Structural Integrity
Over its lifetime a concrete armour unit will be subjected to different loading scenarios as a result of its handling, placement, wave loading and rocking under extreme conditions. As breakwater armour units are unreinforced, it is important that the tensile stresses in the unit are low, even in extreme situations. With low tensile stresses a basic concrete mixture can be used.
For Xblocs a concrete grade C25/30 is used with a minimum tensile strength of 2.5 N/mm2 at 28 days (tensile splitting strength)
The structural integrity of the Xbloc® was evaluated using prototype drop tests and Finite Element calculations.
In order to assess the robustness of the Xbloc®, a series of drop tests were carried out using units of 4 m3 subjected to overturning and free fall tests. During these drop tests the stresses in the concrete were measured.
For the breakwater at port of Poti confirmative droptests have been carried out.
All studies indicate that the Xbloc® is a structurally strong unit able to cope with the loads that can be expected during its lifetime from manufacture to operation. The inherent structural integrity of the Xbloc® makes it a reliable armour unit in the long term.
Finite element mesh of Xbloc® unit 
Internal stresses during free fall (left) and flexure loading (right)
