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GEOTEXTILES IN PAVEMENT

BHAG CHAND MEENA B120915CE

NIT CALICUT

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CONTENTS Introduction Types of geotextiles Placing of geotextiles in pavement Functions and applications of geotextiles in

pavement References

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INTRODUCTION-

Geotextiles are polymer fabrics used in the construction of roads, drains, harbour works, breakwaters, and for land reclamation and many other civil engineering purposes.

Used with geotech. eng. related materials as an integral part of human made structures.

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Types of geotextiles- Geotextiles are usually made from polymers such as

polyester or polypropylene. Further prepared in 3 different categories- 1.Woven type 2.Non-woven type 3.Knitted type

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1.WOVEN TYPE GEOTEXTILE

These were the first to be developed from the synthetic fibers.

Manufactured with a process of weaving narrow strip of film together to form one large piece. Weaving is done by interlocking perpendicular threads.

Can be used in roadways as it has higher load capacity.

Does not have good drainage characteristics.

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Fig1. woven type geotextile

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2.NON-WOVEN GEOTEXTILE

Can be made from either continuous filament or staple fibres, these are continuously extruded and spun, placed on a moving belt, to form mat, which is then bonded by using any of these processes-

1. needle-punching 2. heat bonding 3. resin bonding

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4. combination bonding Thicker than woven type geotextiles. These are flat porous sheets.

Fig.-non-woven geotextile

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3.KNITTED TYPE GEOTEXTILE

Manufacturing process adopted from clothing textiles industry, and that process is called knitting.

Interlocking a series of yarns together is made in this process.

Fig.-knitted type geotextile

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PLACING OF GEOTEXTILE IN

PAVEMENT Between aggregate layer and natural subgrade

layer. Mechanically or with hand. It will be rolled around a pipe, just unroll it.

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Fig.3 placing of geotextile mechanically

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Fig.-placed geotextile

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FUNCTION AND APPLICATION OF GEOTEXTILE IN PAVEMENT

These are the main functions performed by geotextile in pavement-

1. Separation 2. Filtration 3. Reinforcement 4. Drainage 5. Erosion control

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SEPARATION- These are main layer in a section of pavement- 1.Subbase/Subgrade layer 2.Base/Aggregate layer 3.Surface layer Geotextile is placed between subgrade and base

layer-as a separater, so that they can perform effectively.

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Prevent the mixing of two dissimilar materials. Greater density of provided material can be

achieved. Releases pore water pressure, that results in

consolidation of subgrade. Life of pavement increases.

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Fig.-geotextile as separater layer

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FILTRATION-

Oldest and most widely known function. The geotextile is placed in contact with and

down gradient of soil to be drained. Allows water to pass and retains soil particals. Permeability and long time clogging are the

properties of geotextiles, which are considered in this function.

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Fig.-geotextile as filtration layer

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REINFORCEMENT

Geotextile as reinforcement means a significance increase in pavement-strength.

Mechanism-It is the lateral restrain through friction between soil and geotextile.

Geotextile resist the tensile force developed. Geo-grids are in common use in US instead of

Geotextiles.

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Requirement- Geotextile should posses enough strength. Knitted type of geotextile is preferred.

Fig.-geotextile performing like reinforcement in pavement

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DRAINAGE- Geotextile acts as conduit for the movement of liquid

in the plane of geotextiles. Thick non-woven type geotextiles are commonly

used for this function.

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EROSION CONTROL-

The geotextile protects soil surfaces from the tractive forces of moving water or wind and rainfall erosion.

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Fig.-geotextile controlling errosion

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CONCLUSION- Geotextiles are very important part of pavement

construction regarding its strength, durability, and working performance.

Very useful in case of silt and clay.

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REFERENCES 1. Sharma, Kanaungo, Khatri.,2014, “Application of

Geotextiles in Pavement Drainage Systems, International Journal of Civil Engineering Research.volume” 5(4),385-390

2. Chair, Flintsch, Trani., “Effectivness of using geotextitles in flexible pavements: life-cycle cost analysis” Feb 27, 2006.

3. Guyer, Pe, Ra. 2009, “An introduction to geotextile in pavement and drainage application”, C02-019

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ANY QUESTION? PLEASE ASK…

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THANK YOU