The construction of foundations for buildings is one of the oldest arts of human activity. Early inhabitants of the Neolithic age built their houses on long wooden piles driven into the soft bottoms of shallow lakes, high above dangerous animals and hostile neighbours.
Subsequently, the Babylonians and Egyptians used and refined foundations as part of their building structures. And over the intervening centuries the designs, techniques and materials used for foundations have continued to evolve.
What are foundations?
Foundations are said to be the first step in the construction of any structure. They are defined as the lowest part of any structure, whether this be an inhabitable property such as a residential unit or office or non-inhabitable such as a monument, bus-shelter or car-parking structure.
What is the purpose of foundations?
Essentially, foundations provide the structure’s stability from the ground by distributing the weight of the structure over a large area in order to avoid overloading the underlying earth (soil or rocks or other).
In summary, foundations:
- provide overall lateral stability to a structure;
- provide a level surface for the construction of any sub-structure;
- distribute loads evenly;
- reduce load intensity to be within the safe bearing capacity of the soil or rock strata;
- prevent and resist soil movement;
- address scouring and undermining issues
What are the most popular materials for foundations?
Currently, concrete is the most popular foundation material amongst all other building foundation materials because it is hard, durable and strong in compression. It is not affected by moisture and can be made nearly watertight for basement walls.
One major other plus is that It can easily be cast in any shape and adapted to all sorts of foundation requirements. It is the second most widely used artificial substance in the world.
However, one major disadvantage of concrete is the relatively high cost of the cement required to make the concrete.
There are a number of other materials in use or being further refined and developed for use in foundations and these include HempCrete, Ferrock and even bamboo, some of which have positive attributes similar to concrete.
What is the estimated CO2 contribution of concrete foundations?
It’s relatively well-known that the construction industry is a major contributor to global warming. In fact, the industry is said to account for 38% of all CO2 emissions.
Despite its advantages, concrete is a major contributor to CO2 emissions, being responsible for approximately 8% of the carbon dioxide being emitted into the atmosphere, comparable to that of the agricultural industry at 9% and much higher than the aviation industry’s 2.5%.
The production of Portland cement which is a necessary part of the concrete manufacturing process emits an average of 927 kg (2044 lb) of CO2 for every 1000 kg (2205 lb) of concrete produced.
The remaining CO2 emitted is a result of burning fossil fuels such as coal and natural gas to heat the raw materials in the kiln.
Indeed, it said that carbon dioxide emissions from the production of concrete are so high that if concrete were a country, it would be the third-largest emitter of CO2 behind China and the United States.
So, what are some of the alternatives to concrete?
Clearly, if the world’s countries are serious about mitigating the effects of global warming and reducing CO2 emissions, unless a way can be found to dramatically reduce the amount of emissions from concrete, alternatives will need to be pursued.
Of the alternatives to concrete mentioned above:
Ferrock is a new material being researched that uses recycled materials including steel dust from the steel industry to create a concrete-like building material.
It is said to be even stronger than concrete, by up to five times. Furthermore, Ferrock is a quite unique material which actually absorbs and traps carbon dioxide as part of its drying and hardening process. This makes it not only less CO2 intensive than traditional concrete, but actually carbon neutral.
Ferrock can withstand more compression before breaking and is far more flexible than concrete, thereby resisting earth movements caused by seismic activity or industrial processes. One of the unique properties of Ferrock is that it becomes even stronger in salt water environments, making it ideal for marine-based construction projects.
Ferrock also absorbs and binds CO2, resulting in a carbon-negative process that actually helps to trap greenhouse gases not emit them;
HempCrete is a concrete-like material created from the woody inner fibres of the hemp plant, a fast-growing, renewable resource. The fibres are bound with lime to create concrete-like shapes that are strong and lightweight. This can also dramatically reduce the energy used to transport the blocks.
At present, hempcrete can’t be used for a foundation or structure as it’s a material that needs to breathe. However, a number of companies have started making hempcrete bricks using a method that takes less time to cure. As a result, the blocks can be used for load-bearing walls;
Bamboo has been a locally-sourced building material in many of the regions of the world, especially Asia, for centuries. It is an ideal building material for modern buildings owing to its combination of tensile strength, lightweight and, maybe best of all, its fast-growing renewable nature.
Used for framing buildings and shelters, bamboo can replace expensive and heavy imported materials and provide an alternative to concrete and rebar construction, especially in difficult-to-reach areas, post-disaster rebuilding, and low-income areas with access to natural locally-sourced bamboo.
Closing thoughts
In view of the widely accepted concerns about CO2 emissions and global warming, it’s definitely time to re-think construction from the ground up.
What better place to start than by looking at foundations, the bedrock of all buildings! Looking at the materials used and the techniques involved can be the start.
The use of alternative materials for foundations is evolving rapidly. Indeed, changes within the production of such alternative materials are still occurring, for example in Hempcrete.
Current statutory regulations or limitations on use of alternative materials may no longer be applicable if, for example, Ferrock can be proven to be as reliable as concrete in foundations. It’s really a question of watching and waiting to see when, probably, not if alternatives to concrete become more widely used.
For more information about some of the alternative materials for foundations have a look at this link.
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