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Old 09-17-2006, 12:00 AM
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DDA52 DDA52 is offline
Blood, Sweat & Concrete
 
Join Date: Jun 2004
Location: Bulverde, Tx.
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How to order concrete.

It isn't hard. They will ask you questions and you give them what they want to know. I'll try to get it all down for you here so it won't be intimidating. I will cover the normal stuff, but not things like addresses and phone numbers. You can do that part.

First off, they will want the yardage. I will assume everyone already knows basic volume calc and move on. Get a little more than you need. Short loads will often have a fee riding on them. If you figure exactly 5 yards...add 10 or 15% for waste, accidents or irregularities in the base or forms. You can add more, but if dealing with a single truck pour, it is much better to get it all at once. And cheaper. With my area companies, anything under 5 yards includes a short load fee in addition to the regular per yard price. This is normal. Get quotes on this BEFORE you are ready as some are way higher to discourage small loads. Unless they are the only horse in town, you will want to shop around for the best price and closest plant.

They will want to know the mix strength you want. Tell them what you decided on, say 3000 psi. If you want straight cement mix, now is the time to tell them.

Next they will want water content or slump. Slump in a nutshell is the amount in inches the concrete will "slump" down when it is released from a test cylinder. The cylinders are cone shaped and are 12" high. Concrete is filled 50% at a time. It will then be rodded 50 times to get the air and spaces out. Then the last 50% is added and rodded again. The cylinder is then flipped over and removed. The amount the concrete falls in inches from the original 12" height is the slump number. A 4" slump is a good median number. There are lots of factors that influence how wet you want it. Cold weather needs less water, but still enough to work it, while hot weather will want more. Slopes= less water as well. If in doubt, get it drier than normal and add water on site. It is better to add because you can't take it out once it gets there...too bad, that would sure solve lots of troubles. You do not want to add too much. That will weaken it. Most batch recipes allow for a 30% increase in mix water because they already know we will add water. I'll do more on water later when I get to placing.

If there will be multiple trucks, they may want to know how far apart will they need to be spaced. For a slab being placed by hand, 30 minutes is a good starting point. If it is being pumped, then 10-15 minutes may be too slow or just right. You can always call and speed up if possible or slow it down as needed. Just make sure that the trucks do not stay on the job too long. They will charge truck time for waiting over an hour usually. It can get pricey, so avoid it if possible. Another tip is to order one truck or partial truck less than required. For example, you estimate 65 yards to finish...order 60 yards and then order a "kicker" when it is all placed to the 60yd point. It may take 5 yds more, or it may take much less. You don't want to have way too much or order two kickers..that is a bad thing, but if necessary you do it. When you place the order, in the case of the example, tell them 60 plus, and you will order out the last truck. IMO, the worst thing is to pour it out and still have one ormore full trucks waiting out front....if they can use it elsewhere, fine, but ifnot, you have to pay for the extra..not good.

They will also want a time to start. Don't expect them exactly at that time...sometimes they actually make it, most times they will be a tad behind. This is normal. Unexpected things always happen. Murphy's Law applies. If you are pouring a slab, start as early as possible. In the summer it will be easier due to the cooler temps during the harder work. The winter temps will make everything take longer, so get it down as early as possible and try to be done before noon if possible, or be ready to finish under lights...which may happen anyway in the cold.

That should be the common things you will be asked.
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Last edited by DDA52; 09-17-2006 at 12:55 AM.
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