Minimum Aggregate Size for Slab on Grade 1

[Boiler106]

We have an 8 inch slab with rolling equipment and enhanced aggregate interlock utilizing reinforcing crossing the control joints.

i received a mix design that utilizes #78 pea gravel. my gut tells me to reject this for the aggregate interlock issue the pea gravel will likely create, given that its so small.

Is there a minimum aggregate size that should be specified for slabs using aggregate interlock?

 

[dik]

You should use the maximum sized aggregate to reduce shrinkage. For most small slabs I use 3/4" and for 8", depending on the use, I would consider 1-1/2" aggregate. Pea gravel should not be used. Reject...

 

[HTURKAK]

i received a mix design that utilizes #78 pea gravel. my gut tells me to reject this for the aggregate interlock issue the pea gravel will likely create,

I agree with you.
Two reasons;
- Aggregate interlock ( so load transfer) less effective,
- The size of aggregate ( in this case ,#78 pea gravel ) more prone to shrinkage.
Use greater max. size aggregate ( say 1.5 in )

Agree with Mr DIK and a pink star for prompt respond.

 

[dik]

Agree with Mr DIK

Just Dik...

 

[Tomfh]

Too small. 20mm minimum, or preferably bigger as suggested. above.

 

[Enable]

As a contractor I'll sometimes use pea gravel (10mm) in areas of high congestion or those that are difficult to vibrate and where self-consolidating concrete is not an option. But none of that is applicable to a slab-on-grade. I would expect a 3/4" max aggregate size for most slabs-on-grade unless they were rather large and a larger aggregate size was justified. Pea gravel seems like a problem waiting to happen especially if coupled with less than ideal curing conditions, which if we're being honest with each other, is almost always (i.e. a proper wet cure is doubtful).

@Tomfh just because it's confusing in this context we should be clear, I imagine you to mean 20mm (3/4") minimum, maximum aggregate size

 

[Tomfh]

Yes a minimum maximum of 20mm, what’s not to understand??