In 1999 Aarsleff commenced the first stage of the harbour extension at Port of Århus. The first stage comprised a new 200,000m² container terminal to relieve the existing terminal.

At water depths of 12-14 m Aarsleff constructed 2.6 km of outer breakwaters and 1.8 km of access embankment with stone protection. The breakwaters are constructed of a sand core with sand reclaimed from the Århus Bay. The sand slopes were secured using a slope drainage revetment of gravel and grabbed stones and subsequently covered with blocks of rock.

Furthermore, Aarsleff has constructed a 530m quay construction as well as supplied and driven 2,500 tons of sheet piles. Subsequently, 12 km of concrete piles in lengths ranging from 22-31 m were driven. Aarsleff also constructed the reinforcement and concrete works for the quay wall and cantilevers.