The main advantages of Xbloc are:

  • Robust and durable with a track record of more than 15 years
  • Lowest concrete consumption compared to other available armour units (same as XblocPlus)
  • Adaptability to sharp curves and roundheads
  • Rough/industrial appearance


Xbloc units are randomly placed, interlocking concrete armour units. They have been developed by DMC and were introduced to the market in 2003. Since then Xbloc units have been applied successfully all over the world. The units have been used in breakwaters and shore protection projects on 6 continents in block sizes ranging between 1.8ton and 40ton. A track record of the Xbloc projects can be found here.

Xbloc units on the slope of a breakwater
Xbloc units on the slope of a breakwater during construction

Optimized shape

The Xbloc has a high hydraulic stability (Stability coefficient of KD = 16), requires a simple mould to be cast, is easy to handle and to place, and is a very robust block

Xbloc has been developed with ease of placement as main objective. Due to its symmetrical shape, the units interlock on all sides and as a result, less placement rules apply than with many other single layer blocks. Xbloc placement is typically faster than placement of earlier single layer blocks.

Due to the angular shape of the Xbloc, the units interlock very efficiently which leads to the high hydraulic stability. The shape however also leads to a high porosity which reduces wave overtopping. The high porosity also results in a reduced concrete consumption which makes Xbloc the most economic armour unit in the market until the introduction of XblocPlus.

Due to the bulky shape of the Xbloc, it can be made of unreinforced concrete with relatively low concrete strength (C25/30 for blocks up to 24ton). The block shape allows for practical block handling, storage and placement.

Xbloc units have been studied in detail over the last 18 years in scientific research and with project specific objectives. A number of research papers and student thesis’s can be found in the list of publications.