In a context where the transition to more sustainable, environmentally-friendly construction has become a priority, the integration of innovative materials and disruptive technologies plays a crucial role. Among these materials, graphene is a promising solution for revolutionizing the building sector. In this article, Carbon Waters takes a look at the current state of play in the building sector, and explains how graphene and its many properties can help to decarbonize the industry.
What roadmap for the building and construction sector?
A building emits CO2 at two stages in its life cycle:
- During construction,
- During use, notably through energy consumption.
According to ADEME, “the impact on the environment is particularly marked at the time of construction, as the bulk of a building’s CO2 emissions and resource consumption are linked to its construction phase“, representing over 75% of a building’s total CO2 emissions over its life cycle.
According to the current French National Low-Carbon Strategy (SNBC-2), France’s roadmap for reducing the sector’s environmental impact, “the carbon footprint of the building value chain represented 153 Mt CO2 in 2019, or 25% of France’s annual carbon footprint.”
For the coming years, this roadmap calls for a two-stage reduction in carbon emissions:
- -48% by 2030,
- -81% by 2050, i.e. almost complete decarbonization.
In terms of materials, construction products account for almost a third of greenhouse gas emissions in the building sector, and cement is responsible for almost 10% of global emissions. The use of innovative, less polluting materials is therefore one of the solutions envisaged to reduce emissions during the construction phase and achieve the targets set by the SNBC-2.
What is the environmental impact of cement and concrete?
Cement is one of the main materials used in building construction. It is widely used to build foundations, walls, slabs and structures, thanks to its strength and durability. After water, cement is the second most consumed material in the world: fourteen billion cubic meters of concrete are poured every year (source : Global Ciment and Concrete Association).
However, its environmental impact is far from neutral. The main cause associated with cement production today is linked to the production process for clinker, an essential component of cement. To obtain clinker, limestone and clay are heated to a very high temperature (around 1400°C) in a cement kiln or calciner. However, during the heating process, the clinker releases carbon dioxide, so that to produce one ton of cement, the firing stage alone generates almost one ton of C02.
So how to reduce the use of clinker to obtain a concrete that performs just as well?
Alternatives are being standardized to replace traditional concrete. For example, low-carbon concrete contains less clinker, some of which is replaced by limestone, calcined clay or fly ash.
How can graphene help decarbonize tomorrow’s construction industry?
As mentioned above, the use of innovative, less polluting materials is essential if France is to reach the thresholds set by public policy. Indeed, this is what the sector’s roadmap states: “the increased use of low-carbon components that are not today’s standards (innovative and low-carbon products) […], appears to be an essential lever for achieving the objective of decarbonizing the building industry“.
Graphene, a material discovered just 20 years ago with a wide range of properties, can also replace part of the clinker used in buildings, thereby reducing CO2 emissions.
Integrating graphene into concrete would mean using less material, while offering similar or even better performance than traditional concrete. According to scientists at the University of Exeter, graphene concrete is twice as strong and four times more impermeable than traditional concrete.
In collaboration with the Graphene Engineering Innovation Centre (GEIC) at the University of Manchester, Nationwide Engineering has developed an admixture that enhances the performance and durability of concrete.
The very first graphene-enriched concrete slab was laid in England in a local gymnasium three years ago.
Graph’Up Force W: a range of graphene-enriched additives to reduce CO2 emissions of buildings
Carbon Waters has developed Graph’Up Force W, graphene-based additives specifically designed to reinforce cements and concretes. Available in waterborne form and incorporated directly into cement during the mixing stage, these additives enhance the mechanical performance of final materials:
- +70% Young’s modulus,
- +20% tensile strength.
For industry professionals, this is an innovative, sustainable solution that significantly reduces the amount of clinker required, without impacting material quality.
Beyond reducing environmental impact, what does graphene bring to the building sector?
In addition to its role in decarbonizing the construction sector, graphene offers many other advantages.
Firstly, graphene has excellent mechanical reinforcement properties, making it effective even at low concentrations. Thus, replacing part of the clinker in cement with graphene reduces the total amount of material used. As a result, raw material costs and, ultimately, overall construction costs are reduced.
Graphene has antibacterial properties to protect building surfaces
Secondly, graphene has very interesting properties for protecting building facades from weathering and damage (through its incorporation into coatings such as paints, varnishes, etc.).
These include a powerful anti-corrosion action, a hydrophobic effect and antibacterial properties. Carbon Waters has developed Graph’Up Oxi, a range of graphene-based additives dedicated to anticorrosion, as well as Graph’Up Preserv, designed to reduce clogging of facades and thus preserve the exterior appearance of buildings.
Last but not least, the addition of graphene to building materials and coatings extends the life of buildings, reducing maintenance and replacement requirements and saving money in the long term.
Graphene represents a significant step towards decarbonizing the construction sector in France. By strengthening concrete, reducing the proportion of clinker in cement and offering a host of other benefits, graphene opens up new prospects for making the building sector sustainable. By integrating this revolutionary material into construction practices, the industry could meet its 2050 CO2 reduction targets and thus help build a more sustainable future for generations to come.