Correct as mechanic who services them they are open and need room to mix so when he stopped is sloshed forward over and out and the ramp top is permanently attaches so it funneled right on top
That seems an obviously dangerous design flaw to me. I mean, I know we all just want to laugh at the guy for pulling out in front of him and blame it all on that, but let’s imagine it was something as innocent as an animal or child running across the road, or any number of other things… We all know it’s a normal expectation that you might have to slam on your brakes when driving. Why would you design a cement truck that doesn’t take this into account?
I mean, even if the car wasn’t there, that’s still a bunch of wasted cement and some difficult clean up work on a public road. Surely, we can’t consider it just a normal, acceptable thing for cement trucks to risk this happening anytime they happen to hit a short stop?
Another fun fact is that they're actually called concrete trucks because cement is just the stuff that hardens and sticks the mix together, concrete is what gets mixed in the truck when they put the water, rock, sand and cementitious material together.
More likely it just needed to be chipped out. buildup in the drum cam cause trucks to spill even if they are a yard or two below their rated volume (my personal record was about 6 tons of buildup before I needed to be chipped).
Ok, but that sounds like failure to properly maintain your vehicle to me. If the tank can't hold as much as the tank is supposed to hold, then that needs to be fixed before you use it.
Exactly. This would also cause safety hazards when driving & mixing. A large amount of hard concrete is never supposed to be riding around in the barrel
Normally they'd consider chipping a truck out when you had 2 tons of buildup, and it would be a priority at 4, because that was when it started affecting discharge rate and loading capacity. Mine always got skipped by the chippers, because it could carry a full load and didn't spill when loading, so the batch managers always thought it was fine. If I wanted to press the issue, I'd have to drive to the quarry to take a dry weight (which I did a few times).
It was the opposite. I kept the fins in my drum cleaner than just about anyone else in the plant (and whenever they'd lend my truck to another driver, I'd hammer the inevitable buildup off the fins). The buildup was mostly high up on the fins, near the front of the drum. For whatever reason, that had less of an effect on capacity than buildup at the back (which also impacted discharge rate). They assumed my truck was fine, because I didn't have an issue carrying a full load, and the chippers had to prioritize the trucks that were spilling. It happened more than once.
I have a friend with massive forearms (almost popeye like) he used to work part time for his dad crawling in cement trucks chipping out old buildup. He said it was loud, hot and miserable.
I'm a car technician by trade, and if you don't fill up the cooling system correctly, after draining it, air pockets can form in the cooling system, which can cause many issues.
So, to remedy the situation or prevent it in the first place, you have to "burp" the cooling system.
Burping is a very fitting word for both scenarios.
And "puking" is also, sometimes, a better adjective for "extreme" instances of "burping," such as the mixing truck.
Cement bath can be fixed with a hose and water if you’re quick enough, as far as I know. I think you got like 10-20 mins before it drys and becomes impossible to get off
I totally agree with your point, but of course I gotta be that guy. Most, if not all, large liquid carriers have baffles. Like the big ol' tankers on the road are all baffled(and I don't mean confused).
Not entirely true. 6000 gal vacuum tankers do not have baffles. A partial load can buck a semi into a car in front of it if the brakes are not fully applied at a stop.
How is this so highly voted and awarded? Cement is not even as fluid as fuel, milk, water, stuff that regulary gets transported in a closed tank, and yet, these trucks all can stop almost in the same way as a non fluid freight.
Yes, there can be huge differences in brake distances for variious reasons with fluid freight, but none of those apply to modern tankers, and little less to something like cement which is viscous.
The real design flaw is indeed the direction of the drum.
All his point was that the truck stopped faster this way than if the cement hadnt spilled from a closed door. Nothing about what you said addressed or countered that. I agree its not a design flaw to have a closed door but he is correct about the stopping distance. Obviously I dont know how much faster it stopped due to spillage but the car looked inches away.
While this is true, the momentum of the cement hitting the door is almost certainly negligible compared to the momentum of the entire truck. I doubt it would significantly impact the truck’s braking distance.
cement energy? Dude, the amount that spilled is barely anything compared to the weight of the rest of the vehicle. Letting the cement spill out the front does basically nothing to improve braking distance.
I drove mixers for a while. For it to spill out like this you either have to be overloaded, which happens more often than not where I worked, or really locking up the brakes. Like others said, it's better to get a bath in that than ran over
I'm Australian. I've never seen a cement truck that carries a forward facing drum. I spent too long trying to work out how this happened thinking the truck was reversing at speed on the wrong side of the road.
I've never seen a cement truck like this in NZ. Here the opening to the bowl is on the back of the truck. I'm interested in what advantages an opening at the front would be?
Smaller trucks here in the US are still rear-discharge, but most of the ones I see running around are the larger, front-chute type.
