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.

Overlay systems have been used by many states for the protection of bridge decks, but the premature delaminations and failures have been observed in many cases. A comprehensive study was recently defined to investigate overlay performance in collaboration with the West Virginia Department of Transportation-Division of Highways (WVDOH). As part of a comprehensive program, the present study is concerned with the properties of four types of overlay mixtures and the interface bond strengths between the overlays and substrate concrete. All the materials used are of interests to WVDOH. Four overlay types were: silica fume modified concrete, latex modified concrete, fiber reinforced concrete and slag modified concrete. With these overlays, statistical design of experiments were conducted for the evaluation of the influences on bond strength of four factors: aggregate types, surface preparations, use of bonding slurry, and substrate age using a recently developed direct shear test apparatus. Results show that except for bonding slurry, all the parameters had strong influence on shear bond strength. The results of this study will serve the purpose of screening and selection of overlays from a large number of variables, and will finally help to develop guidelines by WVDOH for future implementations of concrete overlays in the field.

This paper presents an experimental study on a high-performance concrete (HPC) bridge in Tennessee. The bridge is a twin-bridge with high-strength concrete (HSC) beams in one bridge lane and normal-strength concrete (NSC) beams in the other lane. The compressive strength of HPC and NSC were 89 MPa and 48 MPa, respectively. The bridge was instrumented for concrete strains and temperatures of precast beams, cast-in-place decks and diaphragms. The cambers of prestressed beams were also measured during various construction stages. Test results presented in the paper include material properties of concretes, temperature changes in concrete, time-dependent strains of precast HSC and NSC beams, cambers of HSC and NSC beams, and strain changes of deck and diaphragm. A comparison study was conducted for the performance differences between the HSC and NSC bridge members. It was observed that the HSC members exhibited rapidly developed early-age creep and shrinkage strains, rapidly developed time-dependent cambers, and obvious differential shrinkage with deck concrete compared to the NSC members. The recommendations for design and construction of HSC bridges are also presented in the paper.

The Montana Department of Transportation (MDT) is performing research to develop a cost-effective, indigenous high-performance concrete (HPC) for use in bridge deck applications. The investigation was divided into two tasks: 1) identification of the optimum cementitious matrix for the HPC and 2) evaluation of the performance of this matrix in combination with aggregates readily available in Montana. The work focused on the use of binary, ternary, and quaternary blends of portland cement with fly ash (Class C and F), slag, calcined clay, metakaolin, and silica fume, in combination with Yellowstone River and Western Montana aggregate sources. Testing included plastic properties, setting characteristics, air-void system parameters, electrical conductivity, strength, chloride diffusion, freezing and thawing resistance, scaling resistance, and drying shrinkage. The paper discusses the process required to test and implement HPC specifically for bridge deck applications and presents the test results for this MDT study. The supplementary cementitious material combinations that produced the best performance were silica fume alone, silica fume and slag, Class F fly ash, silica fume and slag-blended cement, and silica fume and calcined clay-blended cement. The importance of raw material testing and the practical reproducibility of the concrete mixture are also considered.

In the mid-1990s, in cooperation with the Federal Highway Administration, the Virginia Department of Transportation (VDOT) initiated the high-performance concrete (HPC) program. Prior to that time, many improvements had been made in design, materials, and construction practices in VDOT, establishing the needed foundation for the HPC program. Initially, the HPC program entailed work with normal weight aggregates and included high strength, low permeability, and heat control. Afterward, work was started on lightweight HPC with high strength and low permeability. The first LWHPC bridge was constructed in 2001. VDOT also evaluated another characteristic of HPC: high workability. In 2001, VDOT used self-consolidating concrete (SCC) in an arch bridge. This concrete had very high flow characteristics, enabling consolidation without mechanical vibration. VDOT is currently studying the performance of SCC in Bulb-T beams. HPC efforts have led VDOT to investigate ultra-HPC fiber-reinforced concrete in Bulb-T beams with no conventional mild steel reinforcement, very high compressive strength, and negligible permeability.