Abstract
Alkali-aggregate reactions (AAR) can have many different effects,
ranging from nothing happening to total cracking of the structure.
The reason for this is related to the fact that chemistry and
mechanics interfere with each other in the reactions. So, factors
such as the concrete composition, the production procedure, the
design, and the climatic conditions, and in repair situations, the
repair conditions, influence the development of the reactions.An
overview of the many consequences and the influencing factors is
necessary, when a certain structure suspected of being influenced
by AAR is going to be analysed. In the present paper a proposal
for the time development is given. The time development of the
harmful reactions consists of an initiation period, a propagation
period, and a rest period. - For a given concrete in a given
environment, the length of the initiation period depends upon the
square of the dimension of the structural member in the direction
of diffusion. - The time rate in the propagation period is
determined by the rate of the chemical processes and of the creep
and fracture properties of the concrete.Decisions about repair
ought to be made on the basis of a plot of the time development.
As a case study a road bridge is analysed according to the
principles presented. Keywords: Alkali-aggregate reactions,
alkali-silica reactions, bridges, concrete structures, dams,
repair decision, time development.
Original language | English |
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Title of host publication | Proceedings of 11th International Conference on Alkali-Aggregate Reaction in Concrete |
Publication date | 2000 |
Publication status | Published - 2000 |
Event | 11th International Conference on Alkali-Aggregate Reaction in Concrete - Quebec City, Canada Duration: 11 Jun 2000 → 16 Jun 2000 Conference number: 11 |
Conference
Conference | 11th International Conference on Alkali-Aggregate Reaction in Concrete |
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Number | 11 |
Country/Territory | Canada |
City | Quebec City |
Period | 11/06/2000 → 16/06/2000 |