The shotcrete technology consists of applying a layer of special mortar on the interior of the pipeline

So far drinking water supply , sewerage, heating and gas pipelines could not be effectively protected against corrosion.

The rehabilitation technology used by CALA is a trenchless rehabilitation method classified as a No-Dig technology. This method was developed and practically tested by ensuring the recovery of the pipeline’s interior by achieving corrosion protection. This technology allows closing cracks of defined dimensions (diameters of 3 mm).

The conception principles of this technology have developed a method of quick execution, able to undertake the rehabilitation and protection of pipelines, with long term guarantees, and at acceptable costs.

Underground water, sewerage, heating and gas pipelines are subject to permanent damage due to internal corrosion. The cause of this corrosion is largely determined by characteristics of the agent transported through them and the time factor.
The pipes are deteriorating rapidly (sometimes after just a few years), due to continuous action of the transported agent.

For steam and condensation pipelines from central heating, there was no rehabilitation technology, until now, without replacing the pipeline.

Replacing the damaged pipeline implicates a big volume of paperwork and huge costs. Pipeline replacing works require taking the pipeline out from usage for a long period of time, which has negative effects on population activities, economical agents’ activities, and the environment.

Through this technology, CALA offers a relatively quick, economic and ecologic alternative for repairing damaged or worn pipelines.

Main technological stages:

  • Video inspection of the pipeline
  • Cleaning of the pipeline
  • Coating the pipeline with special mortar – shotcrete
  • Post-rehabilitation video inspection and recommissioning of the pipeline

Pipeline rehabilitation is made on sections between expansion joints or between the valves. The maximum length of a section is about 400 m. Pipeline diameters are between 80 mm and 3400 mm. After cleaning, heavily corroded pipes are subjected to a pressure test. If pressure loss is found, the commissioning of the pipeline is done after a minimum of 7 days post rehabilitation.

The shotcrete product is prepared according to the recipe, a mixture in determined proportions of cement, sand and additives. The application process involves coating the pipeline with a cement-like lining. The material ensures a good grip on pipe walls and takes over all temperature variations resulting from heating and cooling cycles.

The economic advantage of this new technology is greater than the costs of replacing the worn or clogged pipelines and, also, the disposal costs for these, according to environmental protection laws.

In case of water pipelines, the economical advantages are even greater, due to the large depths where the pipelines are installed. Therefore, because of the material’s properties and the methods of application of this technology, a pipeline’s refurbishment is very easy to achieve and provides perfect restoration.

The main requirements for materials used in refurbishing the pipelines are:

  • high elasticity at working temperatures between 20 and 250 °C
  • good adhesion to rehabilitated pipeline walls
  • resistance to high temperatures
  • resistance in time to corrosion
  • qualities of filling the holes / cracks of different sizes
  • assuring impermeability at the pressure of the medium transported through the pipeline
  • ability to take over the pressure solicitation from pipelines with little resistance