Reflectance of Gray and White Compressed Concrete Paving Units with Different Surfaces

This study aims to measure the reflectance of outdoor compressed concrete paving units. The samples are in common size of compressed concrete paving units which is 20cm * 20cm * 6cm. The first cause of gradually worsening environment is that most of artificial pavements and building shells in the cities are made of materials at low reflectance, so that a large amount of heat energy accumulates inside the materials. In the development of urban environment in Taiwan, the building roofs and artificial pavements account for 80% of total area of cities. The negative influence of building materials and artificial pavements on the environment is expected to be reduced by improving the utilization of materials at low reflectance. The experimental results of this study showed that the surface roughness of compressed concrete paving units is proportional to the reflectance. When the material surface is smooth, the reflectance of material is high; for rough surface is (e.g. sandblasting, waterproofing), the material reflectance is low. Therefore, it is suggested to use the materials with smooth surface when planning urban paving materials, so as to increase the material reflectance to reduce the urban environment temperature. Keywords-reflectance difference value; flat tile; rustic tile; permeable tile; terrazzo; sandblasted tile.