5 REASONS TO USE RECYCLED CONCRETE

Compared with the 1980s, concrete production has tripled. The world produces 30 billion tonnes of concrete a year. That works out at 3.75 tonnes of new concrete per person (1.63 m3/per inhabitant. One of the main ingredients in concrete is gravel, and around 37 billion m3 of gravel has to be quarried from mountains or dredged from rivers every year.

Cutting the carbon footprint is excellent and very important, yet the first studies show that the mass of man-made material such as concrete will soon exceed the mass of biomass on the planet. Making man-made materials calls for the constant extraction of biomass. The good news is that in the USA 75% of concrete reinforcement is already made from recycled steel and 90% of aluminium is recycled aluminium. Less than half of all plastics are recycled, but the share of recycled materials is fortunately growing. Concrete, and cement in particular, accounts for roughly 8% of global CO2 emissions (90% of the CO2 emissions from concrete come from cement production), so attention needs to go both to improving cement production and to reducing the extraction of new gravel, and not least to the build-up of ceramic construction waste such as brick and concrete. In England, recycled concrete replaces only 5% of new concrete mixes.

Reason number one is, without doubt, protecting nature.

A masonry building with a usable floor area of 100 m2 takes around 55 m3 of concrete, if not more, which is 126 tonnes of material for the concrete alone. To picture it: five large lorries full of material. The material for making concrete can be replaced with recycled material. What does that mean? That your house can spare nature the extraction of 126 tonnes of material and clear 126 tonnes of waste from it at the same time. When building a Talpa House we set very high demands on the concrete, above all on its watertightness, workability and structural performance. Recycled concrete can meet all of this, as our completed buildings show, and as testing in a certified laboratory confirms.

Reason number two is cleaning up the planet.

If we want to reduce the amount of waste, let us start with the largest sources by volume and weight, and old buildings in need of remediation are among them. Ceramic waste such as brick and concrete makes up as much as two thirds of construction waste. Plastic straws have been replaced by metal or paper ones, which is great for the planet (less so for people 😊, once they start dissolving in your drink), but we will do far more for a cleaner country by starting with the biggest sources of waste. Straws and plastic bags travel all over the world, and awareness has led to limits on making them, and so on the waste. Concrete, though, stays behind the village or town, overgrown with weeds, and that does not mean the construction waste has gone away.

Reason number three is the circular economy.

The first tests have shown that concrete can be recycled up to three times over. That means it is quarried once and then in use for 150–200 years, perhaps longer. That is what I call a circular economy. Aluminium, for example, is energy-intensive to produce in the first place, yet it can be reprocessed four times using only 5% of the energy of primary production. The service life of aluminium is 50–150 years. Even though aluminium makes up a small share of waste by weight, recycling it makes sense, in the form of cans among others.

Reason number four is the wish

to leave the earth to our children in better shape, than we took it over from our parents in the industrial age.

Reason number five is financial.

Recycling concrete at this high a rate costs only 0.5% of the construction price, the lowest share of the price of any recycled material used in construction. Wood-fibre insulation, also a recycled material, costs as much as 1.5% of the construction price instead of polystyrene.

We will go on building with ordinary concrete made from new materials. We hope, though, that recycling has struck a chord with you, enough to make you think about how much waste you can take out of the country and what a positive effect that has on society. When the need does arise to build a new house, flat, or space to learn or work in, let us look at where and how to recycle. Talpa House has been using recycled concrete for some time now and pays particular attention to cutting its carbon footprint through recycling too. Will you join us?

Read on to find out where recycled concrete can be used and which types. Coming soon.

Examples of use:

• Two Talpa House homes built in 2022–2023
• A new school in Plavecký Štvrtok (Slovakia): study 2023, construction 2026. A nursery school in Leváre (Slovakia): permit procedure in 2022–2023
• An office building near Zlín (Czech Republic): permit procedure in 2022–2023
• A development project with dozens of houses in preparation: study 2022–2023