Building Information Modelling (BIM) as a basis for handling digital information to optimise material cycles in the construction industry

Funders: DBU - Deutsche Bundesstiftung Umwelt

Project term: 01/2017 to 12/2018

Closing material cycles in the construction sector usually fails because of building products that cannot be recycled or can only be recycled at great expense. In addition to the lack of information on the whereabouts of the respective products at the end of a building's useful life, this is due to the increasing variety of building products used in the building construction sector. Many building products have defined properties that predestine them for use in buildings depending on their area of application and purpose, but also lead to an ever-increasing heterogeneity of construction waste.

The aim of the research project is not only to optimise recycling, but also to increase the ease of repair in the event of damage or renovation, in order to be able to return the highest possible proportion of materials to the raw material cycle. Furthermore, through extensive and early recording and storage of product and material-related information (e.g. with regard to hazardous substances) on the installed materials and their allocation to the installation location in digital building data models, the concerns of occupational health and safety and environmental protection are to be taken into account much better than before during maintenance or repair during the operating phase and during dismantling.

To achieve the above-mentioned goal, it is necessary to analyse, record and document relevant processes and material- or product-related data. For this purpose, two different life cycles are considered from the point of view of building materials, the life cycle of the building material itself (Figure 1) and the life cycle of the building structure (Figure 2). The life cycle of the building material is divided into the phases "Herstellung, Verarbeitung, Rückbau und Aufbereitung bzw. Entsorgung" (production, processing, deconstruction and reprocessing or disposal). In contrast, the life cycle of the building is divided into the phases of "Entwicklung, planung, Realisierung, Betrieb und Abbruch" (development, planning, realisation, operation and demolition). In this research project, the focus is on the "realisation and demolition" phases, which are important with regard to building materials. Demolition is understood on the one hand in the sense of the total dismantling of a building and on the other hand as a sub-process within the framework of a maintenance measure.

By considering both life cycles from a process perspective with a focus on the information flows, all relevant information of the most important construction and mass building materials should be analysed and documented. In the present research project, steel, construction metals, mineral building materials (concrete, masonry, plaster), dry construction materials, adhesives, carpets and interior paints are specifically considered. By overlaying the processes from the different phases of the two life cycles, the emerging requirements for a necessary data profile for building materials are worked out.

With regard to the origin of the substance-related data, a distinction is made between projects in which the data on the building products can be collected during construction - and in some cases must be collected as part of quality assurance during construction - and in retrofitting or conversion measures in the existing building stock, in which the assessment of the existing substances often takes place through visual inspection and sampling. In these cases, only existing, generally accessible databases can be used for building material-related data. Both process variants are to be investigated and presented in the present project.

In this context, the BIM method is considered by pursuing an integration of the analysed data with the building data model. In order to achieve a timely and practical implementation and application of the research results, an expandable software application "RecycBIM" will be developed. The software application will be tested and validated by the practice partners on real construction sites.