The damage was repaired initially using asphalt to fill the gouges (seal delaminated areas, in roading terms), then a week later by re-application of heated aggregate (chip) as hot weather returned, allowing for the chip to stick to the surface.
Contractor Capital Journeys completed the repairs on Wednesday, with traffic being managed down to a 30km/h temporary speed limit in both directions. The highway was back to its original 100km/h speed limit on Thursday.
NZTA regional transport systems manager Mark Owen told Ōtaki Today that the damage could be attributed to a combination of the high temperatures and heavy traffic – compounded by slow vehicle movements.
“Traffic was stationary several times over the busy holiday period,” he said. “This type of damage can sometimes occur on chipseal road surfaces aft er consecutive days of hot weather, combined with a high number of slow moving vehicles, which has then softened the bitumen and caused it to bleed.”
The site will continue to be monitored by NZTA’s maintenance teams and any further damage repaired.
Mark said when the Peka Peka to Ōtaki (PP2Ō) expressway is completed, a review of the surface will be undertaken to determine the future use and demand on the road, and what surfacing will be appropriate.