RILEM State-of-the-Art Reports Bruno Godart Mario de Rooij Jonathan G.M. Wood Editors Guide to Diagnosis and Appraisal of AAR Damage to Concrete in Structures Part 1 Diagnosis (AAR 6.1) RILEM State-of-the-Art Reports Volume 12 RILEM,TheInternationalUnionofLaboratoriesandExpertsinConstructionMa- terials, Systems and Structures,foundedin 1947,is a non-governmentalscientific associationwhosegoalistocontributetoprogressintheconstructionsciences,tech- niquesandindustries,essentiallybymeansofthecommunicationitfostersbetween researchandpractice.RILEM’sfocusisonconstructionmaterialsandtheirusein buildingandcivilengineeringstructures,coveringallphasesofthebuildingprocess frommanufactureto use andrecyclingofmaterials. MoreinformationonRILEM anditspreviouspublicationscanbefoundonwww.RILEM.net. TheRILEMState-of-the-ArtReports(STAR)areproducedbytheTechnicalCom- mittees.TheyrepresentoneofthemostimportantoutputsthatRILEMgenerates- highlevelscientificandengineeringreportsthatprovidecuttingedgeknowledgein agivenfield.TheworkoftheTCsisoneofRILEM’skeyfunctions. MembersofaTCareexpertsintheirfieldandgivetheirtimefreelytosharetheirex- pertise.Asaresult,thebroaderscientificcommunitybenefitsgreatlyfromRILEM’s activities. RILEM’sstatedobjectiveistodisseminatethisinformationaswidelyaspossibleto thescientific community.RILEMthereforeconsidersthe STARreportsofitsTCs asofhighestimportance,andencouragestheirpublicationwheneverpossible. Theinformationinthisandsimilarreportsismostlypre-normativeinthesensethat itprovidestheunderlyingscientificfundamentalsonwhichstandardsandcodesof practiceare based. Withoutsuch a solid scientific basis, constructionpractice will belessthanefficientoreconomical. ItisRILEM’shopethatthisinformationwillbeofwideusetothescientificcom- munity. Forfurthervolumes: http://www.springer.com/series/8780 · Bruno Godart Mario de Rooij Jonathan G.M. Wood Editors Guide to Diagnosis and Appraisal of AAR Damage to Concrete in Structures Part 1 Diagnosis (AAR 6.1) ABC Editors BrunoGodart JonathanG.M.Wood IFSTTAR StructuralStudies&DesignLtd BridgesandStructures NorthbridgeHouse Paris Chiddingfold,Surrey France UnitedKingdom [email protected] [email protected] MariodeRooij TNO Delft Netherlands [email protected] ISSN2213-204X ISSN2213-2031 (electronic) ISBN978-94-007-6566-5 ISBN978-94-007-6567-2 (ebook) DOI10.1007/978-94-007-6567-2 SpringerDordrechtHeidelbergNewYorkLondon LibraryofCongressControlNumber:2013933101 (cid:2)c RILEM2013 Nopartofthisworkmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorby anymeans,electronic,mechanical,photocopying,microfilming,recordingorotherwise,withoutwritten permissionfromthePublisher,withtheexceptionofanymaterialsuppliedspecificallyforthepurpose ofbeingenteredandexecutedonacomputersystem,forexclusive usebythepurchaserofthework. Permissionforusemustalwaysbeobtainedfromtheownerofthecopyright:RILEM. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Dedication This RILEM Report is dedicated to the memory of the two Technical Committee colleagues who worked together to establish, formulate and draft its original contents: Dr Joe Larbi & Dr Sylva Modry. Joe Larbi was born in Ghana, where he graduated in geological engineering, before gaining an MSc in Canada, studying alkali-aggregate reactivity. Joe then moved to Delft University of Technology in the Netherlands, where he obtained a PhD in 1991: 'The cement paste aggregate interfacial zone in concrete'. Afterwards, Joe remained in the Netherlands, working first for Intron and finally for TNO, during which time he took an active part in the RILEM work on alkali-aggregate reaction. Sadly, after many years of poor health, Joe died in 2009. Sylva Modry was from the Czech Republic, where he graduated in chemical technology in 1959 and initially worked at the Raw Materials Institute. From 1962, Sylva was at the Klokner Institute (Czech Technical University) in Prague, where he was awarded a CSc in 1974 and a DrSc in 2001. Sylva gave courses on building chemistry (in English) and on durability and alkali-aggregate reaction for the Ministry of Education. Sylva was created an Honorary Fellow of RILEM in 2000, but sadly died before the formation of the current TC 219-ACS. Foreword This document was drafted by the Working Group Diagnosis and Appraisal of AAR Damage to Concrete in Structures under the direction of RILEM TC 191- ARP Technical Committee: Alkali-Reactivity and Prevention - Assessment, Specification and Diagnosis. The Working Group consisted of the following members: Mario Berra Italy Geoffrey Blight South Africa Sylvine Guédon-Dubied France Bruno Godart France Viggo Jensen Norway Tetsuya Katayama Japan Joe Larbi The Netherlands Tang Ming-shu China Sylva Modry Czech Republic Ahmad Shayan Australia Ted Sibbick UK/USA Niels Thaulow Denmark/USA BorgeWigum Iceland It was later decided to split the draft into two parts. The present Part I on Diagnosis was revised in spring 2006, and subsequently in 2007 and 2008 to improve the material scientist to structural engineer coordination. Modifications and additions to the original draft were supplied by: Bruno Godart France Viggo Jensen Norway Tetsuya Katayama Japan Jan Lindgaard Norway Mario de Rooij The Netherlands Ian Sims UK Hermann Sommer Austria Jonathan G M Wood UK Prognosis, appraisal, management and the influence of AAR on structural behaviour will be dealt with in AAR-6.2, but amendments to improve the interface with AAR 6.2 have been incorporated in AAR-6.1 Diagnosis (see Appendix 2). Contents 1 Introduction ...................................................................................................... 1 1.1 Why the Need for a Diagnosis Document ................................................. 1 1.2 Scope ......................................................................................................... 2 1.3 Definitions ................................................................................................. 4 2 Alkali-Aggregate Reaction ............................................................................. 