Report: Circular materials in infrastructure

The road towards a decarbonised future

If Europe could increase its circularity rate for aggregates from the current 7 per cent to 20 per cent, we would reduce virgin raw material costs of up to EUR 6 billion each year by reusing 546 million tonnes of aggregates. This would not only make quality resources last longer, but it would reduce the need to open new quarries and prevent recoverable materials from ending up in landfills.

By managing the huge amounts of natural resources we use for building our infrastructure, we can take a huge leap towards a circular society.

The world economy is still largely linear, and the extraction of natural resources plays a significant role. Excavated materials from infrastructure projects, such as soil, stone and gravel, are used universally. But despite the large quantities of materials handled and the significant environmental, economic and social effects they have, the average citizen generally has limited knowledge of how these resources are handled.

More than 100 gigatons, or 100,000 billion kilograms, of natural resources were consumed globally in 2019, half of which were minerals and ores. Everything that does not grow and comes from the ground is mined in the form of minerals and ore. All finite, non-renewable resources. The largest share of these resources, close to 40 per cent, is used in construction
and infrastructure.

The management of infrastructure materials can be complex as it generally involves a multitude of stakeholders and tasks across the value chain. Aggregates are a resource and emerging circular approaches can lead to significant environmental, financial and societal improvements compared to current practices. Even marginal improvements can lead to major savings, such are the quantities that are managed. Improvements early in a project, for example, in how we classify, report and track materials, can enable larger savings later on when access to improved data opens up more opportunities.

Annual production of aggregates in Europe 4.2 billion tonnes – only 7% circular

What would happen if we increased circularity from 7 to 20%? Which untapped possibilities and savings would there be? A Sweco study shows that we could reduce EUR 6 billion each year in virgin material aggregate costs by reusing 546 million tonnes in Europe. This is almost the same amount of material that Germany produces in one year.

The savings of up to EUR 6 billion per year could be achieved by reducing the costs of virgin material, based upon prevailing market prices, by increasing reuse and preventing the extraction of raw materials from quarries. There could also be associated benefits in terms of transport reduction, pollution from traffic and environmental degradation. There would, of course, be costs associated with the circular use of aggregates, including crushing and transport, but there would nevertheless be a reduced dependency on virgin material. Which other untapped possibilities and savings would there be, and how could we manage such a shift?

An under-appreciated issue?

Infrastructure materials are not widely understood or appreciated by society, despite infrastructure being a critical part of our lives, just like energy, water and waste management.

There is a much greater engagement, for example, in resources such as waste and recycling across society, because we are actively involved in their management. As the climate crisis unfolds and communities experience water stress, there is an increased awareness of the need for renewable energy.

By contrast, there is less engagement in how infrastructure materials are used, even though we use infrastructure every day. Our relationship with it is much more passive. And while European decision-makers in general have taken the circularity issue on board, they may have yet to fully grasp that in a sector where weight defines your market, decisions which work at the local level are what matters.

Availability and abundance

In some societies, such as in the Nordic countries, raw materials like rocks and sand are regarded as cheap and abundant. In other societies, such as the Netherlands, there is less capacity for raw materials which increases the need for more circular methods.

Europe’s use of aggregates in 2019 was 4.2 billion tonnes. This is equivalent to 33.3 times the amount of the top 300m of a Matterhorn, or about as high as the Eiffel tower. With the same quantity of aggregate, we could cover the whole of Denmark to a depth of 33 cm, or Belgium to a depth of 47 cm, each year.

And yet only about 7% of these vast 4.2 billion tonnes are part of the circular economy. The processes by which aggregate materials are managed are complex and include testing and classification, tender specifications, procurement, regulation, planning and permitting, skills, data, culture, networks, collaboration, business models, supply chain and logistics.

Overall, the current picture is mixed with regards to circular practices. Successes are often thanks to local or project factors rather than institutionalised and universal circular systems. The European Aggregates Association states that up to 20% of the current total demand of aggregates could be recycled in the long run.

