Eight hollow-core precast-prestressed concrete beams were removed and recovered in good condition from the Pahurehure Inlet Bridge No. 2 on the Auckland Southern Motorway, New Zealand, in 1988. The beams had been affected by alkali aggregate reaction (AAR), a reaction between alkalis in the cement and the aggregates in the concrete. One of the beams was test loaded in flexure until failure, using a second beam as a reaction frame for the applied load.
The aim of the test was to determine whether the flexural strength had been affected by AAR. The flexural strength at failure was between 4% and 9$ greater than the theoretical ultimate flexural strength and approximately 30% greater than that which would be required by the then current (1991) bridge design standards.
The effect of AAR on the flexural strength of the beam was not significant because the strength at failure was greater than the theoretical ultimate flexural strength.
Keywords: Alkali aggregate reaction, beams, bridges, flexural strength, hollow core beams, New Zealand, prestressed concrete, strength, testing