Who here hauls asphalt with a tri axle?

What the guys have said so far is very true. Dump trucking is probably the most cut-throat and least rewarding of any kind of trucking I've been in.
I don't know what it's like in your part of the country and I can only address what I see happening in my local area.
There are no contracts. None. You get hired on to haul, usually by a prime contractor or a broker, on a verbal agreement. If they decide to drop the rate you have two choices, go or stay.
The people you'll be working for are almost always well established local boys who have been doing business with each other for years. You're not going to win a fight against them. Ever.
If you have contacts in the industry, or better yet relatives or old friends, you might make a living but that's all you'll make.
Around here paving work used to be hourly. A few hungry junk-equipment operators started bidding the jobs on tonnage. This was a good deal for the contractor and absolute disaster for the truckers.
Say you get hired on to haul asphalt. With no contacts in the industry you'll be the last truck to load in the morning and the first one to be signed out later in the day. You might only work a couple of hours. If you get on a big job where you're working a full day every day start looking for a rate decrease because it's probably going to happen.
Hauling for a concrete plant? Stockpiling? Absolute bottom of the barrel. With what you wind up in your pocket at the end of the week you could probably do just as well working at Home Depot.
And if you stand up on your back legs and complain? The word gets out fast that you're a malcontent and you'll sit. The phone won't ring.
We still do some dirt work and some paving but it's usually for our own projects. Very seldom will we bid on anything else. If things are slow and I need to keep the crew together so they don't leave for better jobs I can always find some dirt work with a contractor but all I'll be doing is trading dollars and too much of that is a death spiral.
I admire your ambition and I wish you luck if you've really made up your mind to try this but go into it with your eyes open, okay?

 

If I'd had better news for you I would have given it. If the opportunity presents itself drive for somebody for awhile.
You're on the outside looking in. You might be surprised how the view changes on the inside looking out.