Research Project REBIBA

Bitumen membranes are an important building material for waterproofing buildings. In Europe, around 70 % of all new flat roofs are waterproofed with bitumen membranes. Bitumen membranes typically consist of a carrier material, usually glass or plastic fleece, which is coated on both sides with bitumen (compounds). Mineral granules, slate tiles or metal foil laminations are used as surface finishes. The bitumen compounds used consist of distillation bitumen in combination with various additives. In particular, elastomers or plastomers are used to modify the bitumen compounds to improve their performance properties. In addition, the properties of the bitumen compounds are further customised with the help of fillers such as limestone or rubber powder.
This project aims to overcome scientific and technical obstacles to the continuous recycling of bituminous waterproofing and roofing membrane waste in Germany. To this end, all processing steps for the extraction and treatment of recovered bitumen membranes from construction waste are being considered as a valuable resource for applications in building construction in the form of new bitumen membranes. New techniques for material characterisation and quality control of the (recovered) bitumen compounds are being developed from a scientifically innovative perspective and the ageing process of bitumen membranes is being fundamentally investigated. The new test methods form the basis for material recycling using rejuvenating agents and the implementation of a continuous recycling process. They also provide new insights into the material science of (aged) bituminous waterproofing membranes. In addition, an iso-compliant life cycle assessment quantifies potential environmental impacts over the entire life cycle of bituminous membranes, identifies sustainability potential and enables targeted optimisation.

Zukunft Bau  Research funding - Basic research

Funding Organisation: Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR)

Titel (translated): "Recycling of bitumen membranes for structural waterproofing" - technology principles and requirements, material characterisation, process engineering, process safety

Acronym: REBIBA

Duration: 24 months (01 November 2023 - 31 October 2025)

Project management: TU Braunschweig, Institut für Straßenwesen (ISBS)

Project partner:

• C. Hasse & Sohn Inh. E. Rädecke GmbH & Co. KG (HASSE)
• Lehrgebiet „Werkstoffe des Bauwesens“ der OTH Regensburg (OTH)
• Institut für Mechanische Verfahrenstechnik und Aufbereitungstechnik der TU Bergakademie Freiberg (MVTAT)

Objectives in detail

• Identification of necessary collection processes, suitability and acceptance criteria with regard to pollutants (asbestos, pesticides, etc.) and foreign materials (wood, polystyrene, etc.) for roofing membrane waste
• Selection and development of suitable mechanical and wet-chemical processing methods as well as production and provision of various roofing membrane components from diversified roofing membrane waste
• Consideration and differentiation of existing recycling technologies through detailed comparison of existing patents
• Development and testing of new characterisation methods for assessing the quality of bitumen compounds (and recycled components) using simple and rapid rheological test methods
• Understanding the ageing behaviour of bitumen compounds for roofing membranes and its influence on the resulting roofing membrane properties as a basis for mix design in the context of recycling
• Development of formulations on a laboratory scale using recycled components, identification of necessary fresh raw material components (bitumen, rejuvenators, etc.) and determination of possible addition quantities depending on the condition of the roofing membrane waste and variation of processing techniques
• Selection of the most promising formulations and production of prototypes of roofing membranes in the laboratory as well as performance of established laboratory tests as proof of suitability
• Identification of necessary process steps and prerequisites, as well as development of recipes for continuous large-scale recycling of roofing membrane waste
• Assessment of the ecological impact and potential savings through recycling