CONTRACTORS ARE to trial the first non-toxic alternative to a long established concrete pore-blocking treatment for highway structures, the UK Highways Agency confirmed this week.
The Agency has granted Pavix, a water based single pass treatment developed in the United States, a 'Departure from Standard' to allow it to be used instead of Silane as a surface impregnant.
This follows a series of tests at London's City University and independent test houses.
Contractor Amec-McAlpine will use Pavix on all new and retained concrete structures, including sign gantries and retaining walls, on its M60 motorway Junctions 5 to 8 widening joint venture.
Surface impregnants are designed to minimise the movement of moisture into the concrete, protecting it against the effects of de-icing salt in road spray.
Silane has been the only material approved for this purpose, but is classified as hazardous waste if spilled. It is an inflammable skin irritant, and has a distinctive and often unpleasant odour.
As a result contractors using it must take special measures to protect waterways and nearby bituminous surfaces, as well as bearings, joints and hand rails.
Pavix can be applied in a single pass and contractors do not need to use special protective measures. It is also claimed to be a much better crack sealer. Its significantly higher initial cost is said to be more than outweighed by time saved on the job.
Agency officials will monitor performance of Pavix on the M60 and have called for testing to determine the depth of penetration into the concrete.