2022 BASt - Trenching in asphalt
Table of contents
Evaluation and optimization of the production and closure variants of trenching cuts in the asphalt superstructure and assessment of the effects in the life cycle of the road
Project staff
Dipl.-Geol.-Ing. (FH) Bettina Gerowski
Contracting Authority
Federal Highway Research Institute
Project period
07/2022 - 06/2024
Abstract
As part of the research project, a basis was created for the application of the trenching process with regard to the use of the selected backfilling methods and the backfilling materials used. For this purpose, extensive laboratory tests were carried out on the backfill materials under laboratory conditions as well as under construction site conditions in the context of a test section. Furthermore, extensive sensitivity tests were carried out using the finite element method.
Comprehensive finite element calculations were carried out using the COMSOL Multiphysics software to evaluate the influence of different slot geometries (trench geometries) on the stress conditions in the individual asphalt layers of a pavement and in the trench laid, as well as on the predicted service life of asphalt base layers.
Based on the finite element calculations, recommendations could be derived regarding the material properties of the asphalt and the backfill materials, the geometry of the slots and the position of the slots in the road cross-section.
Recommendations for the determination of criteria for qualitative design were developed on the basis of the design of the test section.
A simplified approximation method was developed to estimate the subsequent costs for the road construction authority, depending on the backfilling material / backfilling method used.