Iron-silicate stone as an extra load and as harbour bottom protection

Increasingly larger vessels and current action repeatedly cause erosion on the bottoms of harbours, canals, sluice areas and rivers that can be remedied or even avoided by the use of iron-silicate stone.

A hydraulic construction stone mixture for these applications is produced by optimal mixing of individual fractions of iron-silicate stone. Areas of application are:

1. Securing of beds to avoid scour

  • at wharfage
  • in ferry niches
  • in sluice areas
  • in rivers and canals
  • at bridge piers

2. Extra load to increase ground resistance

  • at shore edges and wharfage
  • for troughs
  • in tunnel construction

3. Securing bank slopes/stabilisation against erosion of covering

Large amounts of hydraulic construction stone mixture made of iron-silicate stone have been successfully used for the various problem areas in the whole of the North German region since 1975.

Once applied, this hydraulic construction stone mixture fulfils its task for decades and braves increasingly high exposure to stress. Subsequent improvements or reconstruction are thus kept to an absolute minimum.

Technical data:

Composition of hydraulic construction stone mixture:

  • Crushed stone fines 0/5 mm
  • Balast chipping 5/22 mm
  • Gravel 22/45 mm
  • Hydraulic construction stone CP45/125

The exact composition can be modified individually depending on the project requirements:

  • Dry bulk density ~ 3.65 t/m
  • Bulk density ~ 2.30 t/m
  • Bulk density under upwelling conditions ~ 1.67 t/m



  • Stone mixture low in voids
  • Very high bulk weight under buoyancy
  • Graduated particles with effective filter
  • High inner friction angle
  • Flexible underwater rock position
  • Simple and cost-effective single-layer fixture
  • Simple and cost-effective subsequent improvement
  • Suitable for ramming
  • Unproblematic economical extension

Further information ...

Table of mass per unit area river bed construction