, , ,

The method was patented in 1993 by Professor Elk Richter at Erfurt, Germany. Roads build using this method offer advantages such as it last longer and cheaper to maintain.

English: Close-up of an asphaltic concrete lay...

Close-up of an asphaltic concrete layer of a new road under construction. Photograph by Estr4ng3d, Helwan-Korayimat Road (Cairo, Egypt). (Photo credit: Wikipedia)

Compact asphalt (“hot on hot”) pavements are pavements consisting of surface and binder courses, laid in one operation one after another and compacted together. The heat of binder course ensures better compactability of the surface course. In this case well-bonded package of two courses is produced, without using bituminous binders for a tack coat.[1]

This method differs from the conventional method as in the binder and wearing course is applied to the base course, one after the other in a single pass. Regular asphalt paving involves two separate passes, with the wearing course being applied after the binder has cooled. This can cause problems and lead to uneven compaction especially in bad weather.

In hot-on-hot asphalt laying, the binder and the wearing course are laid at the same time. A total of twelve centimetres of asphalt is applied.

Because the applied asphalt is thicker, the useful compaction time is extended by a factor of at least seven.

As the two layers are applied ‘hot-on-hot’, it is possible to reduce the thickness of the uppermost layer to two centimetres, as opposed to four centimetres with the conventional method.

Since the wearing course mix is particularly costly, this means substantial savings for the contractor and ultimately for the taxpayer.

Compared with the conventional method, this method also gives better bonding between the individual layers, helping to prevent crack formation in the road surface.

On average, the base course of a road needs to be replaced after 40 to 50 years.

While the binder layer needs to be replace after 15 to 25 years and the wearing course after 10 to 15 years.

Impressive result were recorded in a trial on a stretch of road in Alabama, USA and it shows that no sign of fatigue in the form of tracks or cracks. The trial stretch was driven over continuously by 60-tonne trucks, simulating an 18-year service life in just two years.

This method also contributes to positive effects on the environment. It reduce the mixed temperature at 10 °C and this resulting approximately 0.23 litre heating oil per one ton can be saved.

No bitumen emulsion is needed – which is sprayed on the binder layer in case of the conventional laying method.

Source : Asian Infrastructure and Dynapac

(this article written for 1BINA.my)

[1] Perveneckas, Z., & Vaitiuk, V. (2008). Pilot Sections of “Hot On Hot” Asphalt Paving Technology In Lithuania.