What is Light Transmitting Concrete?
Light Transmitting Concrete (LitraCon) is a special type of pre-cast concrete with the light transmissive property. Litracon consists of optical elements like optical fibers. It is based on the principle of “Nano-Optics”. It is translucent in presence of sunlight, has sheathing property, can resist compressive force, and appealing in appearance.
LitraCon is one of the prominent examples of advanced technology. Light transmitting concrete was mentioned in 1935 in Canadian Patent for the first time but Hungarian Architect is credited for the invention of LitraCon in 2001.
LitraCon is basically 96% of fine concrete and 4% of optical fiber by volume. Here concrete comprises of ordinary Portland cement. Sand passing down from sieve no 16 (1.18mm) is preferred.
Sieve designation is on basis of ASTM (American Society for Testing Materials). Water used in the mixture it should be drinkable. The proportion of the concrete can be altered so per the strength requirement needed.
Optical fiber is a medium to transmit the information as light pulses. It is a flexible strand made up of silica and has a diameter just slightly more than hair. It is considered an effective way of transmitting light without minimal loss of energy or no loss at all.
Optical fiber works on the principle of total internal reflection which states when a ray of light is passed from a denser medium to a rarer medium with the angle of incidence greater than the critical angle then it is reflected back to the original medium.
In gist, LitraCon is general concrete with an optical element added to it to alter its some of the property. Therefore, the casting process is more or less similar.
How to make light Transmitting concrete?
While making Light Transmitting Concrete. Optical fibers are placed making layers. The size of the optical fibers used may vary from 2mm to 2 microns. About 2-5 mm gap is left to fill it with fine concrete. Instead, fibers can also be woven in the form of mesh.
Fibers in the concrete act as slits on the walls of concrete to pass light through it. The main thing one should consider while making these types of concrete is, fiber strands must stretch along the length of the block for transmission of light. But it is allowed to bend as numbers of total internal reflection occur till light reaches another end of the light pipe.
These blocks are casted in the mold and cut in the size after it has been set.
LitraCon does not compromise in compressive strength compared to conventional concrete. Tests have shown that the compressive strength of LitraCon is more in comparison to Conventional Concrete up to 4-5% fiber content. The Flexural strength of the LitraCon is about 7.7 N/mm2
It possesses a high-density top surface and is light in weight. LitraCon can be used in Furniture, façade of the building, inner wall, pavements, and exterior walls.
Advantages of light-transmitting concrete
- LitraCon is Energy Saving, lesser light will be required during day time.
- LitraCon gives aesthetical value to the buildings.
- It can be used as a Structural Component.
- It is lighter than Conventional Concrete.
- There is no Maintenance cost for LitraCon.
- Illuminated Pavements can be built.
Disadvantages
- The cost is very high compared to Conventional Concrete.
- Skilled manpower is required for the manufacturing process.
Conclusion
Light transmitting concrete is a new kind of building material which is good for energy-saving concept and has rich architectural value. Also, it retains its strength in compression and bending. But the cost of these blocks is high. It should be made affordable by introducing new methods.
I hope this article remains helpful for you.
Happy Learning – Civil Concept
Contributed by,
Civil Engineer – Rukshana Shrestha
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