DIRECT REUSE OF CONCRETE ELEMENTS: HI-CON ELEMENT GETS A NEW LIFE

A balcony slab from Hi-Con’s surplus stock has become part of a new demonstration building.

Pavilion made from reused materials with a balcony slab in Ultra High Performance Concrete (UHPC) from Hi-Con used as flooring.

A PAVILION BUILT FROM WHAT ALREADY EXISTS

How much can we continue to build with the materials and elements that already exist? That question is at the heart of the new “4>1 Pavilion at Sygehusgrunden, form follows materials” in Holstebro, Denmark. Developed by GXN as a demonstration building, the pavilion explores how existing building materials and concrete elements can be directly reused in new structures.

Among the reused concrete elements are two hollow-core slabs from nearby residential blocks and a balcony slab in Ultra High Performance Concrete (UHPC) from Hi-Con’s surplus stock. Rather than adapting the elements to a predetermined structure, the pavilion’s building system was developed around the materials that were already available.

What is Ultra High Performance Concrete?

DIRECT REUSE OF CONCRETE ELEMENTS

The 4>1 Pavilion was developed as a full-scale study of how existing building materials can be incorporated directly into new structures. With direct reuse, the existing concrete element is retained and used in a new structure rather than first being broken down into raw materials.

The project follows the concrete elements throughout the entire process, from mapping and extraction to testing, processing and reintegration. Along the way, it highlights some of the practical and technical challenges involved in direct reuse.

One of the key challenges is that existing elements come with predetermined dimensions and properties. They do not necessarily fit into a building designed around new standard dimensions. In the pavilion, this approach has been reversed. A flexible, modular building system has been adapted to the materials available, limiting the need for processing.

The meeting between new and reused materials has also been made a visible part of the building. Rather than being concealed, the connections show how elements with different dimensions, materials and origins can be brought together in a single structure.

The pavilion is therefore not a finished standard solution, but a practical demonstration of some of the questions the construction industry needs to address if direct reuse is to become easier to implement in future projects. These include documentation, testing, design and the handling of elements that already exist.

Balcony slab in Ultra High Performance Concrete (UHPC) from Hi-Con, used as flooring in the 4>1 Pavilion in Holstebro.

Processing of a balcony slab in Ultra High Performance Concrete (UHPC) from Hi-Con, used as flooring in the 4>1 Pavilion in Holstebro.

A NEW LIFE FOR LONG-LASTING ELEMENTS

Hi-Con’s Ultra High Performance Concrete elements are designed for a service life of more than 100 years. It is therefore relevant to consider not only the element’s service life in its first building, but also whether its long technical service life can be utilised in a new context.

This is an area we have previously helped explore through the research project (P)RECAST, which investigated the possibilities for the direct reuse of precast concrete elements. Hi-Con was one of the participating partners, contributing to the work on both the reuse of precast concrete elements and the technical and practical considerations involved when existing elements are incorporated into new structures.

With the 4>1 Pavilion, the subject becomes very tangible for us. A balcony slab that was previously sitting in our surplus stock is no longer a surplus element, but part of a new structure. We are pleased to contribute to the project, while gaining further practical experience, together with the wider industry, of what direct reuse requires.

The pavilion is part of the transformation of the former hospital site in Holstebro and was developed in collaboration between Sygehusgrunden in Holstebro, Holstebro Municipality, GXN, Barlby Carlsson, the Danish Technological Institute, BUILD – Department of the Built Environment, Hvidberg A/S, Aarsleff, Skave Nedbrydning and Hi-Con.