Reflective pavement can go a long way toward reducing the urban heat island effect, but the embodied energy and emissions in some materials may present unexpected drawbacks, according to new research from the DOE'S Lawrence Berkeley National Laboratory. The research team conducted lifecycle assessments of conventional and cool pavement materials and simulations of building energy consumption to examine the environmental impact of each material's full lifecycle. Asphalt concrete, the most common material used for pavement, is dark and has a low albedo (a measure of solar reflectance). Cement concrete is lighter, and thus has a higher albedo, but it requires a high-temperature process that is considerably more energy- and carbon-intensive than making asphalt from petroleum.Albedo affects buildings by reflecting more or less sunlight to them and by changing the outside air temperature, though a higher reflectance is generally considered a positive as less heat is absorbed.
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