Investigation of Mechanical Properties of Mass Concrete Affected by Alkali-Aggregate Reaction

Abstract

The alkali-aggregate reaction (AAR) has been detected in the spillway driftway of the Furnas Hydroelectric Power Plant, Brazil, which was built in 1963. To investigate the properties of this concrete, several cores were drilled in the affected structure and ultrasonic tests in association with mechanical tests were conducted. This paper presents the results of the following properties: splitting tensile strength, compressive strength, modulus of elasticity, and ultrasonic pulse velocity. For the ultrasonic tests, initial in situ determinations were performed on the driftway concrete surface under different exposure conditions before actual coring took place. The concrete cores drilled from the same location were tested by direct ultrasonic method before determining their mechanical properties. The ultrasonic results showed that the pulse velocity is sensitive to different degrees of deterioration due to AAR and correlates with the modulus of elasticity of the concretes investigated. Furthermore, the modulus of elasticity was the main property affected by AAR.