×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Rigid Concrete Pavement Construction Joint Detail

Rigid Concrete Pavement Construction Joint Detail

Rigid Concrete Pavement Construction Joint Detail

(OP)
Ladies and Gents,

I'm preparing a rigid concrete pavement design for a small office complex.  The pavement sections will be 4.0 and 5.0 inches thick.  In reviewing details for the different joint designs, I'm in a quandry regarding the "construction" joint detail.

With construction joints in pavements less than 6 inches, using dowels is typically not recommended.  Somewhere in the recesses of my brain, I also recall that using a "key" is also subject to questions, since the pavement section is relatively thin and the key tends to break.

Any thoughts or experience on what such a joint should be so that the slabs across the construction joint are interlocked?

Thanks,

theCorkster

RE: Rigid Concrete Pavement Construction Joint Detail

I see standard details for 6" thick concrete paving with a key.  Why not thicken it at the construction joint and construct the key?

RE: Rigid Concrete Pavement Construction Joint Detail

4" is adequate for only the lightest duty pavement.  You have to be careful in thickening the slab edge for dowels; this can restrain the concrete for thermal movement and can cause cracking.  Concrete should slope 1:12 min.  Because of the flexibility of thin pavements, they are much more susceptible to 'pumping' failure at the joints.  This is where moisture gets in and softens the soil in the vicinity of the joint.  For any type of light useage, I would not use anything less than 6" thickness.

Dik

RE: Rigid Concrete Pavement Construction Joint Detail

Keep in mind that residential driveways are typically 4 to 5 inches thick.  Think back to the condition of these driveways...  If you still want to recommend/construct a commerical parking lot/drive areas of that thickness; I have the following recommendations

1.  Maximum joint spacing should be 8 feet for 4" thick pavement and 10 feet for 5".  This is in all directions.
2.  Try to minimize the number of construction/cold joints.
3.  Where cold joints must be made, thicken the slab to 7" and use 1/2 inch smooth epoxy coated steel bars for load transfer.
4.  Do not use deformed bars and keyway.  Keyway should only be used for longitudinal joints, such as along the center line of a roadway.  When keyway is used, deformed bars must be used to hold the keyway together.  

RE: Rigid Concrete Pavement Construction Joint Detail

Why build cracks in your slab?  If WWF is used to reinforce the slab, then cracks can be kept to a size not visible to normal inspection, (need a microscope). Try WWF of 4"x4", D7xD7 in 12' x 20' sheets. A shrinkage-compensating concrete and a wet cure will allow joint spacing to be at 8 to 10 foot intervals. Place WWF on continuous chairs, (not pulled up by hooks in plastic mix).

RE: Rigid Concrete Pavement Construction Joint Detail

(OP)
cvg, dik, GeoPaveTraffic & civil person;

Thanks for the great input!  This parking lot is small in size, without through access.  4-inch pavement will be in parking stalls for autos/light trucks, and 5-inch pavement will provide parking access, moving, delivery, and garbage truck access.  Sections will be supported on 4 to 8 inches of compacted baserock.  

I plan on 1) limiting construction joints and 2) using a thickened section with dowels where construction joints must be located.

civilperson:  My experience with concrete pavement is to avoid using reinforcement (other than doweled joints), especially wire due to the problems of getting it built properly.  Even with diligent inspection during placement, mesh seems to alway get displaced, and resetting it during the pour is a always battle.  Some structurals I work with will increase slab thickness by 1 inch to avoid the construction problem.      

           

RE: Rigid Concrete Pavement Construction Joint Detail

Error:
For any type of light useage, I would not use anything less than 6" thickness.

should read...

For anything other than light useage, I would not use anything less than 6" thickness.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources