KDOT Asphalt & Concrete Paving Inspection 3

Question 1

What is the primary purpose of tack coat applied between asphalt pavement layers?

Accepted Answer

To bond successive asphalt layers and prevent slippage

Answer

Tack coat (typically emulsified asphalt) creates a bonding interface between existing and new asphalt layers to resist shear forces and prevent inter-layer slippage.

Question 2

An HMA inspector observes that the vibratory rollers are operating with vibration turned on during the breakdown rolling pass near the end of the paving run. What problem could this cause?

Accepted Answer

Checking or cracking of the cool mat at the end of the run

Answer

Using vibration on cooler asphalt (at the end of a run) can cause checking — a surface cracking pattern — because the stiff mix cannot absorb the impact energy.

Question 3

What information must the contractor provide on a concrete mix delivery ticket for KDOT projects?

Accepted Answer

Mix design number, water added, time batched, and truck number

Answer

KDOT requires batch tickets to include the mix design ID, water additions, batch time, cumulative water, and truck/load identification for traceability and acceptance.

Question 4

What does a 'tender' asphalt mix feel like under the roller, and what typically causes it?

Accepted Answer

Mix that shoves or waves ahead of the roller due to excess asphalt or fine aggregate

Answer

A tender mix has insufficient internal friction and shoves or pumps under roller loads, typically caused by excess binder, excess fines, or mix temperature in a critical zone.

Question 5

For KDOT concrete pavement, which type of joint is designed to control where transverse cracking occurs?

Accepted Answer

Contraction (control) joint

Answer

Contraction joints (also called control joints) are sawed to a depth of about one-quarter to one-third of slab thickness to create a weakened plane where controlled cracking occurs.

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

KDOT Asphalt & Concrete Paving Inspection 3