Construction Materials Testing & Quality Control Flashcards

What does the term 'ride quality' refer to in pavement acceptance testing, and which instrument measures it?

Answer: Pavement smoothness measured by a profilograph or inertial profiler

Ride quality refers to pavement smoothness and is quantified using a profilograph or high-speed inertial profiler to produce an International Roughness Index (IRI) value.

When conducting a sieve analysis on combined aggregate for HMA, a gap in the gradation curve most likely causes:

Answer: Potential for tenderness, rutting, or instability in the mix

A gap gradation can create a tender mix prone to rutting and shoving because certain particle sizes are missing, reducing interlock and internal friction.

According to KDOT quality control requirements, who is responsible for maintaining a QC plan on a hot mix asphalt paving project?

Answer: The prime contractor

The prime contractor is responsible for developing and implementing the Quality Control plan, which defines sampling, testing, and corrective action procedures.

What is the significance of the 'P200' value in aggregate gradation analysis?

Answer: The percentage of material passing the No. 200 (0.075 mm) sieve, indicating fines content

P200 is the percent passing the No. 200 sieve (75 microns), representing fines content that significantly affects HMA mixture performance and concrete workability.

A reinforced concrete bridge deck core extracted for evaluation has a carbonation depth of 18 mm. What does this indicate?

Answer: The pH of the concrete near the surface has dropped, potentially depassivating rebar

Carbonation reduces concrete pH from ~12.5 to below 9, destroying the passive oxide layer on reinforcing steel and initiating corrosion if rebar is within the carbonation front.

Under KDOT specifications, what action is required when HMA mat air voids from extracted cores fall below the minimum specification limit?

Answer: A pay adjustment or corrective action is required per the specification table

When core air voids fall outside specification limits, KDOT specifications require a pay adjustment reduction or corrective action such as removal and replacement of the deficient area.

Which condition requires a concrete test cylinder to be discarded and the test result invalidated?

Answer: The end surface was not perpendicular within 0.5°

Cylinders with end surfaces that are not perpendicular to the axis by more than 0.5° produce eccentric loading during compression testing and must be capped or the result invalidated.