Shrinkage Compensating Concrete

[JoelTXCive]

We have some crazy retaining walls that also serve as large architectural elements for a new residential development. The end result is going to be a hike & bike trail along a ditch with a "tiered look".

We looked at doing separate walls of different sizes, but due to the geometry and global stability issues, it was easier to do one huge shared footing between all the walls. (see below)

Our wall panels are vary in size, but the large ones are about 25ft in height and 50ft in length.

The architect would like to eliminate all control joints in the structure.

We are looking at using a shrinkage compensating concrete on the wall stems, but we do not have any experience with it.

We have a call into the manufacturer, but haven't heard back yet.

Questions:

1) Does the stuff work? (We are looking at Euclid's "Conex Type G" additive)

2) Any idea on the percentage cost difference between regular concrete and the shrinkage compensating mix? (We think the wall stems will be about 1000 cubic yards of concrete.)

Thank you!

 

[jayrod12]

I think even with a shrinkage compensating concrete, you're still going to be dealing with cracking on a structure like that given all of the restraint points at the wall junctions and jogs. The contractor is going to require construction joints at a minimum.

 

[JoelTXCive]

I was thinking we could possibly pour each panel monolithically.

There would be construction joints at the various wall returns.

Overall, I'm not a fan of the 'no-joint' idea, but we want to do our due diligence before responding to the architect & client.

 

[jayrod12]

For 50ish feet, you'd likely be able to provide enough horizontal reinforcement to keep the crack widths so thin that you wouldn't notice. And that would be without changing concrete. They do super flat jointless floors by just upping the reinforcing substantially. Seems easiest?

 

[dik]

Because of the transitions, I'd still likely use control joints... you can roughly know where the cracks will occur. If any water behind the walls, they will stain over time... best to drain and control the appearance of the cracks.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[canwesteng]

I understood that shrinkage compensating concrete expanded before shrinking, and so you are left with the same volume as before, but have the same problem with cracking. Extra bar to keep the cracks small and regular is your best bet imo.

 

[bridgebuster]

There was a webinar last moth by CTS Cement on Type K shrinkage compensating cement but I missed it. here's a link to their website:

Link

Personally, I would be leery about eliminating control joints. 9 years I did a project to rehab 2200 LF of gravity walls, which included chipping away the face and placing a 6" reinforced overlay. The panels matched the control joints in the wall - 30 to 40'. We had called for horizontal and vertical control joints in the panels but the contractor complained that the joint pattern was too much work so the owner eliminated the pattern. Most of the wall doesn't look like this - I think in some locations the mix was too wet - but there are cracks everywhere.

 

[dik]

bb... concur.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik