I have only been a mixer driver for a couple years, but in that time, I've seen a lot of things. There are a lot of different types of concrete pours, and a lot of different types of contractors handling them. Here now are a few things that will not only keep your mixer driver happy, but will make your pour a lot easier to deal with.
Our job as mixer drivers is to
safely transport concrete to our customers, all the while keeping it in spec, staying punctual, and protecting the environment. You'll notice the word "safely" was bolded and underlined. I will never do something I deem to not be safe. You can sign all the waivers you want, you can show me a signed letter from Jesus himself, I will not do something I feel will injure myself or anyone else. Concrete mixers are carrying a moving liquid load with a high center of gravity: They occasionally tip over.
Assessing Your Job Site
This is easier for contractors that work exclusively with concrete, because they have a pretty good idea what a mixer will and won't do. This is more aimed toward the homeowner and occasional concrete pourer. It is the contractor's responsibility to make sure the site is safe and has adequate access.
It's fine, I got my pickup truck back there.
I'm glad you did. However, your pickup truck is, best case scenario, half as long as my mixer. It also weighs 1/10th as much. And is half as tall. Please make sure that the ground is sturdy enough to support up to 80,000 lbs.
Otherwise, this happens. I had a damage waiver signed, so the 2 foot deep rut I left was the responsibility of the contractor. Luckily, I was able to be pulled out by another of our trucks, so he avoided a several-hundred-dollar tow bill.
Also, be aware of the grade of the slope you wish us to drive on. If it is steep, request a manual transmission truck: Many new trucks are automatic, and don't have the same compression braking as manuals do. We had a job recently at my company that an experienced driver refused to drive his automatic truck into because it was too steep and muddy. If it leans over to one side or the other, we may not even drive on it. In that instance, it may be beneficial to have a company representative go to your jobsite to make sure it is safe to put a truck on.
Do You Need a Pump?
Most of the time, if you have to ask, yes you do. The chutes only go up so high, and concrete doesn't flow uphill. There is also only 12 feet of them (16 in front discharge mixers), and don't even ask:
We won't put on extra chutes. The extra weight of the concrete will collapse them like drinking straws, and anybody in the way will be hurt. This goes along with the "if it isn't safe, I won't do it" thing.
When considering a pump, look out for overhead obstacles, such as trees and especially power lines. If power lines make it impossible with a boom pump, get a line pump.
Cleanup Areas
I can only speak for my state, Washington, but concrete slurry is a big deal. The state of Washington has deemed the ground (yes, any part of it) as part of the "waters of the state." Concrete slurry is a severe alkaline, therefore knocking the pH of the water around it all out of whack. Simply put,
its a $10,000 fine per offense for getting concrete slurry on the ground. We need to have an area that is lined with an impermiable substance, such as visqueen, in order to keep our washout mess contained. And remember that we can use up to 40 gallons of water, so make sure the hole or pan is large enough. I cannot clean out in a 5-gallon bucket. Trust me, I've been asked to.
The Day of the Pour
So you've set up your forms, made sure access is acceptable, got your tools and crew ready. Now its time to make sure everything goes as easy as possible. Make sure you move all your cars and trucks out of the way. We may be able to get by them, but its a lot easier if we don't have to get too close. If we're pouring from inside the truck, its just one less thing we have to worry about.
Also, don't be insulted if we ask you to sign a waiver. Our company requires one whenever we leave asphalt. Its not that we don't trust you, its just that we're trying to cover our butts. And most of the time, nothing happens.
During the Pour
Many times, I go to houses where the homeowner is DIYing some concrete, and this great. But make sure you protect what is important.
The best place for children is inside looking out the window!
Most children don't grasp the danger of concrete mixers. I've had them ride their bikes inches from my front bumper. Another driver at my plant had to slam on his brakes when he saw a soccer ball come out into the road followed by, you guessed it, the younger kicker of said ball. Keep them inside please, or at very least, behind a fence or barrier or some kind. If I were to hurt one of them, nobody involved would ever be the same, and I don't think I'm being over dramatic by saying it.
Same goes for dogs. I've had several run into fresh concrete.
A word about "handprints:" Concrete will burn your hands and irritate your skin. If you must sign your slab, hose your finger off right away.
Assuming you're using a rear discharge mixer, you have to run the chute. Don't yell out directions, we can't hear you. You must use hand signals. Here they are:
The only one I don't see on this list is the "lock/unlock chute" sign, which is like the "hang loose" hand sign, thumb and pinky out shaking your hand.
Remember, we (usually) don't have backup cameras, so we can't see you when you're directly behind the truck. Make sure I can see your signal, otherwise I will assume that you want me to continue what I'm doing. Sometimes, when you camp out behind the drum for long periods of time, I'll stop discharging to make sure everything is okay.
I will not move the truck if I don't see you signaling.
Front Discharge Vs. Rear Discharge
Most regions in the U.S. run either one or the other. There are front discharge:
And rear discharge (conventional):
If you are lucky enough to have a choice (as you are with my company), there are advantages and disadvantages to both.
Front Discharge:
- Six wheel drive
- Taller chute than conventional
- Four more feet of chute than conventional
- Hydraulically controlled chutes, which means you don't have to run them
However, the aren't as manuverable since they are quite a bit longer than a conventional. They are also taller and heavier.
Rear Discharge:
- Somewhat ligher (not much)
- More configurations (conveyer, tractor trailer, composite drums, etc.)
- Many jobs are set up for them
However, the chute must be controlled by a finisher. The communication between driver and finisher is also compromised, since they are at opposite ends of the truck.
I hope this has given the DIYer a few tips to make your concrete pour go a bit smoother. The most important thing is to be in a good mood. If everybody is ticked off, it just makes it that much tougher on everybody.
So there you go. Happy concrete spilling.
Linear Mode
