GEOTEXTILES IN PAVEMENT BHAG CHAND MEENA B120915CE NIT CALICUT 1
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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