EXTENDING THE SERVICE LIFE OF A REINFORCED CONCRETE RAILROAD BRIDGE
Vector Corrosion Technologies is a leading full-service supplier of corrosion mitigation products and services for reinforced concrete and masonry structures including bridges, parking garages, buildings, marine structures, and industrial facilities.
Two railroad bridges in the Midwest US were showing signs of chloride-included corrosion and becoming a local eye-sore and a safety concern.
The columns were heavily chloride-contaminated from years of de-icing chemical exposure and suffering from extensive concrete cracking, spalling and delamination. In addition to shotcrete repairs and epoxy injection crack repairs of the abutments, the columns were repaired and protected by Vector Construction’s Cedar Rapids, Iowa office using Octaform’s ColumnArmor™.
As part of the concrete preservation process, an evaluation consisting of a combination of non-destructive and destructive testing was conducted to determine the condition of the structures including corrosion potentials, chloride profile and cover depth as determined by ground penetrating radar. Together this information revealed that significant chloride concentrations existed at the level of the reinforcing steel and that corrosion was active throughout the columns.
DECADES OF PROTECTION
The deteriorated concrete was first removed and the rebar cleaned of corrosion byproducts. Then, galvanic anode strips were distributed around the column and connected to the existing reinforcing steel. Once the anodes are secured to the existing concrete structure, the ColumnArmor™ PVC forms are fitted around the columns and filled with concrete.
Aside from the dramatic aesthetic improvement, the rehabilitated structure will have decades of galvanic protection to allow the bridges to remain in service for decades to come, a significant improvement over regular concrete repairs that do not address the fundamental problem, corrosion.