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GEOSYNTHETICS PROPERTIES

Faculty: Prof. Samirsinh .P.ParmarDepartment of Civil EngineeringFaculty of Technology, Dharmasinh Desai University,NadiadMail Add: samirddu@gmail.com

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CHEMICAL PROPERTIES

1) Swelling Resistance2) Chemical Resistant3) Ozone Resistance4) Ultra violate Light Resistance5) Biological Hazards6) Resistance to Fungi 7) Resistance to Bacteria

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1). SWELLING RESISTANCE Swelling due to liquid absorption. Shrinkage after loss of liquid. Continue throughout the service life. Considered especially for the laminated

geosynthetics. (i.e. Geo composites). Tests carried out as per ASTM D570: 2hr, 24hr, or 2 weeks constant immersion at

23° C water. Cyclic immersion. 0.5 hr to 2 hr, constant immersion in boiling

water.

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1). SWELLING RESISTANCE CONT....

Observation: % increase in weight. Chances of solubility. Loss of weight after test. Bond failure ( especially in Geocomposites)

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2). CHEMICAL RESISTANT Effect of Chemicals like Hydrocarbons, solvents,

crude petroleum, alcohols, Acids(organic, inorganic) Bases (organic, inorganic), and salts are analysed at different temperature.

Under the action of chemicals all mechanical properties are checked and compared the behaviour of GT.

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3). OZONE RESISTANCE

Evaluated by ASTM D518 Deterioration property checked. Under bent, looped, straight, or tapered

condition. Also analysed under stress and atmospheric

conditions. Development of cracks observed.

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4) ULTRA VIOLATE LIGHT RESISTANCE

Under constant exposure of GT to UV rays. Progressive increase in brittleness and

cracking starts. Tested b ASTM D3334. Humidity and temperature maintained up to

field simulating condition. To protect GT, clay liners are used over

geosynthetic liners. Sometimes UV effect analysed for GT depth

in soil.

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5). BIOLOGICAL HAZARDS

Burrowing animals makes holes through. No established test procedure. Chances of attack unknown in most of the

cases. Consider regional knowledge for burrowing

animals. Use high tensile and tough material of

Geotextiles. Well compacted soil without organic matter is

also a good option with GT.

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6).RESISTANCE TO FUNGI

Numbers of Fungivaries from 10 to 20 million per gram of dry soil.

Placing of GT in landfill and inclusion with organic soil affected by fungi.

Fungal deposites will cause clogging of GT. Also causes blinding of fuid flow through GT. ASTM G21.

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7). RESISTANCE TO BACTERIA

Increases growth of Fungi. Participate in all organic transformations. Causes polymeric degradation, clog GT

system, fouling of drainage system of GT. ASTM G22. Tests carried out for evaluation of resistance

of plastics to bacteria.

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THERMAL PROPERTIES OF GT

1. Warm Temperature Behaviour2. Cold Temperature Behaviour

• Co-efficient of Thermal Expansion• Thermo-Mechanical Analysis

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1. WARM TEMPERATURE BEHAVIOUR

GT exposed to heat subjected to change mechanical or chemical properties.

Time of exposure is important. ASTM D794 Under temperature looses weight, colour and

thermosets. Also dimension change.

All this changes checked weather they are acceptable for service life or not.

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2. COLD TEMPERATURE BEHAVIOUR

Flexibility decreases with decrease in temperature.

Seam strength should be evaluated for cold region.

Freeze -unfreeze action should be analysed.

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