International Concrete Abstracts Portal

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.

The utilization of high performance concrete (HPC) has increased substantially in the last decade. HPC can provide enhanced mechanical and durability properties and at the same time allow efficient placement and finishing. HPC has been utilized for cost-effective construction of bridges, buildings and pavements in most countries. The Federal Highway Administration (FHWA) has played a key role in the HPC technology transfer from research and development to routine practice for bridge and pavement design and construction. FHWA’s HPC implementation activities began in 1991. HPC implementation for highway bridges in the USA has been a success story. The success has been largely due to a long-term continuing partnership between FHWA, State Departments of Transportation, American Association of State Highway and Transportation Officials (AASHTO), local agencies, industry and academia. This paper provides an historic perspective on the HPC implementation activities since the Strategic Highway Research Program (SHRP) in late 1980’s and the subsequent programs and activities. Forty-four State Departments of Transportation have utilized HPC. HPC implementation has contributed significantly to improvements in highway infrastructure. Implementation of the long-term strategic plan developed by the industry will further contribute toward meeting the goals which include reduced congestion and improved safety, trained workforce, reduced life cycle costs and improved quality as well as reliability.

This paper contains an historical review of self-compacting concrete clarifies and the original concept. Further, combinations of self-compacting concrete for high strength and durability are discussed in relation to structural concrete design, construction and maintenance, and recent development of performance-based design codes and manuals for SCC. On the competitiveness in industries, life-cycle cost is estimated for sustainable development of the infrastructure.

Experimental investigation was conducted to study the pure torsional behavior of sixteen high- (HSC) and normal-strength concrete (NSC) full-size beams with relatively low amounts of torsional reinforcement. The test specimens had variable levels of transverse and longitudinal reinforcements, compressive strength of concrete and aspect ratio of the cross section. The overall behavior, with emphasis on the post-cracking reserve strength, is reported. It was found that the adequacy of post-cracking reserve strength for specimens with the minimum amount of torsional reinforcement specified in the ACI 318-02 is primarily related to the ratio of ?t /?l . Nevertheless, the lower limit of ?total = 1 % should not be ignored. A simple approach to determine the minimum amount of torsional reinforcement is discussed and confirmed by the test results to facilitate the design of torsion for HSC and NSC beams.

Composite structures made of structural steel and concrete maximize the advantages of the two components, especially, when using high strength materials. The interaction of the two materials is guaranteed by shear connectors. Experimental and numerical investigations at the Institute of Structural Concrete, RWTH Aachen University indicate that headed studs in high strength concrete (HSC) show a different behavior compared to those in normal strength concrete (NSC). Headed studs in HSC feature a high load carrying capacity coming along with a high initial stiffness but a reduced ductility. In order to improve the ductility various modifications have been applied to the studs (for example headed studs embedded in ultra-high performance concrete). Three-dimensional finite element simulations have been conducted to obtain an insight into the complex load carrying behavior. Based on a parametric study the influence of the concrete strength on the load carrying behavior has been investigated. This paper presents the experimental and numerical results. The different modifications applied to the shear connectors are judged from both design and economical points of view.