Beyond Europe’s barriers of waste

Recycling roadside guardrails promises to reduce CO2 emissions by 70% and cost 10% less. Refurbished barriers must meet the same stringent safety conditions as newly made guardrails. A trial project in the Netherlands has demonstrated this can be achieved

Words | Nicola Massara, head of international strategy, Meiser Straßenausstattung, Germany

In November 2021, world leaders met in Scotland in the latest attempt to reach agreement on tackling climate change. Since the 2015 Paris Agreement, countries have been committed to adapt to its impacts and mobilize the funds necessary to do so. Environmental conservation and carbon footprintreduction are no longer marginal issues, but global priorities.

For years, the principle of reduce, reuse, recycle has helped reduce the waste we throw away. Waste can be managed in several ways, each with its own climate change impacts. Let’s consider our business at Meiser – the production of steel guardrails for road safety – and the environmental implications of protecting motorists.

Wasted lifespans

Poor road safety is a symptom of transport dysfunction. Road crashes kill and seriously injure many thousands each day and their economic impact is between 2% and 4% of GDP. While the average service-life of steel constructions is 20 years, many guardrails are replaced much earlier. The lifespan of guardrails expire when they are completely rusted or their zinc layer has washed away. When roads are renovated, often the guardrails have not reached this stage.

Renovating guardrails therefore makes sense in terms of emissions reduction. There are several benefits to renovating steel structures, which are already shaped and galvanized. It conserves raw materials and reduces energy-expenditure and CO2 and NOx emissions generated in the production of new steel. The economic advantages compared to new production are also substantial.

US highways departments have conducted in-house recycling operations for used guardrail and guardrail posts for 25 years. These use existing guardrails removed under normal contracts for reconstruction, rehabilitation or widening of primarily interstate highways. Guardrails from such projects are delivered to a dedicated yard, where specialized workers straighten bent or damaged rail or posts with a rolling-machine that restores the rail beam to its original W-shape. Straightened rail and posts are galvanised by a contract vendor then returned to the yard and reinstalled on the roads.

Safety first

Before considering specifications for using recycled materials in highway safety applications, it is necessary to understand existing test procedures and design requirements. The foremost design concern for most safety features is impact performance. Generally, roadside

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safety devices shield or delineate roadside hazards. Although these features are meant to protect motorists and maintenance crews, they themselves also constitute hazards and must be demonstrated to be crashworthy.

European Norm EN 1317 details procedures for evaluating the safety of road restraint systems. The features covered include longitudinal barriers. The procedures are directed at evaluating the safety performance of roadside features through vehicle crash-testing and in-service evaluation. For vehicle crash-testing, specific impact conditions are defined for vehicle mass, speed, approach angle and point of impact. Individual tests are designed to evaluate one or more principal performance factors. These include structural adequacy, occupant risk and vehicle post-impact trajectory.

Longitudinal steel guardrails may be designed to any one of seven containment-levels defined in EN 1317-2. Generally, the lower test-levels are applicable to features intended for lower service-level roads, higher test-levels to features for higher service-level roads or locations requiring special, high-performance barrier. The basic design-level of most existing roads equates to Containment Level N2, whose impact conditions govern the strength of the barrier and its components. Across Europe, the most commonly-used guardrail system is the W-beam (or doublebeam) guardrail, which most European countries have successfully tested and used for many years.

66%

Percentage of W-beams found to be reusable in Good as new? a Rijkswaterstaat trialClearly, any renovated steel guardrail needs to guarantee the same safety and durability as if it were newly made. Therefore any manufacturer wishing to market renovated guardrails - or local authority defining acceptance criteria for its use on roads – should be mindful of the main characteristics that guarantee the compliance of steel barriers with existing regulations.

In recent years, the Dutch road authority Rijkswaterstaat has facilitated a sustainable road equipment programme. It has collaborated with contractors, suppliers and specialized companies to investigate the environmental, technical and economic implications of guardrail renovation. It found renovating guardrails to be both technically and economically feasible with potential for dramatic environmental gains. Consequently, Rijkswaterstaat has set out a policy to increase its use.

Raising the standard

Meiser has always been focused on human and environmental wellbeing. We are thrilled to invest in resource-saving technologies and relish the challenge of potentially reducing the carbon footprint of steel production. Supported by expert Hans Versteppen, Meiser will embrace Rijkwaterstaat policy and implement industrial processes at its Limbach and Oeisnitz plants to refurbish and renew used steel guardrails and return them to the roadside. Meiser has formed a workgroup with several divisions: technical and production managers as well as commercial and quality-management specialists. Its goal was to determine whether renovation is feasible, costeffective and, most importantly, can guarantee the same performance standards as newly-made barriers. The refurbished barrier will be covered by Meiser’s CE marking procedures and certificates according to EN 1317-5. Implementing the renovation process within its overall quality management system entails several selection stages related to criteria for dimension, shape, hole configuration, steel quality, absence of damage, surface contamination and physical characteristics. Only components found to be suitable will enter the reconditioning programme and find their way back to market. The next stages of renovation involve surface cleaning, degalvanisation and regalvanisation according to EN-ISO 1461 to ensure full durability of renewed guardrails.

Planetary guard duty

A first trial project demonstrated reductions of 70% in CO2 emissions and 40% in environmental costs, together with a cost-reduction of more than 10%. In terms of steel parts selection, 66% of W-beams, 57% of spacers and 42% of steel diagonals were selected as reusable after renovation. Facilitated by Rijkswaterstaat in the Netherlands, this project showed guardrail renovation to be both possible and economically viable. Hopefully, road authorities across Europe will be inspired to follow the Dutch example. The importance of a 70% reduction in CO2 cannot be overstated in the context of modern climate concerns. It is crucial for the steel industry to develop processes and technologies with a zero or negative carbon footprint by whatever means available. ■