Date of Graduation


Document Type


Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level



Civil Engineering


Richard Coffman

Committee Member

Rodney Williams

Second Committee Member

Michelle Bernhardt-Barry


Centrifuge;Soil Suction Determination;Soil Water Characteristic Curve


The unit correction constant (B) in the ASTM D6836 standard needs to be evaluated. The B-value was proposed to be 0.00548 instead of 0.00553. This apparent discrepancy led to an investigation comparing the predicted and measured suction values for high air entry (HAE) ceramic disks. A Beckman-Coulter Model J6-MI six-bay centrifuge and a WP4C Dewpoint Potentiameter were used in the testing program. HAE ceramic disks rated with bubbling pressures of 3-bar and 5-bar were used as analogue soil specimens. The HAE ceramic disks were spun in the small-scale centrifuge to apply prescribed suction amounts and then placed in the WP4C Dewpoint Potentiameter to obtain corresponding suction readings. In addition, the weight of the pore water within the HAE ceramic disks was investigated to determine the pressure equilibrium for each ceramic disk. Based on the obtained results, the measured suction values were approximately an order of magnitude greater than the predicted suction values. Three recommendations for the laboratory testing procedure are provided for future research to improve the testing system. Thus, the unit correction constant (B) of the ASTM D6836 standard may be further evaluated to refine the suction measurements.