Construction Materials Testing & Quality Control Flashcards

When performing a sand equivalent test on a fine aggregate sample, what does a higher sand equivalent value indicate?

Answer: Cleaner aggregate with less plastic fines

A higher sand equivalent value indicates the aggregate is cleaner and contains fewer detrimental plastic fines and clay material.

According to KDOT specifications, what is the minimum number of random samples required per lot for hot mix asphalt acceptance testing?

Answer: 3 samples

KDOT requires a minimum of 3 random samples per lot to establish statistical validity for HMA acceptance decisions.

During concrete placement, a slump test result of 0 inches on a mix designed for 3-inch slump most likely indicates:

Answer: Mix is too dry or has lost workability

A slump of 0 inches on a mix designed for 3 inches typically indicates the concrete is too stiff, possibly due to insufficient water or loss of workability during transport.

What laboratory method is used to determine the plastic limit of a soil?

Answer: Rolling soil into 1/8-inch diameter threads until they crumble

The plastic limit is determined by rolling soil into 1/8-inch (3.2 mm) diameter threads and noting the moisture content at which threads begin to crumble.

A proctor compaction test yields a maximum dry density of 118 pcf. Field nuclear gauge readings show 115.8 pcf. What is the percent compaction?

Answer: 98.1%

Percent compaction = (115.8 / 118) × 100 = 98.1%, which meets typical KDOT embankment requirements.

Which AASHTO test method governs the tensile splitting strength of cylindrical concrete specimens?

Answer: AASHTO T 198

AASHTO T 198 covers the splitting tensile strength of cylindrical concrete specimens, also known as the Brazilian split test.

What does the term 'deleterious materials' refer to in aggregate quality testing?

Answer: Harmful substances like clay lumps, soft particles, or coal that degrade performance

Deleterious materials are harmful substances such as clay lumps, friable particles, coal, lignite, and other soft materials that reduce aggregate durability and concrete/asphalt performance.