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Rockman
06-24-2010, 03:38 PM
Just a quick question regarding something that has been boggling my mind for some time now.

The North-South Tollway (I355) in IL was constructed back in somewhere around the mid to late 80s (I think).

They have had to do some minor repair work since initial construction and recently added a few lanes on each side to handle the increase travelers.

Most of the tollway is concrete and it looks good, rides on good and seems to take the beating the Chicago winters can give.

After a year of adding these new concrete lanes, there have been teams of highway workers out there cutting rectangular sections out and then filling again with concrete. These sections are approximately 4 feet by 8 feet.

I do not see a reason for this and thought maybe someone here on the board can explain.

Traffic has been great since last year and now is all F@*%ed again.

Please help me manage my anger! :D

J NORRIS
06-24-2010, 05:01 PM
Soil Conditions:
Stabilization is one reason, normally done to 95% Proctor Density. Basically, roll the sheeps foot roller over the dirt until the "sheep's feet" don't sink into the dirt anymore.
They are probably cutting out sections to restabilize the dirt with lime and flyash.
Sink holes is another reason, when the water table is lowered or water erodes the limestone and the area colapses.

CruisinGA
06-24-2010, 05:06 PM
Probably got some stimulus money to burn. :rolleyes:

joecarew3
06-24-2010, 05:46 PM
Probably got some stimulus money to burn. :rolleyes:

That was my first thought!

mrprostar
06-25-2010, 10:01 AM
Soil Conditions:
Stabilization is one reason, normally done to 95% Proctor Density. Basically, roll the sheeps foot roller over the dirt until the "sheep's feet" don't sink into the dirt anymore.
They are probably cutting out sections to restabilize the dirt with lime and flyash.
Sink holes is another reason, when the water table is lowered or water erodes the limestone and the area colapses.

Not sure what you mean by lime and flyash? They put that in the soil before pouring concrete in the midwest?

Once concrete cracks outside of control joints it breaks up quickly with that much abuse. When it breaks up it causes some serious safety issues. I'm sure they are just being proactive to avoid lawsuits.

Ski-me
06-25-2010, 10:34 AM
If they are symmetrical at each construction joint......they may be putting in dowels (rebar sticks) to tie the concrete roadway together better. I see them do this where there is a lot of freeze/thaw cycles. It keeps the slabs from moving up and down too much, which would create slight bumps in the roadway at each seam.

If they are random patches, there might be some slight bonding issues with the concrete and rebar or the concrete is failing somehow in those locations. Just repairing before any salt/moisture can get down to the rebar to create bigger problems, etc.

Rockman
06-25-2010, 11:36 AM
If they are symmetrical at each construction joint......they may be putting in dowels (rebar sticks) to tie the concrete roadway together better. I see them do this where there is a lot of freeze/thaw cycles. It keeps the slabs from moving up and down too much, which would create slight bumps in the roadway at each seam.

If they are random patches, there might be some slight bonding issues with the concrete and rebar or the concrete is failing somehow in those locations. Just repairing before any salt/moisture can get down to the rebar to create bigger problems, etc.

Yes, they are putting in more rebar sticks within the 4x8 sections. That might be the answer I was looking for.

Thanks!

RM

willgeorge
06-27-2010, 01:38 AM
If they are symmetrical at each construction joint......they may be putting in dowels (rebar sticks) to tie the concrete roadway together better. I see them do this where there is a lot of freeze/thaw cycles. It keeps the slabs from moving up and down too much, which would create slight bumps in the roadway at each seam.

that is exactly what they are doing. dowel bars and sometimes bad sections. its very common in the upper midwest... they usually mill down the entire road surface with a diamond blade after the dowel bars are in.

concrete does 2 things.. shrinks and cracks. guaranteed everytime.

although the construction sucks.. its so much nice driving on a road thats had this procedure done.

cbryan70
06-27-2010, 02:16 AM
that is exactly what they are doing. dowel bars and sometimes bad sections. its very common in the upper midwest... they usually mill down the entire road surface with a diamond blade after the dowel bars are in.

concrete does 2 things.. shrinks and cracks. guaranteed everytime.

although the construction sucks.. its so much nice driving on a road thats had this procedure done.

Not sure why illinois doesnt throw concret in on every tollway we sure do pay for it. seems to last about 50 years longer