The Densiphalt Proposal
Bus areas need durable running surfaces that will not deform or rut from continuous vehicle movements. Fuel resistance is also a critical requirement from the surfacing. CIP submitted a new build Densiphalt design to replace the existing concrete slab, this comprised 40mm Densiphalt, 60mm Heavy-duty Macadam basecourse, 150mm Heavy-duty Macadam Roadbase onto 250mm Type 1 sub-base. This design was based on a CBR value of 5% and a traffic flow of 2 million standard axles per day. We Guaranteed the system would not form cracks greater than 5 millimetres, would not deform, would be resistant to skidding of vehicles, would not spall due to frost and would remain bonded to the sub-base layer over a 12 year design life.

Densiphalt Installation
Works commenced on site on 26th July 2002 and took an overall programme of 4-5 days including a curing period of 24 hours. John Crowley’s Ltd supplied and installed all Basecourse, Roadbase and Wearing Course layers under the supervision of CIP Contract Management. Densiphalt open graded asphalt has to meet a certain specification before pouring the mortars through. It needs to be laid with a 10mm aggregate size to achieve a 25%-30% void ratio and must be rolled without any vibration to ensure minimum compaction. CIP specialist installation team then installed the Densiphalt mortars through the asphalt matrix using rubber scrapers to form a high strength, durable running surface for the end user.

|