A PULSED infra red concrete defects detection system has been used in the field for the first time in the UK near Bristol.
UK research body BRE is developing the new technique, which uses short bursts of powerful light to raise the temperature of the surface under investigation by as little as 2infinityC.
An ultra sensitive infra-red camera then monitors the surface as it cools. Its images are analysed by computer to detect anomalies.
The test was carried out during the recent strengthening of columns supporting the A38 flyover in south Gloucestershire for impact resistance.
This involved wrapping five layers of Sika aramid fibre reinforcement to the two central 1.4m diameter columns, by specialist contractor Concrete Repairs. The infra read detection will allow long term monitoring of the repair system chosen by South Gloucestershire Council's structural engineer, Parsons Brinckerhoff.
To test the system a sacrificial band, similar to the main reinforcement, was installed above the strengthened area.
To this the BRE team deliberately added flaws, a coin, a cigarette end and a crumpled tissue, within the wrapping.