Showing posts with label circular economy. Show all posts
Showing posts with label circular economy. Show all posts

Monday, 28 April 2025

What happens when you build a city from wood?

... one study found that building with wood instead of concrete and steel in 80% of new buildings would help offset half of Europe’s construction industry emissions.
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Monday, 6 May 2024

Denmark passes new law to recycle more building materials


The Danish government has approved new legislation mandating recycling plans for buildings exceeding 250m2 scheduled for demolition. The Danish Minister for the Environment warns: 
We can’t keep extracting sand and gravel.

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Monday, 29 April 2024

‘Circular solutions vital to curb environmental harm from cement and concrete’

* Cement and concrete production is responsible for significant pollution, human health impacts and vast amounts of climate-fueling emissions. 

* Manufacturing cement is particularly problematic as the chemical process used to make it produces nearly 8% of global carbon emissions. Experts also underline that demand for the mined and quarried aggregate materials used to make concrete, such as sand, is responsible for biodiversity and ecosystem harm. 

It’s estimated that around 30 billion tons of concrete now gets used each year, already posing huge extraction, pollution and greenhouse gas emission risks, even as production surges in the Global South as the construction industry ramps up. “That starts looking like quite an enormous pressure on our planetary boundaries,” says Sophus zu Ermgassen, a postdoctoral researcher at the University of Oxford. 

Circular solutions are urgently needed to address environmental threats at multiple points along the cement and concrete supply chain, say experts such as Jonathan Duwyn, a buildings and construction specialist with the UN Environment Programme’s Climate Change Division. Research indicates that quarrying for construction minerals — including sand, stone and gravel — poses a threat to at least 1,000 species planetwide, according to Aurora Torres, an ecology and sustainability researcher at the University of Alicante. 

It’s estimated that around 50 billion tons of sand is used annually for construction, generating an array of environmental problems and social challenges. Research indicates these activities take a toll at the ecosystem level, and with human health by degrading air and water quality, and even influencing infectious disease spread in sand mining areas.
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Thursday, 25 January 2024

Cemex UK trial use of up to 100% recycled aggregates


Mike Higgins, Cemex’s national technical manager for UK research and development, commented: 
Reusing recycled products in our materials where possible not only reduces waste, it helps to preserve our aggregates reserves and protects our business in the long term.
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Monday, 13 February 2023

Industrial trials start on zero-carbon cement production

The Cement 2 Zero project aims to demonstrate that concrete can be recycled to create a slag forming addition that could, when cooled rapidly, replace Portland cement.  

The two-year industrial trial will test each stage of the production process, bringing together the Materials Processing Institute, the University of Cambridge and industry partners – Atkins, Balfour Beatty, Celsa, Day Aggregates and Tarmac. Eventually the zero carbon cement – known as Cambridge Electric Cement – will be used in a real UK construction project.  

Philippa Horton of the University of Cambridge, who created the project consortium, said: "If Cambridge Electric Cement lives up to the promise it has shown in early laboratory trials, when combined with other innovative technologies, it could be a pivotal point in the journey to a zero-emissions society."
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Wednesday, 20 October 2021

Sustainable aggregates

Over the years we have posted about secondary aggregates and recycled aggregates, both of which represent more sustainable alternatives to primary or virgin aggregates. 

Here's another example, this time from a Lanarkshire company that has recently launched a new range of low-carbon aggregate produced from incinerator bottom ash, together with recycled sand produced from street sweepings and gully waste:

Levenseat’s low carbon product offering is designed to help construction firms lower their building costs while also reducing their environmental impact by replacing virgin aggregate within concrete – for each tonne of recycled aggregate used, 29kg CO2 is saved from being emitted. In 2020 2.7 million tonnes of IBA was produced from Energy from Waste plants in the UK. 
Earlier this year, we posted about carbon-negative aggregates. This has now helped Jackson Civil Engineering secure an Environment Agency Flood & Coast 2021 Excellence Award. O.C.O’s aggregates sales and development manager said: 
Not only have we been able to show that carbon-negative aggregates have a role to play in sustainable construction and the road to carbon zero, but also, just as importantly, that they offer a credible alternative to using up our finite resources of traditional sand and gravel. 
I really feel the tide is beginning to change; people will have to start looking for alternatives and I think this award will open their eyes to the fact there is a manufactured product that can be used in various applications – such as asphalt and Type 1 concrete – which is both proven to work and is environmentally friendly.
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Monday, 27 September 2021

‘Stop knocking down buildings, top engineers urge’

The report, steered by the Royal Academy of Engineering, said a new way of thinking is needed before planning new homes, factories, roads and bridges. 

