Fyllning kring kablar och rör med krossat bergmaterial

Sammanfattning: Ground consultants and pipe manufacturers follow various recommendations, two of which are AMA (General Material and Work Description) and EBR (Powerlines branches guidelines). The project focuses on the AMA references to the installation of pipes and cables. The requirements given by pipe and cable manufacturers, as well as why ground consultants in some cases deviate from AMA´s referrals. The project's main goal is to investigate why ground consultants choose to deviate from AMA Construction with regards to protecting cables and pipes. Usually crushed rock is used with a size around 0/16 mm, although AMA Construction recommendations approves backfilling materials with a particle size up to 31.5 mm.  During the course of the project, several ground consultants and manufacturers have been contacted to gain a deeper insight into what controls the choice of backfilling. The second objective has been to evaluate the fractions ground consultants choose to deviate from. By doing so a comparison and an analysis given by the technical data can be done,  to estimate the materials suitability as backfilling. The project has also investigated the possibility to use other materials as backfilling, in this case recycled asphalt. After interviewing the ground consultants and municipalities, our assessment is that they choose to deviate from AMA and use crushed rock fractions around 0/16 mm. The choice of backfilling is governed by availability and manageability of the material. No recycled materials are used by the interviewed parties. Based on the laboratory results, it’s shown that the fractions 0/31.5 mm in theory are better suited for backfill compared to the lower fractions in terms of chipping characteristics.  The fractions currently used lie around 0/16 mm and show a higher proportion of fine materials and significantly higher chipping. The results from recycled asphalt shows that this would be an exemplary replacement for backfilling material, if it weren’t for the fact that it should be reused for the production of new asphalt. Using this for any other purpose would have a negative impact on the environment, also the extra work needed to crush the asphalt to the right proportions, and its availability makes this a less attractive material compared to crushed rock. Key words: AMA, backfilling, ground consultant, crushed rock, particle size, fractions, chipping.