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Asphalt Pavement Construction

While there are an infinite number of questions that can be asked, we have compiled a list of those questions that have been directed to us the most.

These FAQs are categorized into subject areas listed in the contents drop-down box below.

We tried to keep both the questions and answers concise. Additional information is referenced where applicable for those seeking more in-depth information on a given subject.

For further information see the Maintenance & Rehabilitation Documents, other engineering areas, Asphalt magazine and APA websites, Asphalt Institute online store and the links page for other information related to this topic area.

We also recommend that you attend our Asphalt Academy courses at sites throughout the country to obtain expert instruction on asphalt topics.

Prime Coats

What is a prime coat?
What is the purpose of a prime coat?
What asphalt materials should be used for prime coats?
Is a prime coat necessary?

Tack Coats

Why is a tack coat needed?
What material should be used for a tack coat?
What application rate should be used?
When is a tack coat necessary?

Asphalt Mixtures

For an asphalt pavement in a container terminal, are there any rules of thumb as to what the maximum load could be without causing damage?
Can the same paving equipment be used for Superpave mixes that was used for conventional mixes?
Is there a problem with milling up and recycling asphalt mixes that used polymer modified binders?
What is the proper mix temperature?
What is a minimum temperature for asphalt mixes?
How do I ensure HMA is impervious to water?
Is there a limit on the percentage of RAP utilized in new installations? What about RAP use for resurfacing of old asphalt roads? Any limits? If there are limits on the use of RAP in new or resurfacing installations, who sets the limits?
Is it acceptable to run Theoretical Maximum (Rice) Specific Gravity on material obtained from cores or saw cutting?

Aggregate

What is the proper nominal aggregate size to use?

Construction

Should construction crews be allowed to pave in the rain?
Does AI have any recommendations of an asphaltic concrete sealer?
What is the proper thickness of lift that should be used?
What is the proper mix temperature?
What is a minimum temperature for asphalt mixes?
How can you tell that a mix is properly mixed?
What should be used as a mix release agent for truck beds and rollers?
What is the proper paver speed?
Why does the paver pass has a rich shiny strip down the middle with dull, torn-looking edge strips?
What causes the paver pass have rich shiny strips on each side and a dull, torn look in the middle?
Is there a limit on the percentage of RAP utilized in new installations. What about RAP use for resurfacing of old asphalt roads? Any limits? If there are limits on the use of RAP in new or resurfacing installations, who sets the limits?

Placement

Should construction crews be allowed to pave in the rain?
Does AI have any recommendations of an asphaltic concrete sealer?
How do I determine how much asphalt is required for a project?
Can the same paving equipment be used for Superpave mixes that was used for conventional mixes?
What is the proper paver speed?
Is it ok to cool down the laid mat immediately using water for early traffic?
What is acceptable in terms of standing water or ponding on parking lots and other asphalt pavements?

Compaction

Should construction crews be allowed to pave in the rain?
How many rollers are required?
What is the recommended air void content for compaction of asphalt pavements?
How is air void content controlled?
What should compaction requirements be?
What is the best way to check density?
Spoiler title
What might cause surface cracking on newly placed asphalt concrete? The cracking occurred during the breakdown rolling and finish rolling.
Can the same paving equipment be used for Superpave mixes that was used for conventional mixes?
What is the process or how is density target value established or determined?

Lift Thickness

Should construction crews be allowed to pave in the rain?
Can the same paving equipment be used for Superpave mixes that was used for conventional mixes?
What is the recommended minimum lift thickness for placing HMA?

Weather

Should construction crews be allowed to pave in the rain?
Can asphalt be applied in the rain (light drizzle)?

Plant Operations

Is there a problem with milling up and recycling asphalt mixes that used polymer modified binders?
How can you tell that a mix is properly mixed?

Intersections

How do you design a good quality asphalt instersection?
For an asphalt pavement in a container terminal, is there any rules of thumb as to what the maximum load could be without causing damage?
How do the lab-compacted air voids of 'reheated' asphalt mixture samples compare to the air voids of 'original' mixture samples (as-produced, not reheated)?
Is there a problem with milling up and recycling asphalt mixes that used polymer modified binders?
What is the proper mix temperature?

Surface Treatments

Does AI have any recommendations of an asphaltic concrete sealer?
What type asphalt should be used?
How much asphalt should be applied to the aggregate? (chips)
Do the chips need to be clean?
What causes roadway streaking in chip seals?

Mix Release Agents

What should be used as a mix release agent for truck beds and rollers?

Special Applications

Does AI have any recommendations of an asphaltic concrete sealer?
Is there a way to color an asphalt pavement other than shades of black and grey?
For an asphalt pavement in a container terminal, is there any rules of thumb as to what the maximum load could be without causing damage?
How do the lab-compacted air voids of 'reheated' asphalt mixture samples compare to the air voids of 'original' mixture samples (as-produced, not reheated)?

Trouble Shooting

Should construction crews be allowed to pave in the rain?
Does AI have any recommendations of an asphaltic concrete sealer?
What causes tire scuffing and what should be done about it?
The paver pass has a rich shiny strip down the middle with dull, torn-looking edge strips.
What causes the paver pass to have rich shiny strips on each side and a dull, torn look in the middle.
Can the same paving equipment be used for Superpave mixes that was used for conventional mixes?
What might cause surface cracking on newly placed asphalt concrete? The cracking occurred during the breakdown rolling and finish rolling.

Railroads

Does AI have any information about asphalt and its use in railroad beds?