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RE: zonolite topping

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Rich,
I keep forgetting how bad MY memory is;>)
 
I think the antiquated roof system to which you are referring was called "Load Master". 
 
Regarding the other issue.  You are needing to armor the edge to prevent wheel abrasion of the concrete.  The coolest solution that I have seen was to use a vertical bar on each side of the joint.  Forget the epoxy for the reason that you cited.  Use an SCC concrete.  It will flow and consolidate easier without the downside of epoxy.  It will provide about a minimum 10,000 psi concrete. 
 
For details of armoring an edge, contact Kalman Floors in Evergreen, CO.  They do this routinely.  There slabs are grade supported.  They tie two adjacent slabs together with square dowels and PNA clips to allow differential longitudinal shrinkage, but the slabs will not move differentially in the vertical direction.  The edges are armored by vertical bars that are doweled in to the slabs. 

Regards, Harold Sprague


 

From: SEAInt05(--nospam--at)lewisengineering.com
To: seaint(--nospam--at)seaint.org
Subject: zonolite topping
Date: Sat, 14 Aug 2010 16:44:34 -0500

I need some help remembering an old roofing system,  Then I need some help with a precast TEE topping system.

 

First, the roof system.  I know I’m getting old when I can’t remember the way we did it when I got out of school.  I guess it happens when you pass the 50 mark.  I have trouble remembering a lot of my old projects.  But I digress. . . .  I recall back in the 80’s there was a zonolite roofing system that was used.  I recall the metal deck application used vented deck, insulation board and zonolite topping.  I recall the insulation board had holes in it and was put down over the deck.  The zonolite was poured, filling in the cracks and holes, creating the roof slope, etc.  Then it all was covered by a roof membrane.  I recall a similar system on precast hollow core plank.  I can’t find any information on this.  I guess I’m not googling the right words.

 

Now the second issue, TEE topping.  This is what caused me to recall the first.  I’m working on a project, oddly enough constructed in the 80’s, where the TEE was sloped and an insulation board and zonolight topping was placed on it to level the surface.  The zonolite thickness varies from 4.5” to 12”, over a 60 feet length.  Then a 3” NW concrete topping was added for the floor.  The area is a pallet storage area with forklift truck.  The slab has been cracking and multiple repairs made.  Sometimes the repairs included going all the way down to the top of TEE and pouring back NW concrete and sometimes the repair has left the zonolite system in place.  Usually the repair begins to crack again at the edge and just grow bigger.  I’m thinking it might be an issue with the difference of depression the forklift truck makes as it rolls over the joint area. This is kind of like a slab on an elastic foundation.   If one area does not deflect down like the adjacent area then there could be bounce as the tires roll over it, causing the slab to crack near the edge.  This would be pronounced where the zonolite was removed and NW concrete was poured back down to the TEE surface.

 

My thought for the next repair is to try to maintain a constant elastic bearing for the topping slab.  I propose to cut the topping into a square with a saw.  Replace any damaged zonolite.  Fabricate an inverted steel Tee from plates and wedge the flange of the Tee under the existing slab.  Then a new 3” topping is poured and bears on the Tee and zonolite.  I see this as distributing the wheel load over the crack onto the zonolight.  I would like to fill the gap between the existing slab and the steel Tee with an epoxy grout.  One problem I have is that they tried to use an epoxy on a previous patch and apparently the epoxy melts the zonolight, kind of like gas on Styrofoam.

 

I’m looking for anyone who can give some insight into this repair procedure.  Then I’m looking For anyone who can help me get some sleep by helping me recall this outdated roof system.

 

Rich