Researchers at MIT have found a way to strengthen concrete using plastic bottles and thus significantly reduce its damage to the environment
By Alina Fishman, Angle, Science and Environment News Agency
Plastic and concrete are two materials without which it is doubtful whether the modern world would exist as we know it today. Both are also a source of greenhouse gas emissions during their manufacturing process, making both very unfriendly to the environment. However, this may all be about to change: in the framework study Recently conducted by students from the Massachusetts Institute of Technology (MIT), a method was developed to combine these two materials together, to create a more environmentally friendly product. It turns out that by replacing small amounts of concrete with recycled plastic, the price the concrete industry charges the environment will decrease.
Concrete is the second most common consumer product in the world after water. The ever-increasing use of concrete has allowed the tremendous growth in the construction industry in recent decades, but it also brings Various safety and health issues, as well as a lot of pollution caused in its production process, which is responsible for no less than 5 percent of the total carbon dioxide emissions caused by man.
According to Hila Binish, CEO of the Israeli Green Building Council, "Concrete is indeed one of the most common raw materials for construction in the world and in Israel." However, she points out that "besides its many advantages in the construction process itself due to its strength and durability, concrete has many environmental effects in the generation of gas emissions greenhouse and damage to the natural environment through quarrying and more."
"It is important that the industry looks at the material at the level of a life cycle analysis," she adds, "that is, can its production be made less harmful? How does the concrete serve the structure, does it help with insulation (thermal and acoustic), does it not prevent a variety of uses in the building? And finally - The end of its life - when the building is destroyed, what do we do with the concrete waste? The answers to these questions are the ones that change the attitude to concrete."
Now, a group of students from MIT has found a solution that could reduce the environmental impact of concrete production. The group has developed a new method for producing industrial concrete that is stronger and more environmentally friendly, with the secret ingredient in environmentally friendly concrete surprisingly being a material that is not environmentally friendly at all - Plastic.
The new method developed at MIT allows for the creation of concrete that is up to 15 percent stronger than normal concrete, and its products can be used in the construction of houses, buildings and other infrastructure such as roads and sidewalks.
So far the research team has been able to determine that replacing 1.5 percent of concrete with recycled plastic that has been properly treated improves the strength of the mixture. The researchers noted that although this does not sound like much, it is enough to have a significant impact if it is implemented on a global scale.
Bricks reinforced with plastic
The plastic incorporated into the new concrete mix comes from used drink bottles, which were crushed into fine flakes, then exposed to gamma radiation in small amounts. Then they were crushed into a fine powder, mixed with coal ash and micro-silica particles were then added to the concrete mix to strengthen it.
The researchers discovered that exposing the plastic to measured amounts of gamma radiation caused a change in the crystalline structure of the material, which made the plastic stronger, stiffer and more durable. Therefore, adding the gamma irradiated plastic to the concrete mix created a more compacted mix, which contributed to it being stronger.
The researchers observed that the higher the dose intensity of the gamma radiation, the stronger the concrete mixture increased. However, the researchers claim that more studies are needed to find the right ratio of the mixture to get the most effective results. It is important to note that exposing the plastic to gamma radiation does not make it radioactive, this is because irradiating it with gamma radiation does not leave traces of radiation in the final product. However, the coal ash added to the mixture - which is a product of burning coal in power plants - is an environmental pollutant containing heavy metals as well as several radioactive elements. Although its use in concrete is common in the world and in Israel and is considered safe, but the best solution for its treatment is to prevent its formation in the first place by stopping the use of coal in power plants and switching to the use of natural gas and renewable energies.
Most of the plastic used in this process often ends its life in landfills or landfills, thus polluting the soil, the sea and other water sources. Although there are methods that allow recycling of plastic, only a small amount of the plastic waste is actually recycled, and it is often in the processes that contribute to carbon emissions into the atmosphere. Hence, the newly developed method may prevent millions of plastic bottles from ending their lives in landfills.
Binish also supports the idea of using plastic to produce concrete. "The infrastructure for collecting the bottles already exists, and using them as a component in the building is a good idea that should be examined in all aspects," she says. However, she adds a caveat, warning that "it must be made sure that the plastic actually serves the structure and does not cause other constructive or health challenges that are currently unknown."
Building a greener world
Like the group at MIT, a company ByFusion The American also researched ways to create more environmentally friendly concrete, and found that the solution was the use of plastic. The company claims that the production of plastic bricks for the construction industry reduces carbon emissions by 95% percent compared to normal concrete production. Since the plastic from which the bricks are made, similar to Lego bricks, is actually plastic that is thrown in the trash, the company hopes that by using plastic to create bricks it will be possible to reduce the scope of The plastic pollution.
And what is the situation in Israel? According to Binish, since the beginning of the establishment of the State of Israel, concrete has been used as one of the main construction materials. "There are other technologies that rely on steel, but still in most buildings in Israel, concrete is a component that is the main construction material," she adds.
Binish also points out that "in Israel, where there are 2 million housing units, and by 2030 another million will join - the massive use of concrete is probably inevitable, but we must make sure that it is as environmental and responsible as possible. The Israeli Green Building Council encourages alternatives, new methods, new materials and any An innovative idea that can optimize the construction industry in terms of material use and reduce environmental damage."
For this purpose, the Israeli Green Building Council was established Product catalog for more environmentally friendly construction. "This is an up-to-date materials library, where products of environmental value can be accessed free of charge. We maintain a constant dialogue with manufacturers and importers with the aim of increasing the supply, and on the other hand with architects and entrepreneurs with the aim of increasing the demand," Binish concludes.
