Effect of concrete moisture on macrocell development in repair of reinforced concrete substructure with UHPC
Conference
Farzad, M, Fancy, SF, Azizinamini, A et al. (2019). Effect of concrete moisture on macrocell development in repair of reinforced concrete substructure with UHPC
. 2019-March
Farzad, M, Fancy, SF, Azizinamini, A et al. (2019). Effect of concrete moisture on macrocell development in repair of reinforced concrete substructure with UHPC
. 2019-March
In the United States, ~30% of the ~600,000 highway bridges are labeled structurally deficient or functionally obsolete. These bridges should be replaced or upgraded to sustain the transportation needs of the growing public and private sectors of the US economy. It is not uncommon for structures to have advanced levels of corrosion-induced damage where major repair and maintenance are required. However, the transportation infrastructure cannot be out of service without disruption to critical economic public, civil and commercial activities. This mandates the development of new techniques and materials for accelerated rehabilitation and recovery. In conventional repair of reinforced concrete damage by chloride-induced corrosion, delaminated and spalled concrete are restored with repair. However, due to the presence of low-level chlorides in the remaining concrete, the halo effect occurs. The ongoing corrosion at incipient anodes causes premature failure of the repair. Ultra-high performance concrete (UHPC) has been promoted as a durable construction material that can provide a barrier to corrosion due to its low permeability, ideally resulting in a durable repair solution that can slow the level of galvanic coupling between steel in the dissimilar UHPC repair material and the existing concrete. This paper investigates corrosion durability of UHPC repair and its possible use to mitigate macrocell corrosion caused by the presence of incipient anodes in concrete repairs with dissimilar concrete materials. The objectives of the research presented here were to identify if concrete wetness will increase macrocell current and how much repair with UHPC may provide extended repair service life. Conclusions and recommendations are drawn for corrosion protection based on the results which can be used in evaluating the suitability of UHPC as a repair material.
