Externally funded project

Development of self-compacting backfill material with root growth impeding properties under preferential use of locally excavated material – to protect tree roots and subterranean infrastructure in urban areas (Root restraining backfill material)


The Installation of cables, supply and disposal lines is still done by open building method. Here, a ditch is being excavated, pipes and lines are laid and consequently it is filled with and covered by bulk material, which is then compacted. These refilled ditches are areas where the roots of urban trees preferentially grow, due to the limited space that the roots have and the better supply of water and nutrients there. Because the roots are entangling the pipes and supply lines, the tree is severely damaged or even has to be chopped when maintenance work on the lines has to be done. In order to reduce the competition between urban trees and urban subterranean infrastructure, this project, which is funded by the German Federal Environmental Foundation (DBU), aims at studying different recipes for self-compacting backfill materials with root growth impeding properties. These materials are supposed to sheath pipes and lines void-free and without any tension, in order to restrain the root growth in these areas. Trees are of crucial importance for urban ecosystems and therefore it is critical to conserve them. This project therefore targets at not only enabling a balanced coexistence of urban trees and subterranean infrastructure, but also avoiding costly re-opening of ditches, tree harming cutting of roots and time consuming maintenance work. Further positive side effects are reduced costs for network providers and local municipalities, as well as reduced noise and dust emissions for passersby and local residents.

Last updated on 2019-30-01 at 08:07