Quality assurance

Quality assurance

In order to guarantee the high quality of liquid soil in terms of avoiding foreign bodies under roads in backfilling areas, the RAL Gütegemeinschaft Flüssigbodene.V. (Quality Association for Liquid Soil), recognized by the RAL Deutsches Institut für Gütesicherung und Kennzeichnung e. V. (RAL German Institute for Quality assurance and Labelling Association) was initiated by clients, network operators and local authorities and established in 2009 as a representative of the quality requirements of network operators and road builders. The minimum extent of the requirements to be complied with for the application of the liquid soil method, of the necessary tests and the sensible procedures are specified by the Quality and Testing Specifications of the RAL quality mark 507 (RAL Quality Assurance for Liquid Soil e.V.). The requirements of this quality mark, together with the experience gained with the method since 1998, form the basis for quality assurance. 

Qualification and further training

DThe acquisition of the qualifications as a Certified Quality Assurance Commissioner for Liquid Soil according to RAL quality mark 507 takes place with the examination by the RAL quality association liquid soil in co-operation with research facilities of universities and institutes already experienced in this area, and with the developers of the method. 



The regulations governing the principles of quality assurance of liquid soil (eg ZTV-A-StB97) prescribe the forms of monitoring:In the case of self-monitoring, the executing company monitors itself; in the case of external monitoring, an additional recognised monitoring body provides monitoring.Self-monitoring must always be carried out.It includes the execution of necessary tests and their recording.The special quality assurance of the liquid soil is carried out by means of:

  • Scope of initial testing according to the guidelines of RAL-GZ 507 (suitability test)
  • Scope of self-monitoring according to the guidelines of RAL-GZ 507
  • Scope of external monitoring according to the guidelines of RAL-GZ 507

The Quality and Testing Specifications of the RAL Quality Association for Liquid Soil, including the associated test requirements and rules, define all requirements to be met for the use of liquid soil based onthe experience of developers and users.These Specifications are currently available in their secondversion in the form agreed by the quality association.The latest findings from research and applications are continuously incorporated into these principles of quality assurance.