Prof Rebecca Lunn from Strathclyde University, one of the report's authors, said: "Our biggest failure is that we build buildings, then we knock them down and throw them away. We must stop doing this." 

Fellow author, Mike Cook, adjunct professor at Imperial College, challenged the government's £27bn road-building programme because of the embodied emissions created to obtain the concrete and tarmac, as well as the use of very polluting machines to construct the highways. 

Prof Cook told BBC News: "We have to radically revise the way we look at things."

Prof Cook said questions should be asked whether projects such as HS2 - with its massive embodied carbon - will really benefit future generations.
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Wednesday, 30 June 2021

Dawlish sea wall reconstructed with low carbon concrete

According to Hanson: 
Regen Ground Granulated Blast furnace Slag (GGBS) is a cement substitute, manufactured from a by-product of the iron-making industry. Using one tonne of Regen in concrete reduces the embodied CO2 by around 900kg, compared to using one tonne of Portland Cement, and also increases its durability. Regen is more sustainable than other cement substitutes such as Fly Ash. In the UK, GGBS is usually supplied as a separate component for concrete and is added at the concrete mixer. It can replace 70 per cent or more of the Portland cement.

GGBS has been used in the reconstruction of the Dawlish sea wall. The contractor estimates 1,130 tonnes of CO2 have been saved as a result:
The rail line across the Dawlish sea front was washed away by a storm in February 2014. As part of the reconstruction, BAM Nuttall is building a new sea wall using Regen GGBS concrete supplied by Hanson UK. The concrete uses ground granulated blast furnace slag (GGBS) – a waste by-product of steel manufacturing – to replace a large proportion of energy-intensive cement. To date, construction of the second section of new sea wall has used 4,600 cubic metres of low carbon concrete, with around 4,500 cubic metres remaining to pour. By using Regen GGBS concrete, the Dawlish project will have reduced the amount of carbon generated by this process by two-thirds and saved over 1,130 tonnes of carbon dioxide from entering the atmosphere in comparison to traditional concrete, it has been calculated.
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Wednesday, 31 March 2021

Maintaining the same levels of quarried sand “just not sustainable”

Some companies are clearly making progress in the production of construction products from waste, diverting valuable waste materials away from landfill, moving towards a circular economy, moving away from the consumption of finite resources – even if take-make-waste Aggregate Industries is not. 

Here are three recent examples:

Oliver Rees, managing director of SRC Group commented:
Every six months we're recording significant increases in the volumes of material we're moving. As we grow it's just not sustainable – both for us as a business and for the environment – to maintain the same levels of quarried sand and aggregate products. We see recycling as a significant part of our operations and it’s the right thing to be doing for the environment. We’re diverting around 800,000 tonnes of construction and demolition waste from landfill each year; producing sand and gravel for reuse in construction and creating prefab concrete lego blocks for retaining structures as well as paving. 
 
Yorkshire Water’s press release states:
Biffa collects the grit from more than 600 treatment works and transports it for processing into a blended aggregate which is ready for the construction sector to use in materials such as concrete blocks

 

Tarmac’s rubber-modified asphalt:
... incorporates the rubber of up to 500 waste stream tyres in every kilometre of highway surfaced, depending on the thickness of the road. This would help to reduce the up to 150,000 tonnes of rubber waste which is exported annually from the UK as fuel for cement kilns, primarily to countries in North Africa and the Indian subcontinent.
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Thursday, 4 March 2021

Carbon-negative aggregates

Whilst Aggregate Industries clearly couldn’t care that any minerals quarried from Straitgate Farm would have high embodied carbon – not least because of the addition of a 46-mile round trip required to process each as-dug load before any onward distribution – some companies are working towards carbon-negative aggregates, aggregates made from CO2. 

