Sustainable use of materials
The extraction of raw materials and production of materials has a major impact on the environment and specifically CO2 emissions. It is therefore increasingly important to make sustainable material choices and reuse as much as possible. In doing so, we are also involved in the development and application of sustainable alternatives.
Concrete
We use a lot of concrete in our building structures and infrastructure projects. Concrete, and in particular the component cement, still often has a low circularity value at present, because high-quality reuse of concrete is not yet readily possible.
To encourage sustainable use of materials and reduce the environmental impact of concrete, we are investigating sustainable alternatives to traditional concrete mixtures together with clients, regulators and the cement industry. One way we do this is with the Concrete Agreement. We also have our own working group investigating alternative means of using less or no cement.
Some examples of projects in which we used less (primary) concrete are the Haarlemmermeer boarding site and the N391 junction. In both projects we applied geo-polymer concrete which avoids the use of cement. In this type of concrete, the cement is replaced by geopolymer, a binder based on mineral residues, alkalis and an activator.
Asphalt
2020 has developed a sustainability strategy for the next five years, aimed at increasing the proportion of recycled raw materials in asphalt mixtures. We remain fully engaged in research into opportunities for innovative and sustainable asphalt mixtures, both in our own laboratories and at our own asphalt plants.
In 2021, we applied several sustainable asphalt mixtures for the first time, for example KonwéCity Circular. Through local reuse, this requires 50% less primary raw materials. In addition, the lower rolling resistance of KonwéCity Circular reduces tire wear and fuel consumption in the use phase. This reduces CO2 emissions from road traffic. Another example is the top layer SMA circular, in which up to 50% recycled asphalt is also used.
We are increasingly able to produce high-quality new asphalt mixtures that consist largely of old asphalt. The greatest climate gain, however, can be achieved by finding an alternative to natural gas, the fossil fuel on which all asphalt plants are currently fired. For the long term, therefore, the biggest challenge lies in implementing a good alternative such as green hydrogen or green electricity.
Wood
We see a major role for wood in the built environment. Wood is a raw material that can be widely used in both our infrastructure and construction and real estate projects. It also offers a solution for CO2 reduction, making it often more sustainable and environmentally friendly than traditional construction.
In 2021, we built an apartment complex in Monnickendam with 62 homes, made almost entirely of wood. Even the construction in this project is made of wood: the walls, floors and ceilings. The building elements are prefabricated, so they can be assembled directly on site. By using wood from sustainably managed production forests, the construction partners are also planting back more trees than are being used.
As VolkerWessels, we want to contribute as much as possible to the use of sustainably produced wood from sustainably managed forests. For example, we are a partner of FSC Netherlands and build exclusively with wood that is FSC or PEFC certified. By doing so, in addition to storing CO2, we contribute to protecting the biodiversity, soil and waterways of forests.
The Forest50 is a ranking of the 50 largest construction companies in the Netherlands ranked on the basis of their sustainable use of wood and communication about responsible forest management. We are proud to say that we were the leader of the Forest50 in 2021.