How to Mix Concrete |
Mixing concrete is not a difficult proposition but it must be done thoroughly and uniformly for a strong, durable end result. The most common mistakes are adding too much water, too much sand, or poor mixing. To avoid poor mixing use a mechanical mixer whenever possible. First mix the proper ratio of cement and sand together until the mixture reaches a uniform color, then add aggregate. Continue to mix dry until the material reaches a uniform consistency. Adding the right amount of water is the single most difficult step. How much water is required depends on whether the sand was dry, damp or wet; but remember that you want to add only enough water to make the mix workable. The less water there is in relation to cement the stronger the final concrete will be. A very general rule of thumb is to use 5 or 6 gallons of water per 94 lb. bag of cement. The durability and strength of the concrete can be increased by working the mixture into place, which compacts the material. This is usually accomplished with the use of a concrete vibrator. But be careful not to vibrate the wet mix too much as it can cause seperation of the aggregate which will weaken the final resulting concrete. |
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