Fine aggregate failing in Reactivity test

[sxchauhan]

We tested the fine aggregates earlier for the reactivity test per ASTM standards, and it passed. Its been couple of months since this test was done.

Now we are about to pour the concrete,and it so happens that the same fine aggregate is failing the reactivity test. The fine aggregate was tested in a different lab earlier. We have stored the fine aggregate in a ready-mix facility close to the project site. What could be the reasons why the same fine aggregate is failing the reactivity test? Has it do with how we stored it? Somebody suggested that we should stir the fine aggregate heap really well before testing it for the reactivity. Need your suggestions. Thanks a lot.

Sushil, PE
Nebraska

 

[civilperson]

Most pumped sand and gravel pits are high quality in the Platte Valley. I would distrust the failing test results, and run a side by side as well as an independent lab on a split sample. If the results are duplicated switch suppliers.