Geotextile

Cone Drop Test Apparatus
This test is conducted to evaluate the resistance of geosynthetic / geotextile to damage during installation due to dropping of sharp edged or sharp pointed stones on a geosynthetic/ geotextile directly. In this test, a geosynthetic, geotextile is clamped to yield a clear diameter of 150 mm and a brass cone of 45 degree included angle, having a weight of 1 kg, is dropped through a height of 500 mm. The diameter of the resultant hole is measured with a graduated conical device. The smaller the hole, the greater the resistance of geosynthetic /geotextile to damage. When used in combination with other direct tensile test results, it provides a convenient means of qualitative comparison.

Cross Permeability Test Apparatus
Permeability of a geotextile must be substantially greater than that of the protected soil, so that water can pass freely from the soil through the fabric without build up of hydrostatic pressure. A high value of the permeability of the geotextile also infers that partial clogging will not reduce the permeability. Both Constant and Falling Head permeameters are generally used for measuring normal permeability. Permeability is defined as the volumetric rate of flow of water per unit cross sectional area under unit hydraulic head across the plain of the geotextile. ASTM D 4491 - 85 specifies permeability test using Constant Head and Falling Head Permeameters. The constant head test is carried out using a head of 50 mm of water
Optional
Overhead Tank
Loading unit, 300-kPa capacity

Dry Sieve Test Apparatus
The test involves sieving rounded particle sizes for which 5% or less by weight pass through the geotextile. The Apparent Opening Size (AOS) is defined as 'Retained On' size of that fraction expressed as a standard sieve number (size). The test is widely used for relative comparison amongst the geotextiles. Thus AOS is a means of correlating geotextile pore structure to an equivalent screen mesh size. The apparatus consist of a 20 cm dia brass frame with clamp, a receiver and a lid
Sieve Shaker and glass beads to be ordered separately.

Rounded Beads made of glass, size 0.85 mm (passing 1 mm and retained at 0.85 mm)

Rounded Beads made of glass, size 0.425 mm (passing 0.85 mm and retained at 0.425 mm)

Rounded Beads made of glass, size 0.25 mm (passing 0.425 mm and retained at 0.25 mm)

Rounded Beads made of glass, size 0.18 mm (passing 0.25 mm and retained at 0.18 mm)

Rounded Beads made of glass, size 0.15 mm (passing 0.18 mm and retained at 0.15 mm)

Rounded Beads made of glass, size 0.075 mm (passing 0.15 mm and retained at 0.075 mm)

In-Plane Permeability Test Apparatus
This test is necessary for drainage application. The permeameters can be of parallel flow or radial flow type. In either case, flow occurs along the plane of the permeameters. In the apparatus, flow occurs radially outwards, from a central hole to the periphery of a circular specimen. The transmissivity is defined as the volumetric rate of flow per unit width of geotextile and unit hydraulic head.
Specifications
Flow: Radially outwards
Specimen diameter: 100 mm
Range of Pressure: Upto 800 kPa
Head of Water: Upto 30 cm
Optional
Overhead Tank
Loading unit, 300 kPa capacity

Thickness Gauge
Thickness is one of the basic physical properties used to control the quality of many geotextiles and geosynthetic. This equipment is simple to operate and thickness of the geosynthetic / reinforcing material can be measured with an accuracy of 0.002 mm for thickness upto 10 mm. Accuracy is 0.01 mm for thickness greater than 10 mm. Simple mechanism is provided to apply desired foot pressure varying from 1 to 10 kPa as per various international standards. Surface plate is grounded and is rust free to enable reproducible results.

Universal Testing System for Geotextiles
The evaluation of the tensile properties of geotextiles is of paramount importance not only in reinforcement application but also in all other uses. Important properties include stress-strain behaviour, ultimate strength in uniaxial tension (under different widths), creep, etc. Recent researches have made it clear that the measured stress-strain behaviour of geotextiles is significantly influenced by details of testing procedures like method of gripping the fabric, rate of deformation, sample size / aspect ratio, initial preload and fabric conditioning. Universal Testing System for Geotextiles enables determination of these properties under a variety of test conditions. The 100 kN capacity systems have speed ranges from 5 to 320 mm/min. The following attachments are available for this system at extra cost.

Narrow and Wide Width Tensile Strength
Two clamping systems 8 cm wide and 22.5 cm wide are mechanical wedge type and facilitate conducting Narrow Strip and Wide Width Tensile Strength tests as per many international specifications, viz Indian, British, ASTM etc. These grips allow simple and rapid sample loading. Roller type grips required in high strength geotextile testing can be supplied as optional extra.

