Self-consolidating concretes can be easily poured or pumped into formwork without vibration, segregation or bleeding, in new construction or for repairs. The St. Donat Bridge is a project ideally suited for repair with this type of  product. The bridge was built in the 1960’s by the Ministry of Transportation of Québec (MTQ), and is made of reinforced concrete. The two-lane bridge is located 5 km North of St. Donat, Québec, on Highway 125. After fifty years  of freeze-thaw cycling and exposure to de-icing salts, the bridge required extensive rehabilitation to its three 16” x 33” (400 mm x 1000 mm) reinforced concrete beams, and also to portions of its abutments.

The abutments would typically have been repaired with a high-performance concrete such as the MTQ approved, KING MS-S10. However, the bridge beams could only be repaired using a self consolidating concrete, if full structural performance was to be restored. As a result, KING MS-S10 SCC was used. With 600 mm to 650 mm (24” to 26”) slump flow, a 40 MPa minimum compressive strength at 28 days, and excellent durability characteristics, the MTQ approved, MS-S10 SCC brought new life to an otherwise destroyed bridge. In 2011, Les Constructions and Pavages Jeskar Inc. won several MTQ bridge rehabilitation contracts in the Montreal area. The MTQ specified KING’s pre-packaged self-consolidating concrete (SCC) as  the repair material for the St. Donat Bridge beams, as it was the only way to restore full structural performance.

Although an experienced general contractor, Jeskar was a newcomer to the world of SCC repair. To the company’s shock, when workers removed the formwork for the first form-and-pour SCC repair, they found significant air voids. As a responsible contractor, Jeskar immediately called KING for guidance. In turn, KING Representatives recommended that more air vents be added, that  the input ports be spaced closer together, and that the workers follow a pour sequence that moved from the lowest point to the highest point on the bridge With several site visits, excellent cooperation, and by following these guidelines, Jeskar was able to successfully complete the bridge repairs on time and on budget. Philippe Sauvé, from Les Constructions et Pavages Jeskar Inc., even went as far as to say, “We really appreciated KING’s guidance with our first self consolidating concrete job at St. Donat. We know we can count on King for success”.