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Unlocking carbon’s potential: how to make construction greener

By Dr Anthea Blackburn, Senior Scientist – Catalyst Development, Econic Technologies

As sea levels threaten to rise, climate change slides ever further up the political agenda. Few would now doubt the urgent need to tackle global warming, not least the UK’s school children who recently went on ‘strike’ in an effort to encourage the Government to take action.

The business world is no different, where there is a growing awareness of the need to act and mounting public pressure, which has seen companies large and small take steps to make their operations greener. Coca Cola and Ikea, for example, are taking action to ensure their plastics are recyclable or compostable and contain increasing proportions of recycled plastic, whilst Unilever, since 2008, has reduced CO2 emissions by 39% per tonne of product manufactured.

The architecture and construction sectors are no less committed to riding the green wave: in recent years we’ve seen the development of cross-laminated timber; the resurgence of rammed earth as a construction technique; and the use of passive solar building design. And whilst these efforts are a step in the right direction, more still needs to be done. After all, the Government estimates that as much as 40% of the UK’s emissions come from the construction sector, predominately from the manufacture of construction products and materials.

Perhaps inevitably, then, the Government is acting to make the architecture and construction sectors greener, announcing, in its Spring Statement, for instance, a ban on the use of fossil fuel heaters in new-build properties. The Government is certainly onto something in its attempts to make properties themselves, and not just the construction process, greener. But what if a solution to making buildings greener was all around us – literally?

Specifically, CO2 – long maligned as the cause of all the world’s environmental problems – could be used to make all manner of products for the construction sector. It is now possible to create one of the components of polyurethane in a process that replaces some of the oil-based raw materials with captured waste CO2. Polyurethane products are commonplace in construction – from adhesives used to fix roof tiles in place through to window sealants, wooden floor coatings and rigid foam insulation – so the potential uses of CO2 are plenty. What’s more, the process of making these materials is typically less energy intensive than that for the production of oil-based alternatives, and the products themselves function incredibly effectively: they provide good rigidity; increased abrasion resistance; improved chemical resistance; and, in the case of insulation, require less than half the amount of cork or mineral wools to provide the same degree of insulation, and have increased fire resistance.

For years, such a suggestion would have been in the realms of science fiction; CO2 is inherently unreactive, which is why it is such a challenge to find ways of turning it into something that’s useful.

Developments in catalytic science, however, have turned science fiction into science fact. ClimeWorks, for instance, has pioneered a way to capture, purify and then use CO2 as a renewable onsite resource in the food and agricultural industries, as well as for those that use CO2 as a fuel or chemical raw material.

What’s more, it is even possible to create concrete, one of the biggest contributors to emissions, out of CO2. For example, CarbonCure technologies allow the CO2 emitted during cement preparation to be transformed into nanosized mineral carbonates that are embedded within the concrete. Carbon8 Aggregate, meanwhile, has pioneered a process that uses CO2 to transform thermal waste into artificial limestone.

The issue of climate change is ever pressing, and embracing innovations to reduce emissions is but one way we can make a difference. Making use of CO2 as a raw material could help to significantly reduce carbon emissions in the construction sector – indeed, using CO2 in the production of polyurethane could equate to removing as much as 4 million cars’ worth of emissions each year. By acting now and adopting these techniques, the construction sector could not only become greener and reduce its impact on the planet, but it could also fully realise the possibilities offered by CO2.