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Apparent Opening Size Test instrument FOR GEOTEXTIL

Apparent Opening Size Test instrument FOR GEOTEXTIL

Model: UT4062D; ASTM D4751, BS 6906-2

AOS (Apparent Opening Size) is a property that is commonly tested on a variety of geotextile fabrics. 

Apparent Opening Size Test instrument are used for determining the effective apparent opening size of geotextiles and composite geotextiles by the dry sieving method. conform ASTM D4751, BS 6906-2. 

General Introduction

AOS (Apparent Opening Size) is a property that is commonly tested on a variety of geotextile fabrics. 

Apparent Opening Size Test instrument are used for determining the effective apparent opening size of geotextiles and composite geotextiles by the dry sieving method. conform ASTM D4751, BS 6906-2. 

Main features

  • Test principle
  • Technical Advantages
  • Standard

Using geotextiles and other geosynthetic material samples as sieves, a certain mass and diameter of standard granular material is placed on the sample for vibration sieving. The mass of standard granular material that passes through the sample is weighed, and the passing rate is calculated. 


Different diameters of standard granular material are used for testing, and a curve of standard granular material diameter versus passing rate is plotted, which represents the pore size distribution curve of the sample, from which the effective pore size is determined. 


1. The machine adopts an integrated design, saving space without the need for supporting auxiliary equipment.

2. Equipped with 5 sets (10 pieces) of test sieves, allowing 5 samples to be tested in 10 minutes, greatly improving efficiency.

3. Touch screen operation display with a Chinese menu for easy operation.

4. Customized sieve trays and combined sieve mesh prevent leakage of edge particles, effectively holding the samples and improving testing accuracy.

5. Utilizes a high-temperature spraying process, making it rust-resistant and corrosion-resistant.


ASTM D4751

BS 6906-2


JTG E50-2006, SL235-2012, GB/T 14799-2005, IS 14294, JT/T 1432.2-2022 Q/CR 549.5-2016, etc. 

Main Technical Specification

1. Display: 4.3-inch true color touch display screen with English menu operation;

2. Specifications of combined sieve mesh: Ф200mm 5 pieces3. Specifications of sieve tray: Ф200*45 mm 5 pieces

4. Testing quantity: 5 sets/sample, can test 5 sets of samples simultaneously

5. Sieve stacking height: 400 mm

6. Rotation radius: 12±1 mm

7. Lateral shaking frequency: 220±10 times/min

8. Vertical vibration frequency: 150±10 times/min

9. Amplitude: 10±2 mm

10. Time setting: 0-9999.99 seconds or hours, minutes, seconds countdown

11. Can test 5 sets of sieves at the same time, automatically stopping shaking after the set time

12. Motor power: 0.37KW

13. Voltage: 220V

14. Rotational speed: 2800 RPM

15. Dimensions: 800*500*1150 mm

16. Weight: 130KG


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Beijing United Test Co., Ltd.