WALO has world leading, established, technical engineering knowledge and the necessary modern specialist plant and equipment to provide a Dense Asphaltic Concrete (DAC) impermeable barrier system anywhere and for any situation.

WALO’s DAC lining system, made from clean aggregates, fillers, sand and bitumen is installed using specialised laying and compaction techniques. Due to its high density, DAC is extremely resistant to chemical attack, while being very strong and still flexible.

DAC - at a glance

What is DAC?

DAC consists of high-grade aggregates, sands, fillers and bitumen and if needed, additives.

Where is it used?

DAC is used as an artificial sealing system in hydraulic engineering works. It is proven as an ideal solution for lining dams, central dam cores, reservoirs, canals, ponds, tailing lagoons and waste disposal sites.

What special qualities make DAC an ideal lining system?


  • is quick to lay (outputs of over 5000 m2 can be achieved on a daily basis).
  • is totally impermeable against very high pressure of water and liquids.
  • withstands large and rapid changes of water levels and temperature.
  • is relatively thin.
  • remains very flexible, even under extreme pressure.
  • is extremely stable, even on steep slopes (slopes up to 150 m long and gradients in excess of 1:1.6 can be achieved
  • In some circumstances DAC can be placed nearly vertical adjacent to walls.
  • is very robust, so withstands traffic, rock falls or ice abrasion immediately after placing without the need for additional protection.
  • is environmentally friendly and non-toxic.
  • is resistant to ageing with proven longevity.
  • forms a totally impermeable barrier with no joints
  • Approved by Regulatory Bodies around the world