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yellow pavement stripe on black background		 AASHTO Innovative Highway Technologies Alkali-Silica Reactivity

Transition Plan for AASHTO
May 2000

APPENDIX G
FHWA- ACI CONCRETE DURABILITY WORKSHOPS PROJECT
ASR AND OTHER DETERIORATION MECHANISMS

Program Blocks

Instructors:
E - Engineer / Materials Technologist, Concrete Materials and Mixture Experience
P - Petrographer / Geologist, Experience Investigating ASR and Other Deterioration
L - Local / Regional Expert on Deterioration Mechanisms in the Area

Texts Listed by T-#:
1. T-1 -- Notebook Binder Updated for AAR and Other Deterioration Mechanisms

  1. Table of Contents
  2. Syllabus
  3. Print-out of PowerPoint slides and notes (3 to a page)
  4. Copies of Standards That Will Be Referenced in the Workshop (Other than the ones included in separate texts.)
  5. Other miscellaneous required references, worksheets, or updates to publications that need to be Xeroxed, such as alternative specifications: VA, NM, CSA, C 33 Appx.

2. T-2 -- Handbook for the Identification of Alkali-Silica Reactivity in Highway Structures. Publication SHRP-C-315, 1991, Reprinted 1994 by FHWA, and currently for sale by TRB. It is proposed that this handbook be used as now published with reference to the Addendum providing additional text information as given in the Revised Edition on the web site of the AASHTO Lead States Team on ASR. See T-9 below.

3. T-3 -- Manual on Rock and Mineral Identification for Engineers, 1991, FHWA Publication No. FHWA-HI-91-025

4. T-4 --ACI 221.1R-98, State of the Art Report on Alkali-Aggregate Reactivity, Reported by ACI Committee 221 on Aggregates, American Concrete Institute, 1998, 31 pages.

5. T-5 -- ACI 201.2R-92 Guide to Durable Concrete, Reported by ACI Committee 201 on Durability, American Concrete Institute, 1992, 39 pages. (T-5a -- revision to provide updated sections on Chemical Sulfate Attack and on Physical Salt Attack in final review stages by ACI.)

6. T-6 -- Concrete Information on Diagnosis and Control of Alkali-Aggregate Reactions in Concrete, by James A. Farny and Steven H. Kosmatka, PCA, with the Endorsement by ACPA, NAA, and NRMCA, Portland Cement Association, Publication IS 413.01T, 1997, 24 pages.

7. T-7 -- Concrete Information -- Guide Specification for Concrete Subject to Alkali-Silica Reactions, Published by PCA with the Endorsement by ACPA, Developed by the Durability Subcommittee, Portland Cement Association, Publication IS 415.06T, 1998, 8 pages.

8. T-8 -- American Coal Ash Association, Fly Ash Facts for Highway Engineers, Federal Highway Administration, FHWA SA-94-081, 1995, 70 pages

9. T-9 -- AASHTO Lead States Team on ASR, Proposed AASHTO Guide Specification for Highway Construction, Section on Portland Cement Concrete Resistant to Excessive Expansion Caused by Alkali-Silica Reaction, FHWA Focus, October, 1999, and the Web Site 'leadstates.tamu.edu/ASR/library/gspec.stm', at Texas A&M University, October, 1999.

10. T-10 -- TRB Circular 494, Durability of Concrete, Transportation Research Board, Section on Concrete (A2E00), December 1999, 60 pages.

