Photocatalytic asphalt pavement: the physicochemical and rheological impact of TiO₂ nano/microparticles and ZnO microparticles onto the bitumen

Abstract

A cost-effective solution to provide asphalt pavements with the photocatalytic property was addressed for the first time, based on the combination of low percentages of two semiconductors, TiO₂ and ZnO. Two photocatalytic techniques – spray deposition and bitumen modification – were used. With the former, the chemical properties were evaluated by FTIR after spraying the bitumen samples with two aqueous solutions, one with acid PH and another alkaline, of nano-TiO₂. The solution with less chemical impact was the alkaline one. With the latter, Penetration, Softening Point, Mass Loss, Dynamic Viscosity, Complex moduli and Performance Grade, after the modification by TiO₂ nano/microparticles and ZnO microparticles, were analysed with two levels of ageing produced by the RTFOT. TiO₂ nano/microparticles and ZnO microparticles conducted to softer bitumens and better results of short-term ageing resistance and did not cause any deterioration to the bitumen before or after either short- or long-term ageing.

Keywords:

• functionalisation
• photocatalysis
• bitumen modification
• nanomaterials
• TiO₂
• ZnO

ORCID

Iran Gomes da Rocha Segundo http://orcid.org/0000-0002-4199-5994

Elisabete Fraga de Freitas http://orcid.org/0000-0001-5132-7407

Manuel Filipe Costa http://orcid.org/0000-0002-1554-8779

Joaquim Oliveira 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.