A-Jacks are high stability concrete armor units that are used in river, lake,
and coastal applications to control erosion, stabilize shorelines, and provide
Applications in rivers include the protection of river banks, toes, bridge piers,
overflow structures, and drop structures. In lakes, bays,
and other sheltered water settings, A-Jacks are often used to control erosion
associated with small waves. In both river and lake applications they are also
used to provide habitat and may be combined with bio-stabilization methods. In
river and lake applications, the size of the A-Jacks tend to be small, typically
0.6 meters (2 feet) in length with a weight of 35-40 kg (77-88 lb). These units
are small enough that they may be produced in a conventional block machine and may
be hand placed.
In coastal applications A-Jacks are typically used for reefs, revetments, and
breakwaters and may also be used to provide habitat. The size of units in coastal
applications ranges from 2 to over 4 meters in length (6.4-13.1 feet) with
corresponding weights up to 18 tonnes (20 US tons). The larger units may be wet
cast at a prescast yard or produced on site.
A-Jacks are placed in a layer that is one armor unit thick. They may be installed
in random or uniform placement patterns. Uniform corresponds to a
special placement in which the units weave together into an extremely stable geometry.
Technical and product support for A-Jacks is available in many regions. To obtain
contact information for the representative in a specific region, please email: