What is green concrete?

Sustainable concrete, also known as green concrete, is a type of concrete made from materials and production processes that are more environmentally friendly than traditional concrete. It’s designed to reduce the environmental impact of the concrete industry, which is widely known to be a major contributor to carbon emissions  (almost one tonne of c02 is released for every cubic meter of concrete created) and resource depletion.

As a replacement for traditional concrete, green concrete may have slightly different physical and mechanical properties depending on the specific materials and production methods used.

For example, green concrete made with fly ash may have lower shrinkage and creep properties than traditional concrete but simultaneously have higher compressive and tensile strengths. Fly ash is a byproduct of coal-fired power plants that comes in a fine, powdery material rich in silica, alumina, and other minerals. It can be used as a supplementary cementitious material in concrete and is often regarded as the best alternative to traditional concrete.

What is the difference between green concrete vs. traditional concrete?

Traditional concrete is the second most consumed substance on earth after water. The main ingredient is ordinary Portland cement (OPC), which accounts for about 8% of all greenhouse gas emissions. It is made by grinding together a mixture of limestone, clay, iron ore and other materials and heating the mixture in a kiln to produce clinker, which is a small chunk comes after the heating which is then transformed into a fine powder to be used as cement binder.

Green concrete on the other hand is the more durable and environmentally-friendly version of concrete that demands less energy to produce and outputs a just a fraction of carbon footprint compared to Portland cement. Green concrete is made with re-purposed waste materials from the coal industry, through a geopolymer process. This produces sustainable concrete alternatives capable of replacing OPC with impressive strength and durability.

When it comes to fly ash-based concrete, it is mixed by blending various chemicals instead of heating like the OPC. This results in a higher quality cement that can be batched at traditional ready-mixed concrete facilities, allowing you to build with identical construction techniques.

Is green concrete as strong as traditional concrete?

Although it’s made mostly from leftover byproducts and recycled waste, it shouldn’t be surprising that green concrete is just as strong as traditional concrete and in many cases can actually surpass the strength of traditional concrete.

EcoCrete’s geopolymer concrete, for example, uses a proprietary mix of waste materials from coal combustion that would otherwise end up in landfill as a replacement for the cement, sand and aggregates that are traditionally used in concrete. As these ingredients mix with water, they undergo a chemical reaction that “geopolymerizes” the individual ingredients into stronger, non-toxic, sustainable concrete, just like traditional Roman concrete that’s been around for centuries.

One of the overlooked facts in Bali is that builders that are working with traditional concrete almost universally use natural sand in many parts of the island that’s not graded properly and has excessive silt or organic impurities, which makes it difficult to tell if the concrete mix has met the desired gradation and fineness as per requirement. And this can dramatically impact the long-term durability and strength, which eco-friendly geopolymer concrete doesn’t suffer from.

Unlike ordinary Portland cement-based (OPC) concrete, geopolymer concrete is highly resistant to fire up to 1000°C. This is because the water in geopolymer concrete easily evaporates and does not explode the concrete from the inside. As a result, it does not crack apart when heated (which is one of the main reasons OPC concrete fails at high temperatures).

Structurally speaking, geopolymer concrete can reach a high compressive strength of 40 MPa (N/mm2), which gives you more flexibility to grind the concrete slab without ever going too deeply and polish it into a more refined finished product.

If you’re curious you can see the full technical specifications of EcoCrete’s sustainable concrete here.

Applications of green concrete

Green concrete can be used for more than just walls, and it has no shortage of structural applications in everyday construction:

Eco-friendly concrete is excellent for building foundations, columns, and bridges, as well as ensuring water tightness.

Piers, boat ramps, gutters and fountain structures are examples of areas that are closely connected to the water where the use of geopolymer concrete is attractive. This is due to its high resistance against water immersion - seawater and fresh - and its less demand for regular maintenance as required by more traditional types of concrete.

And did you know that there’s an airport entirely paved with geopolymer concrete?

The Toowoomba Wellcamp Airport (TWB) in Queensland, Australia was built in 2014 with approximately 40,000 m3 of geopolymer concrete, making it one of the largest application of this new class of concrete in the world. Heavy-duty geopolymer concrete was used for the turning node, apron and taxiway pavements using a slip form paving machine. It was found to be well suited for this construction method due to its high flexural tensile strength, low shrinkage and workability characteristics.

And thanks to its smooth result, geopolymer concrete can also be cast into bespoke lifestyle applications - plant pots, long benches, outdoor tables, etc.

Talk with us

We wanted to create a product that was not just reducing carbon emissions but actually becoming carbon-negative while also outperforming traditional concrete in every way, and we did just that with EcoCrete. ⁠

We are here to disrupt the concrete industry & show the world that geopolymer concrete is the future of sustainable concrete.

If you have a project that you want us to look at, maybe even have our R&D lab put together something special for you, let us know, we would love to hear from you!