South Africa’s roads could be lasting much longer if the country made more use of EME (“Enrobés á Module Elevé”).
Developed in France in the 1990s by road construction specialists Colas, EME has been applied locally by asphalt experts National Asphalt, with great success. According to Dave Bennett, general manager at National Asphalt, the first official paving trial was done on South Coast Road the high-wear road into the Port of Durban.
“The heavy traffic load of large trucks carrying containers and goods in and out of the port meant that the road was lasting only about three months between repairs,” says Bennett. “We replaced the road with an EME asphalt about six years ago, and it is still holding up well to this day.”
Since then, National Asphalt has laid down about a million tonnes of EME on the country’s roads, mainly in Durban to serve the high-wearing bus lanes in the city’s rapid transit network and N3. In a more recent project and a first for the City of Cape Town, EME is being used in on a new circle intersection on Jan Smuts Street. It was also installed in the Western Cape’s famous Huguenot Tunnel.
Using a hard grade of bitumen, EME imparts a high stiffness and structural strength to the pavement. The added strength even allows for the road’s layer thickness to be reduced by about 30% on average, with the associated cost benefits. Alternatively, EME asphalts of the same thickness have a life span of 5 to 10 times that of regular asphalt.
In spite of its inherent stiffness, EME binder has very good workability and compactability. This means that no specialised production method is required, however attention to detail during the paving operation is extremely important and only experienced contractors should install EME as there is no room for error.
“Experienced contractors will find that there is no difference in the road-building process when using EME, as it lays like conventional asphalt,” Bennett explains.
He highlights that the roll-out of rapid transit bus routes in a number of South Africa’s cities presents an ideal opportunity for the authorities to benefit from this cost effective asphalt technology.
“With its capacity to resist the impact of heavy buses, EME asphalt can add years of extra life to these roads,” says Bennett. “The savings of maintenance costs by metropolitan councils would be significant, not to mention avoiding the transport disruption that roadwork invariably causes.”
National Asphalt’s extensive footprint of asphalt plants around the country enables it to supply EME asphalts efficiently and economically. It is also able to ensure best practice in terms of responsible and sustainable materials supply, by reducing the amount of virgin aggregates in mixes. It does this by combining virgin aggregate with reclaimed asphalt for roadbuilding and resurfacing, thereby promoting reuse and recycling of existing material.