You can explicitly call update() on a Tween or a Timeline with a delta of the duration of your animation (personally I'd use a Timeline).
For example (assuming you have a libgdx Sprite called spr and a SpriteAccessor that correctly implements the relevant tween types):
// scale and move a sprite over 2 seconds
Timeline tl = Timeline.createSequence().
.push(Tween.set(spr, SpriteAccessor.SCALE).target(1, 1))
.push(Tween.set(spr, SpriteAccessor.POSITION).target(0, 0))
.beginParallel()
.push(Tween.to(spr, SpriteAccessor.SCALE, 2).target(2, 2))
.push(Tween.to(spr, SpriteAccessor.POSITION, 2).target(50, 50))
.end()
.start(tweenManager);
// force the animation to complete
tl.update(2);
// no need to call kill() as isFinished gets set implicitly by the update
Hope this helps!