When I am told that I would hear from the construction employer 4 days after my interview, then after 10 days I haven't heard from them. Is that normal?

Yes, I think it's normal.  You have to remember that making a decision about whether or not to offer you a job probably isn't the only thing these people have to do during the course of a week - all sorts of things could have come up that were more important and needed immediate attention - no disrespect intended.