Outdoor performance tests of self-cooling concrete paving stones for the mitigation of urban heat island effect

Rising temperatures worldwide pose an increasing challenge for safe and healthy living conditions. Particularly inner cities have been affected by these environmental changes because of the materials used to build houses, streets and infrastructure. The most common building material is concrete. It shows a specific heat capacity, while the heat conductivity for standard concrete is low. Thus, the use of concrete generates a high capacity of heat storage. In addition, extensive soil sealing also contributes to the temperature rise of inner city areas compared to their surroundings. To mitigate this so-called urban heat island effect, a self-cooling concrete paver was developed. This paver is able to store water. The evaporation of the water at elevated temperatures provides a cooling effect. This paper focuses on determination of this new paver’s capability to cool the surface and the surrounding. The new paver’s cooling qualities were analysed in a series of laboratory tests. To prove the results outside of laboratory conditions, two fields (12 m × 8 m) with self-cooling and reference pavers were installed in Spain. This paper presents and discusses the results of the tests. Correlation between reduced surface temperature of the self-cooling concrete pavers and the air temperature is examined.