Non-Waste-Wax-Formwork: Novel precise formwork-technology on basis of 100% recyclable industrial wax for the fabrication of geometrically complex concrete elements

由于UHPC（超高性能混凝土）的精细度和高强度，为未来与高效细丝结构元件相关的应用提供了新的机会。尽管对超高性能混凝土进行了深入的研究，但迄今为止，超高性能混凝土在工程实践中的应用还很少。原因之一是缺乏国家标准的监管。申请人认为，另一个主要原因是建筑行业的情况尚未准备好使用UHPC。因为用市售的直模板系统生产UHPC制成的板、柱、板和墙不适合材料的潜力，并且在经济上没有用处。事实上，自由模板在技术上是可行的，但需要昂贵的特殊解决方案。这就是研究项目的启动点：该项目的目标是开发一种新型通用模板技术，该技术允许以尽可能高效的方式制造由超高性能混凝土到轻质混凝土制成的混凝土构件，几乎可以采用任何几何形状，并具有最高的精度。此外，新的模板技术是可持续的，为什么要避免废品。因此，工业蜡被用作成型材料，它可以通过熔化完全回收。在正在进行的SPP 1542项目“轻型UHPC结构新连接系统的开发”中，申请人Kloft教授与布伦瑞克工业大学iBMB的Budelmann教授合作，蜡已经用于生产UHPC元件干装配的高精度连接系统的模板。由于蜡在室温下具有非常好的尺寸稳定性和可加工性，因此已经使用各种合成石蜡、聚乙烯和费托蜡进行了各种小规模的初步实验。应用项目应明确该技术对更复杂和更大尺寸部件的可移植性。为了涵盖广泛的形状和应用，“无废蜡模板”项目旨在开发两种基本应用。混凝土浇筑的“外蜡模板”的生产和“空腔蜡模板”的生产，在蜡熔化后，空腔蜡模板取代填充的混凝土，在混凝土构件内产生空隙。通过结构设计研究所（ITE）和机床与生产技术研究所（IWF）的合作，自由模板的经验将被融合到机械工程的制造和自动化技术中。这确保了在短短两年内为SPP 1542的研究小组及时提供结果。

Due to the fineness and high strength of UHPC (ultra high performance concrete) new opportunities are enabled for future applications in connection with efficient filigree construction elements. Despite the intensive research UHPC is until now fewly applied in the construction practice. One reason is the missing regulation by national standards. Another major reason in the opinion of the applicants are the circumstances in the building industry which is not yet prepared for the use of UHPC. Because the production of slabs, columns, plates and walls made of UHPC with the marketable straight and even formwork systems does not fit to the potential of material and is economically not useful. Indeed freeform formwork is technically possible, but requires expensive special solutions.This is where the research project initiates: The aim of the project is the development of a novel universal formwork technology that allows the fabrication of concrete members, made from UHPC up to lightweight concrete, as efficiently as possible, in nearly any geometrical shape and with maximum precision. Moreover, the new formwork technology is to be sustainable, why waste products are aimed to be avoided. Therefore industrial wax is used as shaped material, which can be completely recycled by melting. In the on-going SPP 1542 project `Development of New Jointing Systems for Lightweight UHPC-Structures´, which the applicant Professor Kloft is working on in cooperation with Professor Budelmann from iBMB of the TU Braunschweig , wax has already been used to produce formwork for highly precise jointing systems for dry fitting of UHPC - elements. Because wax has a very good dimensional stability and workability at room temperature, a variety of small-scale preliminary experiments has been performed using various synthetic paraffin-, polyethylene- and Fischer-Tropsch-waxes. The transferability of the technology to more complex and larger sized components should be clarified by the applied project. In order to cover a wide range of shapes and applications, the project `Non-waste-wax-formwork´ aims to develop two basic applications. The production of `outer- wax-formworks´ into which the concrete is poured and the production of `cavity-wax-formworks´, which displace the filled concrete to create voids inside the concrete member after the wax has been melted out. Through the cooperation of the Institute of Structural Design (ITE) and the Institute for Machine Tools and Production Technology (IWF), the experience of free-form formwork will be merged within the manufacturing and automation technologies of mechanical engineering. These ensures the prompt provision of results for the research groups of the SPP 1542 in just two years.