AASHTO T193

Full Name

AASHTO T193 – Standard Method of Test for The California Bearing Ratio

Scope

AASHTO T193 is a standard test method used to determine the California Bearing Ratio (CBR) of soil, aggregate, and other road-building materials. The CBR is a measure of a material’s strength and load-bearing capacity compared to a standard crushed stone material. This test is crucial for evaluating the suitability of materials for use in pavement subgrades, subbases, and bases.

Key aspects of AASHTO T193:

  • Principle: the test involves measuring the force required to penetrate a compacted specimen of the material with a standard plunger at a specified rate. The penetration resistance is compared to the resistance of a standard crushed stone material at the same penetration depth. The ratio of these values, expressed as a percentage, is the CBR.
  • Specimen preparation: test specimens are typically compacted in a cylindrical mold at a specified density and moisture content. The standard allows for both laboratory-compacted specimens and specimens prepared in the field.
  • Test procedure: the prepared specimen is placed in a loading frame, and a surcharge weight is applied to simulate the overburden pressure. The plunger is then driven into the specimen at a controlled rate, and the load and penetration values are recorded at regular intervals.
  • Calculation: the CBR is calculated by comparing the load values at 2.54 mm and 5.08 mm penetration to the standard load values for the crushed stone material. The higher of the two ratios is generally reported as the CBR.

Significance of AASHTO T193:

  • Pavement design: the CBR is used as a key input parameter in pavement design, particularly for determining the thickness of the pavement layers required to support the expected traffic loads.
  • Material evaluation: the test is used to evaluate the strength and suitability of different materials for use in pavement construction.
  • Quality control: AASHTO T193 provides a standardized test method for determining the CBR, ensuring consistency and reliability in the evaluation of materials across different laboratories and projects.

AASHTO T193 Accredited Laboratory

Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T193 standard.

Our laboratory offers comprehensive testing services for determining the California Bearing Ratio (CBR) of soils, aggregates, and other materials according to AASHTO T193. Our experienced technicians utilize calibrated equipment and adhere to strict quality control procedures to provide accurate and reliable test results for your pavement design and construction projects.

Contact us for more information.

Resources

Keywords

California Bearing Ratio; CBR; penetration test; subgrade; subbase; base course; compaction; standard crushed stone; penetration resistance; surcharge; mold; plunger

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