Paths, buildings, bridges, roads, sewage pipes, you name it – it’s probably been made using concrete. It’s the second most used substance in the world, but its production is also the single biggest industrial cause of carbon pollution, making up around 8% of global CO2 emissions.
Cement, which is the base for making concrete, is one of the most polluting and energy intensive products to produce and there has long been a push to make its production less resource intensive and much more environmentally friendly.
With a recent breakthrough piece of research, 91˰涶Associate Professor Safat Al-Deen, Professor Chi King Lee and their PhD student Suliman Khan have been able to do just that.
The researchers have created an eco-friendly, low carbon concrete (LCC) substitute, which replaces up to 90% of cement with other more environmentally friendly materials called supplementary cementitious materials (SCMs), such as blast furnace slag, fly ash, and silica fume. Their motivation was to develop concrete that maintains necessary durability and performance whilst being much more environmentally friendly and sustainable.
One of the biggest concerns when altering cement composition is whether the resulting concrete can withstand real-world demands. Chi King’s research shows that even replacing 90% of the cement with SCMs, creates a concrete that still meets international construction standards.
“Replacing ordinary Portland cement (OPC) with SCMs affects hydration kinetics and early strength development, but our mix designs demonstrated that even with 90% OPC replacement, we could still achieve concrete with characteristic strengths that comply with international standards,” Suliman said.
“These new types of concrete mixes are incredibly durable and ideal for low-to-mid-rise buildings, ground slabs, and pavements,” Safat said.
Aside from their main focus of reducing emissions, the team also found that their new concrete offers significant economic advantages. SCMs are often more affordable and widely available compared to OPC, making LCC a cost-effective alternative – a win-win for both practicality and sustainability.
“Our LCC blend not only reduces costs but improves workability and minimises the inherent issues of concrete like bleeding and cracking. This novel concrete using pre-blended SCMs simplifies production and facilitates large-scale adoption in the construction industry,” Chi King said.
Industries are under increasing pressure to adopt sustainable practices, and this research could play a pivotal role in the future of a greener world.
“Our research proves that high volume, low carbon cement is possible and doesn’t need to compromise durability. This could accelerate the adoption and application of LCC,” Suliman said.
“We plan to conduct pilot-scale testing and collaborate with industry partners to validate these mix designs in actual construction projects,” Safat said.
With Canberra growing rapidly, the team is currently assisting the ACT government in developing the necessary policies and concrete specifications to facilitate the adoption of LCC like theirs in local builds.