just starting a foundation with the logix 12 inch block,my total elevation is 15'4" or 11.5 blocks.The question is whether I can pour this in one day,any advice would be appreciated thanks

Read the manufacturer's installation manual and do not exceed manufacturer's reccomended rate.

Yes you can pour it in one day, you will be bringing it up in several lifts, probably be a long day but it can be done.

Also check your states OSHA code, at one point I was subjected to no more than 12' per day, but have since heard you can go higher, I was under Cal-OSHA which may be stricter than regular OHSA

Does placing concrete in tall lifts run the risk of a blowout.  If so, would it be worth while to add an accelerator additive to the mix?  I know the most common accelerator is calcium chloride but there are others that are safer with rebar.

Placing concrete in tall lifts does increase chance of blow out. However, if you have followed the manufacturer's instructions and not cut corners installing the blocks you should be fine. Just remember with a Logix block, you should not be placing more than 3 feet or so per hour -- depending on the temperature. Try calling the manufacturer and ask them where their 12" block fits on the ACI table for resistance to lateral pressure. You can then simply look up the table and you will know for sure where you are safe.

happy to say that I finished the pour 140 cubic meters total and not one blowout

Any photos showing bracing, the pour and bucking for any openings?