How science and tech are combining to drive more sustainable road construction

An asphalt mixing plant successfully retrofitted for the use of green hydrogen

The sensible caveat to this is that sustainable practices should be found that align with the goal of increasing revenues.

For the road construction sector, this transformation requires improving both production and machine operating processes.

It stands to reason that the next generation of machines is being developed with a strong focus on its climate impact – including the lifecycle emissions of current and future machine operations.

To this end, road construction equipment manufacturers are developing machines and plants that can operate on non-fossil or climate-neutral fuels.

Furthermore, the on-board technology available on these machines will lead to the optimisation of processes, which will reduce emissions further still.

The knowledge to drive change

Wirtgen Group’s Anja Gronschel-Raths, communication expert, and Dr Markus Bach, senior engineer powertrain technology, have recently presented some of the work done on the company´s scope 3 emissions. Gronschel-Raths says, “Emissions regulations have been implemented in many countries, on very different levels, but we also still have regions where there are no regulations at all.”

Wirtgen Group’s communication expert, Anja Gronschel-Raths

“We’ve been looking at the effects of these regulations over the last two-and-a-half decades and we can see that they have generally had a strong positive effect.”

“NOx emissions and particulates emissions, for example, have been significantly reduced. And this has opened the next big challenge namely the reduction of CO₂e emissions, which are mainly caused by burning fossil fuels.”

Defining measurable goals

Wirtgen Group has set ambitious targets to reduce CO₂e (carbon dioxide equivalent) emissions by 2030.

The company wants to reduce its scope 1 and 2 emissions by 50% and its Scope 3 emissions by 30% which are mainly machine emissions from operation. And this will directly help customers to reduce their Scope 1 emissions. Practically, the group has broken down the challenge into three parts:

• operations
• machines and equipment
• production systems of customers

Many of the new features on Vögele’s Dash 5 series pavers are designed with reduced emissions in mind

Within these elements, Wirtgen Group has identified the development of advanced powertrain technology as being one of the big levers to reduce machine emissions.

Gronschel-Raths says, “Our conventional power trains are already using efficient components and operating modes, as well as smart control systems that help operators use the machine efficiently.

“This has laid the groundwork for our research into alternative fuels and zero emissions, where the energy carrier itself is a vehicle to reduce CO₂e emissions.”

Diesel and what comes next

On this topic, Dr Markus Bach points out that, while the growth of electrified powertrains is impressive, the traditional combustion engine (ICE) will remain part of the road construction landscape for years to come.

However, he emphasizes that there are many opportunities within the ICE sector for reducing CO₂e emissions.

Dr Markus Bach, Wirtgen Group’s senior engineer for powertrain technology

“For combustion engines,” he says, “different energy carriers can be used, including fossil-free renewable diesel. Alternative fuels like HVO100 are available and could replace standard diesel, to a certain extent or in specific markets.”

“HVO seems like an obvious choice, but it’s still a carbon-based, though non-fossil fuel which is burned. Also supply might become an issue in the future, as there is not enough of it to exchange for all fossil diesel.”

Dr Bach brings hydrogen combustion engines into the conversation, saying that while they go a step further, to a carbon-free energy carrier, it is unclear when they will be in series production in numbers that could significantly influence the industry’s machine emissions.

Electrification, however, is a different matter. Dr Bach notes the high level of development in this area, which has been accelerated in particular by the tightening of emission regulations and the resulting creation of local emission-free zones in some cities. The answer to this is battery-powered machines.

Overall, he sees the potential for CO₂e reduction as “immense” but points out that “understanding actual energy requirements becomes crucial with reduced energy density.”

The landscape for powertrains within the construction industry is diverse

Dr Bach believes HVO is best suited for high power and high energy applications and can be used as a drop-in solution for existing machines, while battery-electric powertrains are more applicable for equipment in lower power classes.

As new ‘cleaner’ machines come onto the market, it has become clear that environmental goals are inextricably linked to technological innovation, and road construction OEMs, such as Wirtgen, Vögele, Hamm, Kleemann and Benninghoven are increasingly utilising digital technology to reduce emissions.

No transformation without technology

At Vögele, the philosophy of ‘lower consumption – lower emissions – lower costs’ has been embedded in the development of its Premium Line road pavers.

Battery-electric Hamm rollers for local zero emission compaction

Within this philosophy, the EcoPlus low-emissions package integrates tech to significantly decrease fuel consumption and noise levels, delivering fuel savings of up to 25%.

Hamm has been developing fuel-efficient technologies for many years and has more recently put a bigger focus on developing electrified tandem rollers and hybrid solutions.

The company’s Power Hybrid roller from the HD+ series, for example, reduces fuel expenditure by approximately 15%, with the same compaction power as the regular machines.

Furthermore, the battery-electric tandem rollers HD 10e – HD 12e boast the same compaction power as their combustion engine counterparts at zero local emissions. The battery provides enough energy for one typical workday.

Wirtgen, meanwhile, has developed the fully integrated machine control system Mill Assist. Mill Assist is designed to automate the milling process and increase performance while also decreasing consumption and emissions, thereby minimising environmental impact.

The system’s ECO mode optimises machine performance from an ecological point of view, reducing diesel and water usage, as well as CO₂e emissions.

According to Wirtgen, 20% CO2 savings can be achieved when using the new machine generation equipped with the company´s Mill Assist (ECO Mode)

Sustainability is also built into the DNA of Kleemann’s crushing and screening equipment, as seen in recent electric-drive and fuel-saving models.

The company says it now prioritises efficiency and environmental responsibility throughout the value chain, as part of the development process.

By offering low fuel consumption and efficient noise and dust reduction, Kleemann says it is providing customers with both economically and environmentally beneficial solutions.

Benninghoven, which produces asphalt mixing plants, is also rising to the sustainability challenge: With the introduction of the new burner generation, the first green hydrogen powered mixing plant is up and running, free from CO₂e emissions.

The new burner comes along with a unique intelligent control system. New plants as well as existing asphalt mixing plants can be equipped with the advanced burner technology.

Additionally, Benninghoven offers technological solutions that allow the use of up to 100% RAP (recycled asphalt pavement) with its hot gas generator technology.

Growing greener together

These initiatives underscore a collective effort within the road construction industry to embrace greener practices without compromising performance.

That said, the solution to the emissions challenge is complex and that complexity is causing hesitancy among construction businesses, who genuinely wish to be ‘greener’, but are wary of any risks to the bottom line.

Markus Bach highlights the open-technology approach of the Wirtgen Group, ensuring best-fit solutions can be found for future machines and equipment to help customers to reduce their CO₂e emissions.

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This article was produced by KHL’s Content Studio, in collaboration with experts from Wirtgen Group.

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All images courtesy Wirtgen Group