AASHTO T89
Full Name
AASHTO T89 – Standard Method of Test for Determining the Liquid Limit of Soils
Scope
AASHTO T 89 is a standard test method used to determine the liquid limit (LL) of soils. The liquid limit is defined as the moisture content at which a soil transitions from a plastic state to a liquid state. This test is a key component of the Atterberg limits, which are used to classify fine-grained soils based on their plasticity and consistency.
Key aspects of AASHTO T89:
- Purpose: the primary objective is to quantify the liquid limit of a soil, which is a measure of its plasticity. This information is crucial for assessing the soil’s suitability for various applications, such as embankments, foundations, and pavements.
- Test procedure: the test involves preparing a soil paste of known moisture content and placing it in a brass cup with a standardized groove. The cup is repeatedly dropped from a standard height, and the number of blows required to close the groove over a specific distance is recorded. This process is repeated for several moisture contents to establish a relationship between the number of blows and the moisture content.
- Flow curve: the relationship between the number of blows and the moisture content is plotted on a semi-logarithmic graph, forming a flow curve. The liquid limit is determined as the moisture content corresponding to 25 blows on the flow curve.
- Significance: the liquid limit is a valuable parameter in geotechnical engineering. It provides insights into the soil’s behavior under different moisture conditions, its potential for volume change, and its susceptibility to settlement or deformation.
Applications of AASHTO T89:
- Soil classification: the liquid limit is a key component of the Atterberg limits, which are used to classify fine-grained soils according to their plasticity characteristics. This classification aids in selecting appropriate soil types for various construction projects.
- Geotechnical design: the liquid limit is used in various geotechnical design calculations, such as estimating the consolidation settlement of foundations, evaluating the stability of slopes, and determining the compaction requirements for earthworks.
- Quality control: the test is also used to ensure that the soil materials used in construction projects meet the specified liquid limit requirements.
AASHTO T89 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T89 standard.
Our laboratory offers comprehensive soil testing services, including the determination of the liquid limit according to AASHTO T89. Our experienced technicians utilize calibrated equipment and adhere to standardized procedures to provide accurate and reliable results for your geotechnical projects.
Contact us for more information.
Resources
Keywords
liquid limit; soil; Atterberg limits; plasticity; groove closure; moisture content; flow curve; cone penetrometer