Effects of aggregates on the climate

In the UK, the construction, operation and maintenance of infrastructure assets accounts for approximately 16% of total carbon emissions. On many large-scale projects, quantities
of surplus materials can be in the hundreds of thousands of cubic metres, and on many large scale projects the quantities are in millions of cubic metres.

In Sweden, the Swedish Transport Agency estimates that to transport 10,000 tonnes of excavated rock 10 km for disposal, a lorry must make 300 round trips, releasing 12 tonnes of CO2e, costing around EUR 20,000. According to the Swedish Transport Agency, the shadow cost of carbon (the cost of carbon emissions to society) is 7kr/kgCO2e. If we apply that figure to the previous 10,000 tonnes of excavated rock, that would correspond to a cost of about EUR 8,400. So on top of the paid costs, the hidden costs of the carbon are an additional 40%.

Current circularity goals

The circular economy is a key factor in reaching the aims of achieving climate neutrality by 2050. At the EU level, this is highlighted in the new Circular Economy Action Plan launched
in 2020 as part of the EU Green Deal. The EU goal is for 70% of non-contaminated construction and demolition wastes to be recycled by 2020. This includes excavated materials. At the overall EU level, this goal has been achieved, but the challenge is to maximise circularity of materials through optimal use and minimisation of associated activities such as transport. To this end, a great deal is yet to be achieved.

Data reporting

There are shortcomings in the statistics where, for example, construction materials that are used to cover landfills are usually included in the statistics as recycling. There is also a lack of data reporting on the quantities that are excavated. Without seeing the full picture, we cannot understand the scale of the challenges or benchmark the benefits of potential solutions. The lack of statistics indicates that these materials are not yet fully regarded as a resource.

Major challenges, local solutions

The need for the transport of heavy material makes circularity, as in the production of aggregates and transport of materials between projects, mainly a local issue. The need to coordinate materials between different projects and players in the industry makes circularity more relevant in urban areas.

In or around cities, it is often challenging to find suitable storage areas and there can be problems relating to regulatory conflict. One reason the aggregate sector is not yet fully circular is the weight of the product. Rocks used for aggregates are normally 2-3 times as heavy as water. This normally means that if you transport a lorry of aggregates any further than 30 km, the transport can cost more than the value of the load. This again means that the environmental footprint of the material reduces and the financial value increases the closer the quarry is to the project where the material will be used.

On top of this, the transportation of aggregates is a source of climate emissions and congestion. Consequently, you are generally limited to relatively local use of the material, be it virgin or circular. Available space for intermediate storage is also limited in urban areas. And if you cannot find any functional use for the material locally, surplus masses can often be disposed of at a relatively low cost.

Meeting supply with demand

Based on the future needs of investment in transport infrastructure, the Geological Survey of Sweden predicts that the demand for aggregates will continue. Society’s demand for aggregates can partially be met with recycled material from construction; however, it is expected that the extraction of aggregates will still be needed to fulfil society’s needs. The European Aggregates Association states that “In practice, the available number of recycled aggregates of the appropriate quality would not allow for the complete substitution of natural aggregates. Even with the total recycling of all construction and demolition waste, it would only cover some 12-20% of the current total demand of aggregates.”

Material classification has a significant impact on their further use. Materials are subject to testing, risk assessment, classification and assessment of solutions. Contaminated materials are problematic. Materials are tested for the presence of contaminants that determine whether they can be reused or if they should be disposed of. Depending on the situation, sorting and remediation is possible but it adds to the steps that need to be factored in. This report discusses only those materials that are non-hazardous and suitable for use.

The type and characteristics of materials are a major factor in how or if they can be reused or recycled. Materials to be managed on projects can include soil and stone, crushed rock, gravel, sand, ballast material, peat, silt and more. Each type of material has several sub-categories. Added to that there is the question of whether the materials are contaminated and, if so, to what degree, where the materials are located relative to where they might potentially be reused, the timing of their extraction and filling, logistical challenges such as transport and storage, the need to obtain land to manage and store materials on projects and regulatory requirements that need to be fulfilled. The picture can become complex.

Digital tools are invaluable in identifying the factors that affect a project, weighing up the interplay between them and identifying optimal solutions.

