When renovating pipelines using no-dig methods, it is reasonable to also renovate manholes to ensure the entire system is waterproof and has an extended lifespan.
If the diameter of the existingmanhole allows, it is possible to install a new PE well into the body of the old well and fill the gap with sand or lightweight concrete. Usually, the removal of the old manhole cover is still necessary.
A second alternative is to renovate the existing manhole by using the cement grouting method. Firstly, the walls of the well are cleaned and washed with a high-pressure washer to remove grease and fine particles. After that, leaks and damaged areas are repaired with special mixtures. In the last stage, a special cement grouting layer ( in some occasions even more layers) is applied to the body of the well, which protects the well wall from further decay. If necessary, a stainless-steel net is installed to reinforce the body of the well. A screw pump mixing device is used with a rotor sprayer to apply the cement grouting layer.
Nordig OÜ uses a mobile Putzmeister SP 11 LMR mixing device for cement grouting.