Development of a Test and Classification Method to Objectively Determine the Colour of Coloured Bituminous Pavements

Coloured bituminous pavements are increasingly used on our roads, mostly in rural environments to increase safety, road legibility and liveability. Since the expression of a colour is different for every individual, the colours of coloured roads are quite often a subject of discussion between contractors and clients. The perception of colour depends on a variety of parameters: the observer is an important factor, but the incidence of light and the distance between the observer and the object also have a great influence. This article deals with a measurement and classification method to objectively determine the colour of coloured asphalt cores. A round robin test was carried out to verify the repeatability and reproducibility of the test method. Several coloured cores representative of the range of colours available from the Belgian asphalt producers were measured and visually inspected by the BRRC steering committee on Coloured Bituminous Pavements. The results were analysed and have led to a classification into different colour classes, which will be implemented in the Flemish standard specifications.