"Did you put up your umbrella on that trip?"
I'm not a linguist, but I'm a native Japanese speaker. I can't give real grammatical reasoning, but to me, if you put か behind a statement on its own, it makes it seem more rhetorical, like you're asking yourself, not someone else. On the other hand, さした？ sounds naturally interrogative, but it would be only used in casual speech. さしましたか？ would be the formal interrogative form.