Durability enhancement of concrete dams by controlling and mitigating aar problem
Publish place: 4th International Conference on long-Term Behavior and Environmentally Friendly Rehabilitaion Technologies of Dams
Publish Year: 1396
نوع سند: مقاله کنفرانسی
زبان: English
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شناسه ملی سند علمی:
LTBD04_115
تاریخ نمایه سازی: 25 آذر 1396
Abstract:
Many concrete dams have suffered from heavy deterioration due to Alkali Aggregate Reaction(AAR).The alkali aggregate reaction occurs between the alkalies in cement paste and reactive minerals in the aggregate produces expansive gel resulting in map cracking and low service life of concrete dams. Researches show that a solution for controlling or mitigating this problem is the usage of appropriate supplementarycementing materials in the mixture design of concretes. This paper discusses the effectiveness of various artiiicial and natural pozzolans as supplementary cementing materials in controlling AAR expansion for various reactive aggregates. Petrographic examination of aggregates was carried out to determine the types of aetive minerals. Accelerated mortar bar and concrete prism methods were used to evaluate the reactivity of aggregates. Results of the tests show that for each pozzolan there would be an optimum content to be effective in suppressing AAR expansion in accelerated test method. Results of the long-term prism method show that the expansion is not only related to the type and quantity of the supplementary cementing materials but also depends upon the type and the minerals of the aggregates. However reactivity of some aggregates may be controlled by the optimum content of each pozzolanic materials. It is also concluded that individual evaluation test method may not be suitable for some aggregates and final assessment should be based on different test methods
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Authors
Ali Akbar Ramezanianpour
Professor, Amirkabir University, Concrete Technology and Durability Research Center Amirkabir University, Tehran, Iran
amir mohammad Ramezanianpour
Assistant professor, Tehran University