International Concrete Abstracts Portal

This CD-ROM contains eight papers that provide insight on recent slag cement concrete developments in academia, the concrete industry, and in real life applications of slag cement concrete. Topics include materials aspects related to the benefits of adding slag in concrete to prevent alkali-silica reactions, reducing drying shrinkage, and reducing the potential for thermal cracking during the curing period. Also covered are high-volume applications of slag cement in: concrete for transportation structures, high-performance concrete pavements, mass concrete, and high-density concrete. 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-263

Slag cement was introduced to Virginia Department of Transportation (VDOT) in the early 1980s. Laboratory investigations showed that slag cements can be used as an alternative to conventional portland cement concretes in replacement rates up to 50% for pavements and bridge structures. Concrete containing slag cement had lower permeability than the conventional portland cement concrete. Since the mid 1980s, slag cement has been successfully used by VDOT in bridge structures and pavements to reduce permeability and improve the durability of concrete. In large footings, slag cement has been used at a replacement rate of 75% to control the temperature rise and to reduce permeability. Currently, slag cement is used in high-performance concretes to obtain high compressive strength and low permeability. Slag cement is also used in ternary blends with portland cement and fly ash or silica fume to lower permeability, improve durability, and obtain the desired early strengths.

The Federal Highway Administration (FHWA) under its Testing and Evaluation program (TE-30) on High-Performance Concrete (HPC) pavements had initiated several field demonstration projects to evaluate the use of new technology to improve the long-term performance of the pavements. Under this program, the Minnesota Department of Transportation (Mn/DOT) has successfully completed the construction of the first 60-year design life HPC pavement in the state along Interstate I-35W. Significant changes to materials-related specifications that affect the long-term performance of the concrete pavement were implemented in this project. This paper will provide a brief description of the Mn/DOT’s first HPC pavement project along with key design features of the pavement, including use of slag cement in high-performance concrete mixtures, higher level of entrained air content than that is conventionally used, and stainless steel dowel bars. Also, the results of quality control tests conducted on field concrete during construction are presented.

To investigate the relationship between the alkali content of concrete and the expansion caused by alkali-silica reaction, several hundred concrete prisms containing reactive natural aggregate, were regularly measured over a period of ten years. These prisms contained between 0 and 70% slag cement in combination with portland cements, and had concrete alkali contents between 4.5 and 11 kg/m3 (0.3 and 0.7 lb/ft3). The alkali content of the Portland cements ranged from 0.54 to 1.15% and that of the slag cements from 0.58 to 0.83%. Prisms were moist-stored at 20°C (68 °F) and at 38°C (100°F). Storage at the higher temperature accelerated the rate of expansion, and slightly increased the ultimate expansion. The correlation between the two temperatures was very good in terms of classifying mixtures as either ‘expanding’ or ‘non-expanding’. It is concluded that storage at 38°C (100°F) is an accelerated test that can be used to reliably predict what would happen at ‘normal’ temperature. The mixtures containing slag cement, tolerated much greater alkali contents in the concrete, without expansion. This effect was more pronounced for higher proportions of slag cement.

This paper is a collection of over 30 brief case studies about mass-concrete projects using ASTM C989 (AASHTO M302), or similar, slag cement (formerly called ground granulated blast-furnace slag) - undertaken to learn more about concrete mixtures and considerations as they are applied in the field. With the exception of some ternary mixes, generally, the slag cement amounts equaled or exceeded the amounts of Portland cement employed in the mixtures. The information showed that a broad spectrum of proportions featuring slag cement of all grades have been used to achieve desired mass-concrete properties and outcome, including staying under a maximum core temperature, holding within a maximum differential temperature, and achieving specified strength.