Slip form curb

[davethepumper]

What kind of slump does everyone else pour high back machine curb at? We have our own curb crew and I can not convince them they need to add water to the mix and turn down the vibrators. They want it so stiff it does not come out of the drum with out having to spray it with water or squirt water in thru the add line.

I have been telling the drivers to shut the lines off at the tank so they can't do this but they end up using the water off the curb machine.

What do you guys do?

[Matt]

The company I work for has their own curb crew as well. When pouring high back curb, the batch tickets normally show it is batched at a 1.5 inch slump. I would say that they will normally take a 2 inch slump at the machine. They also spray water on the fins of the barrel, and the edges of the cute if need be, to help unload. We have charge hoppers that lift out of the way, and allow the stiff mix to discharge a lot easier as well. On hot days the crew will sometimes assign a guy to climb the cat walk of each truck, and spray the fins as they unload. This makes it a lot easier on the driver and you’re less likely to get soaked by the machine operator using his hose ;D.

[Slick]

The guys I've poured for sometimes just open the valve for a second or two, other than that they want it at a 1 or 2 inch slump. I've had new guys try and spray the chutes and after I am done pouring I explain to them unless they want to clean the splatter off the back of my truck then don't use the hose.

[concretejoe]

We are about to do a whole lot of barrier wall on the highway, and the slump most requested is 1" to 1.5". I've always given small, misting bursts of water while pouring to lubricate the drum. How wet the concrete can be depends on how high the slip form needs to stack the concrete. The higher the stack, the drier the mud. What helps alot is adding fiber to the mix. It helps hold the formed concrete together at higher slumps.

A word of advice. I have found that with a dry mix sometimes it comes out faster if you slow the drum down.

[batchmaster]

the last barrier wall that we shipped, the contractor requested a 1" slump, but he actually wanted closer to a zero, it was crazy.

[concretejoe]

I hear ya batchmaster. We are doing this big highway project now and they order barrier wall on a 1" slump. When the guys get to the machines the operator complains that it's too wet. We actually slumped one he complained about at a 1/4" slump. The problem wasn't the mix, it was the inexperience of the man running the machine in my opinion. He was in too much of a hurry and was operating it too fast. This caused the concrete to pull apart, like it was wet. We eventually got him straightened out.

[slumpy]

Yeah then the CURB machine rams into your front bumper knowing you cant make that turn and laughs piss's ya right off

[Mort]

The wettest I've heard of on slip forms/ curb machines is 2", and that's pushing it. We usually only send composite drum trucks, because the fin design is different somehow, and it allows that stiff stuff to come out easier. Since I only drive steel drum conventional and OshKosh, I'll let the composite guys handle those things. Boring, in my opinion.

[gant]

I hauled 6 loads today and not one of them over a 3" slump.. usually we haul 4's but not today.. and on this job earlier they ordered 3600 lbs of torpedo or pea gravel and 150 gallons of water.. they mixed up their own 9 sack grout mix in our trucks.. they had 3 big bags of sand and cement they used a crane to lift above our hoppers and then a laborer got up top and cut it open and made a big ass mess all over our trucks.. mine was the worst.. the wind started to blow and the guy wasnt paying attention and blew the bag over the top of my drum all over my pedistal, my rollers my catwalk everything.. took me an hour to clean it all out on the job..talk about pissed

[shanine]

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