Mostly developed countries nowadays depends on vast networks of roads for fast transportation between its cities. The US road network exceeds 6.58 million kilometres in length, which makes it the biggest and largest road network in the world 1. A huge amount of energy is required to light such a vast network of roads in night. Very Soon, other countries like China, Russia, and India will require such amount of energy in future. As the looming shadow of climate change pressures society to move toward renewable energy, finding a low-carbon and energy-efficient method to light highways could significantly reduce energy consumption 2. Glow in dark concrete is a new type of multifunctioning concrete that possess the quality of storing solar energy or artificial light and emitting it as a visible light in darkness. . It is also called self-luminous or Glow in the dark concrete (GITD) concrete which is powered by the sun or other lamps without electricity consumed 16. Glow in dark concrete is considered as an Eco -friendly concrete because of less carbon dioxide is discharged into the atmosphere and less light pollution is produced in our living environment. Once the light source is no longer present, they begin releasing their stored energy by glimmering. Glow in dark concrete can glow in dark without any complex support devices and does not require frequent maintenance 3. Glow in dark concrete not only trap solar energy from sun but also light from lamps therefore, it can be applied to building decoration both indoors and outdoors. Instead of using electricity, this concrete is totally sustainable and low-carbon building material and development of green buildings 4. Glow in dark concrete has excellent performance of long duration of glowing in dark and long life span without consuming any electricity, which is considered as a promising smart and sustainable low-carbon concrete 11. Due to the gentle light emitted by this concrete and less light pollution generated, both human beings and wild creatures are less disturbed at night and we are able to create more liable and eco-friendly environment. As a result the application of this concrete is mainly in three aspects: Building environment decoration, Road and lanes lightening and highway signs and safety 3, 5, 17 .This concrete enjoys a broad prospect in building decoration/road lightening and has been used in practical engineering projects in Sichuan province of western china 6,18.
Glow in dark concrete just has a short history and Mexican scientist Rubio is one of the earliest researcher. “Nine years ago, when I started the project, I realised there was nothing similar worldwide, and so I started to work on it,” Rubio said. “The main issue was that cement is an opaque body that doesn’t allow the pass of light to its interior”. His work mainly concentrated on improving the micro-structure of the cement to avoid crystals and make it completely gel, which helped it to absorb solar energy and return it to the environment as visible light when excitation period ended 12. In order to make conventional concrete absorb light and glow in dark, the easy way is to take advantage of luminous aggregates and phosphor powders. At present, there are three main approaches to develop glow in dark concrete. 1. By mixing luminous aggregates or phosphor powders into concrete 2. Modifying microstructure of the concrete 3. By covering the concrete surface with a luminous coat 16. A long afterglow phosphor powder was invented by heating rare earth metals. This long afterglow phosphor powder may be mixed in inks or paints to be used as high intensity luminous paints. It can also be used as pavement marks, toys and other sport goods 9, 13. Wang from Shenyang Jinzhou University developed a new type of Glow in dark concrete by mixing phosphor powders. She tested the luminous performance and gave out an optimum mixing dosage of phosphor powders. The CaO: xDy3+, yNa+ phosphors, were incorporated by high solid state method, and the starting materials are CaCO3Na2CO3 and Dy2O 14, 15. Researchers in Purdue University developed a Soy-based luminous sealant coating concrete recently and tested its performance. Persistent phosphors can emit light for a very long time from seconds to many hours after the excitation period gets ended. Materials showing persistence luminance are referred as “Persistent phosphors” .Persistent phosphors draws attention of people from hundreds of years 10, 19-21. A brightest phosphor material came to existence when Matsuzawa et al. 5 discovered a bright and long-lasting luminescence compound SrAl2O4: Eu, Dy. By co-doping the green-emitting phosphor SrAl2O4:Eu2+ which were able to emit light for hours when excitation period is ended. The real underwater experiment was carried out in the sea at Marine Park in Malaysia. First, the artificial blocks were surface coated with the new phosphor SrAl2O4:Eu2+, Dy3+ which would be excited by sunlight were installed in regions of the sea floor with various relief. Strong and bright blue-green luminescence was been observed 7.
A review of the literature study shows that Glow in dark concrete is rather rare and unsystematic, so more detailed research work is required. It is apparent that the lightening part (phosphor powder) controls the performance of this concrete. Nevertheless, it might shows a negative effect on the other desired properties.Aditionally, this chemical has a greater environmental concern in developing a smart , green and multifunctional construction material. The underlying mechanism for controlling the performance of such material is yet to be investigated adequately 5. Our projects aims to investigate the application of SrAl2O4: Eu Dy-Based persistent luminescence phosphors in Glow in dark mortar. After developing such samples, it is necessary to find out its mechanical properties like compressive strength and flexure strength. Mixing SrAl2O4: Eu Dy-Based persistent luminescence phosphors will either decrease or increase its compressive and flexure strength .Concrete structures are subjected to harsh environments that affect their long-term serviceability and durability. Glow in dark concrete is mostly used in construction of Roads/lanes lightening and highway signs and safety. Such concrete is open in exposure to different types of environments and different types of soil and water. Based on the extensive literature survey, it is ascertained that the effect of Glow in dark concrete on the other desired properties, such as corrosion resistance, sulphate attack, acid attack, freeze-and-thaw durability, is yet to be investigated adequately.
1 https://www.roadtraffic-technology.com/features/featurethe-worlds-biggest-road-networks-41592352 https://www.nature.com/scitable/blog/eyes-on
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