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)的细度和高强度，在高效丝状结构构件方面为未来的应用提供了新的机会。尽管人们对超高性能混凝土进行了大量的研究，但到目前为止，超高性能混凝土在工程实践中的应用还很少。原因之一是缺少国家标准的监管。申请人认为另一个主要原因是建筑业的情况，该行业尚未为使用超高性能混凝土做好准备。因为用超高性能混凝土制成的板、柱、板和墙，用市面上销售的直板甚至模板系统生产，不符合材料的潜力，在经济上是没有用处的。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。这就是研究项目的起点：该项目的目标是开发一种新的通用模板技术，允许尽可能高效地制造从超高性能混凝土到轻质混凝土的混凝土构件，几乎以任何几何形状和最高精度制造。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，通过熔化可以完全回收。在正在进行的SPP 1542项目“为轻质超高性能混凝土结构开发新的连接系统”中，申请人Kloft教授正在与布伦瑞格理工大学IBMB的布德尔曼教授合作，蜡已经被用于生产用于超高性能混凝土构件干式装配的高精度连接系统的模板。由于蜡在室温下具有很好的尺寸稳定性和可加工性，人们已经使用各种合成石蜡、聚乙烯和费托石蜡进行了各种小规模的初步实验。技术是否可以转移到更复杂和更大尺寸的部件，应在应用项目中予以澄清。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。浇注混凝土的“外蜡模板”的生产和“空腔蜡模板”的生产，这种模板在蜡熔化后使填充的混凝土置换，在混凝土构件内部产生空洞。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，自由模板的经验将融入机械工程的制造和自动化技术中。这些措施确保了在短短两年内迅速向战略计划1542的研究小组提供成果。

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.