13 2.1 Introduction ..............................................................................................13 2.2 Alkalis .......................................................................................................14 2.3 Aggregates ................................................................................................14 2.4 Water ........................................................................................................16 2.5 Pessimum Behaviour ................................................................................16 2.6 Summary ................................................................................................... 18 3 Symptoms of an Expansive Reaction during Routine Inspection ............... 19 3.1 General Inspection Remarks .....................................................................19 3.2 Review of Existing Records .....................................................................19 3.3 Planning of a Comprehensive On-Site Inspection ....................................20 3.3.1 Field Equipment and Materials ...................................................... 21 3.3.2 Personnel and Expertise ................................................................. 21 3.4 The Routine On-Site Inspection ...............................................................22 3.5 Concrete Surface Features Suggestive of AAR ........................................24 3.5.1 Crack Pattern ................................................................................. 27 3.5.2 Displacements and Deformations .................................................. 29 3.6 First Assessment of Field Observations ....................................................29 4 Confirmation Investigation ............................................................................ 31 4.1 Introduction ..............................................................................................31 4.2 Available Methods, Personnel and Expertise ...........................................31 4.3 Approach for Diagnosis of AAR in Structures .........................................32 4.4 On-Site Sampling for AAR Confirmation ................................................35 4.4.1 Cores .............................................................................................. 35 4.4.2 Fragments ...................................................................................... 36 4.4.3 Drilled Powdered Material ............................................................. 36 4.4.4 Efflorescence and Exudations ........................................................ 36 4.4.5 Number of Samples ....................................................................... 37 X Contents 4.4.6 Preservation of Samples ................................................................. 37 4.5 Visual Examination of Cores ....................................................................38 4.5.1 Receipt of Cores and Documentation ............................................ 38 4.5.2 First Visual Description of Cores .................................................. 39 4.5.3 Photography and Core-Scanning ................................................... 40 4.5.4 Visual Examination and Stereomicroscopy Aid ............................ 41 4.5.5 Selection of Specimens for Further Testing ................................... 44 4.5.6 Cutting and Grinding ..................................................................... 46 4.6 Petrographic Examination ........................................................................46 4.6.1 Introduction.................................................................................... 46 4.6.2 Detailed Aspects from Optical Microscopy ................................... 49 4.7 Additional Tests ........................................................................................54 4.7.1 SEM Observation ........................................................................... 54 4.7.2 EPMA Analysis ............................................................................. 57 4.7.3 Determination of Soluble Alkali Content ...................................... 61 4.7.4 Tests to confirm Aggregate Reactivity .......................................... 62 4.7.5 Uranyl Acetate Test ....................................................................... 62 4.7.6 Estimation of Cement Content ....................................................... 63 5 Severity Investigation ..................................................................................... 65 5.1 Introduction ..............................................................................................65 5.2 Field Investigation ....................................................................................66 5.2.1 Quantification and Recording of Cracks in Structures .................. 66 5.3 Laboratory Tests .......................................................................................69 5.3.1 Expansion Tests on Concrete Cores .............................................. 69 5.3.2 Mechanical Properties from Concrete Cores ................................. 71 5.3.3 Quantification at the Microstructure Level .................................... 72 5.3.4 Determining Damage Ratios at the Microstructure Level ............. 74 5.4 Summary of Diagnosis .............................................................................76 6 Reporting ......................................................................................................... 