Warming of Urban Street Surfaces During Summer Heat Waves

The global warming of our planet has a special impact on urban areas, because large cities are characteristic for the development of so-called urban heat islands. This modification of the climate of a city in comparison to the climate of their hinterland is based on a multiplicity of factors like the settlement structure, the urban canyon effect, the heat emissions of buildings and the building materials used. To investigate this topic field tests were carried out at the Research Institute of the Association of the Austrian Cement Industry (VÖZFI) to measure the thermal behaviour of different materials used for pavements. These tests showed clearly, that a difference of the surface temperature between concrete and asphalt is clearly noticeable. To analyze the impact of the difference of the surface temperature of concrete and asphalt on the warming of cities, a simulation on a fictitious street canyon was carried out in cooperation with professor Kre? from the Technical University Vienna (TU Vienna). These computer simulations confirm the measured results and show that the felt temperature in the area of a street can be reduced noticeable due to the use of bright concrete as a street construction material.