Dear sir, but about 34% of residue permitted in IS code got referred latter. As far as this is concerned what is your opinion sir. Where as any other tests to be get conducted apart from fineness sir as per codel conditions
Its up to you to define a acceptance criteria on fineness, as this is going to make difference in properties of my concrete.
If you seen 34% then you must have seen definitions and kind of ashes comes from plant like pond, mond etc. highest fineness is found in the flyash.
You can have the acceptance to 34% (as per IS) for retained particle or you can define if you are getting finest quality in your area.
You can do all Physical and Chemical tests as prescribed in IS code on every lot or as per the frequency you or your management specifies.
there is nothing much which can be done with flyash at current condition, also flyash is used when we have RMC plants, it indicates the consumption of flyash does happens in a day or two. so getting something failed result from third party and getting OK results in concrete you produce does not make any sense and situation even goes worse.
Finally it up to us on what criteria to be set for acceptance base on practical conditions and design assumptions.