Concrete dams subjected to alkali aggregate reactions (AAR):
diagnosis, modeling and rehabilitation
About the Course
Alkali-aggregate reaction (AAR) is an internal reaction that occurs between certain type of aggregates and the
alkaline concrete cement paste, resulting in the formation of an alkaline siliceous gel (including also some
calcium and aluminium, as minor elements) that expands in the presence of water. The concrete expansion rate,
that is dependent of water content and temperature, can induce significant deformations on structures,
sometimes causing serious cracking, equipment misalignment, even seepage. Additionally this reaction p
resents a potential decrease in the tensile strength and on the elasticity modulus and, in some cases, also a
reduction in the compressive strength. Dams and hydro-electric plants are particularly vulnerable to AAR
induced effects. In dams, increased long term damage (cracking on the dam body) and irreversible crest
displacements are observed, potentially affecting stability and spillway gates clearances. In hydro-electric
plants, deformations can affect turbines and generators clearances and damage on the powerhouse
his one day short course will provide owners and practitioners with a concise, rigorous and comprehensive
view of AAR phenomena and current methods for its management in major structures. In particular: a) chemophysical
nature of the reaction; b) diagnosis and prognosis test methods; c) monitoring and analysis, including
finite element modeling; and d) management and rehabilitation of AAR affected dams.
Who should attend?
Owners engineers, designers, consultants, contractors and regulators who are faced with having to deal with
dams, hydroelectric plants and concrete structures that has been found to be subject to AAR or some other
chemical expansion phenomena. The course is intended to provide a state of the art basis for making
engineering decisions on the assessment and management of the concrete structures and affected equipment.
Carlos Pina is a Civil Engineer, Principal Research Officer and Director of the Concrete Dams Department of
LNEC, with about 30 years of experience in concrete dams modeling and safety control.
Robin Charlwood is a Civil Engineer with over 35 years of experience focussing on dam safety and
hydroelectric plant rehabilitation. His areas of emphasis include assessment and remedial measures for
concrete structures and particularly ageing structures and those with alkali-aggregate reactions. He is Chairman,
International Commission on Large Dams Committee on Concrete Dams. He was Chairman of ICOLD/Hydro
2007 Workshop on Chemical Expansion of Concrete Dams, Granada, Spain, Q82 on Ageing and Rehabilitation
of Concrete and Masonry Dams, Montreal ICOLD Congress, 2003, and Co-Chairman of the USCOLD 1995
Conference on Alkali-Aggregate Reactions in Hydro-electric Plants and Dams in Chatanooga, TN.
Ian Sims is a Chartered Geologist and Chartered Engineer with 35 years professional experience. He obtained
a doctorate in Concrete Technology, including the first recognized case of AAR in the British Isles, which was
a dam. Since 1975, Ian has acted as a consultant and/or expert witness in respect of concrete materials
worldwide. He is a Director of STATS Limited, a consultancy practice within the RSK Group plc. Ian was the
founding and continuing Secretary of the series of RILEM technical committees on AAR, starting in 1988. He
is co-author of the book 'Concrete Petrography' and is currently co-editing a new edition of Swamy's 'The
Alkali-Silica Reaction in Concrete' (to be 'The Alkali-Aggregate Reaction in Concrete').
Jean-François Seignol is a civil engineer and a Ph-D in solid mechanics. He is a specialist in structures
durability. His researches focus on the mechanical consequences of swelling reactions (such as alkali-silica
reaction or delayed-ettringite formation) in concrete structures, and particularly their numerical modelling with
finite-element techniques. He studied several real cases of affected bridges and hydropower facilities, including
dams. He is now in charge of the "Structures Safety and Durability" research unit in LCPC, Paris (French
national laboratory for roads and structures).
Arlindo Freitas Gonçalves is a Civil Engineer, Principal Research Officer and Head of the Concrete Division
of Materials Department of LNEC, working for over 30 years in the study of concrete, particularly as regards
the use of cementitious materials and chemical
admixtures, control of shrinkage, special concretes, repair
materials and inspection of concrete structures. In recent years he has been studying the durability of concrete,
particularly in relation to reinforcement corrosion and the prevention and identification of expansive internal
reactions. In this area, it should be noted the work in the publication of the specification LNEC and 461, and
the study of a set of public works, namely bridges and viaducts, which are affected by these expansive reactions.
