Physical-Mechanical and Microstructural Assessment of a Concrete Dual Carriageway Affected by Alkali-Silica Reaction in the Province of Buenos Aires, Argentina

In this research a concrete dual carriageway in the province of Buenos Aires (Argentina) was studied. The section analyzed joins a street in Bahía Blanca city with provincial and national routes. The pavement is 0.22 m thick and was built over a cement-soil base 0.15 m thick lying over a 0.20 m thick hardpan. The fine aggregates used correspond to sands from the south of the province of Buenos Aires qualified as reactive in laboratory tests and in some structures in service. The coarse aggregate is a non-reactive crushed granitic rock. The structure shows signs of deterioration that could be associated to the alkali-silica reaction (i.e. stains, map cracks, white products associated with fissures, etc.). In order to verify the occurrence of the ASR and to evaluate the actual condition of the concrete different physical-mechanical and microstructural studies were performed on cores extracted of the structure. Density, absorption, volume of voids, carbonation depth and compressive strength were determined. In addition, Stiffness Damage Test and Damage Rating Index were implemented coupled with polarizing microscopy and scanning electron microscopy.