Photocatalytic asphalt mixtures: semiconductors’ impact in skid resistance and texture

Abstract

Photocatalytic asphalt mixtures have the capability of mitigating air quality problems and degrade oils/greases by using semiconductors. The techniques to do so can change their functional characteristics. This study aimed to analyse the functionalization effect on the essential surface characteristics, such as macrotexture, skid resistance, and microtexture. AC 14 and AC 6 mixtures were functionalised with nano-TiO₂ and micro-ZnO by spraying and bulk incorporation. Mean Profile Depth, British Pendulum and microtexture amplitude parameters were evaluated. TiO₂ application seemed to smooth the surface slightly. In dry condition, the skid resistance of functionalised asphalt and control mixtures was similar. In wet condition, the functionalization caused a maximum decrease of 7% in skid resistance. The amplitude parameters were not affected by any functionalization technique except the skewness of AC 14 with 6% TiO₂ by bulk incorporation. Furthermore, the application of the semiconductors can be used without high impacts in texture and skid resistance.

Keywords:

• photocatalytic asphalt mixtures
• macrotexture
• microtexture
• skid resistance
• optical non-contact rugometric characterisation

ORCID

I. Rocha Segundo http://orcid.org/0000-0002-4199-5994

S. Landi Jr. http://orcid.org/0000-0003-1830-7548

E. Freitas http://orcid.org/0000-0001-5132-7407

M.F. Costa http://orcid.org/0000-0002-1554-8779

J. Carneiro http://orcid.org/0000-0001-9778-5390

Additional information

Funding

This work was partially financed by FCT (Fundação para a Ciência e a Tecnologia) under the project [PTDC/FIS/120412/2010]: “Nanobased concepts for Innovative & Eco-sustainable constructive material’s surfaces” and project [PEst-OE/ECI/UI4047/2014]. Also, the first author would like to acknowledge FCT for the PhD scholarship [SFRH/BD/137421/2018].