By EasyHow

How to calculate amount of concrete

The exact calculation of quantity of concreteto be laid in the formwork – one of the conditions for competent performance of construction works. Excess concrete, as a rule, use nowhere. The mixer will take either pre-ordered and paid for the concrete, or dumped it to a specified location, creating a monument to your stupidity. Violation of the same construction technology due to the lack of concrete will lead to even more serious consequences. Consider the example of a strip Foundation, how to avoid such errors.

You will need

- line
roulette,
calculator.

Instruction

Ready-mixed concrete of various grades, which is a semi-liquid mass, depending on its structure has unequal shrink – the smaller the cement and water, the less significant changes of volumeand of the concrete during curing. In addition, the magnitude of the shrinkage of concrete is influenced by other factors, such as the way of the seal: when shtykovaniem shovel shrinkage is smaller than when sealing concrete with deep vibrator. When calculating the required amount of concrete generally use the same average coefficient of shrinkage equal to 1,015-1,02.

Calculate the volume of the pre-concreted design, according to the draft (sketch). To do this, multiply the width, height and length of the Foundation.

Check after the construction of the formwork according to height, width and length of the Foundation with design values. Small deviations of the dimensions in a big way lead to a substantial increase in the required amount of concrete. Use of inventory formwork of steel frames and plywood allows to minimize these errors.

Multiply the resulting volume by the shrinkage factor.

Subtract from this value the volume of all openings and niches for engineering services (pipes, ducts). To do this, you need to calculate the appropriate volume according to the formula for determining the volume of a cylinder (area of a circle multiply the height) or a parallelepiped (length multiplied by width and height). The resulting value will be the amount of concretethat is required to fill the design.

Note

In order to avoid errors in the calculations, all measurements (length, width and height of the Foundation and openings in it) should be in the same units – metres.

It is very important that in case of using wooden formwork, it was the most aligned and tightly fastened, otherwise the formwork may bursting from the weight of poured concrete. Considerable importance is the absence of gaps between the boards, which will leak water seal pour of concrete, which also leads to change in a big way the shrinkage factor.

Useful advice

When filling large volumes, concrete is always better to order a little more. Just in case on site possible to build the formwork for typical concrete structures, in which, if anything, you can merge the rests of the concrete. It can be Foundation blocks, lintels and other precast products that will sooner or later be used.