BAM Infraconsult / Delta Marine Consultants

XBlocs prevent harbours

xblocksXBlocs are the most economical single layer armor unit. The average concrete saving yielded by incorporation of Xbloc units is up to 15% compared to other single layer armor units.

Casting and placing the Xbloc unit is straightforward and is very cost effective. Xbloc has been applied on shore protections and breakwaters all over the world already for a decade and has proven to perform outstanding.

XBlocs eco and safety

In addition Xbloc has proven to be very ecofriendly as the random structure and high porosity of an Xbloc armour layer provide a good habitat for different kinds of marine vegetation and animals.

  • Xbloc continues to be innovative as the toe unit Xbase and Eco Xbloc show.
  • The special toe unit Xbase has been developed for use with Xbloc armour.
  • On the Eco Xbloc the concrete surface texture can be adjusted to stimulate marine growth and improve the ecological value of the armour unit.

Excellent hydraulic stability

  • For concept design a Kd value [stability coefficient in the Hudson formula] of 16 [trunk section] and 13 [head section] should be applied;
  • The stability coefficient of the Xbloc is the same for breaking and non-breaking waves;
  • Xbloc has a safety margin of at least 20 % without damage to the armour layer. See also: Hydraulic Performance of Xbloc Armour Units.

Automatic interlocking

  • Xbloc units naturally find a stable position on the slope;
  • Self repairing of the Xbloc armour layer after damage is enhanced by automatic interlocking;
  • The Xbloc unit is simple to place, due to the straightforward placement principle.

Low wave overtopping

  • The highly porous armour layer minimizes wave overtopping. For more information see: CLASH test results: Overtopping performance of different armour units for rubble mound breakwaters;
  • For guidance on overtopping coefficients see: Overtopping and Wave reflection.

Low wave reflection

  • The highly porous armour layer minimizes wave reflection:
    Wave reflection from coastal structures by B. Zanuttigh and J.W. van der Meer;
  • For guidance on reflection coefficients see: Overtopping and Wave reflection.

Outstanding structural integrity

The structural integrity of the Xbloc was evaluated by using:

  • Prototype drop tests [The Netherlands, Georgia, Ireland and U.A.E.];
  • Finite element calculations.


facts & figures Xbloc




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Royal BAM Infra
Founder / contact person: Bas Reedijk

PO Box 63
2800 AB Gouda
T. +31 (0)182 59 06 00