Workshop Schedule -- Day 1

Introduction (30 min.)
Objective: Provide background, scope, and purpose for the workshop

  • Host DOT Welcome, Instructors
    • Workshop Schedule, Notebook Binder, and Nine Texts (Listed Above)
  • FHWI-ACI Cooperative Agreement - DOT, FHWA, ACI
    • Communicate the Technology for More Durable Concrete
  • Damage, Money Loss Caused by Premature Deterioration, Life Cycle Costs, E
    • Cost/Benefit, Asset Management
  • Include All Segments of the Highway Construction Industry in Workshop, E
    • DOT's, Local Agencies, Material Suppliers, Contractors, Laboratories
  • Two Tracks - Brief Review of Covered Topics and Methods to Identify, Mitigate, and Prevent AAR and Other Deterioration Mechanisms
    1. AAR is Alkali Aggregate Reactivity. It includes ASR, Alkali Silica Reactivity which is more common, and ACR, Alkali Carbonate Reactivity that is rare, confined to a few areas
    2. Other Durability Concerns that Influence Material Selection and Proportioning Freezing and Thawing, Deicer Scaling, Sulfate Attack (Internal, External), Physical Salt Attack, Corrosion of Steel in Concrete, and the magnitude of Volume Changes - Drying Shrinkage and Thermal Expansion.
  • Historical Perspective of ASR and the SHRP Research Accomplished

Executive Summary (60 min.)
Objective: Provide for top people a summary of the state-of-the-art technology reviewed in the workshop and resources available to help owners, specifiers, laboratories, and consultants reevaluate and update the methods they use to investigate concrete deterioration and to specify durability and assure service in future construction and repairs.

Texts - T-1, T-2, T-5, T-6, T-9, T-10

  • Framework to Identify Existing Concrete Deterioration Mechanisms, E
    • Consider Pavements and Structures -- Bridge Decks, including Walls, Columns.
    • Use Observation, Date Records, and Petrography to Identify Mechanism(s)
    • Find Out What the Problem is Not, and What it Might be.
    • Were the Specifications Wrong for the Application and Exposure, Or
    • Were the Specifications not Followed?
  • Design for Durability, Assessment of Risks, E
    • Do not just use a fixed cement content or just more cement.
    • Use properly other cementitious materials, blended cement, and admixtures.
    • Consider Exposure for the concrete as well as Construction Methods and Structural needs.
    • Do not use the terms 'cement replacement' for other cementitious materials, blended cement, and admixtures
    • Install a Quality Concrete System to address durability improvements of both ordinary and HPC - Learn what is needed for durable concrete in the various exposure conditions unique to areas in your state.
    • TG B on Durability of ACI TAC HPC (Steve Forster, Chair)
      • Definition of HPC
      • Categories of HPC
  • Mitigation, E
    • The best mitigation is applied during design and construction.
    • But there are some things that can be done to slow deterioration once it has begun.
  • Description of ASR and the Conditions Under Which it Can Shorten Service Life, P
  • Samples of the Use of Petrographic Tools to Identify ASR, and to Distinguish it from Other Deterioration Mechanisms, P
  • Alternatives to Provide the Necessary Professional, Laboratory, and Petrographic Resources to Properly Address PC Concrete Durability Issues, P
  • Communication for Durability through Specifications and Inspection

Deterioration Mechanisms (120 min.)
Objective: Provide instruction and resources for the understanding of how these forms of deterioration develop, and how they damage concrete, and how they can be identified with certainty. (Particular emphasis in this session on ASR and ACR. Also the brief introduction of the other mechanisms that will be covered later.)

  • ASR - Explanation of Alkali-Silica Reaction in Concrete and its Identification (60 min.), P
    Texts - T-1, T-2, T-4, T-6
  • ACR - Explanation of Alkali-Carbonate Reaction in Concrete and its Identification as Distinguished from ASR. (Since ACR will not be given much additional time in the workshop, mitigation and prevention of ACR should also be covered here.) (30 min.), P
    Texts - T-1, T-4
  • Introduce Others Mechanisms Briefly, Along with the Inter-Relationship of Mechanisms Often Found in Deteriorating Concrete - (30 min.), E
    Texts - T-1, T-5, T-5a, T-10
    Freezing and Thawing,
    Chemical Sulfate Attack,
    Physical Salt Attack (Various Soluble Salts, Including Sulfates),
    Delayed Ettringite Formation (DEF),
    Corrosion of Rebar, Material from ACI 222
    Drying Shrinkage, Ref?
    Thermal Volume Change, Ref?

