What is the required number of blows for compaction in a 6-inch mold as per AASHTO T180 and ASTM?

The requirement for the number of blows in compaction using a 6-inch mold as specified by AASHTO T180 and ASTM D1557 is indeed 56 blows. This compaction method is crucial in determining the maximum density of the soil or aggregate material. The process involves dropping a weighted rammer onto the material in the mold from a prescribed height, and a specific number of blows is necessary to ensure uniformity and representative results in the testing.

Using 56 blows allows for effective compaction while minimizing variations in test results. This ensures that the density measurements are consistent and reliable, which is essential for evaluating the material’s properties for construction and engineering purposes. The established standard reflects extensive research to achieve a necessary balance between compaction level and workability of the material being tested.