State-of-the-Art Report on High-Strength, High-Durability

0,97
MB Structural Low-Density Concrete for Applications in Severe

119
stron Marine Environments

5018
ID University of New Brunswick

2004
rok

Contents

Preface viii

1—Introduction . 1

2—History. 5

Natural Deposits of Low-Density Aggregates Used for the Port of Cosa in 273 B.C. . 5

Pantheon Dome. 5

The Origin of Manufactured Low-Density Aggregates . 6

Concrete Ships 7

High-Rise Construction 7

Energy-Related Offshore Structures 7

3—Properties of Structural-Grade Low-Density Aggregate 9

Internal Structure of Low-Density Aggregates 9

Particle Shape and Surface Texture . 9

Particle Density. 9

Bulk Density of Low-Density Aggregates . 10

Total Porosity . 10

Grading. 11

Absorption Characteristics . 11

Modulus of Elasticity of Low-Density Aggregate Particles 12

4—Classification of Low-Density Concrete. 14

Structural-Grade Low-Density Aggregate Concrete 15

High-Strength, Low-Density Concrete. 17

Specified-Density Concrete 18

5—Engineering Properties of Structural Low-Density Concrete . 19

Density 19

Equilibrium Density . 20

Compressive Strength. 21

Shear and Tensile Strength. 29

Modulus of Elasticity . 31

Poisson's Ratio . 32'

Maximum Strain Capacity . 32

Abrasion Resistance . 33

Shrinkage 34

Creep. 36

Bond Strength and Development Length . 37

Thermal Expansion. 38

Specific Heat. 39

Thermal Diffusivity 40

Thermal Conductivity. 41

Fire Resistance 45

Seawater Absorption 47

Ductility 48

Fatigue of Low-Density Concrete 49

6—Durability 53

Performance Record . 53

Resistance to Freezing and Thawing 54

Resistance to Sulfate Attack. 55

Resistance to Alkali-Aggregate Reaction. 55

Carbonation 56

Measurements of Carbonation Depth in Mature Marine Structures 56

Recommendations to Limit Rate of Carbonation. 60

Permeability and Corrosion Protection 60

Influence of Contact Zone on Durability 63

Long-Term Field Studies 67

7—Constructibility Considerations 68

Production of Low-Density Aggregate Concrete . 68

Materials for High-Strength Low-Density Aggregate Concrete 69

Proportioning of Concrete Mixtures 73

Mixing, Placing, Finishing, and Curing . 75

Pumping 76

Testing 78

8—Applications 80

Applications of High-Strength Low-Density Concrete 80

Marine Structures . 85

9—Economics, Material Costs, Transportation, and Environmental Considerations 90

Structural Efficiency of Low-Density Concrete. 90

Material Costs 91

Transportation Costs 91

Environmental Considerations . 92

10—Conclusions . 94

References . 95

Appendix A: Structural Low-Density Concrete Guide Specifications .A1