SUSTAINABILITY IN CONSTRUCTION
While “greenwash” (the practice of making an unsubstantiated or misleading claim about the environmental benefits of a product) has become common practice in the marketing world, The Concrete Institute recognised the importance of validating claims concerning the greenness of concrete with integrity and scientific evidence.
To be able to quantify the environmental advantages of concrete, the Institute commissioned InEnergy Africa to determine the CO2 emissions of the most commonly used constituent materials in concrete. i.e. cement, aggregate, water, fly ash, ground granulated blast furnace slag (ggbs) and admixtures, and the processes of production of both precast, and ready mixed concrete. InEnergy was also requested to develop a model to allow users to determine the CO2e (equivalent) from the production of a cubic meter of concrete using various materials.
CONCRETE AND SUSTAINABILITY
Concrete has a number of inherent characteristics that contribute towards achieving sustainability, whether it is for the benefit of the owner, the developer or the designer
Modern civilisation is built on concrete and as such the positive social impacts are immense. The concrete industry supports and uplifts social infrastructure and provides dignified and durable shelter that all human beings have a right to. To address the economical impact, construction and maintenance costs are monitored to ensure positive life cycle costs. On the environmental side, the energy efficiency and thermal mass of concrete increase sustainability. Case studies can already prove that the recyclability of concrete make it a very attractive option as a construction material.
All things considered, concrete is virtually unequalled in combining the many unique qualities and attributes to make it the responsible choice in construction materials, balancing all the elements for increased sustainability. In fact, concrete is much greener than you think.
CONCRETE AS A SUSTAINABLE RESOURCE
The use of admixtures which result in a reduction of cement and water content in mixes, together with the use of cement extenders such fly ash, ggbs, and silica fume have for many years been standard practice in the concrete industry, initially only to reduce costs. The use of these materials have however also a pronounced effect on improving the durability and sustainability of concrete.
Precast products such as hollow-core slabs also reduce the volume of in-situ concrete substantially, while the use of the new generation of permeable concrete pavers form part of a responsible water management and safety programme by getting water off the surface of a road and letting it get back into the groundwater. Self-compacting concrete in sustainable developments allows for architectural shapes and forms previously regarded as impossible.
Moreover, new research is producing exciting data on the re-absorption of carbon dioxide by hardened concrete. A Danish study has found that 50% of the volume of concrete will be ‘carbonated’ over 70 years of any building’s service life. This sponge effect makes concrete a more green choice than previously thought, emphasising how global sustainability can be achieved with concrete.