In the world of road network construction, finding materials that are robust enough to cope with larger volumes of traffic and heavier vehicles is vital. Our roads need to perform for many years without cracking, deforming or wearing out. EME2 is a French technology that will hopefully provide solutions to all this and more. One huge benefit of this technology is that will save on cost as it can be used in thinner pavements with the same longevity and strength. Research and trials into the application of this exciting material in WA have been conducted through WARRIP bringing international expertise to assist in our understanding of this technology.
Enrobés à Module Elevé (EME) high modulus, performance based asphalt mixtures were developed in France. Class 2 EME (EME2) mixes, produced using a hard, paving grade bitumen applied at a high binder content, are typically used in France for roads subject to heavy traffic loads, airports and for maintenance of deteriorated roads.
EME2 technology offers the prospect of reduced asphalt thicknesses for heavy duty pavements. Strong, durable and sustainable EME2 pavements provide economic benefits compared to traditional flexible pavement materials, such as reduced construction periods and cost, longer time between maintenance actions and longer service life.
This project investigated the use of EME2 to reduce the thickness of full depth asphalt pavements. In WA, EME2 may be particularly beneficial where traffic loads have grown substantially, such as mining areas in the Pilbara. The project developed manufacturing, paving and compliance requirements and interim WA EME2 specification limits.
EME2 use in Europe has indicated pavement layer thicknesses can be reduced by 25-30 per cent compared to traditional flexible pavement designs for a given design life. Our review of European practice indicates no significant barriers to EME2 implementation in WA and interim specifications adopted by Main Roads are consistent with European practice.
WA Pavement Design Calculations
Overall asphalt thicknesses using Main Roads’ Engineering Road Note 9 (ERN9) design guides for different asphalt materials were modeled to compare existing pavement configurations (as control) with EME2.
Modelling showed an overall reduction of asphalt thickness using EME2 of 45mm-90mm, depending on which asphalt layers were substituted and whether wearing and binder courses were combined with EME2. It confirmed the benefits of EME2, including improved fatigue resistance and thinner FDA pavements, without compromising performance.
The project team observed an EME2 demonstration trial in Queensland to apply lessons learnt to WA. An EME2 demonstration trial was conducted in metropolitan Perth to assess whether the design mix could be manufactured, placed and compacted to the developed standards using local aggregates and locally-available equipment. A key aspect was input from expert EME2 practitioners.
- The High Modulus Asphalt (EME2) project found potential pavement thickness reductions from using EME2, relative to Main Roads pavement design supplement ERN9, of 45mm-90mm.
- EME2 pavements provide economic benefits, such as reduced construction periods and cost, longer time between maintenance actions and longer service life.
- A review of European practice revealed no significant barriers to EME2 implementation in WA.
- Main Roads has adopted interim specification limits for EME2 asphalt that are in line with the national specification framework.