Benefits of Recycled Aggregates
Recycled aggregates play an important role in decarbonising the construction industry. Here, we break down what you need to know about recycled aggregates, from what they are and where they are sourced to their environmental benefits.
What are recycled aggregates?
Recycled aggregates are aggregates that have not been derived directly from virgin deposits and are not going through their first-use lifecycle.
Sources of recycled aggregates
True recycled aggregates are sourced from construction and demolition waste after reprocessing. This could be from the demolition of permanent or temporary buildings or structures which have reached the end of their service life. These aggregates are not to be confused with primary aggregates, which come from quarrying, sand and gravel extraction, or dredging activities.
Recycled aggregates are also different from secondary aggregates, which are produced from by-products of industrial processes. Secondary aggregates include Cornish china clay aggregates, incinerator bottom ash aggregate (IBAA), or slag.
At Heidelberg Materials UK, we have 16 recycling centres located around the country which provide high-quality recycled aggregates to the UK’s commercial, residential, and industrial construction sectors. Whatever your project, you can find suitable recycled materials in aggregates, concrete concrete, and asphalt at our centres. You can drop your construction waste as well as collect material on the same site for your convenience - tip, collect and go.
Reyclcing centre location finder
How are recycled aggregates made?
Recycled aggregates are produced by processing waste from construction and demolition activities. The waste is sorted, crushed and screened to remove contaminants to achieve the desired size, shape, and particle size distribution for specific construction applications.
Types and applications
Types of recycled aggregate include:
- Concrete
- Concrete products
- Mortar
- Concrete masonry units
- Unbound aggregate
- Natural stone
- Hydraulically bound aggregate
- Clay masonry units (i.e. bricks and tiles)
- Calcium silicate masonry units
- Aerated non-floating concrete
- Bituminous materials
- Glass
The type of recycled aggregate you need depends on the application and the required properties. Primarily, recycled aggregates are found in fill solutions, either in place of or combined with primary aggregates. They can also be used in applications like:
- Concrete
- Concrete products
- Asphalt - though in lower proportions and to a more limited extent due to the material sourced, its consistency, and effect on end use
What’s the difference between virgin aggregates and recycled aggregates?
Virgin aggregates are sourced from activities like quarrying, dredging, and sand and gravel extraction. On the other hand, recycled aggregates are already in the building materials economy, having had a first use. They are sourced from reprocessed construction and demolition waste.
Building regulations for recycled aggregates
All aggregates to be used as, or in the production of, building and construction materials are controlled by the requirements of British and European standards. Recycled aggregates are no different, and legally must comply with all the relevant requirements of these standards (in association with the WRAP protocol). All properties associated to the standards relating to the specific end use must be declared, including areas related to:
Mechanical performance Chemical and petrographic composition Presence/level of potential harmful compounds and leachates
Any reputable aggregate supplier, like Heidelberg Materials UK, will carry out acceptance testing of inbound waste to ensure recycled aggregates meet stringent quality standards. All our aggregates, recycled or otherwise, are ticketed to the appropriate British and European Standards. Certificates that show all properties of the aggregate are available, too, for extra peace of mind.
What are the environmental benefits of using recycled aggregates?
In the UK, around 200 million tonnes of raw aggregates are used every year to fulfil construction requirements, according to the Scottish Environment Protection Agency (SEPA). Of this, almost a third (28.5%) come from recycled or other secondary sources. It’s a promising step in the right direction for a more sustainable construction sector.
Webinar: Decarbonise your construction projects
Turning aggregates that have reached the end of one life into new, recycled aggregates for another is a way of promoting a more circular construction economy. Below are three ways recycled aggregates are more beneficial to the environment than virgin aggregates.
1. Reduces the amount of waste sent to landfill
Repurposing construction and demolition waste that has reached the end of its life reduces the amount of waste sent to landfill. Given the UK Construction Industry Waste Report 2023 found construction generates 62% of the UK’s waste, it’s imperative we repurpose as many materials as we can to establish more circular economies within the sector and drive this figure down.
2. Supports preservation of natural resources
Using recycled aggregates reduces demand on virgin materials which are quarried from the natural environment. By shifting reliance away from virgin aggregates to recycled (and other secondary aggregates, like by-products of mineral extraction), these sources are protected for years to come. Choosing recycled aggregates over virgin aggregates also helps to reduce negative environmental impacts, like habitat destruction and land disturbance.
Watch the webinar: Biodiversity in construction
3. Reduces energy use and financial costs
Reducing the need to quarry virgin aggregates also reduces the need for other activities which aren’t typically beneficial to the environment. By their nature, recycled aggregates are often sourced/produced in areas where redevelopment occurs. With such close proximity to end use, the cost of recycled aggregate haulage (from both financial and carbon standpoints) is less than that of primary aggregates, which often have to be sourced from different geographic areas.
The definition of sustainable construction
The UK Green Building Council defines sustainable construction as construction activities whose ‘negative impacts are minimised’ and ‘positive impacts maximised’ to achieve ‘a balance in terms of environmental, economic, and social performance’. For instance, using renewable energy rather than fossil fuels on construction sites, and making sure natural habitat restoration is in the post-construction project plan to promote biodiversity.
At Heidelberg Materials UK, we also believe sustainability in construction is about more than reducing emissions and protecting the environment. It includes:
Working efficiently Creating value with our projects Investing in people-related issues such as health and safety, wellbeing, succession planning, and diversity Supporting the communities in which we operate
Your reliable recycled aggregate supplier
Heidelberg Materials UK provides a wide range of aggregates to suit a variety of purposes, so you can select the best possible material for your construction project. See our case studies to understand how our aggregates have been applied to construction projects, or view all our aggregate products to find the right one for you.