Lab Testing Procedures Flashcards

When performing a Standard Proctor compaction test (AASHTO T 99), how many layers of soil are compacted into the mold?

Answer: 3 layers

AASHTO T 99 requires 3 equal layers compacted with 25 blows of the 5.5-lb hammer per layer.

In a sieve analysis of aggregates per AASHTO T 27, sieves must be arranged in the stack with the:

Answer: Largest opening at the top

Sieves are stacked largest opening at the top to smallest at the bottom, above the pan, so material is progressively retained on finer sieves.

A concrete slump test per AASHTO T 119 measures which property of fresh concrete?

Answer: Workability/consistency

The slump test measures the consistency (workability) of fresh concrete by recording how much the concrete slumps after the cone is removed.

Which test method is used to determine the liquid limit of a fine-grained soil?

Answer: AASHTO T 89

AASHTO T 89 covers the determination of the liquid limit of soils using the Casagrande liquid limit device.

When extracting asphalt content from a bituminous mixture using an ignition oven (AASHTO T 308), the test results give:

Answer: Binder content and aggregate gradation after washing

The ignition method burns off the asphalt binder, and the remaining aggregate can be sieved to provide both binder content and aggregate gradation.

The purpose of curing concrete cylinders in a standard moist-curing room (AASHTO T 23) is to:

Answer: Maintain humidity above 95% at 73°F to ensure proper hydration

Standard curing at ≥95% relative humidity and 73±3°F ensures consistent hydration conditions for comparative compressive strength results.

In a field density test using the sand-cone method (AASHTO T 191), what is the purpose of the Ottawa sand?

Answer: To replace the excavated soil so the hole volume can be calculated

Ottawa sand of known density fills the excavated hole; measuring the sand used allows calculation of the hole's volume, which is then used to compute in-place density.