AASHTO T208
Full Name
AASHTO T208 – Standard Method of Test for Unconfined Compressive Strength of Cohesive Soil
Scope
AASHTO T208 is a standard test method used to determine the unconfined compressive strength (UCS) of cohesive soil. The UCS is a measure of the soil’s shear strength when not confined laterally, providing valuable information for geotechnical engineering applications such as foundation design, slope stability analysis, and earthwork construction.
Key aspects of AASHTO T208:
- Principle: the test involves applying an axial load to a cylindrical soil specimen until it fails in shear. The maximum axial stress at failure is then determined, which represents the unconfined compressive strength of the soil.
- Specimen preparation: undisturbed or remolded soil specimens can be used for the test. Undisturbed specimens are carefully extracted from the ground to preserve their natural structure, while remolded specimens are prepared by compacting or remolding the soil to a specific density.
- Test procedure: the prepared specimen is placed in a loading frame, and an axial load is applied at a constant rate of strain until the specimen fails. The load and deformation are recorded throughout the test to generate a stress-strain curve.
- Calculation: the unconfined compressive strength is calculated as the maximum axial stress recorded during the test. The stress-strain curve is also analyzed to determine other soil properties, such as the modulus of elasticity and the strain at failure.
Significance of AASHTO T208:
- Geotechnical design: the UCS is a fundamental parameter used in geotechnical design, particularly for evaluating the stability of slopes, retaining walls, and embankments.
- Foundation design: the UCS is used to assess the bearing capacity of cohesive soils, which is essential for designing shallow foundations.
- Material characterization: the UCS provides valuable information about the shear strength and stiffness of cohesive soils, which are essential for understanding their behavior under different loading conditions.
- Quality control: AASHTO T208 provides a standardized test method for determining UCS, ensuring consistency and reliability in the evaluation of soil properties across different laboratories and projects.
AASHTO T208 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T208 standard.
Our laboratory offers comprehensive soil testing services, including the determination of unconfined compressive strength according to AASHTO T208. Our experienced technicians utilize calibrated equipment and adhere to strict quality control procedures to provide accurate and reliable test results for your geotechnical projects.
Contact us for more information.
Resources
Keywords
unconfined compressive strength; cohesive soil; shear strength; soil specimen; strain rate; stress-strain curve; loading frame; undisturbed specimen; remolded specimen; failure