Concrete is the world’s most used building material and a key part of building society. Since Roman times, people have found and used its great qualities. They have used this flexible material to make more complex and ambitious buildings.
“Concrete is the world’s most used building material and is essential for building a sustainable society. This is all about concrete.” – Karin Gäbel, Chief Sustainability Officer.
These are gases in the atmosphere that contribute to the greenhouse effect and global warming.
The main GHGs include:
Each greenhouse gas, GHG, has a different warming potential, or GWP. GWP is a metric used to compare and aggregate the climate impact of different GHGs relative to CO₂. It translates emissions of GHGs into a common unit: CO₂-equivalents (CO₂-eq).
A standardized unit used to express the climate impact of different GHGs relative to CO₂ over a given period of time.
Carbon footprint is the total amount of GHG emissions by a product expressed as CO₂-eq.
CO₂ is the dominant GHG in cement and concrete’s carbon footprint. Other GHGs like CH₄ and N₂O can appear indirectly through fuel use or electricity generation.
Cement is the binder that, together with water, binds stone, gravel and sand into concrete. Concrete consists of approximately 10% cement, but the cement is responsible for 90-95% of its carbon footprint.
CO₂ emissions from cement occur in two ways:
Transport of raw materials to concrete plants, mixing of concrete at concrete plants, and distribution to construction sites contribute smaller amounts to the overall carbon footprint.
Low-carbon concrete is concrete with a lower carbon footprint while maintaining the same high, and sometimes even higher, quality, functionality, and performance as traditional concrete without alternative binders.
We achieve this by
With low-carbon concrete, we can reduce the carbon footprint by 50% or more.
Zero-carbon concrete is concrete that achieves net-zero carbon footprint over its entire life cycle. Net-zero means that all GHGs associated with the concrete over its life cycle are reduced as far as technically and economically feasible, and any remaining unavoidable emissions are balanced by permanent carbon removals.
Near-zero-carbon concrete is concrete where the carbon footprint is reduced to near zero levels, but where not all remaining emissions are yet fully eliminated or balanced.
Near-zero‑carbon concrete minimizes the carbon footprint to near-zero levels, while zero‑carbon concrete goes further by balancing the remaining unavoidable emissions to achieve net‑zero over the entire life cycle.
Alternative binders, which are essentially mineral-based substances, share similarities with cement but produce considerably less carbon dioxide. These binders chemically react to serve as the adhesive in concrete, holding together various aggregates.
Currently, we utilize by-products from other industries as alternative binders. These by-products would otherwise require disposal or other forms of management. Additionally, some alternative binders are derived from natural sources.
Our primary choices for alternative binders include:
Slag: Specifically, blast furnace slag from the steel and iron sector. This by-product is ground into a fine powder and can substitute a significant portion of cement in concrete.
Fly ash: Sourced from the combustion of coal, this by-product is collected after flue gases are cleaned at certain coal-fired power stations with non-toxic burning processes.
Importantly, the alternative binders we employ are free from any toxic or hazardous elements and comply with rigorous chemical regulations. We, along with our suppliers, conduct thorough testing on all alternative binders to ensure they meet the stringent criteria set by standards and legislation.
LCA is an established method for calculating the environmental impact of a product throughout its entire life cycle, from raw material extraction, manufacturing, transportation, use, and end-of-life disposal or recycling.
In LCA terms, the life cycle of a building is divided into three main stages:
Each of these stages is further divided into sub-stages. The three main stages, along with the subdivision of Construction stage.
An EPD is a standardized declaration that communicates the environmental impact of a product based on LCA data. It’s third-party verified and follows international standards.
EPDs for building materials do not always cover the entire life cycle. They typically include stages A1 to A3, and sometimes also A4 and A5. The environmental impact is declared per kg, m2 or m3 of building material.
EPDs for building materials are used in LCAs for buildings, where the environmental impact is often calculated per m2 of built area.
Carbonation is the natural process by which concrete absorbs CO₂ from the air over its entire lifetime. This process does not affect the structural properties of the concrete.
On average, about 20% of the CO₂ emissions generated during cement production are reabsorbed during the service life of a concrete structure, with a significant portion occurring within the first 25 years. When concrete is crushed at the end of its life, it absorbs additional CO₂ quickly.
Standardized methods exist for calculating the amount of CO₂ uptake through carbonation, and how to declare it in EPDs.
In EPDs for concrete, carbonation is declared in the Use stage (B1) as well as in the End of Life stage (C).
When using LCA to compare different buildings or building materials, it is essential that the building materials are incorporated into equivalent buildings with the same function and performance. The assessment must also include the entire life cycle.
Buildings are normally designed and built to last for a long time. By considering the entire life cycle, sub-optimization is avoided, such as reducing climate impact at the beginning of the building’s life cycle, during Construction stage (A) only to shift or even increase it at a later stage, to Use stage (B).
This may involve choosing a material or solution with a lower initial impact but a shorter service life, requiring maintenance, repair, or replacement to maintain function and performance throughout the building’s entire Use stage (B).
This is particularly important in the construction industry, where buildings are used for a very long time and where climate impact occurs during all stages of a building’s life cycle. The impact from each stage varies for different buildings. In this illustrative example from Boverket, the Use stage B, stands for more than 40% of the impact.