Petrography (30 min.), P
Objective: Provide a basic introduction to petrography and its use in improving the durability of concrete and aggregates. Show how the geologist and petrographer can work with highway engineers and technologists to understand mechanisms of deterioration exhibited in the field and to formulate improved specifications and qualification criteria for aggregates and mixtures.

Texts - T-1, T-2, T-3, T-6, T-10

  • Importance of Petrography
  • Introduction to Petrography Standards and Equipment
    • ASTM Practices in Binder
  • Example Case Study Showing the Progression of Field and Laboratory Techniques
    • See list of potential case studies in the agenda.
  • Review of Tools - Stereomicroscope, Petrographic Microscope, and Electron Microscope
    • Petrographic Manual on-line at TF FHWA Lab (TFHRC)

Lunch Break

Rocks and Minerals Hands-on Exercise (30 min.), P
Objective: To reinforce among highway engineers and technologists that these resources are available. Also, they should learn the basics of geology and remember to call upon professionals in these areas when they see deterioration of concrete in the field, or when new, untried aggregates are to be used in a project.

Texts - T-1, T-2, T-3, ASTM Practices

  • Exercise to Identify Some Rock and Mineral Samples Using Published Resources, With Concentration on Those Involved in ASR.
  • Resources on the Web:
    • USGS
    • Minerals Data Base Sites
    • NIST
    • FHWA, Petrography Manual

Identification of Cause of Deterioration - Tools, Indicators (30 min.)
Objective: Use of a check list or decision tree approach to investigate deteriorated concrete both in the field and in the laboratory to identify the cause, or causes of deterioration, with particular emphasis on ASR and how combinations of other mechanisms may interact.

Texts - T-1, T-2, T-3, ASTM Practices

  • Cracks, and Crack Patterns, Measuring and Monitoring Cracks, E
    • Distinguish between large scale cracking (shrinkage and thermal) indicating movement of blocks of concrete and smaller scale cracking indicating internal deterioration and internal volume change.
  • Volume Change Patterns, Monitoring Volume Change with Time, E
  • Spalls, Surface Scaling, Pop-Outs, E
  • Sampling Techniques for Observation and Petrographic Evaluation, E and P
  • Deposits, Exudations, P

Is there a decision tree, flow chart we can use? Or do we need to construct one?

Reference to SHRP-P-338 Distress Identification Manual for the LTPP Project (Pavement)

See Chris Rogers Ontario MOT Form for "Petrographic Examination of Hardened Concrete"

Internal Distress Mechanisms -- Freeze-Thaw, Sulfate Attack, DEF, and Corrosion of Rebar (120 min.)
Objective: To cover the technology for identification, mitigation, and prevention of these non-AAR deterioration mechanisms. Typical test methods, specification provisions, and aggregate and concrete properties will be addressed.

Texts - T-1, T-5, T-5a, T-10

  • Freezing-Thawing -
    1. Coarse Aggregate, D-cracking;
    2. Mortar, A/E, and Paste (60 min.), E
  • Deicer Scaling
  • Corrosion of Rebar (20 min.), E
  • Chemical Sulfate Attack (20 min.), P
  • DEF (20 min.), P

Regional/Local Issues (60 min.), L
Objective: To have a local expert or researchers review the types of durability issues and failures that have occurred in local and/or regional concrete pavements and structures. It is important to have as complete information as possible as to field case studies, along with laboratory and petrographic data to show the applicability of durability considerations in the region. Methods of identification, mitigation, and prevention should be addressed. (Preferably a PowerPoint Presentation that can be loaded on the computer used for the workshop.)

