cement delivery system

cement delivery system

Postby harberconcrete on Thu Apr 23, 2009 6:45 pm

I have been curious about a water tight portable cement feed system that can be taken to a jobsite with about 12 tons of cement and be used to reload my mixer, anyone doing this?
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Re: cement delivery system

Postby smnstn on Wed Apr 29, 2009 11:17 am

I just noticed this post. Sorry for not responding sooner.

During WWII, the Seabees developed what are known as "bladder bags" for use in construction in the South Pacific. As the name indicates, these were large sealed rubber containers with lifting eyes integrated into their structure. This concept has been replaced in recent years by super (or "big") bags. Each was designed to be a one cubic yard container. Obviously, a full cubic yard of cement weighs a lot. If it were a "dry rodded" container of cement, having a true one cubic yard dimension, it would weigh 2,538 pounds + container. This is an unwieldy weight, and can also be an unwieldy size. Whatever vessels are used must be liftable by a small crane or bucket loader to be positioned over the top of the mobile mixer cement bin, and possess a valve or opening on the bottom to allow the cement to flow into the bin. I have used big bags on site successfully when lifting equipment was available. The cost of the cement is close to what it would be with paper bags in this situation, but no expensive peripheral equipment is needed beyond the lifting device.

As Concrete Mobiles gained popularity in the late 60s and throughout the 70s, a truck body called a "tender" was developed so a mobile could be left in position on site to produce concrete typically for grain silos, feed bunks and slabwork. Aggregates were trucked to the jobsite directly from their sources, and the tender brought a load of cement and water in separate compartments to the mobile. The cement was off-loaded by an auger designed for that purpose and the water was delivered through a hose by a hydraulic pump. I doubt any of these tenders are still operating.

Today, a water tanker can be nothing more sophisticated than a large plastic tank anchored to a flatbed truck. This flatbed could also handle a couple of big bags of cement, if capable of handling the weight. Most often, contractors needing to supply mobiles on site today use conventional cement tankers. The mobiles are then outfitted with pneumatic fill systems to vent and filter the air being forced from the cement bin on the mobile. Of course a large supply of compressed air is needed, unles the tanker has an auger delivery system. These tankers can usually haul about 25 tons of cement legally.

I regret to inform you that the one-load portable silos and pyramid-shaped bins designed to feed mobiles are not capable of hauling cement down the road. Even if they were strong enough, the angular cement particles would pack so solidly over the discharge ports of these vessels that they would not be able to unload after being installed. I know. Which reminds me that you want to be careful how far you travel with your regular mobile and a loaded cement bin without making allowances for starting cement flow at the destination.

So, unless you have a spare fifth-wheel road tractor to haul a rented tanker to your project, I think big bags are the best solution. Tankers can be rented from trailer lessors and suppliers, as can "guppies" (the tankers designed to sit on site and hold several trailer loads of cement). Big bags can usually be obtained from paper bagging operations or Spec-Mix dealers. Sometimes cement companies themselves will offer big bags for sale.

Bulk cement can literally be hauled in anything that can hold it. The three factors determining the feasibility are how to load it into the conveyance, the weight capability of the conveyance, and how to unload it at the destination. With big bags, even if your loader won't lift them quite high enough, you can often dig a "slot" to back the truck into, and use the excavated material to make a ramp to further elevate the loader bucket or forks.

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Re: cement delivery system

Postby harberconcrete on Thu Jul 30, 2009 9:15 pm

Simon, I read your reply back in April sorry it took me so long to say THANKS, I have used super sacks and they worked well but we had a large fork lift on site. I spoke with an operator that had modified a truck mounted fertilizer container with a auger feed system that would load his mixer on site, it carries about 12 tons of cement, it seems that a roll off unit or skid mount system could work well also.
Thanks again for your input.
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Re: cement delivery system

Postby JoeC on Mon Aug 31, 2009 10:23 am

All,

I recently supplied 80 cy to a job in 4 hrs with my Reimer 10 cy mixer. We installed 4" dry bulk feed and vent fittings on the cement tank and pumped the powder into the trucks tank. We had to stop production during powder transfer because the 11 psi to move the powder was pressurizing mixer's tank and overloading the auger. Sand and stone was constantly topped off with a loader, admixtures were premixed and topped off, and water was pumped in from a 10,000 gal tanker. The pour went flawlessly. It was almost boring!

