Home 5 Recycled Products 5 Mind the Gap: Barriers to the use of Recycled Aggregates

Mind the Gap: Barriers to the use of Recycled Aggregates

Aug 30, 2023 | Recycled Products

According to a 2021 World Economic Forum survey, over 65% of consumers prefer more sustainable products. Within our industry there’s a growing understanding of the imperative to switch to circular practices as resources dwindle.  

However, in 2020, only 20% of the demand for aggregates was met by recycled materials in Scotland and 28% in the UK as a whole. In addition, there are millions of tonnes of valuable soil and stone materials downcycled or landfilled each year flowing out of the circular economy to an early end of life, when they could be used as feedstock for recycling to supply more recycled aggregates to the construction market. So why is there such a big gap? 

We’ve spoken to 60 professionals in the construction industry including Architects, Civil Engineers, Waste Management Specialists and more to get answers.


Why people aren’t using recycled aggregates 

A third of participants cited a lack of awareness in recycled aggregates causing them to avoid using the materials in their construction projects. When asked what would encourage them to use recycled aggregates or use more of them, 20% suggested better co-operation with building sites and others in the supply chain.  

“Project Specifications need to be tailored, not cut and paste.” 

Our research suggested Designers and Engineers can be potential roadblocks for the use of recycled aggregates. It was noted that in some cases, participants had experienced a reluctance to stray from Project Specifications used on previous projects, meaning recycled aggregates were never considered. 

Money Talks

It’s one of the most common misconceptions we hear anecdotally but out of all respondents involved in our research, only 1 person said that the price of recycled aggregates was a barrier for their use. When asked what would encourage the participants to use recycled aggregates or use more of them, just 3 mentioned financial incentives or a change in price.  

The reality is, recycled aggregates are generally competitive with virgin aggregates, if not cheaper. 

Once Bitten, Twice Shy

There were no instances of negative experiences and almost all participants said they had positive experiences using recycled aggregates.  

Two participants noted having mixed experiences. 6F5 capping, a crushed unwashed recycled aggregate, was the main product of concern due to trash contamination. The 1% tolerance for contamination (e.g., unavoidable wood, plastic etc.) can often lead to misconceptions that the product isn’t fit for purpose when it is in fact compliant and passes testing. Basically, it’s not pretty but it is safe and does what it says on the tin.  

Of course, the 1% tolerance should not be used by recycled aggregate producers to deliberately introduce contamination as an outlet for other wastes as this undermines the whole system. Fortunately, Brewster Brothers does not deal with any other waste streams so customers can be confident that this is not happening within our processes. Washed recycled aggregates, such as Brewster Brothers’ sand and gravel, are almost undistinguishable from their virgin equivalents as the trash fraction is separated by density or ‘floated out’. 

John Logan, Operations Director of the Construction Waste Portal, commented:

The problem with 6F5 in particular is that some ‘producers’ use the 1% detritus loophole as a specification rather than a limit. Regulators need to take a more significant role in regulating the production of recycled aggregates.”


“I fully endorse their use but the critical aspect we continually miss as an industry is that we are fundamentally dealing with a change of legal status in most cases from a waste to a product… and that change in status needs [to be] audited.”

Dean Stone, Chairman of Wilson Stone Group, went as far as to say that washed aggregates are “brilliant” but points out he has experienced some producers creating 6F5 with “pretty much anything in it”.

Quality Over Quantity

When asked what would encourage the participants to use recycled aggregates or use more of them, there was a clear theme – quality assurance. Despite 70% of participants being aware that recycled aggregates go through the same testing as virgin aggregates, quality was still a worry, and even those who believed in the quality of the recycled materials cited needing reassurance.  

Despite the urban myth that there isn’t enough supply of recycled aggregates to meet demand, only one participant cited an increase in supply as the main factor that would encourage them to use more recycled aggregates. Whilst we acknowledge that recycled aggregates can’t meet all of the sector’s demands, and that recycled aggregates (currently) can’t be used in all applications, there is still a considerable increase in supply achievable. With a better understanding of how the circular economy works within the construction industry, untapped materials can be extracted from, for example, the 1 million tonnes of waste soil and stones going to landfill each year (read more about this issue here).  

It is as simple as this – the construction industry needs to actively contribute to the circular economy in order to get quality aggregates back out of it. 

The construction industry is responsible for over 50% of Scotland’s waste arisings (estimated to be 4 million tonnes in 2021 according to SEPA) and around 40% of the country’s natural resource consumption. With virgin sand predicted to run out by 2050, we need to act now to preserve our resources and future-proof businesses. Changing perceptions and removing the barriers to recycled aggregates use is one of the key means the industry can make an impact on the bleak outlook for our natural resources and our industry.


Recycled aggregates are a relatively new product and there are inevitably going to be some reservations until they become the norm. They’re used far more widely than you might realise, however, they’re in the roads you drive on, the pavements you walk on and possibly even below your own house. Recycled aggregates are a high-performing, sustainable alternative to virgin aggregates. As an industry, we’re looking for solutions to reduce our emissions and our waste. Recycled aggregates are a solution, not a compromise.  

If you have any hesitations or concerns surrounding recycled aggregates, please get in touch with our team who are always happy to help. Whether you want to discuss the rigorous testing our products go through, or see them first-hand through a site visit, please get in touch via phone: 01506 431 321 or email: [email protected].