Interlocking Armor Needs an Upgrade

Interlocking armor is used along many of our coasts and waterfronts as a versatile solution for building breakwaters, coastal erosion control, and land reclamation.  For example, the Afsluitdijk, a 32km long dam and roadway built across the North Sea, uses interlocking solutions for stabilization and as shock absorbers.

Proprietary interlocking armor like Accropode or Xblock are commonly used for infrastructures like the Afsluitdijk because they’re affordable, effective, and easy to install.

However, when it comes to the environmental impacts of these technologies, like damages to marine life and high carbon footprints, traditional armoring technologies are problematic. Because of lacking ecological consideration during construction, traditional concrete comes with large costs, both economic and environmental.

When coastal armor can work with nature, there is a high return on investment. A $75 million project to construct 8 breakwaters along New York’s shores faced a shocking $18 million environmental mitigation penalty cost for the infrastructure’s projected damages to the site’s environment. However, when ecological design changes and ECOncrete® technologies were implemented in these breakwaters’ design, the project’s mitigation penalties dropped to only $4 million. 

A Solution for Industry-Standard Coastal Armor 

Traditional interlocking coastal armors have smooth, flat-plane designs and harsh chemical compositions, making it difficult for marine ecosystems to thrive on and around these infrastructures. When the armor is placed in intertidal zones to protect from wave action or control erosion, the structures don’t mimic the form and function of natural coastal systems, like retaining water at low tide and supporting diverse ecology. To bridge the design gaps for interlocking armor, the infrastructure must be reengineered.

The Port of San Diego was searching for a structural solution that would not only protect port assets, but also help adapt to climate change, delivering co-benefits for the local economy, community, and environment. ECOncrete worked with the Port of San Diego to design armor that brings structural support and native habitat to rock riprap.



COASTALOCK is an interlocking single-layer concrete armor unit designed to perform for project and planet.  


“COASTALOCK is the trifecta we love: carbon sequestration, smaller footprint, while at the same time, providing resilience.”

Jason H. Giffen, Vice President of Planning, Environment, and Government Relations, Port of San Diego


Traditional concrete armor’s smooth surface is detrimental to the health of marine ecosystems: it provides no indents or grooves for organisms to grab onto, resulting in a bare, lifeless surface. To solve this issue, COASTALOCK has micro and macro features that allow marine organisms to grab on and thrive.

By mimicking the world’s greatest engineer, nature, COASTALOCK encourages bio-protection: biodiverse marine life which grow on the structure and create a protective layer, shielding the concrete from physical and chemical degradation. Through bioprotection, the magnitude and frequency of structural maintenance is reduced, which results in improved ecological stability as well as a greater return on investment.


“Environmental benefits and social benefits also produce tremendous value. Whenever we can generate more value by spending fewer resources and creating multiple public benefits, that’s smart, that’s good business, that’s positive leverage and that’s what we should be doing.”

Rafael Castellanos, Board of Commissioners, Port of San Diego


A tidepool, integrated directly into COASTALOCK armor, retains water at low tide. When the unit is rotated, the tidepool can also become an overhand or cave, providing shelter and breeding habitat for species that need different conditions. The ability to interlock at any orientation not only accommodates sensitive marine species, but also allows for versatile and flexible infrastructure arrangements. 

Most interlocking armor solutions can incorporate ECOncrete’s admix and texture technology, and most standard rock ripraps, revetments, and breakwater concrete single-layer armors can be fully-replaced by COASTALOCK to create natural and efficient shoreline systems. At the Port of San Diego, ECOncrete’s technology replaced sections of the rock riprap with armor well-suited for the Port’s future: effective, efficient, and climate-adapted. 

With sustainable planning, incorporating marine-friendly infrastructure can help ports build for the future.


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