The ZIN is a massive, multifunctional project that has replaced the old World Trade Centre (WTC) towers in downtown Brussels. The development comprises more than 14 storeys of modern design, fully integrated into Brussels’ existing urban ecosystem. It includes 111 apartments, a hotel with 240 rooms and more than 72,000m2 of office space, as well as spaces for sports, recreation, retail and catering.
The dismantling of the WTC left 30,000 tonnes of rubble to be disposed of, raising the challenge of how this would be done in a sustainable manner, while simultaneously meeting the exacting construction demands of this massive infrastructure project.
CRH Companies Ergon and Prefaco teamed up to deliver Belgium’s first circular concrete elements for the project. To do this, the 30,000 tonnes of rubble from the demolished WTC was collected and processed into 3,500 tonnes of high-quality aggregates. These aggregates were then recycled into the concrete elements used for the new ZIN building, including the floors, stairs, balconies and columns. This was the first time this process has been used on such a scale on a Belgian construction project.
All told, about 30% of the concrete used in the structure came from recycled sources – a remarkable example of sustainable, circular construction in action. For this, Ergon and Prefaco were jointly awarded the ‘Cradle to Cradle’ silver certificate, “the global standard for products that are safe, circular and responsibly made”.