Transparent Concrete

Abstract: Transparent concrete is a concrete based building material with light-Tran missive properties due to embedded light optical elements usually Optical fibres. Light is  conducted through the stone from one end to the other.  Therefore the fibres have to go through the whole object.  Transparent concrete is also known as the translucent  concrete and light transmitting concrete because of its  properties. It is used in fine architecture as a façade material  and for cladding of interior walls. In this paper, to integrate  the merits of concrete and optical fiber, for developing transparent concrete by arranging the high numerical aperture Plastic Optical Fibres (POF) or big diameter glass optical fiber into concrete. The main purpose is to use sunlight as a light source to reduce the power consumption of illumination and to use the optical fiber to sense the stress of structures and also use this concrete as an architectural purpose for good aesthetical view of the building.

I. INTRODUCTION

Just a few decades ago concrete was often  misunderstood, disliked and captured by its image fixed  due to the rapid urbanization of the1960s. But since that  time, concrete has made considerable progress, not only  in technical terms, but also in aesthetic terms. It is no  longer the heavy, cold and grey material of the past; it has  become beautiful and lively. By research and innovation,  newly developed concrete has been created which is more  resistant, lighter, white or colored, etc. Concrete has  learned to adapt to almost all new challenges that  appeared. In 2001, the concept of transparent concrete was first put forward by Hungarian architect  AronLosonzi, and the first transparent concrete block was successfully produced by mixing large amount of glass  fiber into concrete in 2003, named as LiTraCon. Joel S. and Sergio O.G. developed a transparent concrete  material, which can allow 80% light through and only  30% of weight of common concrete. It is worth mentioning that Italian Pavilion in Shanghai Expo 2010  shows a kind of transparent concrete developed by  mixing glass into concrete in 2010. While the transparent  concrete mainly focuses on transparency and its objective  of application pertains to green technology and artistic  finish. Therefore it is imperative to develop a new  functional material to satisfy the structure in terms of  safety monitoring (such as damage detection, fire warning), environmental protection and energy saving  and artistic modeling. Transparent or translucent concrete can be seen as a recent answer to the architects call for  more Transparent Architecture.

II. MATERIAL USED FOR TRANSPARENT CONCRETE

There are two basic materials used for making  transparent concrete, one is from construction field and  another from sensing field. First, concrete is one of the  most important civil engineering materials with the  advantages of rich raw materials, low cost and simple  production process and second the optical fiber has good  light guiding property which can be arrange to transmit  the light and the sun light transmit according to predesign road without light-heat, light-electrical or  photochemical process, and photo elastic effect which can  be used to study the stress distribution of structures.  Combining the advantages of the concrete and optical  fiber, developing a novel functional material called  transparent concrete has an important value in the  application of construction and sensing.

Types of optical fibre

There are three basic types of optical fibers:

[1] Multimode graded-index fiber

[2] Multimode step-index fiber

[3] Single-mode step-index fibers.

A multimode fiber can propagate hundreds of light modes  at one time while single-mode fibers only propagate one mode as shown below.

III. PRINCIPLE

Transparent concrete or translucent concrete is work  Based on “Nano-Optics”. Optical fibres passes as much  light when tiny slits are placed directly on top of each  other as when they are staggered. Principal can carry  because optical fibers in the concrete act like the slits and  carry the light across throughout the concrete.

IV. CONSTRUCTION

Transparent concrete is produced out of fine-grain concrete and translucent fabric which is layer cast in prefabricated mould. Because of relatively small amount of  fabric, solidity and consistency of transparent concrete  are the same as the high-strength concrete. Almost free energy loss light penetration through optic fibres makes it possible to see light, shadows and even colours through

concrete even by very thick walls. It can be produced as  prefabricated building blocks and panels. Due to the small size of the fibres, they blend into concrete becoming a component of the material like small pieces  of aggregate. In this manner, the result is not mixed  material like glass in concrete but a new material, which is homogeneous in its inner structure as well as on its main surfaces. The optical fibres lead light by points between the two sides of the blocks. Because of their  parallel position, the light-information on the brighter side of such a wall appears unchanged on the darker side. The most interesting form of this phenomenon is probably the sharp display of shadows on the opposing  side of the wall. Moreover, the colour of the light also remains the same.

