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IT'S NOT FOR SURE THAT SOMETHING THAT HAS A “ NATURAL NAME ” IS MORE ECO-FRIENDLY THAN A PRODUCT OBTAINED BY RECYCLING MATERIAL DERIVED FROM PETROLEUM.
I often find myself in difficulty when searching on the internet or even talking to those who are sensitive to issues of ecology and eco-sustainability. Being the term quite broad and used a lot, I often don't understand what others mean or I can't make myself understood. What is meant by eco-sustainability? Wikipedia helps us, but not so much since it uses somewhat complicated terms. The essence, however, is the following:
"It is eco-sustainable that leads man to act so that the consumption of resources is such that the next generation receives the same amount of resources that we have received from the previous generation."
In the world of architecture there is another term that is very similar and often used as a synonym for “environmentally friendly”. This term is used for objects (houses, clothes) or processes (such as processing of materials) that integrate into the environment, or that guarantee well-being with a reduced consumption of environmental resources. The concept of reduced consumption is also closely linked to the low level of pollution generated by the product / process.
If you happen to find out about the construction of a passive house, sooner or later some architects will ask you this question: “You do it for save money or respect for the environment? " The simplest answer should be "Both!" but the matter is more complicated. A passive house is a well insulated construction. As you can imagine there are thousands of insulating materials: polystyrene, wood, sheep's wool, cellulose wool, cork. The choice of these materials has exactly to do with the question posed by the architect above. For example, rock wool is often used for insulation. As the name suggests, it is a natural element and it is certainly more ecological than others. To obtain it, however, there is a costly process: the volcanic rock is melted at a temperature of 1500 degrees.
In this case it is said that rock wool "contains gray energy", in the sense that its production "costs" a lot in environmental terms. Does it make sense to talk about eco-compatibility in the case of stone wool? Has the consumption of environmental resources been respected as much as possible?
Another question, always linked to the insinuating question posed by the architect, concerns the reuse / recycling of materials, especially those related to oil. For example, a tire is a very distant product "Naturalness" (presumed?) Of rock wool. Many are produced and perhaps it is worth trying to make an "ecological" use rather than burying them in landfills. There are some techniques that allow tires to be recycled without generating waste or harmful fumes. For example, rubber tiles or acoustic insulators can be created often used in construction.
It would be a perfect world if only natural resources could be used, but this belief must always be confirmed by a careful analysis of the materials and how they are obtained. As we have seen from the comparison it's not for sure that something that has a "natural name" is more environmentally friendly than a product obtained from the recycling of material derived from petroleum.
EXPANDED POLYSTYRENE FOR ECO BUILDING
There house of the future will be ecological: this is the trend presented to Restructura, the exhibition on sustainable construction which was held in Turin from 26 to 29 November 2009. Walking among the stands, one could not help but notice one in particular bearing the wording "AIPE".
L'Aipe (Italian Polystyrene Association Espanso) is a non-profit association, whose purpose is the promotion and protection of the image of synthesized expanded polystyrene (EPS) and involves more than 90 companies belonging to various sectors, from the production of thermal insulation sheets to the production of building and packaging products, from companies producing the same raw material to companies that manufacture EPS processing equipment. AIPE also deals with the collection and recycling of expanded polystyrene waste and is part of EUMEPS - European Manufacturers of Expanded Polystyrene - which brings together the manufacturers of EPS.
Synthesized expanded polystyrene is indispensable for eco-sustainable construction.
It is a rigid, very light, composite material from almost 98% air. It is produced following the polymerization of styrene which is a monomer obtained from petroleum, also present in many foods such as strawberries, coffee, wheat, and meat. From polymerization yes they obtain polystyrene beads which, when in contact with a gas (the pentane, gaseous hydrocarbon) and with water vapor, swell reaching of dimensions up to 50 times greater than the initial ones and constituting al inside them a closed cell structure that holds the air and makes of it consequently an excellent insulator with low thermal conductivity. For these reasons, EPS appears to be one of the most used materials in construction, both for construction of new buildings and for the renovation of existing buildings.
It must be emphasized that the cost of the material, as well as that of installation, is among the lowest.
Added to this are management costs not high at all.
EPS becomes a sustainable material by contributing to energy savings due to its excellent insulating qualities and reduced CO2 emissions, as evidenced by the LCA (material life cycle) studies that take into account of production, transport, use and management and recycling. In this regard it must be said that i costs storage and transport are significantly reduced due to the low weight, that the material is non-toxic, does not contain chlorofluorocarbons (CFC) or hydrochlorofluorocarbons (HCFC), it is permeable to vapor thus allowing transpiration and avoiding the formation of mold, and at the same time it is impermeable to water. It is also, as already mentioned recycled.
