I just read sheet music from a book on country piano with this chord progression: C-C-F-F-G-G-C-G. This is 8 bars long. Would you call this an 8 bar blues chord progression? All the examples I found on wikipedia did mention other 8 bar blues chord progressions but something exactly like this one. How can know if this is an 8 bar blues chord progression or not? As far as I know a lot of country songs actually use blues progressions.
There are many variations possible on the 8 bar blues, so this could certainly be one. I'd say it depends on the tune: does it sound bluesy?
Yes. The last 4 are definitely a blues turnaround. Limited to I IV and V chords is consistent. In fact I can't seem to play it without making it bluesy.
But I also agree with @herman's answer. The ear is the true judge.
Since it is so short, it could even be just a phrase in a larger lyrical structure. If you play it in 2/4, with a Motown kinda beat... yeah that could definitely turn into a song with some tambourine in it. :)
Since a blues progression usually makes use of the Blues scale, then in this case the C blues scale would be being used. This would be the following notes: C Eb F Gb G Bb C(again) Does the melody only make use of these notes? If so then it might possibly be a blues progression. Furthermore it does seem to look a lot like a blues progression, except instead of using 4 bars of the tonic chord (C in this case) to start, they use only 2; and again after the subdominant chord (F in this case) they have left out the 2 bars of the tonic.