The company, which maintains railways and roads and military bases, said revenue rose 21 per cent to £2.3bn in the six months to 30 June from £1.9bn a year earlier.
New first-half orders plus probable orders of £1bn were less than half the £3bn achieved the same time last year, but Carillion said this reflected the usual pause in public sector contract awards after the General Election.
It expects to win a number of new contracts in the second half and meet market expectations for full-year pre-tax profits of £175m.
Carillion’s pipeline increased to £40.5bn from £39.2bn in December.
“With a strong order book, a growing pipeline... and the prospect of market conditions continuing to improve, our expectations for 2015 and the medium term remain unchanged,” Carillion said.