As an insulator, it finds applications in roofs a pitches and flat roofs, as a coat in the vertical walls from the outside, in the vertical walls in cavities and from the inside, in floors, ceilings and foundations. And what more could you ask for from a material? It can only be added that, in addition to the energy insulation of the building, it also ensures its acoustic insulation, following a mechanical treatment of compression which increases its dynamic stiffness, and which is used in the so-called "floating floor", useful for absorbing the noise of the trampling. Italy
SUSTAINABLE STEEL BUILDINGS
In this particular historical moment in which society is moving towards sustainability, the construction sector plays a particularly important role in this context, not only for its contribution and from the point of view economic and social, but above all because of its impact on the quality of our life, on our comfort and our safety. In fact, the construction industry employs 5% -10% of workers in the world, and generates from 5% to 15% of Gross Domestic Product, while the built environment consumes about 40% of global energy, produces about 40% of CO2 emissions, uses 30% of the natural resources available on the planet, generates 30% of waste and uses 20% of water.
The global challenge of the future for the construction industry is, therefore, to respond effectively to the ever-growing demands, limiting its environmental impact thanks to the reorganization of its activities.
In construction, steel has always been used as one of the main materials chosen for the construction of buildings and is able to offer a wide range of solutions that can make buildings more and more efficient from an energy, economic and comfort.
We strongly believe in the value of steel for the construction of sustainable buildings and for this reason we are committed to spreading the advantages that our solutions can bring to our customers, buildings and clients.
High efficiency steel solutions
In assessing the sustainability of a building, the life cycle approach must be used, taking into account all stages of the life of the building, including the production of materials, transport to the construction site, the construction operation itself, the use of the building, demolition or dismantling and end of life.
Steel - the most recycled material in the world
Steel is 100% and endlessly recyclable, without any loss of quality. Once recovered, it is still 100% recyclable. The recycling rate is the percentage of materials that they are disposed of, recovered and reused. This rate is very high for steel but varies from product to product. In construction, for example, it reaches particularly high levels: 98% for beams, 65-70% for reinforcing bars.
For every ton of steel produced, the steel industry produces an advantage for future generations, who will not have to produce any.
Recycled steel represents 40% of the world's ferrous resource for the steel industry.
Saving of raw materials
The recycling rate of a product is a fundamental parameter for evaluating its sustainability.
In evaluating its performance through the LCI (Life Cycle Inventory) methodology, the high recycling rate of steel beams makes it possible to reduce the carbon footprint and more in general reduction of the environmental impact of 40%.
Over time, the steel industry has made enormous progress: production of waste, use of water and emissions into the air are continuously decreasing.
CO2 and energy
In Europe, carbon dioxide emissions and energy consumption per ton produced have halved over the past 30 years. In Canada, the industry has been shown to have reduced carbon dioxide emissions by 30% in 20 years.
Durable and lasting value
In in many applications where steel is used inside buildings or is not visible (for example because it is coated), the intrinsic properties of the material are sufficient to make it resistant to corrosion. For applications where longevity could be impaired by corrosion, a wide range of products or solutions have developed which considerably increase the life of the material and make steel the most suitable material for long life applications:
- Stainless steel, which offers a high level of corrosion resistance thanks to its intrinsic properties
- Metallic coated steel, such as galvanized steel
- Pre-painted steel
Ecological products and coatings
Steel is an "inert" material to the environment: when it comes into contact with air or water, it does not emit or release substances that are harmful to the environment or to humans.
Ecological coatings for steel coils have been developed that reduce the environmental impact of both the product and its production process.
When exposed to high temperatures, organic coatings can release organic particles that pollute the air.
A high level of prefabrication
All steel products, from simple profiles to more complex facades, are produced outside the construction site and are delivered ready to be assembled.
The use of prefabs provides a number of benefits that help reduce risks in the construction phase:
- Quality control
- Ease of construction site management
- Speed assembly, reduction of delivery times
- Greater safety
- Ease of disposal
The advantages of the dry steel construction system
The techniques of construction with steel allow to reduce the environmental impact and inconvenience to the neighborhood.
The use of water, the production of waste, the emission of dust, traffic and noise are in fact considerably lower than those of a traditional construction site. The management of the construction site thus becomes easier.