Japan’s Mitsubishi Corporation has selected O.C.O Technology to be part of its Green Concrete Consortium programme focusing on carbon-negative concrete and aggregate production. 

Stephen Roscoe, O.C.O’s Technical Director, said: 
Using carbon dioxide to transform unwanted waste materials into new carbon negative products is a perfect example of the circular economy in action. It reduces the need for natural aggregates and above all, it enables significant volumes of CO2 to be taken out of the atmosphere – something we all need to work towards to improve the future sustainability of our planet.
O.C.O was apparently the first company in the world to successfully commercialise the Accelerated Carbonation Technology process whereby "carbon dioxide is permanently captured as stable carbonate minerals… (manufactured limestone)". The company produces more than 350,000 tonnes of carbon-negative aggregate each year from its operations in Suffolk, Avonmouth and Leeds.

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Sunday, 21 February 2021

How can concrete be made more sustainable?

Concrete is responsible for huge amounts of CO2. The search is ongoing across the world for more sustainable forms of concrete that use recycled materials. Here are two recent advances.

Recycled concrete aggregates made with everything from coffee cups to building rubble offer huge environmental benefits, from reducing landfill and CO2 emissions, to saving natural resources and boosting the circular economy. Despite ongoing improvements however, challenges with matching the strength and durability of traditional concrete have hindered the practical application of these sustainable alternatives. Now researchers from RMIT [University in Melbourne, Australia] have developed a new method for casting prefabricated concrete products made with rubber tires and construction and demolition waste that are up to 35% stronger than traditional concrete.

 
In a study undertaken at the University of Florida, recycled oyster shells were used as an aggregate to form a permeable concrete tile. The shells came from local area restaurants which were sending around 10,000 oyster shells each week to the landfill. The test results showed that after drying, a concrete tile made with oyster shell aggregate had a similar colour, texture and strength to that of a commercial concrete tile. In the case of mortar, a South Korean university study found no significant reduction in the compressive strength of the mortars containing small oyster shell particles instead of sand. Enormous amounts of oyster shells are discarded each year from oyster farms and restaurants. Oyster shells are non-biodegradable and pollute the land and water when discarded indiscriminately.
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Thursday, 11 February 2021

‘UK’s first cement-free low carbon concrete block’

SigmaRoc, the construction materials group, has today announced the "UK's first Cement Free Ultra-low Carbon Concrete Building Block": 
Greenbloc is completely cement free, making it unique in the UK market and provides on average a significant net reduction in embodied CO2 ('eCO2') of 77% per concrete block, resulting in the following specific decreases: an average reduction of 1.1kg of eCO2 per concrete block; an average reduction of 2.7 tonnes of eCO2 per average semi-detached house...  
Max Vermorken, CEO of SigmaRoc, commented:   
Our Greenbloc range and brand is the brainchild of our innovation and technical teams. It addresses a key challenge in the building products industry, the embodied CO2 in one of the most widely used building materials: the concrete block.


Cemfree is a proprietary Alkali-Activated Cementitious Material (AACM) that activates pozzolanic materials such as Ground Granulated Blast-furnace Slag (GGBS) and Pulverised Fly Ash (PFA) to create a Cemfree Binder which can replace a variety of cement types to create Cemfree Concrete. 
News of cement-free alternatives may be less welcome to LafargeHolcim – parent company of Aggregate Industries – given it’s the world’s largest cement producer, with carbon emissions to match. 

Cement is responsible for about 8% of the world's CO2 emissions – 1 tonne of CO2 can be produced for every tonne of cement produced. If the cement industry were a country, it would be the third-largest source of CO2 emissions, behind China and the US. 

We have previously posted about other cement-free alternatives – including the use of fly ash – for example here and here.  
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Monday, 14 December 2020

Human-made materials now outweigh Earth's entire biomass

The dominant categories in the analysis were human-made mass in the form of buildings and infrastructure, composed of concrete, aggregates, bricks and asphalt.
It can’t go on like this. 

