NL25: weird flop betting

[Mr_Pathetic]

villain is a 57/13/2 who seems to play pretty much like his stats suggest. he doesn't really do much betting PF whether its raising or 3betting. have not seen him do anything stupid or out of the ordinary postflop up until this point. His calling range PF is something like 20% of his hands. I really cannot fathom him playing a set like this ever especially given how aggro I have been on the flop (I am betting this flop >90% of the time against him which might be a leak). I do not think he has A5 since I hold two of the aces and not really sure if he would call PF with 56. He is more the type who likes broadway cards for calling PFRs. Who is calling and who is folding and why? FWIW i interpreted this bet at the time for a "please fold your hand now" type bet.

Full Tilt Poker, $0.10/$0.25 NL Hold'em Cash Game, 6 Players
LeggoPoker Hand History Converter

SB: $26.75
BB: $18.25
Hero (UTG): $28
MP: $23.55
CO: $31.15
BTN: $20.95

Pre-Flop: A[img]/images/graemlins/heart.gif[/img] A dealt to Hero (UTG)
<font color="red">Hero raises to $0.80</font>, 2 folds, BTN calls $0.80, SB folds, BB calls $0.55

Flop: ($2.50) 4[img]/images/graemlins/heart.gif[/img] 3 2 (3 Players)
<font color="red">BB bets $17.45 and is All-In</font>, Hero??????