Sustainable Construction
IN BRIEF
- Because of its thermal mass, concrete can make buildings inherently more energy efficient.
- Concrete roads reduce the fuel consumption of vehicles, especially trucks.
- High durability makes concrete a key material for sustainable construction.
Concrete as the cornerstone of sustainable construction
The opportunity for reducing emissions is not limited solely to the cement production process, but is relevant to the whole life cycle of downstream products, namely concrete. In fact, concrete can contribute much more than the cement production process to achieving the EU’s objectives in terms of reducing CO2 emissions. Energy consumption of buildings is one of today’s major environmental concerns, as buildings account for approximately 35% of total EU greenhouse gas emissions1 (including direct and indirect emissions from electricity generation). As concrete construction offers a higher energy-saving potential than other construction materials, it can become a key lever in achieving the EU’s ambitious carbon-reduction goals, through the construction of very low-energy buildings.
Concrete buildings can achieve considerable energy savings during their lifetime because of the high level of thermal mass they deliver, meaning that the indoor temperature remains stable even when there are fluctuations in temperature outside. Concrete performs very well when accurate and holistic comparisons are made with other building materials. In the energy efficiency field, for example, energy savings of concrete structures (5-15%) in the in-use/operational phase easily offset amounts of energy consumed in their manufacture and installation phases (4-5%). Given that currently 88-98% of total building life cycle emissions are linked to the in-use phase, the savings potential offered by concrete buildings during their lifetime can totally offset initial emissions resulting from the production of cement.
In addition to its inherent thermal mass properties, concrete also facilitates the installation of enhanced cooling systems, such as radiant cooling schemes with chilled-water pipes embedded in concrete structures. Concrete delivers improved air tightness and allows enhanced installation of ventilation systems and shading structures that minimise solar gains and maximise the amount of hot or cold air coming into contact with the material.
By combining all of the above, the thermal mass potential of concrete can be maximised, giving it a strong advantage over other materials and enabling construction of low-energy concrete structures that reduce energy usage from an average of 200-150kWh/m2 to 50kWh/m2, or even zero-emission buildings.2
In the transport sector, which accounts for 20% of total European greenhouse gas emissions, concrete also contributes to reducing CO2emissions in a cost-effective way. According to studies, concrete pavements can lower fuel consumption of heavy trucks by up to 6% by reducing rolling resistance between the road and the truck, as concrete pavements offer a smoother surface with fewer undulations than asphalt pavements. Further reductions in fuel consumption can also be achieved through a decreased need for maintenance and, therefore, lower traffic congestion. Concrete also has a high albedo, or reflection coefficient, compared to asphalt, due to its lighter colour. This means it can reduce the need for street lighting and also reduce the heat island effect in built-up areas. Furthermore, the total life cycle costs of concrete are lower than those of asphalt. A study published by the Highway Administration of Belgium’s Walloon Region concluded that concrete structures become more cost-advantageous than bituminous structures as of the 7th year following construction, out of a lifetime of more than 30 years.
POLICY RECOMMENDATIONS
- There is a need to place a strong emphasis on investments in the construction sector which is a generator of growth and jobs and, therefore, essential to economic recovery in Europe.
- Develop financing schemes to encourage individual homeowners to improve the energy efficiency of their homes through renovation or rebuilding.
- Policies need to be based on building performance and take into account impacts over the complete life cycle. Public procurement policy can lead the way in this.
- Always consider rebuilding as an alternative to refurbishing, where applicable.
- Sustainability assessment must be at the building level and take into account impacts over the complete life cycle.
- Policies such as urban planning, public procurement etc. must take a long-term view in order to encourage the most sustainable solutions.
- Encourage energy efficiency improvement of the current building stock, for example by providing financial incentives for individual home-owners for renovation or rebuilding.