Environmental impact evaluation of five circular concrete scenarios.

R E J van den Bogert and M J Ritzen.

In the Netherlands, the material concrete accounts for 40-60% of the total
environmental impact of the Dutch construction industry. Cement accounts for 80-95% of this
impact, while not being the main component expressed in mass.
Traditional methods of (re)using and recycling concrete in the construction industry have a high
detrimental environmental impact, and are currently not fitting in the transition from a linear
economy to a circular economy.
In the Dutch concrete treaty (DCT) (07-2018), the main goals of the ‘Green Deal for a sustainable
concrete industry’ (2011-2015) became tangible. The goals concerning the (re)use of concrete in
the DCT are:
1. Lowering CO2 emissions by 30% relative to CO2 emissions in 1990, with the
ambition to lower CO2 emissions by 49%, by 2030.
2. 100% high quality reuse of concrete from the demolition stock by 2030.
To achieve these goals, changing traditional use of concrete is necessary. Consequently, there is
a demand for initiatives that boost the development of new, circular methods of (re)using
concrete, resulting in a lower environmental impact. However, data on the actual environmental
impact of these methods is still to be collected. In the European project Urban Innovation Actions
(UIA), Super Circular Estate–SUPERLOCAL, this gap of knowledge is addressed, and the actual
environmental impact of circular concrete methods is studied. In this project, 10-story high
apartment blocks are deconstructed, and circular solutions for material re-use and their
environmental impact are researched.
The aim of this study is the analysis and comparison of the actual environmental impact of
different methods of how concrete, from the existing building stock, not designed for reuse, can
be (re)used in a more circular manner.
This study is designed as a comparative analysis. Based on literature and project-expert
consultation, five circular concrete scenarios and a baseline scenario have been formulated.
These scenarios are considered promising and feasible methods of (re)using concrete from
SUPERLOCAL, in a circular manner. These circular scenarios are compared to the baseline
scenario, using 100% new materials and mainstream/traditional methods of pouring concrete on
site. The five circular scenarios are:
1. Compartments; extracting whole building components from existing building stock to
be reused in new buildings.
2. Slabs; extracting smaller building components that can be used for new buildings.