Making its debut in Qatar, a Dynapac PL2000S planer is ‘milling’ up to 30t every 4 minutes of asphalt for the upgrading of the Dukhan highway. 

Work on ripping up the existing two-lane carriageway of Qatar's Dukhan Highway in order to replace the road with a greatly upgraded four-lane carriageway is being undertaken by the Gamuda-WCT Joint Venture taking delivery of a Dynapac PL2000S high-capacity planer, to remove the entire blacktop surface at the rate of 30t every four minutes.

On the same stretch of highway, Gamuda-WCT JV is also using three Dynapac CP142 Combi pneumatic-tyred rollers to continually compact the newly laid sub-base, preventing it from cracking while it waits for the asphalt; a measure needed with the hard fragmented coral limestone found in this region.

Originally built 18 years ago, the two-lane highway is being upgraded to provide improved access for the development of the Dukhan industrial area, which is developing as a petrochemicals and gas centre.The 43 km stretch of new highway is being built at a cost of 750 million Qatari riyals (US$206 million), with a four-lane dual carriageway with five grade-separated interchanges due to replace the existing two-lane single carriageway.

Gamuda-WCT JV - comprising two of Malaysia's leading civil engineering contractors - has been awarded the main contract on the western section of the highway by client the Qatar Public Works Authority.

The JV plant supervisor, Eddie Mansfield, said that the existing blacktop had to be removed as quickly as possible, and the materials transferred to a central plant on the project for melting down and recycling.

The Dynapac PL2000S works across a maximum width of 2100 mm of carriageway, cutting to a depth of 320 mm and removing both the road surface and the sub-base in one pass. Hydrostatically driven by four steered track drives, the planer has a front-loading system and mechanical, belt driven cutting drum. The operator uses two joysticks for driving and for the conveyor belt functions.

A fleet of 30 t capacity trucks shuttle between the planer and the recycling plant, with the planer taking just four minutes to fill each truck.

Mr Mansfield said the new highway construction would have a 500 mm sub-grade, a 200 mm sub-base and a 330 mm layer of asphalt. Each of the four lanes would have a total width of 14.6 m with a 3 m paved shoulder plus a 1 m hard standing. 

With compaction of the newly graded road following some 2 to 3 km behind the surface removal, 30 km of sub-grade laid, and 15 km of asphalt laid, it is necessary to keep rolling the sub-grade, which has already been compacted by a sub-contractor using two Dynapac CA250 vibratory rollers, to prevent it from cracking before it can be sealed, said Mr Mansfield.

Three Dynapac CP142 Combi pneumatic tyred rollers, each fitted with five oscillating front wheels at the front and four traction rear wheels, and specially designed for the compaction of bases, sub-bases and asphalt mixes, are being used for this part of the project.They have a rolling width of 1.76 m and when fitted with the standard six ballast boxes have a wheel load of 1,330 kg. “These are very easy to operate and we keep the rollers moving all the time,” said Mr Mansfield.

The Gamuda-WCT JV started work on its contract in November 2005, and is due to complete at the end of 2007.