| Author |
Message |
Anonymous
| | Posted on Friday, January 14, 2005 - 02:42 pm: |    |
What is the best installation method for unit pavers as part of a driveway for a residential tower (500 living units)? |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 79
Registered: 05-2003
| | Posted on Friday, January 14, 2005 - 03:49 pm: | |
Depends on what part of the country the work is to be performed and whether the pavers are being laid on mortar over a solid substrate or over sand and compacted fill - check the Interlocking Concrete Paver Institute web site - very good info for Architects, Contractors, or Homeowners:
http://www.icpi.org/ |
Anonymous
| | Posted on Friday, January 14, 2005 - 03:57 pm: | |
It's in the southwest. I guess that was my question - can you use sand/fill in vehicle areas or should it be mortar set |
Ronald L. Geren, RA, CSI, CCS, CCCA
Senior Member
Username: specman
Post Number: 80
Registered: 03-2003
| | Posted on Friday, January 14, 2005 - 04:08 pm: | |
Being from the southwest (Phoenix), I'd go with a concrete substrate. Pavers are used here in crosswalks, accessible ramps at street corners, and medians, and almost all installations I've seen have been in a recessed concrete pad.
With 500 living units, you probably won't see the level of traffic that a city street would experience, but it'll be a lot higher than your typical apartment complex.
I recommend that you discuss it with the project's civil engineer and let him do the engineering. If the driveways are used for fire department access, they may require higher than normal pavement loads. |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 328
Registered: 10-2002
| | Posted on Friday, January 14, 2005 - 04:40 pm: | |
I think there is way more to the recommendation than just geographic location.
There is paver type. Brick, precast (large sized units), precast (brick sized units), stone, asphalt pavers.
Then there is geography/climate...little rain, lots of rain, does it freeze or not. Snow, ice, is ice melting systems used or is there a lot of salts that will be spread about on the surface.
Then there is usage, high traffic, low traffic - heavy traffic like trucks or just cars and vans.
And then do the pavers naturally interlock or not.
All that said, I have put brick sized non-interlocking precast concrete pavers on sand setting beds over compacted fill where it was in a moderately trafficed area and subject to heavy trucks and they are still as flat as the day they were installed. Its not my recommendation to do that, you have to have a good installer and the subgrade has to be the correct type and compaction - lots of things under different people's control.
Then of course there is unintended end user abuse that can screw you up.
We were doing a 4 buiding complex and using interlocking precast concrete pavers. This is in Virginia, it does freeze. These were on sand bed that was only 3/4 inch deep, over correctly compacted fill. It was not even road traffic, it was a paving edge between the sidewalk and the curb, so it did not even get foot traffic. But it was in a December when it we were having warm days followed by freezing nights, and the area in trouble was in the shade of the buildings during the warmest part of the day.
It had us all stumped, and since the landscape consultant was actually responsible for all of this, I was standing to the side and mostly letting everyone else dig in the dirt and poke about.
So it was I that noticed that here it was right after lunch and the owner's building maintenance crew came out to clean up the area, dragging out hoses to wash down the walks. Spotting something interesting I suggested we all step out of the way while they passed by...and the very leaky connection between 2 hoses came to rest at the top of the slope immediately above the area and a virtual river was created right were the pavers were heaving.
It seems that every day they came out and washed down the walks and this leaky joint was positioned right there. I figured that the area got the equivalent of about 2 inches of rain over 40 minutes or so every day except Saturday and Sunday. And once it started to freeze in December overnight, it was doomed.
Our suggestion to the Owner was obvious, they stopped drowning the pavers and it all went away.
There are really just too many issues on this point to be able to give a broad recommendation.
William |
Brian Trimble (Unregistered Guest)
Unregistered guest
| | Posted on Friday, January 14, 2005 - 05:17 pm: | |
As William said, there are a lot of factors involved in this. I personally prefer brick pavers set on sand over a compacted aggregate base. This allows a lot of flexibility, but it also has to be installed according to spec. Otherwise you might as well go to a mortared system. Although the mortared system is good, the joints do have to be maintained over time. That's why I like the flexible system.
For information on brick paving systems, check out BIA's website and the Technical Notes 14 Series (www.gobrick.com) |
Ron Beard CCS
Senior Member
Username: rm_beard_ccs
Post Number: 46
Registered: 10-2002
| | Posted on Saturday, January 15, 2005 - 02:56 pm: | |
Not only does one need to look at the specific units, the installation system, and usage but also what is under and around the system. Several years ago, I had a large ($5M) remedial paving project over a parking garage. The pavers were breaking up (excessive freeze-thaw), ponding at all drains (well naturally, did you expect otherwise?), uneven settlement everywhere, cracked and spalled concrete containment units, etc.
Field investigations determined that the system was improperly designed and specified from the start but that didn’t matter because the contractor didn’t follow the contract documents anyway. Turns out that nearly every expansion joint was defective, there was no geotech fabric around the drains (or anywhere else), the wrong aggregate was used, the drain lines were filled solid with sand for nearly 20' (hence, all the ponding), the ponding water had caused extension damage to adjacent concrete structural members and to garage level decks.
The only ‘good’ news from this project was that the hot-applied WP membrane system (Bakkor, IIRC) was a good one and was properly installed. The system was 30 years old so the owner at least received a reasonable service life even through it should have been a lot longer.
So, going back to my original point, what is happening under and around the system cannot be overlooked. Determinne what is happening to the surface water (mortar joints), water under the system (open or sand joints), drains (hopefully, bi-level type), and expansion joints (if applicable). David alluded to this in his enlightening post.
I wholeheartedly endorse Jerome’s previously posted recommendation of referring to ICPI’s website at http://www.icpi.org. It has some extremely good downloads and spec information - if nothing else the aggregate grading recommendations is worth the effort. I relied heavily on this site for the remedial work for the above discussed project.
Ron |
|
4specs.com Home Page