ACI 221.1R 98:1998 Edition
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221.1R-98: Report on Alkali-Aggregate Reactivity (Reapproved 2008)
| Published By | Publication Date | Number of Pages |
| ACI | 1998 | 30 |
Information that is currently available on alkali-aggregate reactivity (AAR), including alkali-silica reactivity (ASR) and alkali-carbonate reactivity (ACR) is summarized in the report. Chapters are included that provide an overview of the nature of ASR and ACR reactions, means to avoid the deleterious effects of each reaction, methods of testing for potential expansion of aggregates and cement-aggregate combinations, measures to prevent deleterious reactions, and recommendations for evaluation and repair of existing structures. Keywords: aggregates; alkali-aggregate reactivity; alkali-carbonate reactivity; alkali-silica reactivity; concrete; concrete distress; concrete durability.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | CONTENTS |
| 2 | CHAPTER 1— INTRODUCTION 1.1—Historical perspective 1.1.1 Alkali-silica reactivity |
| 3 | 1.1.2 Alkali-carbonate reactivity 1.2—Scope of report CHAPTER 2— MANIFESTATIONS OF DISTRESS DUE TO ALKALI- SILICA REACTIVITY 2.1— Introduction 2.2—Cracking mechanisms |
| 4 | 2.3—Expansion and other indicators of alkali- silica reactivity |
| 5 | 2.4—Alkali-silica reactivity reaction factors |
| 6 | 2.5—Microscopic evidence of alkali-silica reactivity CHAPTER 3— ALKALI-SILICA REACTIVITY MECHANISMS 3.1— Factors influencing the reaction 3.1.1 Cement alkali levels |
| 7 | 3.1.2 Moisture 3.1.3 Reactive silica 3.1.4 Temperature 3.2—Basic mechanisms of reaction and expansion |
| 8 | CHAPTER 4— PETROGRAPHY OF ALKALI-SILICA REACTIVE AGGREGATE 4.1—Introduction 4.2—Potentially reactive natural silica constituents 4.2.1 Opal 4.2.2 Chalcedony 4.2.3 Quartz 4.2.4 Cristobalite |
| 9 | 4.2.5 Tridymite 4.2.6 Volcanic glasses 4.2.7 Chert 4.2.8 Volcanic rocks 4.2.9 Argillites, meta-graywackes, phyllites, and slates 4.3—Potentially reactive synthetic materials 4.3.1 Silica brick 4.3.2 Synthetic glasses 4.3.3 Coatings CHAPTER 5— MEASURES TO PREVENT ALKALI- SILICA REACTIVITY 5.1— Overview |
| 10 | 5.2—Limiting moisture 5.3—Aggregate selection |
| 11 | 5.4—Minimizing alkalies 5.5—Cement selection 5.6—Finely divided materials other than portland cement |
| 12 | 5.6.1 Fly ash 5.6.2 Ground granulated iron blast-furnace slag 5.6.3 Natural pozzolans |
| 13 | 5.6.4 Silica fume 5.6.5 Blended hydraulic cements 5.7—Testing for effectiveness of pozzolans or slags 5.8—Alkali content of concrete 5.9—Chemical admixtures |
| 14 | 5.10—Other methods CHAPTER 6— METHODS TO EVALUATE POTENTIAL FOR EXPANSIVE ALKALI- SILICA REACTIVITY 6.1— Introduction 6.2—Field service record 6.3—Common tests to evaluate potential alkali- silica reactivity of aggregates 6.3.1 Petrographic examination of aggregate |
| 15 | 6.3.2 Mortar-bar expansion test 6.3.3 Accelerated mortar-bar expansion test |
| 16 | 6.3.4 Quick chemical method 6.3.5 Concrete prism test |
| 17 | 6.4—Less common tests to evaluate potential alkali- silica reactivity of aggregates 6.4.1 Potential volume change of cement-aggregatecombinations 6.4.2 U.S. Army Corps of Engineers modified mortar bartest 6.4.3 Concrete cube test 6.4.4 Nordtest accelerated alkali-silica reactivity test |
| 18 | 6.4.5 Gel pat test 6.4.6 Autoclave mortar bar test 6.5—Tests to evaluate alkali-silica reactivity in hardened concrete 6.5.1 Uranyl acetate gel fluorescence test 6.5.2 Methods of evaluation of the state of alkali-silicareactivity in hardened concrete |
| 19 | 6.6—Summary of testing CHAPTER 7— MANIFESTATIONS OF DISTRESS DUE TO ALKALI- CARBONATE REACTIVITY 7.1— Overview 7.2—Field indicators 7.3—Microscopic indicators |
| 20 | 7.4—Role of environment, structure geometry, and restraint on distress development CHAPTER 8— ALKALI-CARBONATE REACTIVITY MECHANISMS 8.1— Overview 8.2—Characteristics of alkali-carbonate reactive rocks 8.2.1 Texture and composition |
| 21 | 8.3—Mechanism of reaction and expansion |
| 22 | CHAPTER 9— MEASURES TO PREVENT ALKALI-CARBONATE REACTIVITY 9.1— Introduction 9.2—Aggregate selection 9.3—Cement 9.4—Pozzolans 9.5—Moisture CHAPTER 10— METHODS TO EVALUATE POTENTIAL FOR EXPANSIVE ALKALI- CARBONATE REACTIVITY 10.1— Introduction 10.2—Field service record |
| 23 | 10.2.1 Factors to consider 10.2.1.1 Aggregate particle size 10.2.1.2 Aggregate proportion 10.2.1.3 Alkali content 10.2.1.4 Moisture content 10.3—Petrographic examination 10.4—Rock cylinder test 10.5—Concrete prism tests |
| 24 | 10.6—Other procedures 10.7—Evaluation of new aggregate sources CHAPTER 11— EVALUATION AND REPAIR OF STRUCTURES AFFECTED BY ALKALI- AGGREGATE REACTIVITY 11.1—Introduction |
| 25 | 11.2—Evaluation 11.3—Repair methods and materials 11.3.1 Structural distress 11.3.2 Non-structural distress |
| 26 | CHAPTER 12— REFERENCES 12.1— Referenced standards and reports 12.2—Cited references |
