Background

Currently, LTA maintains some 2,051 road infrastructures (flyovers, viaduct, underpasses, tunnels, overhead bridges, footbridges, culverts and retaining) island-wide. Over the years, we are beginning to see an increasing number of our concrete structures facing durability problems. This is due to the exposure to weathering, exhaust fumes from traffic and other harmful chemicals. Such durability problems arising from carbonation and the harmful effects of water and chloride ingress, if not properly addressed, would lead to the deterioration of concrete structure in the form of delamination, spalling concrete and corroding reinforcement, which in turn would affect the service life of the road structures.

Annex A shows photos of common defect found on bridges.

Protective coating system is an effective solution to improve durability. With improved durability and extended lifespan by 10 years (conservatively), we can delay the replacement of structures. Improved durability of the road structures would mean the need for less repairs, which would otherwise cause inconvenience to motorists and the public. In addition, the protective coating system also has the capability to repel dust and grime, prevent fungus, biological and algae growth. With the protective coating, the need for washing can be greatly reduced in most areas.

Grey colour protective coating will be applied to key road structures such as flyovers, viaducts and underpasses, as part of our preventive maintenance measures to improve their durability and protect them against deterioration.

Since 1998, LTA has started applying protective coating to bridges, flyovers and vehicular underpasses when they are being upgraded. The upgrading works include structure strengthening (thickening of structure elements and external post-tensioning) and expansion joints replacement. Once upgraded, these road structures could accommodate heavier and larger goods vehicles (gross vehicle weight increases from 24 tonnes to 46 tonnes). The upgrading works are ongoing and are expected to complete by 2008.

Annex B shows photos of upgraded Paya Lebar Flyover.

Since 1998, 86 road structures have been upgraded with protective coating and selective structure strengthening. In Feb 2006, LTA further carried out the application of protective coating on another 86 road structures (consist of 61 flyovers, 9 viaducts and 16 vehicular underpasses). Works are expected to complete in the third quarter of this year.

By end Aug 06, a total of 172 road structures would be applied with protective coating.

Annex C shows photos of 2 road structures applied with protective coating.