Why use DAC to construct a core for an earth embankment dam?

• Provides a highly robust, waterproof layer.
• An asphaltic core’s enormous strength prevents any chance of a hydraulic base failure and, as it is not exposed to any UV radiation or weathering, it does not age so very little ongoing maintenance is required.
• Withstands huge pressure, while remaining flexible and impervious.
• Properties of asphaltic concrete can be tailored to specific design criteria so, which makes these cores well suited to dams located in earthquake regions or on compressible foundations.
• Asphalt is a natural non-toxic material, so it is ideal for drinking water reservoirs and is non-harmful to the environment.
• Construction times are shorter compared with those with clay or moraine cores, reducing cost and enabling the reservoir to be flooded at the earliest opportunity.
• As the core and embankments are constructed simultaneously, water can continue to be impounded during the construction period.
• Installation of an asphaltic core is less affected than other types of cores by bad weather conditions which means works can more easily be kept on schedule.
• This type of asphaltic core can be the sealing method in areas with extreme climatic condition.
• Provides a practical solution if natural sealing materials of appropriate quality are not available locally.

Construction method

The construction of a watertight membrane using DAC, in the axis of the embankment, is made simultaneously with the earthworks. The asphalt and the materials for the adjacent transition layers are placed into a core finisher – a highly sophisticated, technologically advanced machine specially developed for this task by our engineers.

The core finisher travels along the embankment axis and applies both the asphaltic concrete core and the two transition layers (also called ‘filter zones’) in the center of the structure. The asphalt layers are 8 – 10 inch (200 – 250 mm) thick and are heated using infra-red heating appliances, enabling them to be perfectly sealed. The core finisher applies the initial compaction to both the asphalt core and the filter zones, and vibrating rollers do the finishing works.

To ensure consistent quality standards, the WALO laboratory regularly makes on-site checks of all materials.