V. MANUFACTURING PROCESS

The manufacturing process of transparent concrete is almost same as regular concrete. Only optical fibres are spread throughout the aggregate and cement mix. Small layers of the concrete are poured on top of each other and infused with the fibers and are then connected. Thousands of strands of optical fibers are cast into concrete to transmit light, either natural or artificial.Lighttransmitting concrete is produced by adding 4% to 5% optical fibers by volume into the concrete mixture. The concrete mixture is made from fine materials only it does not contain coarse aggregate. Thickness of the optical fibers can be varied between 2 µm and 2 mm to suit the particular requirements of light transmission.Automatic production processes use woven fibres fabric instead of single filaments. Fabric and concrete are alternately inserted into molds at intervals of approximately 2 mm to 5 mm.Smaller or thinner layers allow an increased amount of light to pass through the concrete. Following casting, the material is cut into panels or blocks of the specified thickness and the surface is then typically polished, resulting in finishes ranging from semi-gloss to high-gloss.

VI. APPLICATION

A. Illuminate Your Walls

Transparent Concrete can be used as building material  for interior and exterior walls. If sunshine illuminates the wall structure, then eastern or western placement is  recommended; the rays of the rising or setting sun will hit  the optical glass fibers in a lower angle and the intensity  of the light will be bigger. Besides the traditional  applications of a wall, the light transmitting concrete can  also be used as wall covering illuminated from the back.

B. Watch Your Pavement Shine at Sunset

This concrete can be used as flooring a passable  surface illuminated from below. During the day it looks  like typical concrete pavement but at sunset the paving  blocks begin to shine and in different colors.

C. Get Creative with Design

The building units are versatile and can be used in  many areas of design. Two successful designs using the  light transmitting concrete were a jewel and a concrete bench. You can also create a logo with colorful figures, inscriptions, and pictures and can used for beautification purpose

D. Artsy Reception Desk

If you really want to create a look that stands out, you should opt for this artsy and vogue reception desk wherelight up in the front and the sides.

E. A Lighting fixture and Conversational Piece

The transparent concrete cube is, without a doubt, a great conversation piece. The new cube line consists of  four identical pieces of concrete and, due to its special  geometry; the pieces form a stable structure without  fixing them together

It can be also applicable at:

• ·         Transparent concrete blocks suitable for floors, pavements and load-bearing walls.
• ·         Facades, interior wall cladding and dividing walls based on thin panels.
• ·         Partitions wall and it can be used where the sunlight does not reach properly.
• ·         In furniture for the decorative and aesthetic purpose.
• ·         Light fixtures.
• ·         Light sidewalks at night.
• ·         Increasing visibility in dark subway stations.
• ·         Lighting indoor fire escapes in the event of a power failure.
• ·         Illuminating speed bumps on roadways at night.

VII. ADVANTAGES AND DISADVANTAGES

• ·         The main advantage of these products is that on large scale objects the texture is still visible - while the texture of finer translucent concrete  becomes indistinct at distance.
• ·         When a solid wall is imbued with the ability to  transmit light, it means that a home can use  fewer lights in their house during daylight  hours.
• ·         It has very good architectural properties for  giving good aesthetical view to the building.
• ·         Where light is not able to come properly at that  place transparent concrete can be used.
• ·         Energy saving can be done by utilization of  transparent concrete in building.
• ·         Totally environment friendly because of its  light transmitting characteristics, so energy  consumption can be reduced.

·         The main disadvantage is these concrete is very  costly because of the optical fibres.

·         Casting of transparent concrete block is difficult for the labour so special skilled person is required.