In other news, a symposium facilitated by CDE has examined trends and challenges in construction and demolition waste recycling. Here are two paragraphs from a longer article that can be found here: 
Focusing on the recycling sector, CDE’s Eunan Kelly, Head of RECO, was joined by a panel of construction, demolition and excavation waste pioneers to discuss challenges and opportunities for sustainable construction in the UK and Ireland. Commenting on the sharp rise in public awareness of sustainability issues, Scott Brewster, Managing Director at Brewster Bros. Ltd, said, “There’s never been a time in history when the general public have been more informed about the environmental crisis we face.” He referenced how self-discipline and external pressures are leading a shift in how companies in the construction industry operate, citing they have become “leaner and cleaner” for their adoption of recycled aggregates which is improving profit margins and reducing environmental impact. As well as public pressure, he believes political pressure, including ambitious zero waste and net-zero emissions targets, and fiscal pressures, such as landfill tax and the aggregates levy, will encourage more construction businesses to turn to high quality recycled sand and aggregate products. 
Viv Russell of Longcliffe Quarries and James Thorne from the Institute of Quarrying joined with CDE to discuss the hidden value in by-product stockpiles. Russell explained, “A lot of things have changed over the years. Certainly, overburden was something you would muck away… and potentially, in the life of a quarry, you would move around three or four times. “You can’t afford to transport this material anymore,” he added. Pressures and influences on the industry, such as the Aggregates Levy in 2002, meant that a solution to costly waste products had to be found. Russell continued, “Touching them [the waste products] once and turning them into a product is common sense. Now scalpings and crushed rock fines…once seen as a waste are now seen as a resource.” Commenting on the evolution in practice in the industry, Thorne said, “The drivers are changing and the industry is moving its focus to reflect that.”
Regarding the latter paragraph, those reading the extensive phasing and soil movement plans for Straitgate Farm will wonder if Aggregate Industries has seen the memo.
  
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Monday, 9 November 2020

Overuse of sand ‘one of the major sustainability challenges of the 21st century’

SandStories aims to raise awareness of the "looming global sand crisis": 
SandStories works to create awareness about the urgent need to manage our consumption of sand as a resource. We aim to bridge the gap between science, policy and industry by identifying and promoting potential solutions to the looming sand crisis.

 A new book is in the pipeline: 

Sand has always been perceived to be a symbol of abundance in many cultures. It is popularly believed to be both renewable as well as inexhaustible. This book will challenge that perception and draw the reader's attention to a common yet surprising phenomenon of the scarcity of sand as a resource. From glass to urban infrastructure, from silicon chips to pharmaceutical products, sand is used in mind-boggling volumes. But extensive consumption has resulted in several social, environmental, economic and geopolitical impacts across the globe. Although specific industries have already begun to find alternatives due to shortage of sand, the gravity of the situation hasn't percolated into the mainstream yet. This book attempts to fill that void and make the subject readily accessible to those who wish to delve deeper.
  

Whilst Aggregate Industries’ business model relies on digging up precious farmland to extract more of this limited resource, some companies are operating in a more sustainable way; we posted about one recently, who stated:
It largely goes unreported that sand is on the endangered natural resource list. Globally around 13 billion tonnes of sand are mined for construction and the impact on the environment is vast and unsustainable. 
Natural resources will not be able to cope with on-going demand, but there are alternative solutions that are sustainable.
Of course, there's another way too:
 
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Thursday, 10 September 2020

‘More contractors are requesting recycled sand’


Sheehan Group – an Oxfordshire-based company recycling construction and demolition waste – claims "more and more contractors are embracing high-grade recycled sand, which has a lower carbon footprint and protects a scarce natural resource". Sheehan's finance director commented in AggNet:
It largely goes unreported that sand is on the endangered natural resource list. Globally, around 13 billion tonnes of sand are mined for construction and the impact on the environment is vast and unsustainable.
Natural resources will not be able to cope with ongoing demand, but there are alternative solutions that are sustainable. Our circular driven economy approach to recycling C&D waste not only reduces the amount of waste going to landfill, but it also creates high-quality recycled products that can be used in local projects.
In eight years, we have produced 333,000 tonnes of recycled sand, which competes with mined products on the market. We are finding more contractors are requesting recycled sand for use in construction projects and, by doing so, are helping make a positive difference to the climate emergency.
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Farringdon ‘smart’ building to be cement-free

LafargeHolcim – parent company of Aggregate Industries – is one of the world's largest cement producers. If the cement industry were a country, it would be the third largest emitter of CO2 in the world.


