Slab-on-grade maximum pour size

[ajk1]

Two questions:

1) Is the ACI recommendation for slab-on-grade pour size 9000 SF? If so, in which ACI document is this?

2) Is there a maximum recommended length of pour?

 

[Ingenuity]

For saw-cut joints where "sizable" shear transfer is required across the joint we use steel plate dowels like DANLEY Plate Dowel Cradles:

http://www.danley.com.au/Product_Joints_Plate_Dowel_Cradles.htm

We always use WWF (aka mesh or fabric) with min of 8mm dia deformed wires at 200mm c/c, chaired up on correctly sized plastic supports chairs so it stays in the top of slab - way different to the US practice of "chicken mesh" in SOG.

The only SOG's that I have seen without reinforcement (other than engineered unreinforced pavements of significant thickness) are council/city footpaths, and driveway crossings to dwellings.

 

[racookpe1978]

Details are not clear from that link, but is that OZ/NZ connection like a 4 inch (100 mm) hollow tube slipped on to the stub ends of a cut mesh wire. (It is slipped over the mesh stubs before the pour, so it is concentric to each mesh wire; but the hollow tube is not crimped to both mesh stubs.)

 

[Ingenuity]

DANLEY's are a fully prefabricated dowel plate assembly in 3 m lengths, with SOLID 6mm or 10mm thick plates, slipped into alternating HDPE slip-sheaths. Prefabed to correct depth to match the design slab thickness. First install the assembly over the proposed joint location and then install mesh/fabric either side of assembly joint. Place conc, then saw cut to required depth.

 

[hope9010]

If I may return to my original question, about whether any limit should be specified on the length of pour of slab-on-grade, to avoid slab performance issues, or excessive opening of the joint between pours when the slab dries out: Is it the consensus that there should or should not be such limit? If there should be such a limit, what do you think that it should be, for the normal slab placed on 6" to 8" clear crushed stone granular fill on soil subgrade, assuming the concrete is not a special low shrinkage mix?

60 feet?
75 feet?
100 feet?
150 feet?
200 feet?
no limit?

 

[jayrod12]

If it is a poll then my vote is no limit provided there are no constraints or man hours or supplies.

 

[cvg]

The only SOG's that I have seen without reinforcement (other than engineered unreinforced pavements of significant thickness) are council/city footpaths, and driveway crossings to dwellings.

There are literally thousands of miles of interstate highways and freeways as well airport runways and taxiways, all constructed of jointed plain (un-reinforced) concrete. Some state DOT's do require full slab reinforcement, but plain un-reinforced concrete is by far the most commonly used.

http://www.pavementinteractive.org/article/pcc-pavement/

http://www.pavementinteractive.org/article/jointed-plain-concrete-pavement/

 

[hope9010]

Thank you cvg. Much appreciated.