The ‘NIMBY’ challenge

‘NIMBY’ (not in my back yard) is defined as ‘facilities which offer useful services to the general public and often considered necessary by society, but almost everybody agrees that they should be placed outside their neighbourhood’. This reaction makes industries and infrastructure hard to site, as they often generate opposition from affected stakeholders. The management of materials and minerals has local impacts, such as traffic, noise, dust and land use claims, which can make them unpopular with neighbours. This is relevant for circular materials as well as for virgin aggregates, mines, and many necessary but unpopular installations and constructions.

The local perspective

The Nordic countries in general have higher aggregate production per person than other European countries. Access to large sources of virgin materials is relatively high and weather and population densities are also a factor. Rain, storms and frost call for a higher yearly consumption of aggregates. Infrastructure must be sturdy to withstand the weather. Norway has a particularly high production per person due to exports.

The countries which have the highest percentage of recycled aggregates have an aggregates levy which is exempted for recycled aggregates (UK), or have a shortage of available natural rocks (the Netherlands). In the Netherlands, however, due to a shortage of natural rock that can be used for road foundations, crushed concrete and masonry granulate is used. Whilst this is circular and can be reused over and over again, it is also downcycling and can prevent this material from being used in new concrete constructions or products.

Environmental impacts

There are significant environmental impacts associated with aggregates and infrastructure. Transportation and excavation of materials produces CO2, CO, CH4, NOx, volatile organic compounds (VOCs) and particulate matter, which impacts human health and the natural environment, especially in the vicinity of projects. Other environmental risks include dust, vibration, spills in the natural environment and road accidents. Traffic, noise and dust are amongst the most common causes of objections to construction projects. There is also increasing focus on the cost of reducing natural habitats by building infrastructure.

In June 2022, the Norwegian Ministry of Infrastructure asked the transport directorates to present their new national transport plan one year earlier than agreed, in order to reduce costs as well as the impact on nature and the climate by increasing the focus on maintenance. The focus on operation and maintenance and on prioritising the projects which have already been started has been confirmed in the Norwegian Government’s state budget for 2023, which was presented in October 2022.

Economics and time are big traditional drivers

Given that infrastructure projects often generate millions of cubic metres of surplus materials, the management of these materials is a major project cost and local disposal to landfill can be financially more viable than reuse slightly further afield. The sector is transitioning from a model where low cost has traditionally been the driver with all components of the market configured towards linearity rather than sustainability. However, the sector is gradually developing, as the discussions about sustainability and climate evolve.

There’s also a risk of depending on local construction projects for reusing surplus materials since timing is a factor. When aggregates appear, it doesn’t mean that local projects for reuse of those materials are available, which means there is a matching problem. In that case, storage space is needed to save rock masses to be handled later. The lack of areas for sorting, crushing and handling (sustainable management of these materials) is also a limitation. Better collaboration may succeed in identifying a greater range of options for storage. This could open up the market to more businesses and not just those who already have storage facilities.

Procurement and policy geared towards linearity

Procurement of public infrastructure contracts has traditionally focused on low cost. Risk-averse attitudes have also seen ‘gold-plating’ specifications in procurement where very high requirements are stipulated which are often better than what is really necessary. This makes it harder for recovered materials to be used, even where they could have been used.

Attitudes and carbon costs

Legal frameworks, attitudes and behaviours often still regard such materials as waste rather than resources where the burden is on safe disposal. As a consequence, skills and supply chains develop around these objectives. Without strong leadership, carbon reduction is, at best, a passive environmental aspect that has no bearing on a design. With strong leadership, proactive carbon cost management occurs at every design decision point.

Regulating the circular economy using linear-era legislation

Legislation on the classification of materials excavated from projects can create barriers to reuse. This includes the classification of materials as waste, which requires additional measures to handle it despite it being no different in character to other materials that are not classified as waste.

The regulation of surplus aggregates still often treats materials as if they are waste that should be safely disposed of even when they are a clean and suitable resource. Without compromising the safe disposal of contaminated waste, circular practices should be embraced thanks to, rather than in spite of, regulatory frameworks.

