Ultra-Thin Sealing Surface Treatments for Solar Radiation Screening on Asphalt Facing Dams

Abstract

Bituminous materials are widely used in a large range of hydraulic applications due their excellent waterproofing properties. More than 300 asphalt facing reservoirs were built in the last century, presenting higher mechanical and hydraulic performance when compared with other facing alternatives, such as cement concrete or steel membranes. On the other hand, the dark colour of bitumen may lead to high temperatures inside asphalt paved system, affecting long term ageing of binder and jeopardizing the quality of the impervious layer. Recently, multifunctional ultra-thin surface treatments are becoming an alternative to demolition-reconstruction of the impervious layer, significantly abating the quantity of energy and raw materials required for maintenance. High-reflective surface treatments may represent also an effective solution to reduce the temperature of asphalt layers, extending the service life of the dam embankment and reducing the need of maintenance. In fact, there is a lack of literature concerning the assessment of thermal impact on asphalt dams. In the light of above, a number of different combinations of sealing surface treatments were investigated in this study. An ad hoc testing equipment and procedure were designed to perform an artificial solar irradiance test. A complete colorimetry analysis was performed and the outcomes were compared with temperature data, making use of a thermal camera and of embedded sensors for surface and base temperature measurements, respectively. Major results and their relationships have been commented in-depth along with proposed further research activities.

Keywords: Asphalt dams, Sealing membranes, Colorimetry analysis, Solar irradiance, Lightweight aggregates