According to Willmott Dixon, "around half of all non-renewable resources that mankind consumes are used in construction, making it one of the least sustainable industries in the world". If the construction industry is to move to greener practices, it must remove cement from the equation. This new £140m office development, to be built close to Farringdon station in London, will do just that:


According to The Construction Index:
To boost green credentials, Mace has committed to using cement-free concrete, which uses ground granulated blast furnace slag (GGBS) and fly ash instead of Portland cement. The material, called Earth Friendly Concrete and made by Australian materials firm Wagners, made its UK debut on Landsec’s Nova East development in London Victoria last year.
We first posted about using fly ash as a cement substitute back in 2013.
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Wednesday, 5 August 2020

‘To fight climate change – don't demolish old buildings’

To fight climate change, old buildings should be upgraded, not demolished – urges RetroFirst, a campaign by the Architects’ Journal supported by "more than 100 architecture practices, organisations and individuals".



It was once thought better for the climate to demolish old energy-hungry buildings and build well-insulated replacements. This view is now regarded as mistaken, given how much carbon is emitted by creating the cement, bricks and steel for new buildings:
The Royal Institute of Chartered Surveyors (RICS) estimates that 35% of the lifecycle carbon from a typical office development is emitted before the building is even opened. It says the figure for residential premises is 51%.
These calculations suggest it will be decades before some new buildings pay back their carbon debt by saving more emissions than they created – and these are decades when carbon must be sharply reduced.


As we posted, "Never demolish, never remove or replace, always add, transform, and reuse!"

In the UK, the construction industry accounts for 60% of all materials used, while creating a third of all waste and generating 45% of all CO2 emissions in the process. It is a greedy, profligate and polluting monster, gobbling up resources and spitting out the remains in intractable lumps. On our current course, we are set to triple material extraction in 30 years, and triple waste production by 2100. If we stand any chance of averting climate catastrophe, we must start with buildings – and stop conceiving them in the same way we have for centuries.
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Sunday, 5 July 2020

CEMEX invests in start-up creating aggregates from plastic waste

California-based Arqlite SPC processes unrecyclable plastic waste into artificial gravel, avoiding the use of natural quarry aggregates and boulders in the production of light concrete and in drainage beds for construction and landscaping.
It has developed technology that allows most of the plastic waste to be recycled instead of disposal at a landfill or polluting the environment. Cemex said that the light aggregates it produces multiply thermal and acoustic insulation by ten times compared to mineral aggregates and offer better construction quality and higher energy conservation.
The aggregate is three times lighter than stone; benefits include lower transportation costs. The low thermal conductivity of plastic reduces its reaction to extreme temperature variations and, therefore, the possibility of fracturing or altering the concrete mix, said Cemex.
The process is claimed to be capable of processing the vast majority of plastic waste as raw material.
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Thursday, 18 June 2020

Sustainable brick made from recycled sand & plastic waste

A company in India has launched the 'silica plastic block' – a sustainable building brick made with 80% recycled foundry dust and sand waste and 20% mixed plastic waste.

The SPBs were found to have 2.5 times the strength of normal red clay bricks while, to be consumed they need... 80% lesser use of natural resources.
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Wednesday, 13 May 2020

Recycled roads

We've posted about recycled asphalt – including in 2018 about the World’s first ‘fully recycled road’:
Eurovia, part of Vinci – the company that now owns South West Highways – has recently completed a motorway renovation project in France using 100% recycled asphalt; in other words, "extracts from quarries were not used at any stage":
The bulk of the supply can be sourced from the milling of materials produced by the site, thereby partly or fully protecting natural resources and reducing both transport logistics and the site’s carbon footprint to a minimum, with a 50% reduction in greenhouse gas emissions.
We’re working to create systems which will significantly reduce the reliance on quarries, prevent more material from going to waste and reduce the distance that material has to be transported.
What does he see as the main obstacle? Mindset:
...the difficulty is in changing the mindset of the industry to accept this way of working, rather than the cost of it.

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