Air Void System - Harden Concrete 1

[gosai]

I would like to get some information about testing concrete for AVC. There is no test data provided by concrete supplier with submitted mix design. Is there any test method I can ask supplier for trial batch and test concrete for AVC as per ASTM C457? Any special requirement for minimum quantity of concrete for Trial Batch? ASTM requires minimum three samples. What is minimum age requirement for testing AVS?

Thanks to all

 

[Ron]

There are essentially two ways to determine air content. One is on the plastic concrete at the time of delivery. There are at least two valid methods to do the air content at this point...the volumetric method and the pressure method.

The other way to determine the air content of the concrete is to take a core specimen from the hardened concrete, cross-section and polish the specimen, then perform point-count measurements of the physical air voids under a microscope. This requires special equipment and expertise.

The hardened concrete method is good because it can show the differences between entrapped air and entrained air. The methods used for air content on plastic concrete can only measure total air content, without distinguishing between entrapped and entrained air.