Light Transmitting Concrete: A Review

: Researchers have focused on the concept of sustainable developmentlooking forward to invent something new using non-conventional energy. Light transmitting concrete(LTC) or LiTraCon is an example of such phenomenal invention. This review evaluates the principles involved in it, manufacturing process, pros andcons and applications of LitraCon. It has been described how the Litracon developed from 90's and outstretch.Embedding optical fibres in the concrete reduces electricity demands. Hence, it can be used as an eco -friendly alternative to traditional concrete in the near future. The applications of LiTraCon illustrates its positive impact worldwide. LiTraCon can become an affordable alternative for both commercial and residential projects.


I. INTRODUCTION
The proliferating urbanization reveals the growth of concrete fathomlessly. There is no denying that concrete and the technology surrounding it has come a long way since its discovery and development.From the great pyramids at Giza to smart sensors for testing concrete properties,technology swiftly ameliorated. Although extension development creates hazards which includes high production,high consumption,high pollution and other ill-effects to environment.Among all these,power production by using a non-renewable resource is deep-rooted day by day.In 2021,about 4,116billion kilowatt hours of electricity were generated at utility-scale electricity generation facilities in the United States where 21.8% share of total is coal energy source. The world has proven reserves equivalentto 133.1times its annual consumption. This means it hasabout 133yearsof coal left(excluding unproven reserves).
To reduce the consumption of power of illumination, effective and efficient material usage introduced Light Transmitting concrete, making use of such elements which has high illuminative power.
"LiTraCon" is the abbreviated form of light transmitting concrete." Figure 1" Other names of this concrete are Light Emitting concrete and Translucent concrete.LiTraCon is a concrete based building material with light -transmissibility properties due to embedded light optical elements. We can use optical fibre made up of glass or plastic as optical elements.
" Fig.1" The purpose of saving electricity is satisfied in such type of concrete.Addition to it, architectural purpose for good aesthetical view of the building is also persuaded.Now it is increasingly used in fine architecture and cladding for interiors.

II. HISTORICAL DEVELOPMENT
Light transmitting concrete was first stated on October 27, 1922 a patent filed under United States Patent office Paul Liese of Tempeloh of Germany. His inventions were related to transparent building blocks or panels on August 4, 1925. Later in 1965, a method of constructing a translucent panel by James N. Lowe, London, England; was patented in United States Patent office. The invention relates to a method of makingtranslucent concrete panels which are used, for example, church windows. In the early 1990s, when major advancements in the field of polymer-based optical fibres led to its development, LiTraCon was introduced. " Figure 2" In 2001, first, the concept of Transparent concrete was put forward by Hungarian architect Aron Losonczi, and the first transparent concrete block was successfully casted by mixing a large amount of glass fibre into concrete in 2003. Joel s. and Sergio O.G. casteda transparent concrete material, which allow 80% light through and only 30% the weight of common concrete. The hope is that the new material willcreate new interior aspect. The working principle depends on total internal reflection. " Figure 5" When a ray of light travels from a denser to a rarer medium such that the angle of incidence is greater than the critical angle, the ray reflects back into the same medium this phenomena is called total internal reflection. In the optical fibre the rays undergo repeated total number of reflections until it emerges out the other end of the fibre, even if the fibre is bent.  Figure 6" An optical fibreis a flexible ,transparent fibre made by drawing glass (silica), or plastic to a diameter slightly thicker than that of a human hair. Optical fibres typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fibre to act as waveguide.

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International Journal of Creative Research Thoughts (IJCRT) www.ijcrt.org e264 " Figure 7" The four primary components of a fibre optical or cableare, a)Jacket,which protect the fragile fibre within. b) Buffer. c) Cladding, which surround the core with a lower refractive index. d) The core, which carries the light. No coarse aggregrate is used in this process. " Figure 10.a" For manufacturing LiTraCon several sequential methodologiesare to be taken, so that the productacquiredenough qualities. Following are the steps of manufacturing process: