A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Alkali-aggregate reaction in concrete dams
The Alkali-Aggregate Reaction (AAR) is a reaction between the hydroxil ions associated with the alkalis (sodium and potassium) in the pore fluid within concrete and certain forms of reactive aggregates (e.g., silicate microinstabilities). The alkalis usually derive from cement but they may also come from other concrete constituents (aggregates, mineral additions, mixing water, admixtures or external sources). Interest in the alkali-aggregate reaction in concrete structures has increased to such an extent in recent times as to draw the attention of international committees on concrete dam materials. In fact, although AAR's do not specifically concern the concrete of dams, one of the first structures in which deterioration was later diagnosed as an alkali-aggregate reaction was the Parker Dam (USA). An international survey was conducted in 1985 to identify the magnitude, frequency and distribution of damage (e.g., mass movement, swelling, cracking, pop-outs, etc.) all over the world and to prepare some adequate recommendations on this subject, specifically concerned with concrete dams. This paper reports on the survey's findings and its recommendations.
Alkali-aggregate reaction in concrete dams
The Alkali-Aggregate Reaction (AAR) is a reaction between the hydroxil ions associated with the alkalis (sodium and potassium) in the pore fluid within concrete and certain forms of reactive aggregates (e.g., silicate microinstabilities). The alkalis usually derive from cement but they may also come from other concrete constituents (aggregates, mineral additions, mixing water, admixtures or external sources). Interest in the alkali-aggregate reaction in concrete structures has increased to such an extent in recent times as to draw the attention of international committees on concrete dam materials. In fact, although AAR's do not specifically concern the concrete of dams, one of the first structures in which deterioration was later diagnosed as an alkali-aggregate reaction was the Parker Dam (USA). An international survey was conducted in 1985 to identify the magnitude, frequency and distribution of damage (e.g., mass movement, swelling, cracking, pop-outs, etc.) all over the world and to prepare some adequate recommendations on this subject, specifically concerned with concrete dams. This paper reports on the survey's findings and its recommendations.
Alkali-aggregate reaction in concrete dams
M. Berra (author) / P. Bertacchi (author)
1990
27 pages
Report
No indication
English
Hydrology & Limnology , Materials Degradation & Fouling , Miscellaneous Materials , Nondestructive Testing , Electric Power Production , Physical & Theoretical Chemistry , Dams , Cements , Chemical Reaction Kinetics , Concretes , Crack Propagation , Damage , Hydroxides , Recommendations , Silicates , Surveys , Swelling , Foreign technology , EDB/130300 , EDB/360604 , EDB/400201 , EDB/420500
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