced concrete (GFRC), both accelerated aging and real time data. It will compare real time data with predicted data from accelerated aging tests and describe the design principles that have been established for GFRC based on this durability data. Applications over 20 years old will be reviewed.

Ultra high performance concrete (UHPC) containing steel fibers was used in five beams of the bridge on Route 624 over Cat Point Creek in Virginia. A test beam was also fabricated and tested to failure. The beam had strands but no shear stirrups. Test beam results indicated satisfactory load-carrying capacity. Preparation of the beams involved a longer mixing time and a two-stage steam curing to ensure optimum concrete properties. Testing of specimens at the hardened state showed that UHPC has high strength and high durability attributable to a very low water–cementitious materials ratio, low permeability, a high resistance to cycles of freezing and thawing, and tight cracks.

Experimental and analytical studies that led to the incorporation of strain-hardening, high-performance fiber reinforced concrete (HPFRC) coupling beams in the design of a high-rise core-wall structure in Seattle, WA, are described. A total of eight HPFRC coupling beams with span-to-depth ratios ranging between 1.75 and 3.3 were tested under large displacement reversals. The tension and compression ductility of HPFRC materials allowed an approximately 70% reduction in diagonal reinforcement, relative to an ACI Building Code (318-08) compliant coupling beam design, in beams with a 1.75 span-to-depth aspect ratio and a total elimination of diagonal bars in beams with a 2.75 and 3.3 aspect ratio. Further, special column-type confinement reinforcement was not required except at the ends of the beams. When subjected to shear stress demands close to the upper limit in the 2008 ACI Building Code (0.83 f’c [MPa] (10 f’c [psi])), the coupling beams with aspect ratios of 1.75, 2.75 and 3.3 exhibited drift capacities of approximately 5%, 6% and 7%, respectively. The large drift and shear capacity exhibited by the HPFRC coupling beams, combined with the substantial reductions in reinforcement and associated improved constructability, led Cary Kopczynski & Co. to consider their use in a 134 m (440 ft) tall reinforced concrete tower. Results from inelastic dynamic analyses indicated adequate structural response with coupling beam drift demands below the observed drift capacities. Also, cost analyses indicated 20-30% savings in material costs, in addition to much easier constructability and reduced construction time.