The history of concrete is a fundamental chapter in the history of architecture, since it is the most widely used building material in the world. Currently, we can say that it is the material that sustains our daily life.
From homes and hospitals to bridges and sidewalks. His omnipresence is undeniable. However, not everything is good and it is also known that its production releases tons of carbon dioxide and other greenhouse gases into the atmosphere each year.
However, in the field of construction there is not only concrete. That is why I bring 10 materials used in architecture that represent an alternative with less environmental impact.
But before developing the 10 examples, I want to talk about a very useful program when we talk about materials. This is the CES EduPack program, for my stranger until a few months ago, since architecture is still not used too much. This program presents a database that allows consulting and comparing different materials.
It specifies both physical characteristics, such as finishing or maintenance or even the price. Above all, I wanted to highlight the built-in Eco Audit tool that assesses the environmental impact of a given design taking into account both the production of the material and other factors that influence the construction, such as the transport of the same.
It is not convenient to lose sight of this interesting and useful program on which I will write very soon in another post.
Let’s now with the 10 alternatives to concrete:
Wood still has many advantages over other more industrial construction materials such as concrete or steel. On the one hand, trees absorb CO2 as they grow, and on the other, to process the material and turn it into construction products, much less intensive methods are required in terms of energy.
This type of wood stands out and although it may seem that bamboo is a material that is currently fashionable, the reality is that it is a fundamental element of the vernacular architecture of many places.
It is used both in enclosures and structural longitudinal element. It stands out its mixed use together with other materials, reinforcing walls and slabs, thus guaranteeing a secure stiffness and a good seismic resistance.
3. Straw bale
Bales of straw are used in housing constructions where little energy is used, so materials near the work are usually used as the earth itself that comes from the excavation for the foundation. Straw, earth and wood are worked by simple and artisan techniques that give rise to houses of optimal energy performance and good quality.
Both walls and roofs, this system has high thermal inertia which ensures thermal comfort for users with less use of alternative energies.
According to the chosen structure we can speak of self-supporting houses (where the bullets themselves bear the weight of the roof), carriers (where their use is restricted to the enclosure, arranged between pillars) or Canadian model (where the bullets are joined with cement mortar and they are arranged as columns forming something similar to pillars).
4. Rammed earth
Within the methods of construction with material products, the most immediate is to use what we have under our feet.
Building with rammed earth, means assembling a mixture of land poured into a structure to shape a wall. The earthwork can be done by hand or machine, and once it is complete, the auxiliary structures can be removed, obtaining earth walls from 46 cm to 61 cm thick.
It is due to the material and the great thickness of the walls that this solution provides great thermal inertia.
The walls can be finished with stucco or left uncovered but with an internal stabilizer with a little cement. When they are well built, the mud walls have great durability and resistance to bad weather, as with much of the Great Wall of China.
The word hempcrete is a mixture of the English words hemp (hemp) and concrete (concrete). And the truth is that it is exactly that, a concrete made with hemp fibers. Although in reality it is not a concrete as such, by not including coarse aggregate, so it would be rather a conglomerate of fibers and portland cement or hydraulic lime.
Hemp is a good enough insulator, so the thermal resistivity of this conglomerate should not be too much to envy to the values of the most common insulators such as rock wool or glass wool.
The HempCrete is also a relatively heavy material (300kg / m3) which gives it thermal inertia, something that we must not forget to build with the standards of bioclimatic architecture.
Although it is a conglomerate formed from cement, this material may not seem worthy of being included in this list, it has a property that clears all doubts. The hempcrete is a negative carbon material.
This means that during its production it is possible to destroy more carbon dioxide than is generated. This is due to the fact that hemp is one of the plants that more CO2 is able to absorb during its cultivation, which comes to compensate the one that is generated during the production, distribution, commissioning and recycling of the hempcrete.
The following two examples are also conglomerates, where the aggregates have been partially or totally replaced by natural or recycled elements.
It is an eco-concrete, bioconcrete, or material composed of ceramic matrix (waste chip cement from the wood industry, lowering the costs of raw material), for sustainable design in architecture, whose density is 47% lower than conventional concrete.
It presents a modular dry joint system design, which accelerates construction times.
With this type of materials, it is sought to obtain a strong social impact on the housing demand of the sectors of scarce economic resources that face places like Latin America.
Although there are concretes composed of certain fly ash as an addition to vary its conventional characteristics, in this case it is the exclusive use of ash as a substitute for cement.
The cenocell is a resistant concrete, lighter, more insulating and sustainable than the conventional, based on the reuse of the waste generated by the combustion of coal.
This material is very different from concrete in reality, as is the case with HempCrete, since in its preparation carbon dioxide and greenhouse gases are not generated, besides not using any aggregate.
In this list could not miss a material that although most people would associate before the crafts that architecture, it is their research in our field that led Shigeru Ban to take the Pritzker Prize in 2014.
This renowned architect since the beginning of his career he has always been linked to the use of both cardboard and paper in general.
Currently, the Wikkelhouse project stands out, from the Fiction Factory studio in Amsterdam. The patented construction system consists of a total of 24 layers of virgin cardboard fiber obtained from Scandinavian trees, on a mold shaped like a house.
The different layers adhere to each other, creating a resistant and insulating structure.
The use of cork as insulation in construction is common but more and more examples are betting on this material as a coating.
It is a material that has been used throughout history for various uses, from the Egyptian era to today, but it is true that in recent years has reappeared with more force.
I say reappeared because maybe for a while not too far the plastics dominated many uses, whereas now that we are much more aware of the environment it seems that the natural materials are reused as they may have never stopped being used.
The cork has great insulating properties to withstand large changes in temperature. This, together with its lightness, has always been present in the aerospace industry. It is also a good acoustic insulation, waterproof, resistant, inert, with friction and grip power.
Finally, the mycelium is a futuristic building material that is actually totally natural, whose structure is comprised by the roots of fungi and mushrooms.
The mycelium can grow around a composite of other natural materials, such as earth or straw, in molds of different shapes.
Finally the blocks are air dried to create light and strong bricks or other shapes.