Performance of repaired concrete piles partially embedded in Sulfate-Bearing soil

•Physical salt attack (PSA) is a key damage mechanism of concrete in salt-bearing environments.•The current paper presents a case study analyzing the condition of repaired concrete piles in 47-year-old administrative building.•Deterioration of the concrete piles was observed above the ground level and repair zones.•Thermal, mineralogical and microscopy analyses showed that the underlying mechanism of damage was PSA.•The repair concrete could not stop the progress of PSA on the concrete above it.•Recommendations for future repair strategies are made. Physical salt attack (PSA) is a key damage mechanism of concrete in salt-bearing environments. Multiple case studies were reported throughout literature on PSA of concrete; yet, without any case on the performance of repaired concrete elements. The current paper presents a case study analyzing the condition of repaired concrete piles in 47-year-old administrative building in Winnipeg, MB, Canada, after 22 years from repair works. Deterioration of the concrete piles was visually observed above the ground level and repair zones, in the form of scaling, crumbling and reduction of cross section. In addition to fluid transport and pore structural features tests, mineralogical, thermal and microscopy analyses were performed on concrete chunks/cores extracted from the piles to elucidate the underlying mechanisms of damage. The repair concrete was capable of mitigating chemical and physical sulfate attacks; however, it could not stop the progress of PSA on the concrete above it, urging for careful design of repair strategies for elements subjected to PSA. Recommendations for future repair in this case are also presented.