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Re: Control Joints

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Curt:

Thinking back to my John Deere days where fork trucks and raveling floor
joints were common, your question indicates you are on the right track,
which ever joint width you use.  The most damage is done when there is
vertical movement across the joint.  It's so slight that it cannot be seen,
but it can be felt when standing on the joint as fork truck rolls by.

The object of the semi-rigid filler is to protect that slightly exposed edge
on the far side of the joint as the fork truck approaches.

I think of aspect ratio of joint filler in respect to horizontal joint
movement and adhesion.

Semi-rigid joint filler is about as flexible as a wood pencil.  This doesn't
accomodate much horizontal joint movement.  So joint spacing, mix design,
curing, temperature, and area of floor placed at one time are the controls
influencing the performance of the joint in the horizontal direction.

That leaves adhesion to be considered in the joint design.  I go with the
manufacture's instructions on this, which includes surface preparation and
field quality control as well as joint width.




Paul J. Martin, PE, SE
ADM Design Services
Decatur, IL
217-429-4412
-----Original Message-----
From: La Count, Curt <Curt.LaCount(--nospam--at)Jacobs.com>
To: 'seaint' <seaint(--nospam--at)seaint.org>
Date: Monday, September 20, 1999 5:21 PM


>I need some opinions from members of the list.
>
>Floor joints exposed to hard wheeled traffic are often filled with a semi
>rigid epoxy joint filler.  The joint filler supports the joint edges and
has
>some limited  capacity to move with the slab as it shrinks.  At sawn
joints,
>the joint width is often 1/8" to 1/4" wide and the saw cut depth is around
>1/4 of the slab depth.  My question is;  At construction joints, what would
>be a reasonable joint depth and width?  Is there a minimum aspect ratio to
>the joint filler for proper performance?  I've got the joint filler
>manufacturer working on the answer too, but I thought that I would tap into
>the collective wisdom of the list server.
>
>TIA,
>
>Curt La Count
>Jacobs Engineering
>Portland, OR
>
>
>