Order Ready Mix Concrete
A giant ready-mix concrete truck driving up to your house can be intimidating, but it doesn't have to be if your site is prepared, you have all your tools at hand, and you've ordered the right amount. Dispatchers are quite helpful, but you should know the basics before you call so you don't wind up with more or less than you need.
Steps
- Calculate the right volume. In the U.S. Concrete is always ordered in cubic yards. First figure out the cubic footage, then convert to yards by dividing by 27. Here’s how: multiply the length of your project times the width times the depth (4 in. = . 33 ft.) and divide the total by 27. Using a sidewalk as an example: {{safesubst:#invoke:convert|convert}}. (long) x {{safesubst:#invoke:convert|convert}}. (wide) x {{safesubst:#invoke:convert|convert}}. (deep) = 79.2 cu. ft. ÷ 27 = 2.93 cu. yards.You can also figure your cubic yards by this example: length, times, width, divided by, 12, times, thickness, divided by, 27. using the figures from above example. 60 ft ( length ), times 4 ft (width), divided by 12, times {{safesubst:#invoke:convert|convert}} (thickness), divided by 27 = 2.96 cubic yards. Concrete is cheap and nothing is worse than coming up short (except rain). A good rule of thumb is to order an extra 5 percent rounded up to the next {{safesubst:#invoke:convert|convert}}. to handle spillage and uneven bases.
- Order from the nearest supplier. Get fresh concrete mixed near the site, not mixed across town by some company with a lower price.
- Ask for 5 percent “air entrainment” in the mix. Suppliers add a chemical that traps microscopic air bubbles to help the concrete handle the expansion and shrinkage caused by climatic changes such as freezing.
- Get the right strength. Tell them you’re pouring an exterior sidewalk and they’ll recommend the correct “bag mix” (ratio of cement to gravel and sand). In cold climates, they’ll probably suggest at least a 3,000-lb. mix. That means concrete that’ll handle a 3,000-lb. load per square inch without failing.
- Have your checkbook ready. You’ll have to pay on delivery after the concrete’s unloaded.
Tips
- See the external links below for more detailed instructions.
- The truck comes with the concrete premixed with the correct water content. But the driver may send a little concrete down the chute and ask if you’d like more water added. Only add water that brings it to the desired slump you ordered, for example if it is a 5" Slump and you ordered a 6" and you have {{safesubst:#invoke:convert|convert}} on, then you may add {{safesubst:#invoke:convert|convert}} of water and or {{safesubst:#invoke:convert|convert}} per yard to bring it to the ordered slump. All ready mix companies add a chemical to the concrete when batching, this allows the slump to change. "Just don't wet it up past the ordered slump, because it is not designed to have that much water for the ratio of chemicals added, this will decrease the P.S.I. dramatically and even cause cracking.
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Sources and Citations
- http://www.holessolutions.com/services/concrete.shtml More information about Concrete Property managers, cities, towns, highway authority, real estate brokers
