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Concrete is the most frequently used building material.
And this, at the global level! Composed of a mixture of aggregates, sand and water agglomerated by a binder, generally cement, concrete is a real challenge in terms of recycling.
For good reason, concrete production is estimated at one ton per inhabitant. Each ton alone emits (on average) 575 kg of CO2. Translation? Concrete accounts for 5% of the planet's greenhouse gas emissions. Not to mention that its production requires a large quantity of water and sand.
However, concrete is a construction material with multiple uses and advantages that would be a shame (or even impossible) to do without.
Therefore, to counter the pollution emitted by concrete while extending its life cycle, concrete recycling has already proven its usefulness.
And careers have a role to play! Synaxe takes stock for you of this turning point represented by the recycling of concrete for your quarries.
Recycling and valorization of concrete: where are we?
Concrete is not the most used building material in the world for no reason! Its durability, its very good thermal capacities and the possibility of making it take any shape, make it a first-choice material.
And that is not new! In fact, concrete was already used in Antiquity. It was even considered to be A military secret by the Egyptians and the Phoenicians. It was then between the 19th and the 20th centuries that the use of concrete accelerated, positioning it among the essential materials - long before there was any question of concrete recycling.
Result:
- 80% of single-family homes now have concrete floors;
- 70% have concrete block walls;
- 60% have concrete wastewater and storm water tanks;
- 1 tile out of 2 in the Paris region is made of concrete.
The only downside is that although the raw materials that make up concrete are very present on the planet (sand, water), their quantity is tending to decrease. In addition, their use is becoming more and more expensive and has an impact on the environmental balance.
As you will have understood, the recycling of concrete is a necessity for ecological reasons, but also for costs. Sorting and recycling reduces the number of waste generated. And so much the better, because waste storage - too - is expensive.
Another advantage: the recycling of concrete makes it possible to act in favor of the environment by reducing the quantity of natural raw material used, during the repair of roads, among others. And contrary to popular belief, recycled concrete is a qualitative material!
As proof, it has better performance than road waste according to some professionals experts in concrete recycling. ” It can even be a substitute for new natural materials treated with a hydraulic binder, because during the crushing of concrete, parts of cement are released and rehydrated by the natural humidity of the crushed waste..”
Circular economy: recycled concrete is good for everything!
Nothing is lost, everything is transformed.
Concrete recycling is the perfect example! Today, it is an effective way to meet the constant needs of construction. Needs that, on the one hand, are constantly increasing due to population growth; but on the other hand, they must meet new environmental and regulatory requirements - RE 2020 at the top of the list.
As a reminder, the new Environmental Regulation known as RE 2020, which came into force last January, imposed significant changes for building manufacturers - especially in terms of recycling (and not only concrete).
Objective: to reduce the carbon impact of construction and renovation on the planet.
How? By promoting the circular economy and therefore reuse (to name a few). As the first building material, recycling concrete quickly became a matter of course.
For good reason: concrete recycling is a modern action that allows:
- An economy of resources
- The “creation” of a responsible and quality substitute material
- The development of local production
- Optimizing transport thanks to double freight
Concrete waste: a second life thanks to the recycling of concrete
In practice, concrete recycling involves two types of concrete flows:
- Concrete resulting from deconstruction.
- Concrete from manufacturing processes − that of prefabrication plants, ready-to-use concrete production units or even returns from construction sites.
The majority of concrete waste, i.e. used concrete, can benefit from the recycling of concrete: fresh or hardened concrete, manufacturing scrap or concrete waste sent back from construction sites.
Good to know: the recycling of concrete does not necessarily require a transformation operation. Recycled concrete can perfectly be reintegrated on site (in situ) to allow the manufacture of new products. Even if the concrete has hardened, without the need for additional sorting and using simple crushing plants. As you will have understood, even during its recycling phase, concrete has many advantages, even a certain flexibility of use.
For optimal concrete recycling, it is better to prioritize sorting!
On construction sites, concrete is obviously not the only material to be recycled! Let's say it, recycling now concerns the majority of materials. Therefore, during deconstruction, and in order to recover as much used concrete as possible for recycling, sorting is essential. The latter makes it possible to separate concrete from other materials.
