Aggregate Testing for Akali (ASTM C33 & ASTM C295)

[BatMan]

When aggregate is tested per ASTM C33 on alkalinity, what additional (or more valuable) information on alkalinity when petrographic examination (ASTM C295) is performed? Or are these two complete set of testing requirement?

 

[Ron]

One has little to do with the other. When you test for alkali, you want to know the susceptibility of the aggregate to attack by alkali in the cement. This is sone with a separate test that measures expansion of mortar bar specimens to see if alkali reactivity occurs. There are two forms of alkali reactivity that are deleterious...... they are alkali-silica and alkali-carbonate reactions. Both can destroy a structure.

 

[BatMan]

Thank you. I appreciate the comment.