separate concrete samples from plastic cylinders

[Struct123]

Hi,

I would like to know if there is any material/compound that I can put into the plastic cylinder before the placement of concrete mix so that when cured, the concrete sample can be taken out of the cylinder easily.

Thanks.

Mike

 

[henri2]

ASTM C 31 Section 4.1 last sentence states " Resuable molds shall be lightly coated with mineral oil or a suitable nonreactive form release material before use".

 

[boffintech]

We used to flip the cylinders upside down, use a small nail to puncture the bottom of the plastic mold, and then use an air gun with a rubber nipple to inflate the mold causing it to rise off of the concrete cylinder. The plastic mold could then be reused.

However, we discontinued this because we felt green cylinders were adversely affected by the pressure needed to blow off the cylinder. Plus on occasion the mold will explode during this operation.