Every Readymix operator in the area drove by that day! We have since supplied a 50 cy job and have 2 more pours scheduled with my portable batch plant on wheels. This is possible and repeatable. The flexability of the mobile mixer made QC simple. The material tester would notice the air was off, so we made the adjustment. If it dryed out, we could adjust the water reducer. Cylinder breaks were high and the owner is happy. I have pictures of the placement I will post on my website.

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Re: cement delivery system

Postby Darin@DarCole on Tue Sep 01, 2009 9:47 am

Sounds like yall did a LOT of planning before pouring Joe!! Everyone mustof been working in some pretty good harmony as well to keep things running so smoothly!
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Re: cement delivery system

Postby smnstn on Thu Sep 03, 2009 2:41 pm

I think I should add the following: I have often used standard cement tankers for large volumetric pours. Many of the machines I sold and supervised in the field were equipped with a standard cement silo fill pipe, with a quick coupler on the end of it. The tanker could move right along with the mobile unit, or set in place for periodic refill. The secret to using one of these successfully is to tune the manifold valve for high volume/low pressure delivery. If the mobile unit is fitted with two ports on top of the cement bin with collars, standard filter bags can be clamped over the openings for dust control. When the machine is not filling, the socks are tucked inside against a small crossbar to keep them from falling into the feed mechanism, and caps are pinned in place over the holes. Another advantage to this method is that the tanker can be left free standing on site, or supported by a 5th wheel dolly. It doesn't have to remain hooked to an expensive truck that could be hauling other stuff. An air compressor used for air hammers and other needs can be utilized for the air supply. In an HVLP setup, it is usually more than adequate.

There are also "Guppies" that are self-contained and hold several tanker loads of cement. You often see these docked alongside portable paving plants. They do have to be empty to move to a new location with a standard road tractor.


Yet another option is the cement tanker with an auger discharge mechanism. These are old technology and can be bought cheaply, if you can find them. They are ideal for feeding volumetric cement bins, and if used judiciously, may not require sophisticated dust control.

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Re: Question about cement delivery system

Postby JayD on Sat Dec 19, 2009 2:47 am

I am not sure that the consensus of these post reccomend that if you are planning on using a 12 ton pyramid style cement vessel with a bottom auger, vertical auger & swing boom placement auger. that one should not travel very far with it loaded. but rather have it filled on site where you plan on using the cement.
I have one of these type of cement tenders & was planning on restoring it. It is currently truck mounted. I have never used it. It was formely used to keep a 10 yd volumetric mixer supplied. although I never saw it in action.
I do see a lot of pipe wrench markings on all of the shafts. & judging by the size of the hydraulic motors, the augers look to have been underpowered. There is a air manifold assembly plumbed into the bottom of the pyramid tank for fluffing. I was planning on elimanating the upper swing boom placement auger & angling the vertical auger to keep my much shorter trailer mounted volumetric mixer supplied.
any suggestions or comments would be appreaciated.
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Re: cement delivery system

Postby smnstn on Sat Dec 19, 2009 10:27 am

I do not believe that any of the portable, load on site bulk cement tanks are designed to roll down the road loaded with cement -- with the exception of bulk tankers that are designed to carry powdered substances with a specific gravity of 3.15, or better. Incidentally, the lighter the specific gravity, the more volume a given weight will occupy. Thus, if you fill a standard 3-pot tanker without weighing it, you will be overweight, because it is designed to carry a wide range of materials, some with low relative specific gravities, or unit weights.

If you do not have a method now for loading on site, big bags are likely your best bet as you can usually cut a trench and mound up a ramp to be able to lift them over the cement bin of the mobile mixer. Otherwise, there was a genuine "tender" developed by the Daffin Corporation to be truck or trailer mounted and to carry a bin refill or two, plus a lot of water. These were indeed underpowered as hydraulic units, but as mechanical systems they did a pretty good job. They have not been manufactured for probably 30 years, and with today's demands may not be a viable method of supply.

One of my customers that did a lot of highway work used a tandem straight truck with a large plastic farm tank strapped to its flatbed for water, and pulled a self-contained cement tanker on a 5th-wheel dolly with a pentile hitch behind it. This arrangement could creep down the highway in a "train" feeding the mobile unit being supplied with sand and stone from a front end loader and piles judiciously placed down the planned route of activity.

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