混凝土中硅灰使用指南

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The page contains a table of contents (red text) and the beginning of "CHAPTER 1—INTRODUCTION" (black text).

The layout is two columns.

I need to follow the strict constraints:

- Allowed tags: p, h2, h3, h4, h5, strong, em, b, i, u, s, sup, sub, table, caption, thead, tbody, tfoot, tr, td, th, ol, ul, li, blockquote, span, pre, code, hr, br

- Allowed classes: align-center, align-right, indent, small-note, layout-columns, formula

- No style attributes.

- No , tabs, multiple spaces.

- No Markdown fences.

- No forbidden tags (h1, div, section, etc.).

- No attributes on ol/ul/li.

- Only td/th can have rowspan/colspan.

- Must start with

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- Use

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- Ignore headers/footers/page numbers.

Let's analyze the layout:

Left column:

3.6—Heat of hydration

3.7—Reactions with chemical admixtures

Chapter 4—Effects of silica fume on properties of fresh concrete, p. 234R-13

4.1—Water demand

...

Chapter 8—Specifications, p. 234R-33

8.1—General

8.2—Specifying silica fume

8.3—Specifying silica-fume admixtures

Right column:

8.4—Specifying silica-fume concrete

Chapter 9—Working with silica fume in field concrete, p. 234R-36

9.1—Transporting and handling silica fume and silica-fume admixture products

...

Chapter 11—References, p. 234R-41

11.1—Recommended references

11.2—Cited references

CHAPTER 1—INTRODUCTION

1.1—General

In recent years significant attention has been given to the use of the pozzolan silica fume as a concrete property-enhancing material, as a partial replacement for portland cement, or both. Silica fume has also been referred to as silica dust, condensed silica fume, microsilica, and fumed silica (this last term is particularly incorrect - see Section 1.3). The most appropriate term is silica fume (ACI 116R).

The initial interest in the use of silica fume was mainly caused by the strict enforcement of air-pollution control measures in various countries to stop release of the material into the atmosphere. More recently, the availability of high-range water-reducing admixtures (HRWRA) has opened up new possibilities for the use of silica fume as part of the cementing material in concrete to produce very high strengths or very high levels of durability or both.

Investigations of the performance of silica fume in concrete began in the Scandinavian countries, particularly in Iceland, Norway, and Sweden, with the first paper being published by Bernhardt in 1952. Other early Scandinavian papers included those by Fiskaa, Hansen, and Moum (1971), Traetteberg (1977), Jahr (1981), Asgeirsson and Gudmundson (1979), Loland (1981), and Gjørv and Loland (1982). In 1976 a Norwegian standard permitted the use of silica fume

Wait, the two columns are not perfectly aligned. The left column has Chapters 3 (partial), 4, 5, 6, 7, 8 (partial). The right column has 8.4, Chapter 9, 10, 11, and then Chapter 1 Introduction.

Actually, it's a two-column layout for the whole page.

Left column:

3.6—Heat of hydration

3.7—Reactions with chemical admixtures

Chapter 4—Effects of silica fume on properties of fresh concrete, p. 234R-13

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—Unit weight (mass) of fresh concrete

4.10—Evolution of hydrogen gas

Chapter 5—Effects of silica fume on properties of hardened concrete, p. 234R-14

5.1—Microstructure modification

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 conjunction with fly ash

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

Chapter 6—Applications of silica fume, p. 234R-27

6.1—Introduction

6.2—Abrasion resistance

6.3—Alkali-silica reaction

6.4—Cement replacement

6.5—Heat reduction

6.6—Chemical attack resistance

6.7—Corrosion resistance

6.8—Grout

6.9—High early-strength concrete

6.10—High-strength concrete

6.11—Lightweight concrete

6.12—Offshore and marine structures

6.13—Overlays and pavements

6.14—Shotcrete

6.15—Underwater concrete

6.16—Waste isolation

Chapter 7—Proportioning silica-fume concrete, p. 234R-32

7.1—General

7.2—Cement and silica-fume content

7.3—Water content

7.4—Aggregate

7.5—Chemical admixtures

7.6—Proportioning

Chapter 8—Specifications, p. 234R-33

8.1—General

8.2—Specifying silica fume

8.3—Specifying silica-fume admixtures

Right column:

8.4—Specifying silica-fume concrete

Chapter 9—Working with silica fume in field concrete, p. 234R-36

9.1—Transporting and handling silica fume and silica-fume 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, p. 234R-39

10.1—Frost resistance

10.2—Sulfate attack

10.3—Drying shrinkage and creep

10.4—Steel corrosion

10.5—Performance under high-temperature conditions

10.6—Long-term durability

10.7—Pore structure and permeability

10.8—Rheology and setting properties

10.9—Mechanism of strength development

10.10—Role of silica fume in special concretes

10.11—Effect of silica fume on hydration

10.12—Curing

10.13—Recommended field practice

Chapter 11—References, p. 234R-41

11.1—Recommended references

11.2—Cited references

CHAPTER 1—INTRODUCTION

1.1—General

In recent years significant attention has been given to the use of the pozzolan silica fume as a concrete property-enhancing material, as a partial replacement for portland cement, or both. Silica fume has also been referred to as silica dust, condensed silica fume, microsilica, and fumed silica (this last term is particularly incorrect - see Section 1.3). The most appropriate term is silica fume (ACI 116R).

The initial interest in the use of silica fume was mainly caused by the strict enforcement of air-pollution control measures in various countries to stop release of the material into the atmosphere. More recently, the availability of high-range water-reducing admixtures (HRWRA) has opened up new possibilities for the use of silica fume as part of the cementing material in concrete to produce very high strengths or very high levels of durability or both.

Investigations of the performance of silica fume in concrete began in the Scandinavian countries, particularly in Iceland, Norway, and Sweden, with the first paper being published by Bernhardt in 1952. Other early Scandinavian papers included those by Fiskaa, Hansen, and Moum (1971), Traetteberg (1977), Jahr (1981), Asgeirsson and Gudmundson (1979), Loland (1981), and Gjørv and Loland (1982). In 1976 a Norwegian standard permitted the use of silica fume

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