Re­search 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



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.

Pro­ject Leader

Prof. Dr. Stephan Peth


01.09.2014 - 31.08.2015


Deutsche Bundesstiftung Umwelt

Pro­ject part­ners

  • Universität Kassel
    Prof. Dr. rer.nat. Bernhard Middendorf
    Fachbereich Bauingenieur- und Umweltingenieurwesen
    Fachgebiet Werkstoffe des Bauwesens und Bauchemie
    Mönchebergstr. 7
    34125 Kassel
  • Stefan Kimm-Friedenberg
    KIMM Sand-Kies-Betonerzeugnisse Fertigbeton GmbH & Co KG
    Stegerwaldstr. 26-28
    34123 Kassel

Doc­toral stu­dent

MSc Vincent Felde