Aerated Concrete

Void Filling Method|NLG method

NLG method (Non-air Long Distance Grout Injection Method)

NLG method is to fill back-side cavity of tunnels and hollows between structures and natural grounds by using non-air plastic grout. Especially, it is superior in long-distance pneumatic transportation, which is most suitable for long-distance tunnel maintenance/repair works. Plus, it can keep stable condition (no separation) underwater, which can be used where spring water is and underwater.

Advantages of NLG method (Non-air Long Distance Grout Injection Method)
  1. 1. Possible to transport long distance
    ●Long distance transportation has been made possible by pneumatically feeding main material (Liquid A) with high fluidity and plasticizer (Liquid B) in separate pipes respectively, and mixing them and injecting the mixture at the injection point (end of pipes)(Able to transport pneumatically 5,000m of horizontal distance)
  2. 2. Superior in fillability
    ●This method maintains fluidity by applying force (slight pressure) with plastic material, and fills without any material separations into cavities.
  3. 3. Excellent in both non-leakage and non-shrinkage
    ●By using plastic grout, this method prevents leakage from cracks and joints in tunnel lining and structures. In addition, since shrinkage of materials used is low, it is possible to keep tight adhesion between tunnel lining/structures and back side natural ground.
  4. 4. Superb underwater separation resistance
    ●Hardly get affected by water such as underwater placement and drift ice etc.; therefore, uniform condition can be maintained in underwater application, which makes it suitable for filling where there is spring water or retained water.
  5. 5. User-friendly and stable
    ●It is easy to prepare and handle Main material (Liquid A) and plasticizer (Liquid B) , which makes it easier to place and has high workability. In addition, non-air grout would not get affected by environmental conditions of where placement is taken place, which achieves quality consistency.


Maintenance and repair tunnels/conduits (Backfilling injection)
Void filling Method for under construction
Void filling Method for dugouts
Void filling Method for under abutment
Void filling Method for river revetment
Void filling Method for harbor revetment

Example of Construction

Long-distance pumping test
Void filling Method for waste pipes
Void filling Method for under construction

Major Achievements / Construction type and application ▶

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