How does this make sense?

Villian seems extremely loose-aggressive. Don't have much info on him, but for the 30 or so hands I have on him, he is playing at 70/21.

pokerstars Game #15953808477: Hold'em No Limit ($0.25/$0.50) - 2008/03/13 - 16:10:48 (ET)
Table 'Handahl IV' 6-max Seat #5 is the button
Seat 1: P1 ($19.65 in chips)
Seat 2: Villian ($96.95 in chips)
Seat 3: P3 ($57.50 in chips)
Seat 4: Hero ($49.50 in chips)
Seat 5: P5 ($163.75 in chips)
Seat 6: P6 ($59.55 in chips)
P6: posts small blind $0.25
P1: posts big blind $0.50

*** HOLE CARDS ***
Dealt to Hero A♥ Q♦
Villian: raises $1.50 to $2
P3: folds
Hero: raises $4 to $6
P5: folds
P6: folds
P1: folds
Villian: calls $4

*** FLOP *** 6♣ 10♠ K♥
Villian: checks
Hero: bets $8
Villian: calls $8

*** TURN *** 6♣ 10♠ K♥ 10♦
Villian: checks
Hero: bets $17
Villian: calls $17

*** RIVER *** 6♣ 10♠ K♥ 10♦ 8♦
Villian: checks
Hero: bets $18.50 and is all-in
Villian: calls $18.50

*** SHOW DOWN ***
Hero: shows A♥ Q♦ (a pair of Tens)
Villian: shows 9♠ 8♥ (two pair, Tens and Eights)
Villian collected $96.75 from pot

When he called me on the turn, I expected to be behind, but when he showdowns 98, I don't understand it. Also, how was my betting? Should I have fired the 2nd barrel after he calls the flop, or should I have just checked behind on the turn?

Appreciate the help, thanks.

his calldown is obv silly, some people play bad.

still, i would have given up on the river (and on the turn, for that matter). if he called flop and turn, he's not folding anything on the end getting like 3.5:1 except for missed draws, which you mostly beat anyway. his most likely draw i guess would be QJ, and you also beat AJ. and basically if he's bad enough to play any of those hands this way, he's probably not "good" enough to fold some really weak pair on the end

in this general sort of situation whether or not to fire the 2nd barrel is read dependent. in this specific case i definitely wouldn't. you're well ahead of his draws anyway and he's never folding a T, probably not folding a K, maybe not folding JJ. i mean, 70/21s don't like to fold by definition... so why try to make them?

1) Don't bluff loose players. When you bluff, you want them to fold. Thus, bluffing players who are unlikely to fold is... um... a bad idea.

2) Check behind on the turn. The T pairing is a bad card to bluff again on, since often players will check/call with second pair. Plus, if the ten pairs, and you don't slow down any, it makes your bluff a little less believable.

Check the turn and save yourself $35.50.

If your J (or the A is probably still clean as well) comes on the river, you'll probably still get paid.

Against extremely loose players don't fight aggression with aggression, just wait for a legit hand and slowplay let him try to bluff you. Don't bluff these types of players. Preflop and on the flop you played it fine IMO. On the turn though you should have slowed down and just checked and check on the river.