The road towards circular aggregates: Significant investments are made in European infrastructure

The management of infrastructure materials is subject to many overlapping factors and complexities. This report has, however, identified key areas that can contribute to the circularisation of this sector.

Large sums of money are continuously invested in infrastructure projects. In 2017, across the EU there were over 217,000 km of railways, 77,000 km of motorways, 42,000 km of inland waterways, 329 key seaports and 325 airports. The German Federal Transport Infrastructure Plan 2030 identifies the need for EUR 141 billion expenditure on road, rail and waterways by 2030, with EUR 98 billion of this earmarked for expansion and new construction projects. The French Government announced EUR 100 billion of investment in infrastructure to help boost the economy after the Covid pandemic.

In the summer of 2022, the new Elizabeth Line was opened on the London Underground, the culmination of a 12-year construction project costing GBP 18.8 billion and involving the excavation of 8 million tonnes of material. In France, another underground rail project, the Grand Paris Express will extend the Paris Metro by 200 km, costing around EUR 35 billion.

Across Europe, transport infrastructure ranging from rail to roads to waterways, projects ranging from small-scale local works to those of national strategic importance will cost hundreds of billions of euros, with large associated environmental financial and social impacts. The World Bank estimates that around 1 trillion dollars is spent globally on infrastructure.

Leave no stone unturned – seek solutions to circularity in many ways

There is no single solution to increasing circularity. Greater circularity can be achieved through a wide range of measures, such as better legal frameworks and guidance, use of financial instruments, better reporting, increased planning, greater collaboration between projects, better procurement and specification, use of mass balance analyses and digital tools that can identify optimal solutions.

New requirements for circular infrastructure

The circular economy is becoming increasingly enshrined in policy and legislation at different layers of governance. ‘Construction and Buildings’ is listed as one of the 6 key value chains identified by the EU’s Circular Economy Plan (the others being electronics and ICT, batteries and vehicles, packaging, plastics and textiles). Within Construction and Buildings there are five key actions identified of which the sustainable and circular use of excavated soils is one.

There is also an increased focus on the circularity of mineral resources on a national level. For example, the Norwegian Government states in its political platform ‘Hurdalsplattformen’ from 2021 that they will facilitate the circulation of mineral resources and reduce the waste from mines through stricter requirements for resource utilisation and backfilling. In June 2022, the Norwegian Ministry of Industry made it clear that circularity of surplus minerals and masses will be part of the Norwegian mineral strategy which will be presented in the autumn of 2022. In the UK, the government requires Whole Life-Cycle Carbon Assessments for all public works projects to understand and minimise greenhouse gas emissions. Also in the UK, an aggregates tax is levied which is only applied to primary aggregates, the objective being to make secondary and recycled aggregates more competitive.

However, aggregates producers state that this tax in general increases the costs of construction and that suppliers of recycled material have increased their prices accordingly. There are also some, but not many, other examples of taxation on the use of raw materials.

Clear guidance is needed on the use of materials

Legal frameworks and associated guidance are still, to a large degree, emerging from the linear era. To help pave the way for a more circular use of materials, clear guidance and reviews of legislation are needed to help managers navigate towards the most optimal outcomes. Examples include the need to clarify when a material is a waste or a product.

When materials are classified as waste, existing requirements can be obstacles to their reuse, both in terms of handling and administration. Guidance is also needed on the criteria to be used to allows waste to be treated and, therefore, no longer classified as waste but instead classified as a product, on testing protocols and thresholds of environmental quality standards, and on the use of materials that contain lower levels of contamination, but which could conceivably be put to certain uses if treated accordingly.

Some materials are contaminated and cannot be reused, but with updated legislation and clear guidance that helps keep suitable materials in circulation, existing barriers to circularity, such as uncertainty and risk, can be addressed.

Circular procurement

Requirements to use recycled materials in public procurement have increased, which drives demand. All public works in Zurich, for example, must use recycled concrete that contains a minimum of 50% recycled concrete or 25% recycled mixed demolition aggregate. In Switzerland, the builders are responsible for the materials extracted from a project, according to Annina Margreth, researcher at the Norwegian Geological Survey, who used to work at the 57 km long Gotthard Basis Tunnel and who thinks that the contracts of projects should be drafted so the materials must be used for as beneficial a purpose as possible.

