An Investigation on the Alkali-Silica Reactivity of Đzmir Region Aggregates Cement and Concrete Technology in the 2000 s Second International Symposium, 6-10 September, 2000. Istanbul, Turkey Halit Yazıcı Research Assistant Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey Selçuk Türkel Assist. Prof. Dr. Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey Bülent Baradan Prof. Dr. Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey
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An Investigation on the Alkali-Silica
Reactivity of Đzmir Region Aggregates
Cement and Concrete Technology in the 2000 s
Second International Symposium, 6-10 September, 2000. Istanbul, Turkey
Halit YazıcıResearch Assistant
Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey
Selçuk TürkelAssist. Prof. Dr.
Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey
Bülent BaradanProf. Dr.
Dokuz Eylül University, Department of Civil Engineering, Đzmir, Turkey
ALKALI-SILICA REACTION IN CONCRETE
WITHIN TIME (∼ after 1 year)
ALKALI OXIDES FROM HIGH ALKALI
CONTENT CEMENTS
FORMATION of GEL (sodium + potassium +
calcium silicate)
VOLUME EXPANSION
CRACKING (MAP)
SILICEOUS CONSTITUENTS ( Opal, Calceduan,
Tridymite, etc. ) of SOME AGGREGATES
The mechanism of the alkali-silica reaction
Diffusion of water and alkalis into concrete
Water and/or alkalis from the environment (e..g. From de-
icing salts)
Crack formation (map cracking and surface
parallel cracking)
Diffusion of alkalis present in pore system (e.g. From cement
and admixtures)
Conversion of reactive
aggregate (formation of
gel); expansion
ReactiveAggregate
GEL FORMATION
The gel is usually transparent and resinous in appearance
Local pop-out: spalling or
micro-cracking due to ASR
GEL
CRACKING and SPALLING
ASTM C 227 Standard Test Method for Potential Alkali
Reactivity of Cement Aggregate Combinations (Conventional
long term- 6 Months)
CSA A23.2-25A Test Method for Detection of Alkali-
Silica Reactive Aggregate by Accelerated Expansion of