Con­crete Form­work Sys­tems

Best Thesis 2016!
Congratulations to Anne Liebringshausen for the award of the Pfeiffer Foundation for Architecture at the University of Kassel for the best final thesis from the winter semester 2015/16 and summer semester 2016 in the category analytical-reflexive oriented / scientific final theses. The master thesis by Anne Liebringshausen: "Sustainable & reusable concrete formwork systems made of sand and wax" deals with the development of a new and sustainable as well as reusable concrete formwork system made of sand and wax for the realisation of extremely thin and double-sided curved concrete freeform forms.
The introduction of parametric design tools in architecture and the design possibilities they open up seem almost endless today. Experimental forms must make their way from digitisation to realisation before they fall by the wayside due to a lack of implementation skills. New forms also need new forms of implementation. In practice, however, there is a lack of suitable and, above all, sustainable and reusable concrete formwork systems. Today, non-standardised concrete formwork still requires a great deal of material, energy and financial input - it cannot be reused and only one geometry can be represented. Sand and wax formwork, on the other hand, can be used again and again and constantly optimised. The new "zero-waste process" makes it possible to produce thin, double-sided curved free-forms from concrete without material expenditure and with simultaneous reusability of all forming components. The process plays with the given, changeable properties of the materials sand, wax and concrete. Sand, as an originally porous element, can be tamped, moistened, dried, shaped, destroyed and reshaped, and depending on the transformation, different creative concrete surfaces can be achieved. Wax changes its aggregate state by heating - it can be poured into moulds, it hardens and can be melted down again to start a new moulding cycle - again without material losses and CO2-neutral.
The basis of the new shuttering process is a highly compacted sand bed of oil-bonded moulding sand, which is milled into shape using digital data. The sand chips produced during the milling process can be collected by an industrial vacuum cleaner and reused. The resulting positive mould is cast with a model wax compound for investment casting. After curing, the resulting wax negative formwork is set up vertically, placed in a formwork frame and poured with concrete. The wax formwork can be reused or it is melted down and reshaped.

supervision: Prof. Manfred Grohmann, Philipp Eisenbach
author: Anne Liebringshausen
cooperation partner: AMPA - Universität Kassel, Dyckerhoff, Romonta

Liebringshausen A., Eisenbach P., Grohmann M.: Re-usable concrete formwork system made of sand and wax; In: Bögle A., Grohmann M. (eds.) Proceedings of the IASS Annual Symposium 2017. Hamburg. 2017