Concrete Mix Design

[SperlingPE]

I am looking for information or experience with low drying shrinkage concrete. I am specifying an industrial type floor slab. The owner has had material handling operation issues with their current floor slab at the joints.

This will be a floor slab in an addition. I am reviewing the joint design and lay-out as well as the concrete mix design.

The goal is to have little or no curling at the concrete joints. Predictable joint sizes prior to filling/sealing.

 

[shin25]

Few things that may add to excessive shrinkage are higher than required w/c ratio, quality of your aggregates, use of high range water reducers, types of cement like type III for example or use of high quantity than needed cementitious materials etc. While reviewing mix you may need to keep all these in mind.

Also, if you like you may specify type-K cement, which is shrinkage compensating in nature. You also can specify shrinkage compensating admixture for your mix.

You may need to pay spacial attention to curing of the concrete. If you do not like cracking or curling at all then you may have to prescibe longer curing period. You have to select the amount of reinforcement and spacing of contraction joints more carefully.

 

[hokie66]

You may wish to consider a posttensioned slab on grade, thus eliminating a lot of joints.

 

[DarthSoilsGuy]

Smithfield foods used the shrinkage compensating concrete in their mega-processing plant in NC i worked on a couple of years ago. i think the metal embedded joints were around ~? 100 ft. the crew that did it were specialty contractors who travel to pour this type of slab. i may be wrong, but my initial guess would be that if you found a contractor who does this in your area, they'll provide you with sample projects and guidance. "Concrete International January 2006 (vol 28 no. 1)" has a good article on SCC Pavements if you're near an engineering library.

 

[unclesyd]

I recently witnessed a large slab being poured for high load use that used Force 10000 in the mix. Another thing I noticed was that the mix used blast furnace slag instead of river rock, normally used in this area.
This pour was in a closed building and it looked like they were taking extra care in curing of the concrete.

http://www.na.graceconstruction.com/concrete/download/FT-26E_2.pdf