SP-228CD This CD-ROM of Special Publication 228 contains the papers presented at the Seventh International Symposium on the Utilization of High-Strength/High- Performance Concrete that was held in Washington, D.C., USA, June 20-24, 2005. The symposium continued the success of previous symposia held in Stavanger, Norway, (1987); Berkeley, California (1990); Lillehammer, Norway, (1993); Paris, France, (1996); Sandefjord, Norway, (1999); and Leipzig, Germany, (2002). The symposium brought together engineers and material scientists from around the world to discuss topics ranging from the latest applications to the most recent research on high-strength and high-performance concrete. In the years since the first symposium was held in Stavanger, there has been worldwide growth in the use of both high-strength and high-performance concrete. In addition to more research and applications of traditional types of high-performance concrete, the use of self-consolidating concrete and ultra-high-performance concrete has moved from the laboratory to practical applications. This publication offers the opportunity to learn the latest about these developments.

One of the breakthroughs in concrete technology is ultra-high-performance concrete with a steel like compressive strength of up to 250 N/mm2 and a remarkable increase in durability compared even with high-performance concrete. In combination with steel fibres it is now possible to design sustainable filigree, lightweight concrete constructions with or even without additional reinforcement. Wide span girders, bridges, shells and high rise towers are ideal applications widening the range of concrete applications by far. In addition e.g. to some pedestrian bridges heavily trafficked road bridges has been build in France and in the Netherlands. Bridges are already under construction in Germany as well. A wide range of new concrete formulations has been developed to cover an increasing number of applications. Technical recommendations have recently been published in France and in Germany covering material as well as design aspects. The paper will report on the state of research and application of UHPC in Europe, on material and design aspects of UHPC and will present the state-of-the-art based on an International Symposium on UHPC held in Kassel in 2004.

Construction of modern structures and reconstruction of the existing onesimpose very demanding requirements for the quality of used materials. Highperformance hybrid fibre reinforced concrete appears to be a material of great importance in the future. An innovative type of this concrete was tested and its properties were compared with those of reactive powder concrete, high performanceconcrete and plain concrete. Compressive strength, flexural strength, toughness and modulus of elasticity were measured. For the purposes of toughness testing, an acousticemission technique was used to detect cracking and fracture properties.

Pure bending loading with a constant moment is frequently used as a loading method in experiments on lap splices. However, the stress state of the concrete around the lap splices must approximate that of the actual reinforced concrete members. This paper discusses the mechanical properties of lap splices based on results from combined flexure and shear loading tests conducted on high-strength concrete (70-MPa grade) and normal-strength concrete (30-MPa grade) beams with all lapped splices in a critical section with high stress. The results revealed differences in concrete strength in terms of the splice characteristics under flexure and shear stress. For example, the maximum flexural crack width in the high-strength concrete specimens under service loading is smaller than that of normal-strength concrete specimens. The expansion of the yield zone of the main reinforcement in lap splices was greater than that in the normal-strength concrete specimens. Furthermore, the ratio of ultimate bond strength, which was obtained from the equation for bond splitting strength, to bond strength at the time of yield was small in the high-strength concrete specimens.

A study was performed to develop high-performance concrete (HPC) mixesand specifications for transportation structures using resources that are readily available in New Jersey. A total of 87 mixes, with the water-to-cementitious (w/cm) ratio ranging from 0.27 to 0.55, were developed. Both mineral and chemical admixtures—silica fume,fly ash, superplasticizer, and air-entraining agent—were used to improve the mechanical properties and durability of concrete. Out of these 87 mixes, three mixes with different compressive strengths were selected as base mixes. Both the mechanical properties and durability tests were performed on these mixes, which consisted of compressive strength, modulus of elasticity, drying shrinkage, creep, freeze-thaw durability, chloride permeability, and scaling resistance. Moreover, the effect of curing methods (dry, wetburlap, and compound) on the strength and durability of HPC were also investigated.Results show that the strength and durability of HPC could be enhanced with ternary blended mixes.