Highways Agency Interim Advice Note (IAN) 157/11 has advised that any laying of thin surface course (TSC) on its strategic highway network in the winter will require ancillary substrate heating and drying equipment to be available on site. This is because in cold weather adequate compaction is not achieved which leads to reduced durability.

This means that at the moment the HA’s preferred and most cost effective surfacing solution can technically only be carried out between April and October.

However surfacing expert Colas says its Repave technique which preheats the surface before application of a new TSC provides the required tight bond and so gives contractors an option to work in the winter.

The IAN does specifically allow for exceptions to the winter prohibition. 

It states: “The thinner (surfacing) systems lose heat extremely rapidly and therefore should not be laid in the winter months unless the surfacing substrate is adequately pre-heated.

“When laying is likely to occur at close to the minimum temperature or after rain, plant must be available on site so that the existing surface can be warmed and dried by means of infra red or similar heating immediately in front of the paver.”

Colas believes that with Repave it has the only integrated solution in the country to meet the need for heating the surface ahead of laying TSCs. Repave heats the existing pavement using LPG burners while steel tines scarify the road surface to a depth of 25mm before a TSC is applied.

Cores taken after a road has been Repaved show no separation between the compacted scarified material and the new thin layers. And they demonstrate that a tight bond has been achieved delivering a long lasting road surface without the need for application of a bond coat.

“Laying a hot surfacing over heated recycled asphalt creates a homogenous bond between the two layers, removing the need to spray a tack coat and giving the resulting carriageway great all round durability,” says Colas recycling manager Jochen Troeger.

To prove the point Colas completed resurfacing of 16,000m² of carriageway on the M45 in November.

Repave has a long pedigree and has been around for over 30 years. It has been used recently on the carriageways of the M1 and M56 as well as on major trunk roads, motorway junctions and local roads.

Mr Troeger says the system also addresses HA concerns about failure of TSC longitudinal joints. “By using Repave these joints are pre-heated as well resulting in a much better bond and a longer life expectancy.”

The Repave procedure is not only for use on long stretches of resurfacing. A recent project on the A1 demonstrated its suitability for patch work, resurfacing 12,000m² of patches of lengths as little as 30m.

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