Matthias Raudaschl (2020): Hook-and-loop-concrete - Analysis and manufacturing of joinable concrete structures based on the model of the hook-and-loop fastener, 1st reviewer: Roger Riewe, 2nd reviewer: Harald Kloft; 144 pages, German

The application of the hook-and-loop fastener, consisting of two complementary connecting partners or hook-and-loop components, at the constructive interface from primary structure (structural elements) to secondary structure (finish) and tertiary structure (technical building equipment) enables, in accordance with its functional principle, a composite of easily detachable and reconnectable short-lasting and long-lasting components and therefore easy maintenance as well as adaptability to new uses and requirements. This opens up great potential for increasing the lifespan of buildings and individual building components, while at the same time the functionality of the corresponding hook-and-loop component must be ensured beyond the lifespan of the individual structural element.
The research subject of relevant projects, patents and applications in the building industry are mainly retrospectively applied hook-and-loop components made of plastic materials. Generally, components made of plastic can be very weather-resistant, but due to the complex interactions in the building industry caused by changing humidity, temperature and UV exposure, they can age faster. In addition, hook-and-loop components are usually attached to rigid surfaces by adhesive bonding, a connection method with a considerably shorter lifespan than that of the structural elements.
In order to overcome this problem, this thesis proposes a change of material and a resulting manufacturing method for hook-and-loop components. With regard to the versatile mouldability of concrete as a building material, the research objective is the basic investigation and manufacturing of a concrete-hook-and-loop component, based on the application of Wax-Formwork technology and on the model of industrial hook-and-loop products. Applied to the building industry, in addition to the main functions of load-bearing, force transmission and forming a shell, concrete components could permanently provide a directly joinable fastening surface to a corresponding connecting partner without additional processing steps.
The research begins with the determination of the state of the art and a preparation of basic principles. This includes an analysis of the hook-and-loop fastener, fastening technology in concrete as well as Wax-Formwork technology. Based on these principles, three manufacturing concepts for the production of hook-and-loop concrete structures are developed and examined in a feasibility study based on manufacturing and hook-and-loop tests. The result of this thesis consists of geometry-specific as well as material-specific requirements for the production of hook-and-loop components in concrete, basic concepts for the production of “hook-and-loop-concrete” using Wax-Formwork technology, the examination of these concepts and exemplary approaches concerning the particular complementary connecting partner.