NTU invents tougher, flexible new concrete for paving roads

Prof Yang En-Hua, showing the effect of applying pressure using the four point bending machine (behind).
Prof Yang En-Hua, showing the effect of applying pressure using the four point bending machine (behind).PHOTO: TIFFANY GOH FOR THE STRAITS TIMES
Prof Yang En-Hua, with the bent ConFlexPave concrete slab after the bending test.
Prof Yang En-Hua, with the bent ConFlexPave concrete slab after the bending test.PHOTO: TIFFANY GOH FOR THE STRAITS TIMES
The ConFlexPave concrete slab which has bent after increased pressure was gradually applied to it.
The ConFlexPave concrete slab which has bent after increased pressure was gradually applied to it.PHOTO: TIFFANY GOH FOR THE STRAITS TIMES
Pressure is gradually applied to the new concrete material using the four point bending machine.
Pressure is gradually applied to the new concrete material using the four point bending machine.PHOTO: TIFFANY GOH FOR THE STRAITS TIMES

SINGAPORE - Nanyang Technological University scientists have invented a new, flexible type of concrete that bends rather than breaking under pressure.

In collaboration with JTC, this new material named ConFlexPave will be test-bedded as road paving over the next three years.

Conventional concrete is already used as road paving in some areas in Singapore such as traffic junctions, as it is more durable than asphalt.

But ConFlexPave is at least twice as tough as regular concrete, meaning that the slabs used can be half the thickness, making them lighter and easier to transport and install.

The durability also gives it a longer expected lifespan: possibly twice the 20-year lifespan of conventional concrete road paving.

Said Assistant Professor Yang En-Hua: "Because we use special materials, the upfront material cost is slightly on the high side.

"But if you look at it over the entire lifecycle and take into account the manpower reduction since it is easier to install, you can actually save more."

Dr Yang leads the research project at the NTU-JTC Industrial Infrastructure Innovation Centre.

Besides cement, water and sand, which are also components of conventional concrete, ConFlexPave also contains two special materials in the mix.

The materials cannot be named as they are trade secrets, but they are special synthetic fibres which allow the concrete to flex rather than break under pressure, and a hard mineral which replaces the regular gravel used in typical concrete.

The next challenge is to produce this concrete on a larger scale rather than in the laboratory, while ensuring that the fibres are evenly distributed so that the concrete achieves the same level of flexibility, said Dr Yang.

The slabs will then be test-bedded at a JTC site within the next year, and monitored for at least two years.

Based on that, JTC will work with the Land Transport Authority to see if the use of ConFlexPave can be scaled up, said Mr Koh Chwee, director of JTC's technical services division and co-director of the Centre.