The good news is that sorting techniques are improving more and more and are saving time and efficiency. For good reason, each recycled material represents a boost for the environment, but also for the finances of the company behind the recycling. Moreover, faced with the importance of recycling concrete and all construction materials, a Waste diagnosis has been mandatory since January 1, 2022 before each deconstruction of a building considered to be “important”.
Enough to optimize the quality of sorting, and at the same time, the rate of recycling of concrete.
Did you know that? The concrete sector is committed to better concrete recycling!
Recognizing the challenge of recycling concrete, actors in the concrete sector are working to change the design of construction systems and products.
From this commitment was born the revision of three standards that affect the recycling of concrete:
- The NF EN 12620 aggregate standards of June 2008 and NF P18-545 of September 2011. Both specify the characteristics and properties of recycled aggregates.
- The NF EN 206-1/CN concrete standard of December 2012, which authorizes the use of recycled aggregates from deconstruction for the manufacture of concrete.
Likewise, the anti-waste law for a circular economy (AGEC) also acts in favor of the recycling of concrete. How? By having opened the extended producer responsibility (EPR) regime since January 1, 2022, to construction products and materials in the building sector. A new obligation supposed to lead to more recycling for concrete, but also for all mineral construction products that generate inert waste. To do this, all construction players can now rely on ECOMINERO. An eco-organization whose mission is to improve the recycling of inert waste - including the recycling of concrete.
Concrete recycling and quarries: what is the link?
In 2019, aggregates from the recycling and reuse of inert waste from construction sites covered 28% of the needs for the construction and maintenance of infrastructures and structures, according to the ECV balance sheet (Commitment to Green Growth).
Relating to the recovery and recycling of inert construction waste, the ECV currently aims for a recycling rate of 90% by 2028. And in practice, the recycling of concrete will contribute to this objective. As proof, the recycling of demolition concrete alone represents a recycling potential of 19 MT (see visual opposite).
Concrete recycling that can be done in three different ways. Via :
- Valorization in quarries in embankments
- Reuse directly on construction sites
- Recycling through platforms
How does it work to recycle concrete in a quarry?
Recycled concrete is made from 247 million tons of construction waste, 90% of which is inert waste: soil and pebbles, demolition concrete, road asphalt, bricks, mixtures... Quarries already handle a large part of this waste via two methods: recycling and the redevelopment of quarries for the non-recyclable fraction. For your careers, concrete recycling is a complementary activity that allows you to be more competitive.
Concretely, recycled concrete — made on your sites from waste from external construction sites — represents a resource complementary to the natural resource. The latter allows:
- to optimize the exploitation of deposits;
- to use the resource as efficiently as possible;
- to extend the life of natural deposits.
In practice, building actors must send their inert waste from construction or demolition to aggregate recycling centers or to Inert Waste Storage Facilities (ISDI).
By equipping yourself with a recycling center capable of sorting concrete and any other material, you have the possibility of meeting the real needs for the management of inert waste - stone, concrete... A need that is constantly increasing due to regulations and the inevitable shift towards a circular economy - less polluting.
Of course, receiving and taking care of concrete waste or scrap requires a dedicated organization. In this sense, many quarries have set up areas for receiving and storing demolition concrete pending retreatment/recycling.
Likewise, not all concrete can be treated in the same way. While non-reinforced concrete must simply be crushed again, reinforced concrete must be further sorted to remove the scrap metal. **In general, **Construction concrete returns are recovered in skips where they harden to form large blocks − before being crushed. Finally, once crushed, the recycled concrete is screened to produce cuts adapted to the needs of the market - mainly that of public works.
Conclusion
Collected and processed close to its consumption area, recycled concrete perfectly meets new regulatory requirements as well as circular economy criteria that increasingly require the use of a proportion of recycled materials, with a very low carbon impact. The recycling of concrete also allows an undeniable saving of resources, especially water, but also sand and gravel.
A major subject that summer 2022 is particularly bringing to light due to an unprecedented drought! Technically, the recycling of concrete will allow you to take action, to save, but also to valorize. And not only concrete!
Participating in the recycling of concrete is a great opportunity to promote the commitment of your careers in the circular economy and the reduction of waste.
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