highways
GO GREEN WITH COLAS! Figure 2: Surface dressing with bitumen emulsion technology is the most environmentally friendly road re-surfacing technique - in addition to being the most cost effective.
Earlier this year, Gearoid Lohan, CEO of Colas Ireland, launched a “Go Green with Colas” initiative to encourage all Colas subsidiaries to play a more pro-active role in meeting their environmental responsibilities. An additional aspect of this initiative is to raise awareness with our many customers and stakeholders of how Colas can help them meet their carbon reducing targets. Since its establishment over 70 years ago, the Colas Group has led the way in the development of environmentally friendly pavement materials. In fact, the name Colas comes from the words COLdASphalt. Cold-mix asphalt is similar to the more commonly used “hot-mix” asphalt but is producedby using a bitumen emulsion instead of the conventional hot bitumen. As bitumen emulsions can be used with aggregates at ambient temperatures, as opposed to the high temperatures required to manufacture hot-mix asphalt, there are considerable energy and, thereby, carbon savings to be achieved by their use.
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PLANT & CIVIL ENGINEER
Colas first introduced the coldmix asphalt technology into Ireland in the 1980’s. In 1990, a cold-mix asphalt called “Graveémulsion” was used inthe base course of a40 km section of the N8 from Dublin to Cork.At that time, the N8 was the highest trafficked road in the country. But the grave-émulsion cold-mix
material well and truly survived the test of time. In fact, when it had reached the end of its design life in 2006, there were no signs of distress or failure, with no cracking, an average rut depth of only 3 mm (versus the failure criteria of > 10 mm) and an IRI smoothness indicator of 1.7, which is well below the
Figure 1: Cold-mix asphalt trial in Colas yard in Mallow, 1984.
smoothness criteria for a new road!Since then, Colas Ireland has led the development and promotion of other emulsionbasedmaterials and techniques such as surface dressing, coldasphalt micro-surfacing and in situ pavement recycling. In addition to being a cold-mix technique, in situ cold recycling is one of the most environmentally sustainable and low carbon maintenance techniques that is available to the Local Authority Engineer. As well as being a cold technique, use is also made of the aggregate material already in the pavement. Consequently, there is less use of this valuable resource and there is less or no transporting of aggregates from a quarry or asphalt plant to the jobsite. In addition, the bituminous binder already present in the pavement can also be recycled. Much of these developments have been made possible thanks to Colas Ireland owning and operating its own speciality chemicals company in Oranmore, Co. Galway.Chemoran’s range of emulsifiers and bitumen additives enables Colas subsidiaries
