Concrete dominates the Hong Kong cityscape, with the vast majority of both high- and low-rise buildings using concrete instead of steel. However, cement production creates approximately 8% of the entire world’s carbon dioxide (CO2) emissions. In fact, cement manufacturing produces around 0.9 pounds of CO2 for every pound of cement. As the leading source of cement production, China produced over 1500 million tonnes of CO2 in 2017 from cement production alone.
Last month, cement industry leaders met in Poland at the United Nation’s conference on climate change, COP24. Their mission was to discuss ways to meet the Paris Agreement on climate change, which stipulates a 16% reduction in annual emissions from cement by 2030. Overall, China has agreed to lower carbon emissions from all sources by 60-65% from their 2005 level by 2030 (which also applies to Hong Kong.)
Why Not Use Steel?
With the pressure to reduce CO2 emissions, it may seem easier to use steel-framed structures rather than concrete. Steel, while not inherently low-carbon, does produce fewer CO2 emissions than concrete. It’s lighter, offers high strength and stiffness, is easier to produce and quicker to install, and doesn’t require formwork – though at a higher cost than concrete. It also requires more skilled labour to erect a steel structure.
Steel is also prone to corrosion, which in a maritime climate such as Hong Kong is a real concern. In addition, concrete creates a more rigid, monolithic structure, which is useful for the high-rise buildings Hong Kong is known for as it can resist the high wind loads much better. In a steel structure, the joints and connections between elements such as beams and columns make the structure insufficiently rigid. Cranes are also required to install steel elements, which requires space that isn’t always available in urban Hong Kong. Add in the lower cost for both the material and the labour required, and it’s obvious why concrete is still the favoured option.
What Can Be Done?
Clearly, there needs to be a change in the way buildings are constructed in Hong Kong in order to meet their ambitious CO2 reduction targets. Optimising the structural design is one solution, but on its own is likely to not generate enough of a reduction in CO2 emissions.
Fortunately, new materials, technologies, and methods are being developed all the time. Mitigation measures such as using state-of-the-art energy production can improve energy efficiency, as can switching to alternative fuels that are less carbon-intensive than conventional fuels. Excess heat recovery and carbon capture, use and storage technologies are also emerging. There is even bendable concrete now being developed. When these measures are paired with an optimised design, suddenly the reduction targets don’t look quite so unachievable.
Do You Want to Get Involved?
Sustainable concrete has a huge role to play in the future of construction in Hong Kong. If you would like to be a part of that story, take a look at our vacancies in Hong Kong. We have a range of roles for engineers, project managers, estimators and quantity surveyors.
 Source - https://reader.chathamhouse.org/making-concrete-change-innovation-low-carbon-cement-and-concrete
About the Author
Construction Recruitment Director, Hong Kong
I am responsible for the recruitment business in Hong Kong, Asia, and the Middle East. I was a civil engineer and project manager for 15 years before becoming a construction industry recruitment consultant in 2004. I am based in the Hong Kong office and specialise in placing professionals in engineering, project management, planning, HSEQ and risk.
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