Grab Tensile Strength Test
This test measures the ability of the geotextile to distribute concentrated loads. Specially devised clamps (25 mm wide) with a gauge length of 100 mm are placed across 200 mm square samples or 200 mm x100 mm samples. The sample is then subjected to tension at a specified rate until failure occurs. It is widely used by manufacturers as a quality control tool and as such is the most commonly reported tensile strength value. It can also be used for relative comparisons between geotextiles of the same type.

Trapezoidal Tear Resistance Test
Geotextiles can be cut or punctured during field installation, which can create a possible condition by which strength is controlled by a tearing resistance. In the method suggested by ASTM-D4632, an outline of an isosceles trapezoid is marked on a rectangular specimen (150 mm x 75 mm) cut for the determination of tearing strength, (with a 6 to 9 mm cut) and the non-parallel sides of the trapezoid marked on the specimen are clamped in parallel jaws of the Tensile Testing System. Thereby, the separation of the jaws is continuously increased with simultaneous recording of the load, so the tear propagates across the specimen. The tearing strength is the value for estimating the relative tear resistance of different geotextiles or different directions of the same fabric

CBR Push Through Test
In this test developed in West Germany (DIN-54307 E), fabric is clamped to give an inner diameter of 15 cm and a standard CBR plunger is pushed centrally through a fabric at a specified rate. The load at failure is the push through load and when divided by the cross-sectional area of the plunger, gives CBR push through resistance. This gives the resistance of fabric to withstand localised pressure, which is particularly noticed in pavement systems.

Thickness Gauge
This is used for measuring the thickness of the geotextile. The thickness of the geosynthetic material can be measured with an accuracy of 0.002 mm for thickness up to 10 mm. Accuracy is 0.01 mm for thickness greater than 10 mm. Simple mechanism is provided to apply desired foot pressure varying from 1 to 10 kPa Surface plate is grounded and is rust free to enable reproducible results.

Puncture Test
In this test, developed by the Corps of Engineers, USA, the geotextile specimen is clamped to obtain an inside dia of 44.45 mm and force is applied through an 8 mm dia plunger till failure. The Modified ASTM D-3787 provides for a hemispherical plunger and accordingly has been developed. The puncture strength so obtained is felt to reflect the fabric's ability to withstand aggregate penetration.
Specifications
Specimen diameter: 100 mm
Mould for compaction of soil : 10 cm dia x 11.2 cm high
Head of water: Upto 37.5 cm
Optional
Overhead Tank

Hydrodynamic Sieve Test Apparatus
The percentage passing of different fractions determines the porometry of the geotextile investigated. In the Hydrodynamic Sieving Method, the geotextile specimen, loaded with a certain quantity of glass bead fraction, is continuously rotated in a water trough, forcing the glass beads to pass through the geotextile openings. The apparatus consists of two test drums of 14 cm dia and 7 cm effective length with 16 nos. of 4 mm dia rods provided circumferentially at equal spacing to hold the geotextile specimen in position. Two troughs to contain the test drums are supported on horizontal axis, facilitating free rotation and capable of being filled with distilled water to a level of 20 mm below the drum axis. The clearance between the trough and the geotextile could be maintained at about 40 mm. The apparatus is provided with a motor drive and gear assembly to enable rotation of the drums at a speed of 5 rpm to 30 rpm. For conducting the test, the Geotextile specimen is cut and stitched to get a shape of 14 cm dia and 10 cm length to insert over the drum tightly, after immersing the specimen in distilled water for one hour, and secured by rubber 'O' rings. After placing 50 g of smallest size glass beads inside the drum, the lid is secured and the drum with the geotextile placed in distilled water to the desired level and rotated at 20 rpm for 1,500 cycles. In order to get the optimum filtration opening size, the drum is rotated at a speed of 5 rpm to 30 rpm for 250 to 2,500 revolutions. The percentage of beads passed through the geotextile by dry weight is determined. The test is repeated with increasing size of glass beads till 5% or less of the beads by weight pass through the geotextile.
Rounded Beads made of glass, size 0.85 mm (passing 1 mm and retained at 0.85 mm)
Rounded Beads made of glass, size 0.425 mm (passing 0.85 mm and retained at 0.425 mm)
Rounded Beads made of glass, size 0.25 mm (passing 0.425 mm and retained at 0.25 mm)
Rounded Beads made of glass, size 0.18 mm (passing 0.25 mm and retained at 0.18 mm)
Rounded Beads made of glass, size 0.15 mm (passing 0.18 mm and retained at 0.15 mm)
Rounded Beads made of glass, size 0.075 mm (passing 0.15 mm and retained at 0.075 mm)

Interface Friction Test Apparatus for Geotextile
Note Direct shear apparatus not a part of this instrument