The Times Australia
The Times World News

.
The Times Real Estate

.

How a concrete alternative can cut emissions, resource use and waste

  • Written by Aliakbar Gholampour, Senior Lecturer in Civil and Structural Engineering, Flinders University
how a concrete alternative can cut emissions, resource use and waste

Building materials and construction generate about 20%[1] of global greenhouse gas emissions[2]. Much of these emissions are due to the environmentally unfriendly process of producing ordinary Portland cement[3], which is widely used in construction materials such as concrete and mortar.

Portland cement production generates about 2.6 billion tonnes of carbon dioxide (CO₂) a year – more than 7%[4] of annual global emissions. Cement emissions have doubled in the past 20 years[5]. And over the next 40 years, construction is expected to double the building floor area[6] worldwide.

Read more: Buildings produce 25% of Australia's emissions. What will it take to make them 'green' – and who'll pay?[7]

Every tonne of cement produced also uses about 1.6 tonnes of raw materials[8], including fuels and other resources. Concrete production also uses large amounts of aggregate such as sand and gravel. This requires energy-intensive quarrying operations that deplete non-renewable natural resources[9] – the world is running out of building sand[10].

The problems of emissions and resource depletion mean suitable substitutes for Portland cement and natural aggregate are required. Our research[11] shows it is possible to develop more sustainable construction materials, reinforced using natural fibres. Industrial byproducts and waste materials can be used to replace cement binder and aggregate, reducing emissions, resource depletion and waste.

Read more: Green cement a step closer to being a game-changer for construction emissions[12]

Recycling cuts waste

Recycling waste materials in construction can help reduce the environmental impacts of concrete and mortar production and the disposal of waste materials in landfills.

These materials include industrial byproducts (fly ash and blast furnace slag), waste glass and lead slag. Fly ash comes from coal-fired power stations. Blast furnace slag is a byproduct of iron and steel production.

A new type of eco-friendly material, geopolymer[13], has received significant attention as a replacement for conventional concrete. A geopolymer is a hard and durable human-made substance. Geopolymer production produces up to 90% less CO₂ emissions[14] than conventional concrete.

The properties of waste glass and lead slag make them suitable for use in making geopolymer.

Read more: Australia needs construction waste recycling plants — but locals first need to be won over[15]

Natural fibre reinforcement is sustainable

Steel or other synthetic fibres have been widely used as reinforcement material to improve the mechanical properties of geopolymer. However, steel fibres are expensive and corrode in harsh environments.

The synthetic alternative, mineral fibres, such as polyvinyl alcohol and polypropylene, are produced using antioxidants and amines. This process makes these fibres a non-eco-friendly material.

Natural fibres obtained from plants are a viable alternative to non-renewable, corrosive and expensive synthetic fibres. Natural fibres are renewable, eco-friendly, non-corrosive, cheap and abundant. These properties make natural fibres a sustainable material.

What did the study find?

Any substitutes for the concrete and mortar used today should at least match their engineering properties, such as strength and durability. Our study[16] evaluated the production and performance of geopolymers made with waste glass and lead slag instead of natural sand. We used a combination of fly ash and granulated blast furnace slag as binders instead of Portland cement.

These geopolymers were reinforced with different types of natural fibres such as coir[17], ramie[18], sisal[19], hemp[20], jute[21] and bamboo[22] fibres.

Compression load testing of a geopolymer concrete cylinder. Author provided

Our experimental results showed geopolymers containing waste glass sand have higher strength and absorb less water than those containing lead slag and natural sand. Water absorption reduces the durability of concrete.

Geopolymers prepared with lead slag show a lower drying shrinkage than geopolymers made with waste glass sand and lead slag. Drying shrinkage also reduces durability, as it leads to cracks in the concrete before it bears any kind of load.

We found that geopolymers with 1% ramie, hemp and bamboo fibre have greater compressive and tensile strengths than unreinforced geopolymers. This means the reinforced geopolymer resists breaking when squeezed (under compression loading) and when pulled apart (under tension loading). The higher strength of natural fibre-reinforced mixes is because of the bridging effect of the fibres inside the geopolymer.

Our study also shows that ramie, hemp and bamboo fibre-reinforced geopolymers shrink less than unreinforced geopolymers.

The results of tension loading tests on different geopolymer samples. Author provided

Read more: Greening the concrete jungle: how to make environmentally friendly cement[23]

What next?

The next steps in this research would include study of:

Read more: Future cities could be 3D printed – using concrete made with recycled glass[24]

Developing sustainable concrete will provide us with a next-generation construction material that greatly improves the sector’s resource efficiency while reducing its emissions and other environmental impacts.

References

  1. ^ about 20% (architecture2030.org)
  2. ^ global greenhouse gas emissions (www.ipcc.ch)
  3. ^ Portland cement (www.britannica.com)
  4. ^ more than 7% (phys.org)
  5. ^ doubled in the past 20 years (phys.org)
  6. ^ double the building floor area (www.worldgbc.org)
  7. ^ Buildings produce 25% of Australia's emissions. What will it take to make them 'green' – and who'll pay? (theconversation.com)
  8. ^ 1.6 tonnes of raw materials (www.buildinggreen.com)
  9. ^ deplete non-renewable natural resources (www.conserve-energy-future.com)
  10. ^ running out of building sand (www.bbc.com)
  11. ^ Our research (www.sciencedirect.com)
  12. ^ Green cement a step closer to being a game-changer for construction emissions (theconversation.com)
  13. ^ geopolymer (www.geopolymer.org)
  14. ^ 90% less CO₂ emissions (www.geopolymertech.com)
  15. ^ Australia needs construction waste recycling plants — but locals first need to be won over (theconversation.com)
  16. ^ Our study (www.sciencedirect.com)
  17. ^ coir (ecoworldonline.com)
  18. ^ ramie (ecoworldonline.com)
  19. ^ sisal (edition.cnn.com)
  20. ^ hemp (cfda.com)
  21. ^ jute (www.recycledmats.com.au)
  22. ^ bamboo (ecoworldonline.com)
  23. ^ Greening the concrete jungle: how to make environmentally friendly cement (theconversation.com)
  24. ^ Future cities could be 3D printed – using concrete made with recycled glass (theconversation.com)

Read more https://theconversation.com/a-green-trifecta-how-a-concrete-alternative-can-cut-emissions-resource-use-and-waste-192501

The Times Features

Why Regional Small Businesses in Bendigo Deserve Better Access to Finance in 2025

In the heart of regional Victoria, Bendigo has long stood as a beacon of innovation, resilience and community spirit. As we step further into 2025, the importance of nurturing sm...

Is It Time for a Deep Cleaning? Signs You Shouldn’t Ignore

Most people know they should visit the dentist for a regular check-up and cleaning every six months. But sometimes, a standard cleaning isn’t enough. When plaque and tartar build...

The Hidden Meaning Behind Popular Engagement Ring Cuts

When it comes to engagement rings, the cut of the diamond is not just about aesthetics. Each shape carries its own symbolism and significance, making it an important decision for...

Annual Health Exams in the Office: How They Can Reduce Sick Days and Healthcare Costs

Regular health check-ups, especially annual health exams in the office, can significantly impact the overall well-being of your workforce. A proactive approach to employee health...

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping