Photoluminescence is a clean and renewable source of energy for environment. Photoluminescent concrete is a concrete for flooring with an architectural and photoluminescent effect, capable of absorbing solar energy and re-emitting it as a light source at night.
These concretes are, therefore, ideal for slow mobility, for example for the construction of sidewalks, pedestrian and bicycle paths, squares and parking lots in areas with poor lighting. The low heat of hydration concrete is designed for massive castings in order to counteract the risk of cracking, ensuring high durability.
Once cast, in fact, the concrete hardens thanks to the hydration reaction of the cement. This process produces a certain amount of heat. In the case of massive structures such as foundations, the heat produced is high and there is an increase in the risk of concrete cracking, with negative consequences on the structure itself.
This is why in such situations a cement is used which is capable of developing little heat and therefore avoids the risk of cracking of the concrete. It is a product that combines efficiency in production, quality and safety of the result with a reduced environmental impact, thanks to the low clinker content.
There is also photocatalytic concrete, which thanks to photocatalysis is able to accelerate the oxidation processes already existing in nature, favoring a more rapid decomposition of pollutants. Used in an urban environment it contributes to the improvement of air quality and to keep the surfaces of buildings clean.
Photocatalytic concrete, in fact, avoids the accumulation and adhesion of pollutants to the surface.
Plastic recycled into the concrete
The most important thing we need to do in the fight for a concrete economy with recycled plastic instead of sand? It could be an innovation in the fight against waste and for a more sustainable economy.
Our planet deserves great respect, and should not be treated as a mine of infinite resources, much less as a landfill. Recycling is important, just as it is important to understand how certain materials can be reused in a sustainable way.
Plastic, which is already found at the bottom of oceans or landfills, can be used, for example by mixing it with cement instead of sand. A new study published in the scientific journal Science Direct, plastic bottles could one day be used to build stronger and more flexible concrete structures, from sidewalks to road barriers to buildings and bridges.Concrete with plastic is an idea that in 2018 was nominated by the international scientific committee for the Atlas prize, in recognition of its potential positive social impact.
The final properties of concrete are also influenced by factors such as the type of plastic or the size and shape of the particles. USA has made quite good progress in this area, and the latest generation plastic concrete is about 15% stronger than traditional concrete.
These results were obtained by subjecting the plastic particles to delicate gamma radiation, which modifies their structure and the addition of fly ash. Authors of the study said that by replacing only 1/10 of sand in concrete with plastic could help save up to 820 million tons of this raw material per year.
Concrete is, after water, the second most used material in the world. Production of concrete generates about 4.5% of the world's human-induced carbon dioxide emissions. Replacing even a small portion of concrete with irradiated plastic could therefore help reduce carbon levels in the cement industry.
Before MIT, others had tried to introduce plastic into concrete mixes, but the plastic had done nothing but weaken it. So the MIT students tried to expose the plastic to small doses of gamma radiation, to change its crystalline structure.
The plastic has become stronger, stiffer and harder. And without residual radiation. Obviously it is not yet possible to use this compound in construction, but this is a first step towards a more sustainable future, even when it comes to concrete.