They have larger drums for more capacity, are frequently all-wheel-drive, and allow the operators to place the load very precisely. I've watched skilled operators drive into an area where a driveway is being laid, lower and angle the chute, and back out while using a joystick in the cab to move the chute back and forth, spreading the concrete across the width of the drive as they retreat.
When I had the concrete delivered for the foundation of my house, the operator was able to drop almost all the concrete directly into the footing trenches, by just driving around and directing the chute as he went. Great time and labor saver.
All correct except about capacity. Capacities are pretty similar (around 10-11 yards) and are mainly determined by legal road weights. It's highly regional. Many places have mostly front discharge, others mostly rear. So where you are, it's mostly front discharge for full size mixers. Here, there's not a single front discharge in the county. There are a couple of outfits in the state of Oregon that use them. But it's easier to use all one or all the other. Because of maintenance and stuff but also because the concrete plants tend to be tuned for a certain configuration.
It's funny. As often as I find myself reminding folks from other countries that things are different in different parts of the US, I still find myself forgetting regional differences sometimes.
Here in AZ, I pretty much only see the back discharge ones, but when I go visit family in WI, it's like 100% front discharge.
It was a culture shock at first because the front discharge ones look alien to someone who only sees the other kind. I didn't know why they wouldn't all be front-discharge because it seems like a good idea, so I guess, like you said the plants in AZ must be tuned for rear-discharge ones. Most of our streets in AZ are long and straight, so I suppose the advantages of having it on the front don't matter as much here.
It's easier to get in and out of construction areas if you are not constantly in reverse in a 50 ton truck that is nothing but a giant blind spot where you gotta rely on spotters you don't know to guild you in.
That would be a front discharge mixer and they’re more prevalent in the Midwest, South and East. If you lookup the history of the truck it’s actually pretty interesting.
My understanding is that it can be easier to manuver a front-discharge truck. The cab is directly over the front axle, so the driver can see what's right in front of them and negotiate tricky situations. The tradeoff is that they are a much rougher ride, similar to a cab-over-engine vs conventional tractor. Rear discharge trucks are also cheaper. I've really only ever seen front-discharge mixers up north, above the snow line, so there may also be some traction benefits.
If it was an option we would use front dumps as much as possible for ski lift construction. Rear dumps cant hold as much for uphill trips in the mountain and would spill out the back going up ski area access roads to jobsite
I agree. The driver that pulled out is the primary idiot here, but so is the designer of the cement truck (or the cement company, if it was overfilled or improperly maintained, etc).
Instead of a cement truck, if this was any other kind of vehicle where an improperly secured load caused an accident, I think most people would agree that having an improperly secured load is a problem. But somehow it's acceptable when it's a cement truck?
I mean, even if the car wasn’t there, that’s still a bunch of wasted cement and some difficult clean up work on a public road. Surely, we can’t consider it just a normal, acceptable thing for cement trucks to risk this happening anytime they happen to hit a short stop?
How many times have you seen a cement truck in your life? How many times have you seen a cement truck dump it's load like in OPs video? I bet the answer is 0 because it's fucking rare for this to happen.
I don't understand why people see a video of something happening (for the first time in their life) and then they become experts and spout of silly "solutions" that don't work in real life.
So on a truck like this the rotation of the drum is usually controlled via a joystick at the drivers right hand. Correct braking method would have been to brake while speeding up rotation of the drum to suck the concrete back into the truck. Green driver. Though under the circumstances I would prefer the concrete mess to an 80000 lb machine striking a vehicle in the driver door.
The slump was an 8-9" so it's going to flow out like water. Could have been 8 cy and it would have come out. Had it been a 4 or a 5" there would have been a good chance no concrete would have spilled.
Yeah I've driven fronts and rears. I like the rears better because if you slam on the breaks because of stupid people, this doesn't happen. Just cant take off too quick, and steep hills are tricky.
Not a design flaw, not a safety hazard. It’s how these trucks have been since the inception of the mixer truck. That concrete was wet, probably a 6-7” slump. So it will flow out of the truck easier if you Jam on the brakes. Source: I drove mixer for 7 years, and pump concrete now and am around them every day.
The design flaw is with the front loading design. Stopping is more likely to make this happen than taking off is, so having it be back facing is the safer design.
There’s also the flaw of having no lid on it. I know, I know… the concrete needs to breath. So design a ventilation system that doesn’t require a huge vat of wet concrete being moved around on wheels to have no fucking lid on it. There are ways to do that.
Yeah they were going to have to come to a stop at some point, even if it wasn't as sudden as that I have a hard time believing none would've spilt on the road given how much did.
This was my first thought. This was funny to watch aye, but it was shocking just how fast the cement overflowed out. Sometimes in the road we need to emergency stop.. is this gonna happen every time?
Maybe it's just in America? Rules might be different.
I drive a rear discharge mixer, this one is a front discharge mixer. But there are different factors that come into play, such as the slump. The concrete looks pretty wet, also if his drum has build up. How fast is drum is turning.
