Bituminous Joint Sawing and Sealing 2

[Scoomer]

I work for a municipality in Minnesota that is currently in the throes of an agressive capital improvement plan for reconstructing residential streets and improving utility service. As part of our street projects, we specify a bituminous joint saw-and-seal after the wear course lift is placed.

The saw-and-seal that we specify is sawcutting a joint 2-1/2" deep. The width of the cut is 1/8" with the exception of the first 5/8" depth for which is it is routed to 1/2" wide at the surface. A bond-breaker tape is installed in the cut with a bituminous sealant to the 5/8" depth. The cuts are generally done about every 40 feet or at every perforation through the pavement (i.e. gate valve or manhole iron) matching the nearest concrete curb joint.

Most of the streets that we reconstruct are typically low-volume residential streets with a few minor arterials. Our main purpose is thermocrack control.

Questions:
1) Does anyone else do saw-and-seal on their roadways?
2) How has it worked out?
3) Can you suggest any modifications to the design above, if any?
4) If you have quit doing saw-and-seal, why? (and if it's a money reason, please provide an engineering justification).

Your advice is appreciated!

 

[GeoPaveTraffic]

I've never seen asphalt streets sawcut and sealed.

For concrete streets, we used a maximum joint spacing of 15 feet for 7 inch thick pavement, 3/8" wide for the top 1", then 1/8" to 2.5". Joint sealed with a rubberized hot pour sealer.

 

[civilperson]

Asphalt topping, (2 1/2"), on a Portland cement concrete subbase in Lincoln, Nebraska, has no surface joints. The top lift is scheduled to be milled and replaced every five to seven years depending on traffic and plumbing cuts. No problems with cracks if the p.c. concrete does not fail, (due to subgrade soil).

 

[ACtrafficengr]

We overlayed HMA over a PCC highway last year, and sawed and sealed over the existing joints in the PCC to address reflection cracking. I understand that this is an old practice. Time will tell how well it holds up.

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[cvg]

have never seen this done for AC, only for PCCP

 

[GoldDredger]

LIke stated above, I have never heard of a sawcut contraction joint, construction joint or expansion joint for asphalt, only portland cement concrete.

What is more, I don't think a joint would work for a material like asphalt. I think any joint would end up closing itself together.

As far as sealing is concerned, that is something that is used. The surface of the asphalt can be sealed after installation to offer more water proofing. Also, asphalt is usually laid against concrete curb, or asphalt in place (at the sawcut). At those areas a 'tack' coat of substance like a hot tar is applied, and creates a bond at the 'cold joint'.

Remember their are temperature minimums for asphalt, I'm sure it would be a factor in the winters of Minnesota. I've heard it lasts from about July 20th to July 15th.

 

[dicksewerrat]

Call the Minneapolis Paving Dept. about this. It seems to me that they were sawcutting the AC streets. 612-673-3000 is the general info number.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[LCruiser]

I would think that might help with pre-PG oils. However, with polymer modification and the right temperature grades to keep the viscosity constant over a wide temperature range that should not be necessary.

See here for details:

http://www.fhwa.dot.gov/PAVEMENT/ltpp/ltppbind.cfm