  • Types of Deterioration
  • Samples and Pictures
  • Methods of Identification, Mitigation, and Prevention Used
  • Case Studies
  • Recommendations

End of Day 1

Workshop -- Day 2

Other Mechanisms - Drying Shrinkage, Thermal Volume Change, Physical Salt Attack (90 min.)
Objective: To cover the technology for identification, mitigation, and prevention of these mechanisms as a cause of deterioration. Typical test methods, specification provisions, and aggregate and concrete properties will be addressed.

Texts - T-1, T-5, T-5a, T-10

  • Drying Shrinkage (30 min.), Additional references?
  • Thermal Volume Change (30 min.), Additional references?
  • Physical Salt Attack (30 min.), Recent ACI literature

Designing and Specifying Durable Concrete (90 min.), E
Objective: Alternative approaches to give durability considerations a high priority in the design, specification, construction, and maintenance of concrete pavements and structures. Balancing strength requirements with durability and permeability requirements.

Texts - T-1, T-4, T-4, T-7, T-8, T-9, T-10 and other specification options
for ASR.

  • Design for Durability (30 min.)
  • Assessment of Risks (30 min.)
  • What cementitious Materials are Economically Available in Your Area.
  • Decision Tree for Performance Concrete (30 min.)
    • We have one for ASR from the Lead States and other publications.
    • Are there others that include the other mechanisms?

Aggregate Source Evaluation and Qualification (60 min.), P
Objective: To review the alternatives to qualify aggregates for different types of highway and transportation construction - both for new or changed aggregate resources with no service record, and for existing sources where detailed field service evaluations can be a valuable tool in the improvement of concrete durability.

  • Evaluation of New Aggregate Resources (20 min.)
  • Service Record of Existing Aggregates and Mixtures (20 min.)
  • Special Aggregate Tests that are Useful for Different Climate Areas.

Lunch Break

Samples of Various Deterioration, Hands-on Exercise (30 min.), P
Objective: To reinforce among highway engineers and technologists the importance of detailed examination of suspected cases of deterioration in the field. The objective is to gather credible information about the mechanisms involved so that the durability of future construction can be improved. Also, in some cases mitigation measures can be applied to existing concrete.

  • Exercise to Look at Hand Samples, and Sides from Microscopy Used in Investigations.
    • Slides on Computer or Web for Viewing?
  • Uranyl Acetate-UV light AASHTO T 299 Method to Identify Possible ASR Gel
    • Have a few Pre-Treated Specimens for Observation with the UV Light
  • Will it be Useful to Have a Microscope in the Back of the Room with Samples of ASR, ACR, and Freeze-Thaw Deterioration?
  • Include an Exercise with the ASR DetectTM system developed at Los Alamos.

Methods for Mitigation of ASR (60 min.), E
Objective: To review the proven and experimental methods that can be used to reduce or eliminate the incidence of deleterious ASR in concrete used in highway and transportation concrete.

Reference ASR Texts and Recent Research

  • In Existing Concrete, To Slow the Deterioration (15 min.)
    • Dry the Concrete, Apply Lithium, Confine the Concrete (Post-Tension?)
  • The Use of Lithium Products (15 min.)
  • In New Concrete, To Insure Against Damage (15 min.)
  • The Use of Blends with Fly Ash, Ground Slag, Silica Fume, and Other Products (15 min.)

Specifications, Tests, and Laboratory Evaluation Techniques (120 min.)
Objective: To review the test methods and specifications that are now on the books, or have been proposed for use by agencies and specifiers to assure durable concrete construction.

  • Specification Options - AASHTO, CSA, ASTM (30 min.), E
  • Tests of Aggregates (30 min.), P
  • Test of Mixtures (30 min.), E
  • Inspection Methods and Management of Pavement and Structures (30 min.), E
  • Communication for Durability

Summation and Question Period (30 min.), E, P, and L

  • Suggestions for the Application of the Technology Covered in the Workshop
  • Questions and Comments from Participants
  • Evaluation of the Workshop, Suggestions for Future Workshops

End of Workshop

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See also the web site for the AASHTO Technology Implementation Group