Permeability Test equipment of Bentonite Liners, Sodium-based bentonite waterproof blanket , ASTM D5887

Bentonite liners are widely used in geotechnical engineering such as landfills, reservoir and waterproofing. When bentonite is in touch with water, it swells and causes a significant increase of permeability. This paper reports a series of permeability tests on bentonite liners. Six samples could be 

tested independently. An experiment setup similar to the Rowe cell was used for the experiments. Two types of Bentonite mat were used in the experiments such as powder from and granular from. The experiments were made with and without 30kN/m2 normal stress and the diameters were varied as 75mm and 150mm. The permeability was tested under different conditions such as, after wet and dry cycles, after freezing and thawing cycles, and in overlapping region of two bentonites. Unitedtest ASTM D5887 Sodium bentonite geosynthetic clay liner Permeameter UT4067A. Moreover, the effect of punctures was investigated by testing liners with a hole of about 8 mm diameter.

Test Method 

The testing device is a modified Rowe cell for permeability tests with falling hydraulic head. The hydraulic head of the samples can be read from standpipe. The pressure head is maintained constant. Some water need be refilled into the system because of the sinking head in standpipe with time. The period of time between refilling the standpipe gives rise to some variations in the gradient. For the control of ventilation in every possible time, all of the pipes are made from Plexiglas. By means of compressed air, additional load at the sample in the Rowe cell can be applied. The normal stress can be read from a manometer.