234R-06
Guide for the Use of Silica Fume in Concrete
2006, 63pp.
$85.50

This report describes the physical and chemical properties of silica fume; how silica fume interacts with portland cement; the effects of silica fume on the properties of fresh and hardened concrete; recent typical applicationsof silica-fume concrete; how silica-fume concrete is proportioned, specified,and handled in the field; and areas where additional research is needed.

Keywords: curing; durability; high-range water-reducing admixture; high-strength concrete; placing; plastic-shrinkage cracking; silica fume; time ofsetting; water-reducing admixture; workability.

Contents:

CONTENTS

Chapter 1—Introduction

1.1—General

1.2—What is silica fume?

1.3—Silica fume versus other forms of silica

1.4—Using silica fume in concrete

1.5—Using silica fume in blended cements

1.6—Worldwide availability of silica fume

1.7—Types of silica fume products available

1.8—Health hazards

1.9—Environmental impact

Chapter 2—Physical properties and chemical composition of silica fume

2.1—Color

2.2—Specific gravity

2.3—Bulk density

2.4—Fineness, particle shape, and oversize material

2.5—Chemical composition

2.6—Crystallinity

2.7—Variability

2.8—Relating physical and chemical properties to performance in concrete

2.9—Quality control

Chapter 3—Mechanisms by which silica fume modifies cement paste, mortar, and concrete,

3.1—General

3.2—Physical effects

3.3—Chemical effects

3.4—Microstructure modifications

3.5—Self-desiccation and water of hydration

3.6—Autogenous shrinkage (volume change)

3.7—Chemical composition of pore fluid

3.8—Reactions in combination with fly ash or groundgranulated blast-furnace slag

3.9—Reactions with different types of portland cements

3.10—Heat of hydration

3.11—Reactions with chemical admixtures

Chapter 4—Effects of silica fume on properties of fresh concrete

4.1—Water demand

4.2—Workability

4.3—Slump loss

4.4—Time of setting

4.5—Segregation

4.6—Bleeding and plastic shrinkage

4.7—Color of concrete

4.8—Air entrainment

4.9—Bulk density (unit weight) of fresh concrete

4.10—Evolution of hydrogen gas

Chapter 5—Effects of silica fume on properties of hardened concrete

5.1—General

5.2—Mechanical properties

5.3—Durability aspects

5.4—Miscellaneous properties

5.5—Use of silica fume in combination with fibers

5.6—Use of silica fume in ternary blends

5.7—Property variations with respect to type, source, and form of delivery of silica fume

Chapter 6—Applications of silica fume in concrete

6.1—Tsing Ma Bridge, Hong Kong

6.2—311 South Wacker Drive, Chicago

6.3—Kuala Lumpur City Center, Malaysia

6.4—Kinzua Dam Stilling Basin, United States

6.5—Stolma Bridge, Norway

6.6—Highway bridges, United States

6.7—Parking structures, United States

Chapter 7—Specifications

7.1—General

7.2—Specifying silica fume

7.3—Specifying silica-fume admixtures

7.4—Specifying silica-fume blended cement

7.5—Specifying silica-fume concrete

Chapter 8—Proportioning silica-fume concrete mixtures

8.1—General

8.2—Cement and silica fume content

8.3—Water content

8.4—Aggregate

8.5—Chemical admixtures

8.6—Proportioning

8.7—Ternary mixtures

Chapter 9—Working with silica fume in field concrete

9.1—Transporting and handling silica fume and silicafume admixture products

9.2—Producing concrete

9.3—Transporting

9.4—Placing

9.5—Finishing

9.6—Curing

9.7—Accelerated curing

Chapter 10—Research needs

10.1—Frost resistance

10.2—Scaling resistance

10.3—Sulfate attack

10.4—Drying shrinkage and creep

10 5—Steel corrosion

10.6—Long-term durability

10.7—Rheology of fresh concrete

10.8—Mechanism of strength development

10.9—Role of silica fume in special concretes

10.10—Effect of silica fume on hydration

10.11—Later-age cracking

Chapter 11—References

11.1—Referenced standards and reports

11.2—Cited references