Waste management and recycling offer major benefits in transport infrastructure

Guidance on recycling in transport infrastructure is provided in a new document produced by TRL Limited. Much has been achieved to remove obstacles to recycling, but some issues still need to be addressed. Dr Murray Reid of TRL Limited reviews progress on the road to recycling

As the modern world comes to terms with the fact that the planet’s resources

are finite, the pressure to increase recycling is affecting all sectors of the

construction and waste management industry. In many areas this requires a considerable

readjustment in attitudes. In the construction and maintenance of transport

infrastructure, as in many other branches of construction, there has in the

past been a reliance on using only high quality natural aggregates, and sending

any marginal or unfamiliar material to landfill. Transport infrastructure includes

the earthworks, pavements and drainage required for roads, railways, airports

and canals.

These powerful drivers have resulted in an increase in the use of alternative

materials and in the development of in-situ recycling techniques. However, in

some areas progress has been slow because of real or perceived problems with

the application of these materials and techniques. Reasons often given for failure

to use recycling include a lack of specifications for the materials and techniques,

lack of appropriate test methods, concern about quality control and variability

of the materials and methods and difficulty in ensuring an adequate supply of


Waste classification

The waste management licensing regulations are often seen as a barrier, as it

is not clear whether alternative materials are classed as waste, and, if so,

whether they are covered by exemptions. Contractors are very reluctant to take

on the burden of a waste management licence, and the timescale required to resolve

these issues often precludes the use of these materials in construction contracts.

In some cases, the environmental regulators may be concerned about the use of

certain materials in terms of dust or gaseous emissions or contamination of

surface and ground waters.

Operators of recycling centres often experience difficulty in obtaining planning

permission and other approvals and adversarial conditions of contract can inhibit

the use of innovative recycling techniques. Overall, there is a lack of awareness

of the possibilities of recycling, coupled with a strong awareness of potential


To help overcome these problems and increase the amount of recycling in transport

infrastructure, TRL Limited (formerly known as the Transport Research Laboratory)

carried out a research project funded by DTI and the former DETR under the Partners

in Innovation programme. Lafarge Aggregates UK and the Hanson Environment Fund,

through landfill tax credits, provided additional funds. A steering group with

cross-industry experts supported the project team and ensured that all the important

issues were covered. The main output from the project is a guidance document,

entitled *Recycling in transport infrastructure. The document is targeted

at managers and technical personnel in the main stakeholder groups, including

local authorities, contractors, designers, producers of secondary/recycled materials,

environmental regulators, owners and operators of transport infrastructure.

Guidance content

The document consists of three parts. In Part 1 the main issues affecting recycling

in transport infrastructure are identified and discussed. Part 2 contains available

guidance on these issues. Because different stakeholders can have different

views on the same topic, sub-sections of the text have been prepared for each

stakeholder group. Some issues require further action: these are summarised

in Part 3 in tabular form for each stakeholder group.

The actions are ranked in terms of relative priority, timescale and nature.

Fourteen case studies are presented in an appendix to illustrate how greater

recycling can be achieved in a range of situations, and how common problems

can be overcome.

The project revealed that guidance is available for many of the issues that

were raised as potential obstacles to recycling. In recent years a number of

specifications have been developed to cover many of the materials and techniques

that are now available.

There have also been major improvements in quality control procedures. Materials

produced under a quality control plan should be at least as fit for purpose

as natural aggregates. Guidance was published by the then DETR on controlling

the environmental effects of recycled and secondary aggregates production. This

will benefit planning authorities and the owners and operators of recycling


Examples of the use of partnering and global costing by organisations, such

as the British Airports Authority, illustrate the economic and environmental

benefits that these approaches can bring A number of the case studies describe

the successful use of particular materials and techniques.

The current waste management licensing and exemption process, as it applies

to recycling in transport infrastructure, is described, and regional variations

in Scotland, Wales and Northern Ireland are given.

Difficulties remain

The available guidance indicates that recycling can be successfully carried

out, and local authorities have often been to the fore in taking new techniques

forward. Some areas of difficulty remain, particularly connected with the application

of the waste management licensing regime. This is acting as a significant restraint

on the use of alternative materials in construction projects, where the short

timescale of the projects means it is often impossible to resolve issues with

the environmental regulators in sufficient time to enable the materials to be

used in the contract. Variation in interpretation of the regulations between

different offices of the environmental regulators is often cited as another

reason for not using recycling. In return, the environmental regulators point

out that contractors often submit applications at extremely short notice, often

without sufficient information to enable them to make a decision. The Environment

Agency has a process handbook for processing waste management licensing applications,

which should ensure uniform treatment of applications throughout the country.

They also point out that the licensing process has statutory consultation periods

of 28 days built into it, and that contractors should allow a reasonable time

for this process.

Clearly, the waste management issues need to be streamlined if the full potential

for recycling is to be realised. The Environment Agency launched a construction

campaign in March 2001 to improve the environmental performance of construction

sites and to engage in more liaison and training with industry. In time this

may bear fruit with a greater understanding by each side of the other’s position

and a more constructive dialogue. Another idea that arose out of the TRL project

is to establish a National Industrial Forum where environmental regulators,

industry, infrastructure owners and operators and government could meet to discuss

problems such as these and agree ways to move forward. The idea arose out of

the constructive, but often vigorous, debates in the steering group over the

course of the project, which were very helpful in clarifying what the real issues

were and identifying ways to deal with them. Anyone with views on this topic

is invited to contact the author.

In the areas where progress has been made, it is because the stakeholders involved

have acted to address the problems, for example in the preparation of specifications

and design guides for new materials and methods. This has often involved commissioning

research to obtain the necessary data on which to base the specifications. Where

a number of stakeholders have acted in concert the results have been particularly

effective. A good example is the production of a quality control document for

recycled aggregates by a working group involving BRE, the then DETR, the Highways

Agency, local authorities (via CSS), the Quarry Products Association and a number

of aggregate producers and consultants. A similar approach will be required

to overcome the remaining obstacles to recycling.

*The guidance document “Recycling in transport infrastructure”

is available from TRL Publications, Tel. 01344 770783 or by email at info@trl.co.uk.

For further information on technical aspects, contact Dr Murray Reid, TRL Limited,

Tel. 01344 770283, email jreid@trl.co.uk.

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