Development of a test method to determine the colour durability of coloured bituminous mixtures

Abstract

Coloured asphalt pavements are increasingly used in large public spaces and also at hazardous junctions. In the former application, the role of the coloured pavement is often to give the area a particular aesthetic character or to integrate it well with its surroundings; in the latter, its major role is to improve the safety of users by improving visibility and road legibility. Once coloured asphalt mixtures have been laid, their colour tends to alter irreversibly (paling, pastellisation, etc.) due to climatic agents. Colour durability, therefore, appears to be very important. In this respect, it has been proved necessary, on the one hand, to identify the climatic agent, the composition, and the components of coloured bituminous mixtures actually having a substantial impact on colour development (using a natural weathering method) and, on the other, to develop an accelerated weathering methodology for a faster evaluation of colour durability. This paper will present results and findings from both natural and accelerated weathering methods developed at the Belgian Road Research Centre.