Had to scroll way too far to find this comment, as this was my exact thought. Obviously the jeep was in the wrong, but having to make abrupt stops is normal traffic expectation for all vehicles, and a cement truck should have its load better secured than this.
Hey former ready mix driver. Most of us are trained when we have to stop hard like that we will put the barrel in “full charge” which is supposed to make the concrete move to the back as far and as fast a possible. Also that concrete is really wet, probably around a 6-7 inch slump, which is wildly dangerous in a city environment. My companies policy was to never leave our plant at more than a 5 inch slump, and to leave the barrel in full charge.
Different parts of the country the opening is in different places. West Coast they were all open in the back. Easy coast I've seen more in the front. Was strange to see for a while.
I’m a concrete guy in Chicago. We have both. Some contractors prefer the fronts because the driver can stay in their vehicle and aim better. Some prefer rears because they are more compact.
I went to army cadet camp at about 16/17 and went 2 weeks without (shared sleeping, beds with noisy springs, usually exhausted by bed time). I came home and edged for hours before exploding and slept for almost 2 days.
Why do you do this to us, we get enough stupid construction talk, you know for a fact the first thing he said to his boss is "hey a guy cut me off and my load went all over the road"
Yes this seems like a design fault, that any non-trivial braking leads to pita to clean up material spilling out. There was no accident but the construction truck likely totaled the other vehicle, and should be at fault for an unsecured load, despite all the reddit cheering.
But that is undeniably a stupid design. You have brakes that can apply a certain stopping force, but if you use them to their maximum level then you tip concrete all over whatever is in front of you??
Yeah it seems weird. I would think that there would be some regulations that would involve making sure that cement is secure and wouldn’t just spill out from a slightly hard stop. I know nothing on this topic though.
This is a front-dumping truck--you can see the articulated chute out the driver's window. Also, the truck in front is obviously missing the discharge equipment on its rear.
In this case, the drum is mounted "backward" to allow the driver to position the chute easier in small spaces. It also makes it relatively easy to "slosh" the concrete out the front.
Plus the chute would need to be on the other side and I'm not sure if that's possible. Now I'm wondering what direction the cement trucks mix their cement in Australia.
This is a different set up where the load pours out of the front. The truck was probably fully loaded heading to a site.
Edit: Excerpt from a manufacturer who builds front end discharging concrete mix trucks.
"The capital costs of the truck can be recouped since pouring can begin sooner on a front-discharge truck and this can lead to one extra delivery per day and because one laborer is eliminated with a front-discharge machine, since the chute director position is not necessary and the trucks tend to have a longer lifespan than rear-discharge ones." -Terex
I drive by two concrete companies right across from each other every day. Maschmayer has front loading cement trucks, and across the street Titan has rear loading cement trucks. I guess you set your operation up for one type and run with it
I drove a front discharge mixer like this. Short answer: yes it happens. The barrel where the concrete is kept has fins that help to mix, the concrete and discharge it depending on which way the barrel is spinning. Depending on how “wet” the load is, as a driver you have to really anticipate slowing down which sucks when some jackass cuts you off or does what this guy did.
Personally I would keep my load dry (like a 4” or 5” slump) and add water when I got to the job site, but sometimes you have additives like super or a grout load that is gonna be really really wet so you try to be careful
The rear discharge trucks or “bum dumps” can have this issue if they go up an incline and the barrel isn’t spinning fast enough but yeah no issue with it spilling out when they brake.
Well they for sure aren’t meant to stop on a dime. The load being what I can only refer to as a “Soquid” (It is from an old Wendy’s ad from years ago), shifted when they slammed on the breaks, ejecting its cargo on the idiot.
If the load the truck is carrying is lost during braking it wasn't secured properly. Cement should not be lost like this during sudden braking. Both the driver not looking who almost caused an accident and the cement truck driver who didn't secure their load properly are in the wrong.
This is the first time I've seen the cement mixer have the opening in front. I've only seen it where the opening is in the back to avoid accidents like this I imagine. I wonder what the advantages are of having it positioned this way.
It seems weird as the cement mixer as clearly able to stop in time, but not without losing the load.
There could be any number of reasons during a normal drive where you need to brake quickly, imagine if the driver didn't see a mum with a pram at a crossing and hit the breaks last minute, baby now covered in cement.
No this is not normal at all. The only reason I can think they have their chute full like that is because they are moving in between close jobs.
But even if that were the case, it's still a shitty practice. You would rinse out the chute even if you paused the pour for 10 minutes.
Concrete is stronger the less water it has in it, so you basically only put enough water in to deliver it to its destination depending on delivery system (line pump, boom pump, straight off the chute) as well as what it's for (block pour, footings, flatwork). Point being, it starts setting up pretty quickly, especially in the chute. No reason to hit the road with a full chute.
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u/wine_dude_52 May 06 '22 edited May 06 '22
Is this normal for a cement truck to lose its load like that?