In the early phases of a project, procurement can be informed by studies which examine different options and identify sustainable solutions. This information can be taken forward into project design and procurement and raise the bar on circularity. Contracts can also incentivise circular practices, for example through payment systems that reward circular outcomes.

Large amounts of materials are used as if they are lower quality than they actually are, in other words: downcycling. Transportation is often excessive and different builders have different quality specifications. Identifying suitable material quality standards for the application would ensure increased sustainability. Too many procurers ‘gold-plate’ the procurement unnecessarily leading to over-reliance on raw materials. Different specifications are used for materials from quarries compared to materials recovered from construction sites.

Procurement can be documented via environmental product declarations, which is normal for concrete, but not yet fully for aggregates. Recycled materials are slightly cheaper but not by enough if the customer is worried that the quality is not good enough. Quality specifications are available, and these materials can be used in most layers of the road except the top layer.

The solution is to avoid being conservative and to stop asking for ‘what you know works’ just because this is a comfortable choice. The documented properties that are stipulated in the procurement documents should be ones that recovered materials can fulfil.

Data has a huge role to play. Better and earlier data on the materials that need to be managed greatly improves the ability of a project to manage them in an optimal way.

The building industry is embarking on a new circular path whereby buildings are increasingly regarded as digitalised asset and material banks, enabling forward planning for the reuse of materials. Collaboration between stakeholders has enabled the emergence of shared material banks and resources, driven by access to good data. Infrastructure materials could follow the same path. Flanders in Belgium operates a national excavated soils database. Sweco Belgium has carried out projects using BIM Track and Trace to optimise material management during projects.

CEEQUAL is a certification system to document the scope of sustainability work related to project implementation and choices of sustainable solutions for different types of infrastructure and civil engineering projects. Taking into account the use of circular solutions for handling materials will be viewed positively when deciding on individual projects.

The same thing applies to achieving a good mass balance. Sweco has CEEQUAL assessors that carry out evaluations of projects and has been involved in the assessment of several road projects, both in the early planning phase as well as for design and construction. Modern IT tools for earthworks modelling, such as MAGNET Project, may support the supervision and management of infrastructure and construction projects. These projects are growing in complexity and size. MAGNET Project gathers the relevant parameters and data into a single model. The model provides new ways of visualising the earthworks and automated estimates of the material usage and transportation options. This in turn can be used to identify alternative solutions, such as designs, alignments or supply chains, thus providing decision support throughout the project for improving the earthworks.

BIM modelling can help optimise material management during the project by visualising types and quantities and enabling optimal solutions to be identified. As databases of materials develop, there will be increased opportunities for interrogating a much wider field of materials than was previously possible. Material passports such as Sweco’s Obsurv provide essential material data on an accessible web-based portal.

Collaboration and partnership are crucial

Cooperation and a running dialogue between actors are crucial. There are moves towards this, such as the Pådriv Arena in Oslo, which enables organisations to store and exchange materials. Collaboration between partners was essential in achieving this. The Swedish Transport Agency has also established a research project to investigate how the circular management of materials can be developed, using projects in Stockholm, Sörmland and Östergötland as a testbed for collaboration, new business models and exploring the roles of different actors in a circular system.

Infrastructure management is a multidisciplinary issue, which therefore requires multidisciplinary responses. Project teams looking at the circular reuse of materials should draw upon the necessary skills from Day 1. This includes data modellers, geotechnical specialists, planning and permitting specialists, sustainability specialists, and external parties such as local authorities and regions. There is a growing recognition that materials management is dependent upon coordination and that lead regional coordinators, such as regional administrations, will emerge.

Although it is vital that coordination takes place, it is of even greater importance that the coordination effort includes the right people. Effective collaboration can also avoid problems. The need for temporary set-down and storage areas on projects is vital. If such areas are lacking, this can restrict the available options for material management, for example sufficient space and time for treating excavated materials so that they can be used on site. It is therefore critical to identify this need as early as possible, as planning and permitting can take time. The best circular intentions can be hampered by issues such as space and time.

