The Zero-Waste Project – Recycling of waste concrete from own production

Project start in January 2018. Completed April 2019.

Experiments with recycling of concrete to be applied as crushed aggregates in new concrete has been going on since the late 80’s. To date, several full-scale demonstration projects proved it possible to build new constructions with recycled concrete aggregates. However, there has not been a demand for such concrete types, let alone the fact that the incentive to introduce waste products in concrete production is rather negligible. Such trend is slightly changing, especially because over the past years Danish political initiatives addressing efficient resource strategies and implementation of certificates for sustainable constructions, supported by new R&D projects in the field of concrete recycling, triggered an unprecedented interest in the utilization of the waste resources in concrete production, in particular, recycled concrete aggregates.

The zero-waste project addresses such a demand for recycled concrete aggregates by the Danish construction industry. Specifically, the project focuses on the utilization of concrete waste generated directly from the manufacturer’s production rather than recycling of construction waste after demolition. The advantage in this type of recycling is that the waste material composition is fully traceable, i.e. the waste constituent materials and composition are known, which enables to optimize the application of the recycled concrete aggregate resulting from the recycling. At a manufacturing level, the average concrete waste generation comprises 2 to 5 % of the total production in Denmark, such share of concrete waste includes for instance products that do not conform to the aesthetic requirements from clients, returned concrete, or cut-out concrete from precast concrete production. The scale of the waste generation is known to be highly depended on the product type. In the zero-waste project, we address the production of (a) Hollow core slabs, (b) Paving blocks, and (c) Ready-mixed concrete.

Project aims

The primary goal of the project is to expand the waste recycling in concrete production by:

• creating publicly available results that highlight the environmentally facts related to concrete waste recycling.
• devising a guide that can help the concrete industry to implement the use of concrete waste in their own production. 

Participants

• Dansk Beton
• Danish Technological Institute
• CRH Concrete A/S
• DK Beton A/S
• IBF
• Aalborg Portland A/S
• Emcon A/S