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AASHTO T248 – Standard Method of Test for Reducing Samples of Aggregate to Testing Size


AASHTO T248 is a standardized procedure developed by the American Association of State Highway and Transportation Officials (AASHTO) that outlines the methods for reducing large aggregate samples to a size suitable for laboratory testing. This reduction process is crucial for ensuring that the tested sample accurately represents the characteristics of the original, larger aggregate source.

The primary purpose of AASHTO T248 is to minimize bias and variability during the sample reduction process. Large samples collected from stockpiles, quarries, or construction sites may not be practical for direct testing due to their size and weight. Reducing the sample to a manageable size while maintaining its representativeness is essential for obtaining reliable test results.

AASHTO T248 covers two primary methods for sample reduction:

  1. Mechanical splitter method: this method utilizes a mechanical device with multiple chutes to divide the aggregate sample into two equal portions. The process is repeated until the desired sample size is achieved. This method is generally preferred for its speed and efficiency.
  2. Quartering method: this manual method involves thoroughly mixing the aggregate and forming it into a conical pile. The pile is then flattened and divided into quarters. Two opposing quarters are discarded, and the remaining two are recombined and the process repeated until the desired sample size is reached. This method is suitable when a mechanical splitter is not available.

Adherence to AASHTO T248 is crucial for ensuring the accuracy and reliability of aggregate testing. By following the standard’s procedures, laboratories can confidently reduce large samples to a testing size without introducing significant bias or altering the sample’s properties. This enables accurate determination of aggregate properties such as gradation, durability, and soundness, which are essential for ensuring the quality and performance of construction materials.

AASHTO T248 Accredited Laboratory

Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T248 standard.

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aggregates; sample reduction; mechanical splitter; quartering; bias; variability; gradation; particle size distribution; representativeness