After water, concrete is the most used construction material. However, concrete has a huge ecological footprint in the form of greenhouse emissions and natural resource exploitations. Therefore, the construction industry is in search of concrete alternatives, which are cheap, viable, and environmentally friendly. In this blog post, I will discuss 13 cheap concrete alternatives.
Environmental Impact of Concrete
The global concrete market is worth around $237 billion. Concrete production has a significant ecological impact.
For instance, the global carbon emissions of the cement industry stand at a whopping amount of 2.8 billion tonnes annually.
In equivalent terms, if the cement industry were a country, it would be the third largest greenhouse gas emitter.
Concrete, when all its stages of production are taken into account has around a 4-8% share in global carbon emissions.
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Along with greenhouse gas emissions, concrete is a massive natural resource exploiter. For example, concrete production consumes around a 10th of the world’s industrial water use.
Moreover, concrete also adds to the heat-island effect by absorbing solar energy and trapping gases from car exhausts.
All these environmental downsides have been shadowed by the benefits of concrete. But environmental responsibility is equally important, therefore, humanity is in search of alternatives that reduce ecological footprint while also retaining properties of the regular concrete.
Having said that let’s explore some of the major cheap concrete alternatives.
13+ Cheap Concrete Alternatives
Different concrete alternatives have been proposed. These alternatives offer similar properties as concrete such as durability, strength, longevity, and workability in addition to being environmentally friendly.
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1. Belite Rich Cement
Four major components of cement include Tricalcium Silicate (C3S), Dicalcium Silicate (C2S), Tricalcium Aluminate (C3A), and Tetracalcium Aluminoferrite (C44AF).
The first two components i.e., Alite (C3S) and Belite (C2S) make up 90% of cement. Currently, cement is produced using 55-65% Alite and 25-35% Belite.
In the production of Alite, an enormous amount of energy is required. It is produced at 1400 degrees compared to Belite which can be produced at 800-1000 degrees Celsius.
Cement can be produced cheaper by reducing the energy requirement in cement production. This can be achieved by reducing the amount of Alite and increasing the quantity of Belite. The resulting material is belite-rich Portland cement (BPC).
It is eco-friendly since it produces low carbon emissions. Moreover, BPC offers high long-term strength.
BPC was used in the construction of the Hoover Dam in the USA in the 1930s.
Pros:
- Produces less heat
- Lower water demand
- Higher resistance to corrosion
- Higher mortar flow ware
- Better curing at high temperature
Cons:
- Longer setting time due to the slower reaction rate of Belite
2. Fly ash / Ashcrete
Fly ash is a green alternative to the use of cement in concrete. It is a fine powder obtained as a byproduct of burning pulverized coal in thermal power plants. Fly ash is a pozzolan containing aluminous and siliceous material.
Fly ash has many similar properties to cement both physically and chemically. To improve the strength fly ash is mixed with lime and water.
Fly ash can be used in concrete to reduce the energy demand of cement plants. Fly ash offers good performance in terms of the strength and workability of concrete.
Pros:
- Better use of coal waste
- Reduce carbon emissions
- Replace up to 25% of cement
- Reduced bleeding and shrinkage
- Increased concrete strength
- Higher resistance to alkali-silica reactivity
Cons:
- Limited scalability
- Slower strength gain
- Seasonal limitations
3. Ground Granulated Blast Furnace Slag (GGBFS)
Ground Granulated Blast Furnace Slag or short GGBFS has been proposed as an alternative to regular concrete. It is a cementitious material that is obtained as a byproduct from the blast furnace used to make iron.
Although, GGBFS is relatively a non-traditional concrete alternative only a handful of projects have used this material, such as Sydney Harbor Tunnel mix designs, where a blend in 65:35 ratios of GGBFS to Portland cement is used.
Blast furnace slag may replace 65-80% cement. The produced concrete releases less heat and improves the overall durability of concrete.
Pros:
- Release less heat
- Improves the durability of the concrete
- Reduce cement use
- Eco-friendly alternative
- Cost-effective
Cons:
- Scalability problems
4. Ferrock
Ferrock being carbon-negative is one of the most attractive concrete alternatives. The material is composed of waste steel dust and ground silica glass, which can be sourced from ferrous rock.
In addition to being environmentally friendly, the construction material is around 5 times stronger than regular Portland cement. Moreover, the material sets faster than regular concrete, making it ideal for jobs where speed is necessary.
However, there is one downside of using Ferrock which is low accessibility. The material is not available everywhere. Therefore, it is only suitable for areas, where it is available.
Pros:
- Stronger than concrete
- Carbon neutrality
- High resistance against saltwater
- Sustainable
Cons:
- Unsuitable for large-scale construction
- Limited supply
5. Grasscrete
Although, grasscrete is not a type of concrete but more of a method of laying concrete. Grasscrete is an efficient method of reducing concrete use. It is suitable for outside spaces such as sideways, concrete flooring, driveways, and walkways.
The concrete is laid in such a way that there are open patterns that allow plants and grass to grow.
In addition to reducing concrete consumption, grasscrete is also beneficial for drainage, stormwater absorption, and maintaining clean and fresh air.
Pros:
- Attractive aesthetic appeal
- Reduce concrete use
- Improves water absorption
- Improves drainage
Cons:
- Doesn’t completely eliminate concrete use
6. Wood
Proposing wood as a concrete alternative doesn’t mean promoting deforestation. The source of wood should be properly accessed.
Additionally, wood is affordable and easy to transport. Wood offers pleasing aesthetics.
