Environmental Friendly Concrete Pavement Blocks: Air Purification

SUMMARY The use of materials can influence to a large extend the environmental impact of traffic and of road infrastructure. Especially at urban areas, where the risk on smog formation during hot summer days is high, the use of photocatalytic pavement blocks can reduce the air pollution significantly. A project on environmental friendly concrete pavement blocks is conducted at the Belgian Road Research Centre, subsidised by the Flemish government (IWT). The use of photocatalytic material in the surface of pavement blocks to obtain air purifying materials is investigated. In contact with light, TiO 2 as photocatalyst, is able to reduce the NO and NO 2 content in the air, caused by the exhaust of traffic. The efficiency is tested on pavement blocks, but the technique can as well be applied on other road elements (noise reducing walls, linear elements, etc.) or as a coating on new materials or existing structures. The first part of the project concentrated on the behaviour of the material in the laboratory. The parameters of the testing method are determined, as well as the behaviour of the material over time. The second part of the project concentrates in the translation of these laboratory results to real site measurements. A pilot project is started in Antwerp, at a main city road through the centre. 10 000 m² photocatalytic pavement blocks are placed. Measurements on the efficiency towards air purification of the pavement blocks are carried out. This paper focuses on the environmental aspects of the types of materials, the mechanism of air purification. A review of the results obtained in the laboratory as well as first results from the site is discussed