Armando Camelo is a Civil Engineer at Dams Department of EDP Produção SA, with activity in the last 25 years mostly in concrete technology relating to dam design, construction and rehabilitation. He is also member
of the International Commission on Large Dams - Committee on Concrete Dams for the last 18 years. He was involved with the assessment and rehabilitation of dams affected by AAR owned by EDP (Pracana and Alto
Ceira dams), and more currently with specifications for construction of new dams in order to minimize risks of the expansion phenomena.
Isabel Fernandes, currently Assistant Professor at the University of Porto, holds a PhD in Geology on alkali-silica
reaction (ASR) and the evaluation of aggregates for concrete. She has been a regular contributing
member of the RILEM Technical Committee TC 219-ACS: Alkali Aggregate Reaction in Concrete Structures,
since 2008. She is also member of the Applied Petrography Group (APG), which is part of The Geological
Society of London, and of the International Alkali Aggregate Reaction (AAR) Committee. She also develops
R&D activities with commercial companies, in the areas of aggregate characterization and diagnosis of
concrete deterioration mechanisms by petrographic methods.
António Lopes Batista is a Civil Engineer, Senior Research Officer and Head of the Monitoring Division of
Concrete Dams Department of LNEC, PhD (IST, Lisbon, 1998), with 20 years of experience in concrete dams
monitoring, modeling and safety control. He has been involved, during the last years, in studies related with
dams affected by AAR, namely Santa Luzia dam (Portugal) and Cahora Bassa dam (Mozambique).
António Bettencourt Ribeiro is a Civil Engineer, Senior Research Officer at LNEC, PhD (FEUP, Porto, 1999),
with more than 20 years of experience in concrete research. He has been involved in studies related with
different civil engineer structures affected by AAR, namely bridges, viaducts and dams.
José Piteira Gomes is a Civil Engineer, Research Officer at LNEC, PhD (FCT/UNL, Lisbon, 2007), with more
than 10 years of experience in concrete dams monitoring, modeling and safety control. His PhD thesis is
entitled “Structural Behavior Modeling of Concrete Dams subject to Swelling Reactions”. He has been
involved in several studies related with structural behavior of dams affected by AAR, namely Pracana, Santa
Luzia and Fratel in Portugal and Cahora Bassa in Mozambique.
António Santos Silva is a Chemist, Researcher at LNEC, PhD in Civil Engineer at Minho University in 2005,
with several years of experience in diagnosis and prognosis of the causes of damaged concrete structures. His
PhD thesis is entitled “Concrete Degradation due to Alkali-Silica Reaction. The use of Fly Ash and Metakaolin
for its Prevention”. He has been involved in several studies related with concrete structures affected by internal
expansive reactions, namely the Portuguese dams of Pracana, Santa Luzia, Alto-Ceira, Picote, Fagilde, Fratel
and Cahora Bassa in Mozambique, and also some brigdes, including Duarte Pacheco, Pedrogão, Edgar Cardoso,
8:30 - 9:00 Welcome remarks. The AAR problem
9:00 - 9:45 Physical and chemical phenomena involved on AAR. Standard tests and the RILEM committee experience
9:45 - 10:30 Laboratory and microstructural tests on the detection and prediction of AAR
10:30 - 10:45 Coffee Break
10:45 - 11:30 Integration of AAR tests results on the evaluation of concrete properties
11:30 - 12:30 Structural modeling and analysis of AAR in dams
12:30 - 14:00 Lunch
14:00 – 15:00 The LNEC experience on monitoring and analysis of AAR affected dams
15:00 - 16:00 Rehabilitation techniques of AAR affected dams
16:00 - 16:15 Coffee Break
16:15 - 17:00 The EDP experience on management and rehabilitation of AAR affected dams
17:00 - 17:45 Managing AAR-affected structures: the LPC approach
17:45 - 18:45 Round table discussion
AAR problem and research trends.
Laboratory tests, characterization and
prevention. Structural monitoring,
modeling and analysis. Rehabilitation
Participants will receive a comprehensive set of notes, articles and documentation. Lunch and refreshments are included in the registration fee.
The number of participants will be limited to 30. If you are interested in attending this course you can pre-register, please, send an e-mail to the Conference Secretariat in Lisbon (