KDOT Asphalt & Concrete Paving Inspection 5

Question 1

What is the purpose of the 'nuclear density gauge' in asphalt paving inspection?

Accepted Answer

To rapidly measure in-place density and moisture content of compacted pavement non-destructively

Answer

The nuclear density gauge uses gamma radiation to measure the density of compacted asphalt in place quickly and non-destructively, allowing the inspector to assess compaction in real time.

Question 2

What does 'segregation' in an asphalt mat visually appear as, and what equipment issue typically causes it?

Accepted Answer

Coarse, open-textured streaks or areas where fines are absent, often caused by paver hopper or auger problems

Answer

Segregation appears as coarse-textured, open areas where fine aggregate is missing, often caused by cold hopper wings being folded in, auger starvation, or improper truck loading practices.

Question 3

When concrete pavement is placed in cold weather (air temperature below 40°F and falling), what primary precaution must the inspector verify?

Accepted Answer

Concrete and subgrade must be protected from freezing; insulated blankets or enclosures required until adequate strength is gained

Answer

Concrete must not freeze before it reaches sufficient strength (typically 500 psi), so the inspector must verify that insulated curing blankets, enclosures, or heated water are used to maintain the concrete above 50°F.

Question 4

A KDOT inspector is checking the asphalt mix for 'fat spots.' What are fat spots and what do they indicate?

Accepted Answer

Shiny, excess-binder areas in the mat indicating localized over-asphalting or mix design issues

Answer

Fat spots are localized areas on the mat surface that appear shiny and rich in binder, indicating either excess asphalt in those areas or migration of binder due to mix instability.

Question 5

What is the maximum allowable water-to-cementitious material (w/cm) ratio for KDOT Class P (pavement) concrete?

Accepted Answer

0.45

Answer

KDOT Class P concrete for paving typically has a maximum w/cm ratio of 0.45 to ensure adequate durability and strength for pavement applications.

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

KDOT Asphalt & Concrete Paving Inspection 5