Rediset® WMX
When improved performance and environment go hand in hand
Most people probably don’t think “technology” when they come across a road crew, but building roads to last is more complicated than it looks. So it’s not surprising that there are people who make it their business to apply science to the development of improved paving materials. Indeed, AkzoNobel has been applying technology to road-building since the 1940s. It’s most recent innovation is Rediset® WMX, a product delivering significant advantages to the road-construction industry in one very convenient package.
Road-building primer
Understanding all the advantages of Rediset® WMX requires a brief explanation of road construction. Roads are paved with a mixture of crushed stone (aggregate) and a binder, asphalt (or bitumen). That mixture is prepared at a “hot-mix plant”, transported to a work site, and compacted to form the roadway. Typically the temperature of the hot-mix must be around 160˚C to be sufficiently workable. That requires considerable energy and results in fumes that are the tell-tale sign of a road crew.
Energy savings, reduction in emissions, and longer lasting roads
Rediset® WMX reduces the temperature at which the mixture remains workable by around 30˚C, cutting energy costs by 20% and reducing worker exposure to noxious fumes released at higher temperatures. What’s more, Rediset® actually helps the road to hold together better and longer because it improves adhesion between the binder and the aggregate, promotes better cohesion in the asphalt binder itself, and impedes damage to the asphalt as a result of moisture intrusion.
The key is what is called an “amine surfactant”, which changes asphalt that would normally be slightly acidic into a weak alkaline material. Since aggregates are usually weakly acidic as well, and stronger chemical bonds are established when one material is acidic and the other is alkaline, Rediset® promotes bonding in the paving material. “Normally, explains Dr. Sundaram Logaraj, Business Development Manager for Surface Chemistry business, “water can displace the asphalt from the aggregate surface and damage the pavement. But because Rediset® promotes much better bonding with the aggregate surfaces, it impedes water damage. The hydrocarbon chain becomes part of the asphalt, so you have a sort of water resistant bridge holding the aggregate and the asphalt together.”
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