HONG KONG airport's northern runway surfacing is to be repaired barely a year after it opened for 24 hour operation.
Chek Lap Kok Airport Authority also plans to resurface the southern runway at the same time to overcome differential settlement that has occurred since the runway became operational in July 1998.
The airport authority is set to appoint a contractor for the work tomorrow. Bidders include Pioneer in joint venture with Tarmac; Irish firm Lagan and two local firms, Anderson Asphalt and Asphalt Surfaces.
Up to 40,000m 2will be regrooved and relayed on the northern runway and 30,000 m 2on taxiways. A further 30,000 m 2is earmarked for replacement on the southern runway.
A spokesman for the airport authority explained that the bitumen used in the asphalt on the northern runway showed greater variations of viscosity than that used on the south runway.
'As a result there has been some minor fretting in areas such as the runway touch down zones and high speed exits, ' he said. 'There was no way of knowing this until the material was laid and subjected to use and weather.'
But industry insiders this week claimed that, while the asphalt used for the southern runway was independently tested and quality assured, there was little monitoring by the airport authority during construction of the northern runway. This was because work was running months late and the airport authority was keen to get the facility open.
Concern about the viscosity of the asphalt mix led the airport authority to appoint an independent consultant to look into the issue. The consultant concluded that the differences in the consistency of the asphalt would only have become apparent during normal operations and not while it was being laid.
Explaining the need to resurface the southern runway, the spokesman said the use of both marine sand and hard rock caused differential settlement, although this was taken into account when the runway was being constructed.
He added: 'We have stated in the past that the south runway will display differential settlement, especially in its initial years of operation. The need for this work after some three years was predicated during the planning and design stage and settlement has been within the forecast limits.'