Expansion behavior of a biaxially reinforced concrete member affected by alkali-silica reaction

The development and multiaxial distribution of mechanical expansions caused by alkali-silica reaction were quantified for a large-scale reinforced concrete beam containing top and bottom mats of bidirectional reinforcement with no reinforcement through its depth. The effects of different conditioning environments and the influence of reinforcing bar size and layout on the expansion behavior of the beam were also considered. Expansions in the unreinforced direction exceeded those in the reinforced directions at all times. Expansions in the reinforced directions stopped prior to steel yielding and before concrete finished expanding in the unreinforced direction. Expansion behavior in biaxially reinforced beam regions was not influenced by triaxial restraint conditions at adjacent beam ends. Varying moisture exposure conditions along the length affected the time development of expansions but not the distribution of given volumetric expansions among primary directions.