Coloured pavements utilization is rapidly increasing, mostly in urban areas, as valuable mitigation strategy for the phenomenon of heating concentration through the cities connected to the presence of black and high-reflective surfaces favouring the air warming. Moreover, coloured road pavements are already employed as traffic calming measures for the pedestrians and cyclist protection and as eco-friendly solutions in terms of aesthetic preservation. In view of a wide diffusion of such technologies, a consistent knowledge of the mechanical and thermal behaviour is needed. In this regard, the present paper proposes a laboratory investigation aimed at assessing some preliminary characteristics of different construction solutions to obtain coloured asphalt pavements. Different materials for wearing courses were investigated. Red, yellow, green and blue specimens were produced alternatively utilizing mortars and resins for surface treatments, or tinted oxides for the colour modification of the asphalt mixes. Roller compactor was used to obtain slabs suitable to be tested with thermic analysis, determining in-service reached temperatures. Functional properties were investigated through empirical assessments, analysing peculiarities such as horizontal drainability, skid resistance and macro-texture. Mechanical properties were also analysed in case of black and coloured asphalt concretes. Dynamic tests were carried out at different temperatures both on prismatic specimens, in 4-point bending configuration, and cylindrical samples, in indirect tensile configuration. Preliminary rheological tests were also performed on the plain and the oxide-coloured bitumens utilized to produce the “fully-coloured” asphalt concretes. Main findings allow to recognize the strong contribution of colour in terms of heating processes and in-field reached temperatures, which also sensibly affect the performance of in-service pavements. Stiffening effects due to oxides were evinced for asphalt mixtures and were confirmed by preliminary tests at binder scale.

coloured asphalt, thermal behaviour, mechanical properties, oxides addition