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Hesselberg Hydro

Open Stone Asphalt

Structure and Properties

  • An underfilled, gap-graded mixture of mastic and limestone (other rocks may be substituted where water is acidic or abrasion is likely)
  • Permeable
  • Strong and porous so it absorbs wave energy without damage
  • Can be placed on slopes up to 1:1.5
  • Follows all shapes and contours when placed in situ above the waterline
  • Can be placed underwater as prefabricated mattresses


  • Armour layer for river training
  • Armour layer for revetments in flood control and coastal protection
  • Armour layer for dam upstream faces
  • Armour layer for spillways and dam downstream faces
  • Scour protection for quays