PG 52-40 Asphalt Binder 1

[AKSherpa]

We have a road paving project specifying PG 52-40 asphalt binder. I have never worked with this grade of asphalt, we typically use PG 52-28. I am interested in information from anyone who has experience with PG 52-40 We are specifically interested in information concerning workability and the use of WMA.

Thanks

 

[dik]

Can you tell me what the numbers represent? Are they a measure of the viscosity of the binder?

Dik

 

[AKSherpa]

Dik, PG 52-40 is Performance Graded Asphalt Binder. The numbers stand for 52 & -40 Celsius.

 

[dik]

Thanks, Dik

 

[geomane]

The 50 degrees Celsius is the max 7-day average temp expected during the design life. The -40 degrees Celsius is lowest expected temp. These temperatures represent pavement temperature, not air temperature.

 

[dik]

jmcc: Thanks... 50C might be a little low... with the sun beating down on the roadway...

Dik

 

[AKSherpa]

"Way Up North, Way Up North, .. North ..to Alaska, Go North the Rush Is On!

dik, Good point on the pavement temperature. Even in cold climates, 120 plus pavement temperatures occur and rutting seems to be one of the major issues. Peak traffic coinciding with relatively high pavement temperature. That would be more on the design end.

Currently facing production, information concerning the manufacture and placement could be helpful and valuable.

Thanks

 

[dik]

Just recently doing a bit of asphalt repair, but, not an asphalt pavement 'guy'... because it is relevant and recent, I've been keeping my eyes peeled for asphalt related stuff...

Is there a PG 100-40? or something of that ilk?

Dik

 

[AKSherpa]

Dik,

While I have been around quite a bit of paving over the last 15 years working as QC for a paving contractor I am not extremely educated on the various binders. We almost always use PG 52-28 and occasionally have used some modified binders, but never PG 52-40 that I remember.

I have never seen any info on a binder with a grade of 100 Celsius. I have seen an asphalt binder listed in a table that was around PG 86-22.

Can I ask what type of project you are involved in that would require a binder in the vicinity of PG 100-40?

AKS

 

[Ron]

If you're in Alaska, wouldn't you be more likely in a PG 58-34 region? That's more along the lines of The Asphalt Institute recommendations and consistent with dik's area as well.

Dik....the PG grades go in 6 degree increments, up and down, based on high temp being 7-day average and the low temp being a 1 day minimum, as jmcc noted.

 

[AKSherpa]

Ron,

In Alaska there is way too much climate variation from region to region to pin it down to one grade of asphalt. We have used PG 52-28 thru PG 64-40.

 

[dik]

AKS...

It's for a project I've already done and just gaining additional information for my own use. The earlier work was simply to replace a little roadwork that was cut out to do some work on a retaining wall and concrete wall.

I guess averaged day and night the 7 day could be in the order of 58.

Thanks, Ron

Dik

 

[cvg]

76-16 is about the best you can do

http://www.pavementinteractive.org/superpave-performance-grading/

 

[nkrigPE]

I work in the Texas panhandle region and we typically specify a 70-28. We had never really put a lot of thought in to our binder selection and then we had an owner allow 64-28 to be used on a project that we paved in the middle of June.

It was 100+ degrees everyday for like 2 weeks. The pavement couldn't make density, as soon as traffic got put on it the road pretty much failed at every intersection due to shoving. It was quite the learning experience.

 

[dik]

Thanks cvg... good link

Dik