Cementing a sustainable future with greener concrete

OVER in the far west of Singapore, a revolutionary development crucial to the country's economy is taking shape. When fully completed in the 2040s, the Tuas Megaport will be the world's largest container terminal, facilitating millions of tonnage every month and cementing Singapore's place in global trade.

But more than that, it is also showing the world how a massive development does not need to leave a big impact on the environment. Going green and striving for sustainability are 2 key aims of this next-generation port.

Indeed, its green footprints can be found in every aspect of its construction, right down to the most fundamental of building materials being used to create the maritime facility's pavements and structures: concrete.

The Maritime Port Authority is using a greener version of the material to construct the megaport: CO2 mineralised concrete. This product harnesses industrial carbon dioxide and converts the gas into a solid mineral that is permanently embedded within the concrete itself. In other words, this carbon mineralisation process reduces emissions of the environmentally harmful greenhouse gas.

With five million cubic metres - the equivalent of 2,000 Olympic-sized swimming pools - of CO2 mineralised concrete being poured into the port, carbon emissions have been reduced by a staggering 1.3 million tonnes. This is equivalent to permanently removing 260,000 petrol cars from the roads.

On the other side of the island at the Tampines Wafer Fab Park, the sprawling 32,000 square metres JTC semiconSpace - a semiconductor facility - is also currently being built entirely with CO2 mineralised concrete.

These are just 2 examples of a wider trend that is growing in Singapore's Built Environment (BE) sector: using green materials to fight climate change, which is being flagged as humanity's biggest threat today.

New ideas needed

Climate change is our biggest crisis. Prime Minister Lee Hsien Loong has called climate change an "existential crisis" for Singapore, given that the country is surrounded by the sea. Rising sea levels could create severe consequences for the island.

Urbanisation is a key factor for the rise in carbon emissions, with the growing number of buildings taking its toll on the environment. The global BE sector contributes to a considerable 39 per cent of all carbon emissions.

Of this number, 11 per cent comes from embodied carbon - the amount of carbon emitted from the use of materials and construction processes. This includes the manufacturing of building materials and their transportation to the construction sites.

As the most widely-used man-made substance in the world, concrete is the foundation of modern society - for every person, 3 tonnes of the material are used annually. But concrete is also traditionally associated with being a heavy carbon emitter. In fact, the production of cement, which is a key raw material required in manufacturing concrete, accounts for 8 per cent of global carbon emissions.

The BE sector has looked to reduce emissions, with the bulk of efforts focused on building green buildings that reduce energy consumption. But so far little attention is given to the building process itself.

If the sector is to make further advances in reducing carbon emissions, it needs to reduce embodied carbon by switching to greener alternatives such as mineralised concrete.

Durable, efficient, and sustainable

Mineralised concrete is created when carbon dioxide is injected into the concrete, creating a solid mineral called calcium carbonate. The manufacturing process brings with it multiple benefits.

For one, it allows developers to build better. When it comes to strength and durability, CO2 mineralised concrete performs better than its regular counterpart, thanks to the formation of calcium carbonate minerals that provides added strength and durability.

This process makes CO2 mineralised concrete a much more efficient material than regular concrete, as less of the material needs to be used with no compromises on quality and performance. The concrete's enhanced strength allows for a reduction in the amount of cement being used during mixing. It is estimated that a cubic metre of CO2 mineralised concrete can reduce cement use by between 3 per cent and 7 per cent.

Most importantly, CO2 mineralised concrete drastically reduces carbon emissions. The injected CO2 is permanently locked away within the concrete through the mineralisation process, reducing the levels of embodied carbon during construction. In fact, each cubic metre of the material prevents an estimated 17 kilograms of CO2 from entering the atmosphere.

The correct path

The multiple benefits are a key reason why we decided to bring mineralised concrete to the market.

One obstacle that some developers have raised is of cost. CO2 mineralised concrete is more expensive to produce because of the new technology involved. But taken against the total development cost, the increase is minimal and the overall gains clearly outweigh the slight differential, and hence its acceptance by more and more owners, including PSA and JTC.

But we believe that the goal should still be moving towards mass adoption of the material for the sector. Awareness of the threats from climate change is rising - there is a clear advantage for first movers in adopting such materials from an environmental, sustainability and governance point of view.

A survey by Accenture and the World Wildlife Fund showed that 30 per cent of Singaporean consumers would make most purchasing decisions based on product sustainability and environmental impact. A further third of consumers were willing to pay a premium of up to 10 per cent for sustainable alternatives.

While this survey looks at retail and not property purchases, there is clear evidence that environmentally-conscious consumers are voting with their wallet.

The government is also moving quickly on this front. The Building and Construction Authority's new regulations now require buildings to be constructed more sustainably in order to be certified green.

Its revised 2021 Green Mark scheme will focus on reducing the amount of embodied carbon in buildings in particular, as it takes into account the whole life carbon footprint of buildings.

Striving for a low-carbon built environment aligns neatly with Singapore's sustainability targets through its wide-ranging Green Plan 2030 as the country pushes for a more sustainable future in all sectors within this decade.

Using CO2 mineralised concrete can significantly help the BE sector strive towards these sustainability targets. Fighting climate change is a tall order but using greener concrete will go a long way towards building a foundation for success.

The writer is director of operations and sustainability at Pan-United Corporation