Function in focus

Resource and climate effects should be part of the tender process to a greater extent than today. The function of the road should be more important than absolute requirements of quality.

The innovative use of materials and techniques can unlock huge benefits that prolong the lifetime of infrastructure and reduce the demand for new materials. An example of this is the use of circular business models in infrastructure, and the use of new materials such as mycobase in the Netherlands, where Sweco supported a pilot project that tested the use of a bio-based raising material for roads in soft soils. By using innovative local materials, the downcycling of other materials into road sub-bases can be avoided, thereby freeing up that material for reuse and recycling elsewhere.

Temporary landfills and geoscans

The geotechnical properties of the cut materials and, where relevant, pollution levels are often unable to meet the requirements of all the fill materials. There are, however, examples of contractors that are establishing temporary landfills where they clean lightly contaminated materials and market and sell these to the next project. We are also seeing increased use of tunnel rock mass to create new areas, for example, by reclaiming new land along the coast.

Countries like Norway have successfully used rock mass from projects to improve agricultural land. Furthermore, contamination levels and geotechnical properties of the cut materials are often not fully ascertained until construction has started, by which point it is too late to adjust the design or treatment routes that could otherwise have brought unsuitable materials back into play. In many projects, more environmental surveys could reduce such uncertainty. Geoscan by helicopter can be combined with regular geotechnical surveys and machine learning to provide more information and sometimes full geomodels with information on depths, weaknesses and layering.

What if?

Large sums of money and material are invested in infrastructure projects. The impacts are large, but so are the rewards if circular methods become normalised. And yet, as a system it still has a high leakage rate in terms of materials and value.

Sweco has looked at two current European railway construction projects of different scales and considered the impact of an issue that is one of the most visible of all: material transport. One is a major national project, the other is the Gävle project described on the next page. Options for the management of non-contaminated, reusable materials have been assessed and, using the Magnet Project tool, Sweco has identified solutions that minimise haulage requirements in terms of kilometres travelled, carbon emissions and costs.

The large project is faced with significant challenges of scale, time, geography and complexity. Nevertheless, the example shows that, given the scale of the activity even a 3% reduction can yield large benefits. The Gävle project demonstrates the benefit of good collaboration with local parties who can benefit from using material in applications such as embankments and noise barriers.

Transport optimisation analyses reflect the effects of a range of circular measures. If the whole project ecosystem embraces circular approaches from the outset, the field of options are widened considerably, and it is highly likely that the savings will be more significant. Even measures that implement savings of 1% can yield significant results. The challenge lies with everyone involved in the management of these materials, at all stages of projects and at all links in the material value chain.

Marginal gains, major benefits

Consider that an additional 1% savings on the large railway project would reduce haulage further by 347,000 km, saving EUR 3.2 million and 1500 tonnes CO2e. If, through a combination of measures, we were able to reduce haulage by 10% that would save EUR 31 million and 15,000 tonnes of CO2e. And remember, transport is just one factor in infrastructure construction.

The Gävle project, being smaller, has smaller overall savings even though percentage-wise they are larger. But there are hundreds of similar-sized projects in Europe each year. If there were a hundred projects in Europe of a similar size and with similar potential to reduce their impact from haulage, annual savings would be around EUR 270 million and 70,000 tonnes of CO2e.

Governments across the world continue to invest considerable sums in infrastructure. Given the scale of such works, even modest increases in circularity can have significant benefits. Given the size of major infrastructure projects, a 1% savings can lead to substantial real benefits. The challenge for greater circularity is that there is no simple solution that solves everything. Greater circularity can be achieved through a wide range of measures, such as better legal frameworks and guidance, use of financial instruments, better reporting, better planning, greater collaboration between projects, better procurement and specification, use of mass balance analyses and digital tools that can identify optimal solutions. As a result, there are potentially many 1%s to be achieved. Add to that more substantial savings of dozens of percentage points thanks to circular solutions, and replicated across many projects, the benefits are potentially enormous.