When calculating the environmental impact during the use stage, a calculation period must be defined. The LCA standard for buildings states that the calculation period should match the service life required by the client, developer, or applicable regulations.
Buildings typically have a very long service life and are generally designed and constructed to last more than 100 years. From a sustainability, resource, and climate perspective, it is important that the buildings we construct are designed for long service life and that the materials we use have a long lifespan with minimal need for replacement and maintenance.
It is neither realistic nor sustainable to build structures today with a service life shorter than 100 years. Therefore, the entire life cycle of a building should be included, and the calculation period should be 100 years. This provides an accurate picture of a building’s climate impact and its potential to reduce and optimize that impact throughout its life cycle.
Despite this, the calculation period is often limited to 50 years. Sometimes this is justified with the argument that there is uncertainty or limited knowledge about future maintenance. At other times, the argument is that a 50‑year period corresponds to the time until a major renovation or performance upgrade is expected. Arguments which underestimate the buildings full impact and creates a future climate debt.
The GHG emissions produced during the use stage of a building. These emissions are linked to energy consumption during the building’s operation, including energy for heating, cooling, lighting, equipment function, and water heating.
The GHG emissions associated with materials and construction processes throughout the life cycle of a building, including raw material extraction, manufacturing, transportation, construction, maintenance, and end-of-life disposal.
Cement acts as a glue that, when mixed with water, secures stone, gravel, and sand to create concrete. Despite the fact that cement makes up only about 10 percent of the volume in concrete, it is important to note that it is responsible for as much as 90 percent of the carbon dioxide emissions associated with the material.
Concrete stands out as the most vital and cost-effective construction material. Moreover, it’s the most widely used material globally for compelling reasons: its durability, longevity, and resistance to extreme conditions such as weather extremes, fire, moisture, and mold. Additionally, not only is concrete fully recyclable, but it also absorbs carbon dioxide over time.
In many instances, concrete is the sole material that satisfies the stringent standards for quality and durability in construction. Looking ahead, concrete will continue to be indispensable in forging strong and sustainable communities.
Concrete with a lower climate impact, made with alternative binders, is called low-carbon concrete.
*The amount of added alternative binders depends on the type of construction and exposure class.
A sustainable society is built with low-carbon concrete.
Indeed, utilizing low-carbon concrete is the single most important measure for diminishing the environmental footprint of the construction sector.
In our commitment to promoting sustainable practices, we are constantly refining ‘Our Green Offer’ to make the selection and application of low-carbon concrete more accessible. Additionally, our research and development efforts are dedicated to realizing the goal of net-zero emissions in concrete construction.
Furthermore, collaboration is essential at the design phase, involving all stakeholders, especially concrete manufacturers, to ensure the success of net-zero emission concrete projects.
The Colosseum in Rome was largely built with concrete and the Pantheon’s concrete dome is still the world’s largest unreinforced concrete dome.
The Romans’ use of concrete freed the building projects of the time from the limitations of stone and brick, which enabled the revolutionary constructions of the time, both in terms of complexity and size. But after the fall of the Roman Empire, concrete construction technology fell into oblivion and it was only in the middle of the 18th century that the technology was redeveloped.
Concrete, a composite material, consists of ballast—usually sand, crushed rock, or stones—and a binding agent made of Portland cement and water. Since these ingredients are locally available almost everywhere, concrete is easy to produce.
Moreover, ballast can be replaced by recycled material, while ash and slag can substitute Portland cement. Additionally, supplementary cementitious materials (SCMs) enhance concrete properties and reduce environmental impact. Ultimately, this versatility showcases concrete’s adaptability.
Across the world, people use over 24 billion tons of concrete annually in diverse projects, including homes, commercial premises, infrastructure, and power plants. Its uses are almost too many and varied to mention. However, this is unsurprising when considering what concrete is capable of.
Furthermore, concrete can be adapted to fulfill a wide spectrum of technical requirements. It is a proven construction material that is both inexpensive and durable. Additionally, it is highly durable, fire and water-resistant, and noise insulating. Moreover, fresh concrete is soft and malleable, making it a versatile, creative material.
Concrete’s popularity as a building material stems from its many characteristics, especially its versatility. For instance, producers can create special concrete to fulfill a wide variety of specific functions. This includes aesthetically adapted concrete for visual purposes, fiber concrete, self-compacting concrete, and high-strength concrete, among many more.
Concrete is much more than a high-quality construction product. It’s one of the world’s most sustainable and versatile building materials.
For thousands of years, concrete has been a popular and widely used construction material. There are many reasons for this, not least its natural beauty and ability to be formed and used creatively. However, from sustainability to health, safety and durability, concrete is a material defined by outstanding functional performance and real benefits.
Over its entire lifetime, concrete is an efficient absorber of CO2.
Concrete is highly durable, fulfilling its intended function for long periods of time.
Because concrete can be manufactured close to where it’s needed, transport distances and their climate impact can be minimized.
Concrete’s high density helps insulate buildings, lowering energy consumption and costs and reducing our climate footprint.
Concrete can withstand moisture, fire and the effects of extreme weather.
Concrete has effective noise insulation properties, contributing to calm, quiet interior environments.
