3" DIA x 6" CONCRETE TEST CYLINDERS

[PT999]

I am seeing these smaller concrete test cylinders being used to mold concrete for compressive strength vs the traditional 6" dia x 12" high test cylinder molds

Is this permitted by ACI

 

[msucog]

4x8's are now permitted by aci and ibc. you should read the documentation though since it requires more specimens and possibly different equipment.

 

[conceng]

I would guess you are seeing 4"x8" cylinders rather than the 3"x6" in the thread title. As msucog pointed out, ACI standard strength acceptance is based on 2 - 6"x12" cylinders or 3 - 4"x8" cylinders at 28-days. No matter what, you are still limited to 3x the maximum aggregate size of the aggregate in the concrete per ASTM C 31, and the consolidation procedure is 2-lifts with a 3/8" diameter rod. The 4"x8" cylinders can only be used for concrete containing aggregates up to 1 1/4" maximum size.

Greg