The Core-loc®

The Core-loc concrete armour unit which is patented by the United States Army Corps of Engineers represents the latest technology in armour units. The new unit has been used in coastal breakwater structures since 1996. There are currently (2003) 19 structures worldwide where Core-locs have been used. The development of the Core-loc represents the culmination of many years of research at the US Army Waterways Experiment Station’s Coastal and Hydraulics Laboratory (CHL). The armour unit has been developed to produce an efficient use of concrete with sufficient strength and robustness to achieve a cost effective, highly stable structure.


The Core-loc is available world wide through a network of five exclusive international licensees covering specific geographical areas of the world. The licensees work together with CHL on research and development, project technical advice and quality control to support users in the appropriate and correct use of the unit.

A royalty for the use of the unit is charged to cover the development, research, and project specific technical assistance on design and construction. This advice is available to the project owners, project designers and construction contractors. As a rough guideline the royalty is equal to approximately 10 percent of the cost of the placed armour units.