Sustainable Eco-friendly Roads

Dutch construction firm, Royal BAM Group, has developed sustainable asphalt that lasts just as long and is as resistant to road damage as conventional asphalt concrete. LEAB (Low Energy Asphalt Concrete) leads to a cleaner living environment and is also 100% recyclable.

Foam bitumen generator

Royal BAM Group has developed this sustainable asphalt over a period of several years. Various experiments have resulted in a foam bitumen generator which replaces the warm bitumen dosing system of a standard asphalt plant. The secret behind its success is mainly in the mixing procedure. The entire production process is protected by a EU-paten and opens up a new road for a sustainable infrastructure.

Asphalt mixture for a clean environment

Due to the innovative foamed bitumen process, Royal BAM is able to produce this asphalt at 105°C/ 220°F instead of 165°C/ 330°F . The half-warm production and processing of LEAB requires less energy and goes hand in hand with lower greenhouse gas emissions. Specifically this means at least 40% less CO2 emissions as compared to the production of conventional asphalt. These environmental benefits are achieved without compromising the performance of the mixture. In fact, LEAB mixtures provide an equivalent or even better performance as compared to their hot-mix equivalents. Studies by the independent research agency SGS-Intron demonstrate how sustainable LEAB actually is. They show, for instance, that the environmental performance of LEAB is significantly better than that of standard asphalt concrete: 40% energy reduction and 40% less CO2 emissions.

Approved by Dutch Department of Transportation (Rijkswaterstaat)

Extensive laboratory research and field tests show that LEAB mixtures meet all functional and technical requirements within the relevant European legislation in terms of water sensitivity, stiffness , resistance to fatigue and resistance to permanent deformation.

Savings value

Using the objective True Price method, the social value of LEAB compared to conventional asphalt has been evaluated according to Dutch standards. Evaluation is made in relation to the environmental impact of asphalt production, transport and end-of-life treatment. The social benefits of applying LEAB on one kilometre of motorway base on the existing standards amount to €257,000. That is comparable to the average annual energy consumption of 119 Dutch households.

Next step from LEAB to LE2AP

The next step BAM has made in developing an even more sustainable asphalt production method is LE2AP. LE2AP is a demonstration project made possible with an EU grant of € 1.300.000,00.

In LE2AP reclaimed asphalt is mechanically decomposed into stone fractions and mortar sand. After decomposition mortar sand is separately available as a new type of raw material. The mortar sand can be heated in a closed environment so that emissions are prevented. Using LEAB experience and technology the heated, treated and homogenised mortar can be foamed. The foamed mortar can be mixed with fresh or reclaimed stones at lower temperatures and still provide a workable first-rate mixture. The decomposition of reclaimed asphalt gives full control over the mixture recipe even at high rates of reclaimed asphalt usage.

In LE2AP reclaimed asphalt is decomposed and the aged component is separately heated, rejuvenated and homogenised. This provides high quality reclaimed raw materials and control over the mix recipe which does enable the production of Major League mixtures such as an open graded noise reducing surface layer.

This was demonstrated by the production and installation of in total 2.3 km of a 2-layer PA asphalt with an initial noise reduction of up to 8.3 dB(A).

With the LE2AP production method it is possible to reduce CO2 emissions up to 70%, reduce energy use up to 50% and reduce odour emissions up to 75%.

Holland – fertile ground for innovation

The Dutch have the character and attitude of reinvention. Its people have embraced new ideas and innovation, with an ethos of ‘boldly going where none has gone before’ and ‘making things happen. We see it as crucial for economic growth, but moreover that it improves the well-being of society as a whole.  Still, we strive to instil integrated approaches and holistic vision in our industries, knowledge institutes and citizens toward finding innovative solutions within high-tech, logistics  to further secure the Netherlands leading international position in innovation and sustainability.