79 6.1 Purpose .....................................................................................................79 6.2 Scope ........................................................................................................79 6.3 Objectives of the Investigation .................................................................79 6.4 Information Concerning the Structures .....................................................79 6.5 Methods and Techniques Used .................................................................80 6.6 Interpretation of Results ...........................................................................80 6.7 Conclusions ..............................................................................................81 6.8 Author .......................................................................................................81 References .......................................................................................................83 Appendix 1. Proceedings of ICAAR ............................................................89 Appendix 2. Diagnosis of AAR within an Overall Investigation ..............91 1 Introduction 1.1 Why the Need for a Diagnosis Document Diagnosis of damage to concrete in structures caused by Alkali-Aggregate Reaction (AAR) often involves complex processes because of the resemblance of the external characteristics of the damage with those caused by other actions, such as e.g. frost attack or shrinkage. The wide variety of aggregate types used in concrete worldwide, the different reactivity and proportions of the reactive constituents in the aggregates involved and the wide range factors that influence the reaction result in wide variability found in site samples. This makes diagnosis difficult and has sometimes led to subjective or even erroneous interpretations and conclusions. Furthermore, there has frequently been a lack of agreement amongst experts on how to approach the issues of diagnosis and prognosis of AAR damage in structures. The reasons for the differences in opinion include: 1. The wide range and often inconclusive methods used for performing the assessment. 2. The limited number of reliable internationally applicable standard procedures or methodologies for performing the diagnosis and prognosis. 3. The inherent variability of aggregate sources and of concrete which make AAR diagnosis from limited sampling dependant on the local composition of samples selected. 4. The not uncommon occurrences of localised patches of AAR cracking in site concretes, which leads to diagnosis of AAR as a problem, even though the magnitude of the reaction is not sufficient to produce significant problems of serviceability or structural function. 5. The assessment that is often carried out from core samples without reference to the structure itself. 6. Difficulties in simulating the long term AAR damage in a structure with short term laboratory tests and the translation of the test results to the actual structures. 7. Several national laboratories, private companies and even individuals using their own procedures, which are very often ‘tailored’ to solve only specific local types of AAR damage, thus limiting their flexibility in use. Over the past few decades, experts in several countries with AAR problems have pooled their resources and expertise to prepare national guidance documents for assessing damage of concrete caused by AAR. The current document presents an international procedure for the diagnosis of AAR damage to concrete in structures. B. Godart et al. (Eds.): Guide to Diagnosis & Appraisal of AAR Damage, RILEM 12, pp. 1–12. DOI: 10.1007/978-94-007-6567-2_1 © RILEM 2013 2 1 Introduction The guidance outlined in this document is based on experiences, recommendations or national guidance of several countries throughout the world where the AAR problem is well understood and documented [1-10]. Experience in Austria, Australia, Belgium, Canada, Czech Republic, China, Denmark, France, Iceland, Japan, The Netherlands, New Zealand, Norway, United Kingdom, United States of America and several other countries has been documented in the proceedings of the thirteen ICAAR (International Conferences on AAR) since 1974 in Denmark (see Appendix 1). Like many other causes of damage in concrete, diagnosis and prognosis of AAR in structures relies to a large extent on the judgement and the level of expertise of the personnel involved. A reliable analysis to identify, evaluate and establish the extent of the damage and to make prognosis of its effect on the structure requires a clear and thorough understanding of the mechanisms and processes of damage resulting from AAR. To do so, the effects of AAR need to be considered as part of a complex of structural and ‘non-structural’ actions and deterioration which lead to cracking and damage in the concrete. Complete diagnosis of distress caused by ASR usually involves a series of steps involving multi-disciplinary tests and investigations, performed in a systematic manner. Figure 1 shows an outline flowchart of these interactions relative to the main diagnostic procedures; the complete flowchart showing the place of the diagnosis within an overall investigation and making the links between AAR-6.1 and AAR- 6.2, is presented in appendix 2. 1.2 Scope This document describes procedures and methodologies used predominantly to obtain a diagnosis of damaged concrete possibly caused by Alkali-Aggregate Reaction (AAR). The document has two primary objectives, namely to: 1. Identify the presence of AAR reaction, and whether or not the reaction is the primary or contributory cause of damage in the concrete. 2. Establish its intensity (severity) in various members of a structure. The guidance includes aspects such as field inspection of the structure, sampling, petrographic examination of core samples, and supplementary tests and analyses on cores, such as mechanical tests and chemical analysis. Evaluation of test data for prognosis, consequences and appraisal will be more fully set out in AAR-6.2. The document begins with a brief overview of the alkali-aggregate reaction, the various types involved and conditions under which it causes damage to concrete. Next, routine inspection and visible effects of damage is picked up. If these inspections results contain observations or symptoms that may be due to an expansive reaction of concrete, chapter four helps to determine whether or not it could be AAR. A detailed outline of the various systematic methodologies for diagnosing, establishing and assessing AAR damage to concrete in a structure is presented, illustrated where appropriate with diagrams and photographs.