Reinstatement of Effective Cover on Pre-cast Concrete Segments
Built on reclaimed land, the West Kowloon Expressway opened to traffic in 1997. This four kilometre highway runs from Kwai Chung Viaduct to the Western Harbour Crossing toll plaza, carrying traffic out to Hong Kong International Airport.
Whilst the southern section is at ground level, the northern section is carried on a viaduct which is constructed from precast concrete segments. During construction, low concrete cover was detected on a number of segments, requiring an innovative engineering solution.
In a pioneering move which followed similar use on the Channel Tunnel, Cementitious Coating 851 was approved as an economic and practical solution to enhance effective cover to reinforcing steel. The contractor cleverly blended white and grey grades of Cementitious Coating 851 to provide a colour matched solution which could be used in discreet patches. Applied directly to concrete in two coats in a thickness of 2mm, Cementitious Coating 851 confers an additional 100mm of effective cover. This application has lead to the use of 851 on many major infrastructure projects.