The wood used in the construction should be obtained from managed forests that are renewable and have no harmful impact on biodiversity.
Pros:
- Cost-effective
- Reduce carbon emissions (including carbon sequestered in the material itself)
- Lightweight
- Faster construction with lower labor cost
- Better seismic performance
- Appealing aesthetics
- Good insulation
Cons:
- Vulnerable to fire
- Termite attack
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7. Bamboo
Bamboo has long been used as an excellent construction material due to its high tensile strength, renewable nature, lightweight and easy availability.
It can be used as an alternative to concrete and rebar. Moreover, Bamboo is an ideal choice for remote areas with low accessibility, post-disaster reconstruction, and under-developed areas.
For small buildings and shelters, bamboo completely eliminates the use of concrete.
The best thing about Bamboo is that it is a locally sourced material that reduces the need to import expensive materials.
Pros:
- A reliable carbon-thermal energy solution
- A promising alternative for developing countries
- Lightweight
- Faster construction
- Cost-effective
Cons:
- Area-specific
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8. Mycelium
Mycelium is a root-like fiber from fungi, which can grow around organic material such as straw. When the fungi are dried and processed, they can be turned into building materials of various shapes or forms.
Bricks made up of mycelium are lighter and more durable. Moreover, they have high resistance to fire, water and mold.
The current application of this material is limited to small-scale building projects. However, in the future, the material can be used for bigger construction projects as well.
Pros:
- Eco-friendly
- Cost-effective
- Lighter
- Durable
- Capable of self-healing
- Fire, water, and mold resistance
- Can be shaped into different forms and designs
Cons:
- Limited to small-scale construction projects
- Not strong as concrete
- May take a while to grow
9. Gravel
Proposing a component of concrete as an alternative to the concrete itself can be confusing. But gravel can be used as an alternative to concrete for several applications, most notably for driveways, walkways, and other outdoor settings.
Gravel is a cost-effective, durable, and versatile construction material. It is a great option if you are looking for a concrete alternative for your outdoor setting.
Pros:
- Eco-friendly option
- Easy to maintain
- Cost-effective
- Low-cost to install
- Comes in different sizes, colors, and shapes (pea gravel, quarry processed, crushed stones, etc.)
- Unique look
Cons:
- May develop holes and gaps
- Can get dirty
- Rocks can go missing or sink into the ground
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10. Steel
You might not expect steel to be on this list. But steel is an eco-friendly option than concrete due to its high-tensile strength and reusability. Owing to its high strength, a Steel structure offers superior seismic performance.
Steel is a versatile construction material that can be used in almost every type of construction be that a small project or a mega project. Steel goes everywhere. The good thing about steel is its availability. Moreover, it can be used multiple times. All these characteristics make steel a good substitute for concrete.
Pros:
- Eco-friendlier option
- High-tensile strength
- Better seismic performance
- Versatile application
Cons:
- High cost
11. Timbercrete
Timbercrete is made from a mixture of cement and recycled sawdust. This construction material is lighter than regular concrete.
Timbercrete offers many benefits such as reducing the consumption of cement, reducing greenhouse gas emissions, and weather resistance to mention a few.
Though Timbercrete offers less strength than regular concrete, nevertheless, it is an alternative that can help reduce cement use and greenhouse gas emissions.
Pros:
- Lightweight (2.5times lighter than concrete)
- Reduce cement consumption
- Reduce greenhouse emissions by trapping carbon dioxide
- Weather resistance
- Thermal insulation
- Bullet-proof
- Locally available
Cons:
- Reduced strength
12. Ramped Earth
Ramped Earth is the application of natural raw materials to construct floors, foundations, and walls. Ramped Earth is not a novel construction material rather its application can be traced as back as 8000 BC.
Ramped earth is produced by compacting a damp mix of sub-soil that contains sand, gravel, clay, and stabilizer (lime or maybe animal blood) into a formwork.
In the past, compaction of ramped earth is done through manual tamping. However, nowadays tamping is done using modern pneumatically powered tampers, which increase work speed and efficiency.
The strength increases as the material cures. The compressive strength is somewhere between 5 and 20 MPa. The strength of ramped earth depends on soil type, compaction level, moisture content, stabilizer, and particle size distribution.
Pros:
- Good regulator of heat
- Attractive texture and color
- Fireproof
- Sustainable and environmentally friendly/ Green alternative
- Easily available
Cons:
- Need an overhang portion to protect it from rain and erosion
- Poor insulation in a colder climate
- Labor intensive
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13. Greencrete
Greencrete is an umbrella term that includes different concrete alternatives which are eco-friendly and sustainable.
It is produced from waste and recycled material such as rice husk, saw dust ash, plastic, coconut husk, shell, molasses waste, fly ash, silica fumes, rubber waste, recycled coarse aggregate, bio-waste, cow dung ash, and polystyrene. This material can be easily collected from landfill sites.
Although greencrete isn’t a widely used construction material, it is an alternative that can help reduce our reliance on concrete.
The production and implementation of green concrete are still in their infancy stage. The research is ongoing.
Pros:
- Minimize CO2 emissions
- Recycling of waste
- Keep environment clean
- Check on land pollution
- Reduced burden on natural resources
Cons:
- Not a viable alternative
- Limited scalability
Conclusion
Although, the above-mentioned construction materials are viable and cheap. But there are a few barriers that impede the mass adoption of these construction materials such as low availability of material and low scalability.
Therefore, additional research to address these issues is recommended. So, that these materials can be used on a large scale, thus reducing the reliance on regular concrete.
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