Highways work helped Costain to deliver a big rise in profits despite challenging trading in general construction during 2012.
The group posted a 16% rise in pre-tax profit to £30m on turnover down around 5% to £934m.
The infrastructure division, which includes it highways business, proved the star performer of 2012 with profits nearly trebled at £26m on turnover of £526m.
Andrew Wyllie, chief executive, said the infrastructure division had a very successful year generating strong operating returns and additional gains on successfully completed and final accounted projects.
He said the highways, rail and airport division continued to see high tendering activity.
"Costain has delivered another strong performance and demonstrated again that it has the right strategy to drive profitable growth even through the most challenging of economic conditions.
"We entered 2013, having already secured over £700m of work for the year and we continue to benefit from a strong pipeline and high levels of tendering activity."
New contract awards include the upgrade of the A8 Belfast to Larne carriageway for the Northern Ireland Roads Service.
Costain was also selected for both lots of the Highways Agency Asset Support Framework during the year.
Wyllie said he was also delighted Costain had picked up its first highways technology framework contract for the Welsh Government, an important contract given the increased levels of investment in technology expected in the highways sector.
This four-year technology deal covers maintenance of road network communications and tunnel systems across Wales.
Costain will maintain CCTV cameras, variable messaging signs, emergency telephones and traffic signals along all major strategic routes.