Air purification by pavement blocks: final results of the research at the BRRC

status: publishe

Hoe dragen betonstraatstenen bij tot het comfort van de fietser?

status: publishe

Water pervious concrete pavement blocks: durable structures for an integrated water policy

Water pervious pavement blocks are a durable and ecological solution to prevent water run off, to minimize the risk of flooding and to increase the efficiency of water purification. The application of water pervious pavement blocks on a permeable base and/or sub base allows buffering of the rainwater in the structure and infiltration or retarded outflow to the ground or infiltration system. This paper presents the results of a research project, conducted at the BRRC during 4 years. The efficiency of water buffering and infiltration in relation to the choice of material is investigated in the laboratory, on a test parking lot and on site. To allow a good choice of the materials and the application site and to control the efficiency on site, different test methods are optimized. Results for different types of concrete pavement blocks (pervious blocks, blocks with enlarged joints or drainage holes), different types of base layer (hydraulic bounded or unbounded materials) and different types of sand layer and jointing materials are looked at. Finally this paper focuses on several applications in Belgium, where measurements have shown a good behavior of the structure and a good durability of the permeability. Data from newly constructed projects, as well as projects in use for more than eight years are presented.status: publishe

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

Fotokatalyse: een toekomsttechniek?

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Recent Photocatalytic Applications for Air Purification in Belgium

Photocatalytic concrete constitutes a promising technique to reduce a number of air contaminants such as NOx and VOC’s, especially at sites with a high level of pollution: highly trafficked canyon streets, road tunnels, the urban environment, etc. Ideally, the photocatalyst, titanium dioxide, is introduced in the top layer of the concrete pavement for best results. In addition, the combination of TiO2 with cement-based products offers some synergistic advantages, as the reaction products can be adsorbed at the surface and subsequently be washed away by rain. A first application has been studied by the Belgian Road Research Center (BRRC) on the side roads of a main entrance axis in Antwerp with the installation of 10.000 m² of photocatalytic concrete paving blocks. For now however, the translation of laboratory testing towards results in situ remains critical of demonstrating the effectiveness in large scale applications. Moreover, the durability of the air cleaning characteristic with time remains challenging for application in concrete roads. From this perspective, several new trial applications have been initiated in Belgium in recent years to assess the “real life” behavior, including a field site set up in the Leopold II tunnel of Brussels and the construction of new photocatalytic pavements on industrial zones in the cities of Wijnegem and Lier (province of Antwerp). This paper first gives a short overview of the photocatalytic principle applied in concrete, to continue with some main results of the laboratory research recognizing the important parameters that come into play. In addition, some of the methods and results, obtained for the existing application in Antwerp (2005) and during the implementation of the new realizations in Wijnegem and Lier (2010–2012) and in Brussels (2011–2013), will be presented