Silver Hope Overpass

The corrosion of reinforced concrete is a significant problem affecting concrete infrastructure, leading to deteriorating concrete structures around the world. Largely attributed to the corrosion of steel reinforcement, concrete structures built to last 50 to 100 years routinely need substantial repairs and rehabilitation during their service life. The continuous repair and rehabilitation of concrete infrastructure results in a high life cycle costs over a structure’s service life.

The Silver Hope Overpass spans the Trans-Canada Highway near Hope, BC, and is a five span braced steel girder bridge with an epoxy-coated, rebar enforced, concrete bridge deck. Shortly after the bridge was constructed, cracks developed full-depth through the deck slab at approximately 1-2 m (3-6 ft.) on centers. The Initial cracks were believed to be caused by reduced bond associated with epoxy-coated, reinforcing steel and partially to the predominantly round course aggregate used in the deck concrete.

Solution

Rebar corrosion is a killer for any concrete project, weakening the structure and leaving the public at risk on Canada's largest highway. A permanent solution was needed for a project that served so many and needed quickly - only the best would suffice. The province of BC, along with consultations from HBT Agra Ltd decided that Kryton's innovative Krystol Technology would be best suited to save the overpass in Hope.

Within one year of Krystol application, the underside of the deck was observed to be free of leakage. Over a period of nine years, both the Ministry of Transportation personnel and HBT Agra Engineering personnel continued to perform inspections on the bridge, and no subsequent leakage occurred. In 1994, core samples were taken from the bridge deck. The samples were petrographically examined and determined to be in excellent condition with no evidence of corrosion. The bridge and its waterproofing system continue to perform as specified.