A high-performance concrete may posses satisfactory performance in many aspects other than compressive strength. In the context of in situ strength development, the performance of concrete at an early age is important. The temperature development, resistance to thermal cracking, early age engineering properties, and in situ strength development may all play a significant role in insuring satisfactory long-term performance. Describes the engineering properties of some very high-strength and high-performance concretes containing blast furnace slag with compressive strengths in excess of 80 Mpa under simulated "in situ" conditions of restricted moist curing and high-hydration temperatures. The influence of blast furnace slag content and the implications of the in situ development of engineering properties on performance are discussed.

An experimental investigation was conducted on the shear behavior of deep beams made with steel fiber reinforced high performance concrete (HPC). Twenty-six beam specimens with various shear span-effective depth ratios, steel fiber contents, amounts of vertical and horizontal web reinforcements were tested under static loads. In addition to the strength test, extensive instrumentations were designed for the measurements of average strains of reinforced concrete in the shear span and strains of web reinforcements. The web-shear cracking initiated as the first inclined shear crack. About 30% increase in the inclined shear strength and 25% increase in the ultimate shear strength can be achieved with addition of 1 .O% steel fiber for specimens having a/d= 1 .5. The strain of vertical web reinforcements became negative and the horizontal web reinforcements were stretched to yield state for specimens having a/d ratios approach 0.5. The measured load-deformation relationships of reinforced concrete and strains of web reinforcements were compared with the prediction of the softened truss model of steel fiber reinforced concrete proposed by other investigators. Good correlation was found from the comparisons.

Basic studies were conducted to develop high-performance concrete, with low-heat and high-strength characteristics under low-temperature environments, using blast furnace slag. The purpose of this study was to clarify the effects of slag fineness, slag content, gypsum content, limestone-powder content, and high-range water-reducing admixtures (HRWRA) on the strength development, adiabatic temperature rise, porosity, amount of Ca(OH) 2, and carbonation of concrete; and the effect of curing temperature on concrete strength development. As a result of this study, it was found that it is possible to produce high-performance concrete with low heat and high strength under low-temperature environments, by properly combining, and taking into consideration, their respective properties, granulated blast furnace slag, HRWRA, and other admixtures.

Presents the results of an investigation on the long-term deformation of steel fiber reinforced concrete containing silica fume. The influence of loading ages on the creep and ages of curing on the shrinkage of specimens was investigated. The volume fraction of steel fibers used in concrete is 0, 1, and 2 percent. The addition of silica fume is 0, 5, and 10 percent by weight of cement. Test results indicate that the combined effect of fibers and silica fume reduces the creep and shrinkage and enhances the development of compressive strength of concrete. At specific silica fume content (10 percent), the effect of increasing fiber content to reduce creep and shrinkage decreases gradually as the fiber content increases. This phenomena is similar to the addition of silica fume in concrete with 1 percent volume fraction of steel fibers.

The Strategic Highway Research Program (SHRP) awarded a contract to North Carolina State University (NCSU) to investigate the use of high-performance concrete (HPC) in highway pavements and bridge structures. The goals of the project were threefold. First, a number of HPC mixtures were developed for highway applications. Second, laboratory testing of the HPC mixtures was conducted. Finally, a number of field test sites were constructed and monitored. Three different classes of HPC were established for this research. These are very early-strength (VES), high-early-strength (HES), and very high-strength (VHS) concrete. Two types of VES and VHS concrete were developed. The VES mixture was developed for use primarily as a rapid repair material where time is critical and cost is a lesser concern. The HES mixture was developed for bridge deck construction where deterioration due to freezing and thawing and steel corrosion is a major problem. The HES mixture can also be used for repair where cost is important and time is a lesser concern. The VHS mixture was developed for use in bridge structures where high-long-term strength is needed rather than rapid strength gain characteristics. Paper summarizes the development of the mixture proportions for the three classes of HPC. Included in the paper are the strength and serviceability requirements for the mixtures. Recommendations are made for adapting the HPC mixtures for local conditions.