THE MAIN ADVANTAGES OF USING CONCRETE
Concrete is produced by mixing coarse aggregates (gravel or crushed rocks), fine aggregates (sand), water, cement and products derived from other industrial processes (slag, fly ash and silica fumes). Aggregates are generally available locally in large quantities and can be replaced by using aggregates made from recycled concrete.
In the production of concrete, cement, aggregates and other suitable materials are mixed with water.
When mixing the concrete, additives (chemicals) are also added in small quantities for modify the properties of the concrete both in the plastic state and in that hardened.
Cement acts as a hydraulic binder, hardens when water is added and binds the other constituents together concrete. The main component of the cement is the clinker that comes produced from raw materials such as limestone and clay, ground finely, mixed and introduced into a rotating oven which heats them up to a temperature of about 1,450 ° C. Gypsum and other additional materials are then added to the clinker (such as slag, oil ash, natural pozzolan, limestone, etc.) and ground until everything is a fine powder: The cement.
The production of cement generates emissions of anhydride carbon dioxide through two different sources: combustion (40%) and calcination (60%).
The CO2 emissions generated by combustion depend on the fuel used. CO 2 emissions from calcination are generated when the raw materials, mainly limestone and clay, are heated and the CO 2 is freed from the decomposition of limestone.
Concrete is one of the building materials that when properly designed, produced and used can actively contribute to achieving more sustainable development, precisely thanks to the aspects described below.
Production of cement using fuels and alternative raw materials
In the production of cement it is possible to reduce the use of non-renewable resources (fuels and raw materials) thanks to the fact that in the production of clinker it is possible to use the co-processing of alternative fuels and alternative raw materials. This allows to recover energy and material from waste. Furthermore, in the grinding of cement, the use of clinker can be replaced by materials alternatives such as slag, fly ash, silica fumes, limestone, etc.
Use of alternative materials in the production of concrete
The partial replacement of some materials in the production of concrete can improve the sustainability of the material such as:
• The use of recycled concrete mixed together with natural aggregates.
• The use of alternative materials such as slag, fly ash together with concrete.
If these materials are not used in concrete, they can be used either as filler materials or considered as waste and sent to landfill.
Production of concrete
A correct assessment of the mix design of the blend can improve sustainability through:
• The type of strength of the material and the porosity, which they can be easily adapted to meet performance criteria prescribed.
• The optimization of the concrete mix design, basing it on the local availability of raw materials, so to minimize the need to transport large quantities of materials.
• The addition of additives that significantly affect the properties of the concrete resulting in the improvement of quality and performance correlated with various aspects of sustainability
• Improved fluidity thus reducing the emission of noise and energy required during installation.
• The optimization of the mix design, reducing energy incorporated and increasing the effectiveness of the cement components.
• The reduction of permeability by increasing the durability of the concrete.
• The reduction of damage related to environmental conditions such as corrosion induced by carbonation, that induced by chlorides in the marine environment and not, the attack of freeze-thaw cycles or the chemical one deriving from substances present in the soil or in the water.
• The improvement of the quality that leads to better finishing and a reduction of maintenance interventions.
Concrete as a building material
• It is a versatile material that can take on all kinds of shapes and geometries and is available in a rich variety of colors.
• IS a robust material, which is able to provide protection against all climatic conditions, earthquakes, fires, floods, explosions, etc.
• IS a durable material and the original service life of a concrete structure can easily be extended through the application of simple measures.
• IS a material with high thermal mass and actively contributes to maintaining good climatic conditions inside the buildings.
• IS a heavy material that has good soundproofing capabilities.
• IS a material that provides good protection against radioactive emissions produced by the presence of radon in the soil.
• IS a non-flammable inorganic material that does not rot and does not develop mold.
• IS the best construction material that can be used in infrastructure projects for subways, such as tunnels and stations.
• IS a material with a high albedo and its use in road pavements and roofs helps to reduce the
urban overheating present in large cities and especially in Italy
Demolition and recycling
• Concrete can be fully recycled within the construction industry after demolition.
• Recent studies show that, considering the entire life cycle, including the demolition and recycling phases, significant quantities of CO2 emitted during cement production are reabsorbed by the concrete.
This occurs if at the end of its useful life the concrete structure is demolished, crushed like rubble and deposited in the open air. In this way a large amount of porous surface comes into contact with the air and the recarbonation reaction can proceed quickly. They can be reabsorbed in this way, in a period between 2 and 3 years, from 15 to 35 kg CO 2 / m3 concrete.