Batching of concrete - types and their importance.

 1. What is batching of concrete?

The measurement of different raw materials and ingredients that are involved in making concrete, for the preparation of the defined mix grade is called batching of concrete.

Batching of concrete is classified into two types.

They are,

a. Volume batching &

b. Weight batching.

Now we will go through the procedure for each of these types.

a. Volume batching:

Here, the quantity of raw materials is proportionately taken by volume using a measurement box or by a mortar pan (ghamela).

Mortar pan.

You might be knowing that the volume of one bag of cement is 1.23cft. or 34.72litre. So the standard dimension of the measurement box will be made to match the volume of one bag of cement, or 1.5 to 2 times the cement bag, or multiples of it.

MS measuring box.

Suppose if you are preparing M15 grade concrete with 1:2:4 proportion, for every bag of cement, poured in the concrete mixer, you have to add 2 nos. of sand and 4nos. of coarse aggregate in the mixer, using a measurement box filled to its top level. Following the same procedure for every batch of concrete, provides us a homogeneous mix of even quality, resulting in cohesive concrete.

In volume batching, we have to take into account the following three factors.

1. The bulk density of coarse aggregates and sand.

2. Bulking of sand.

3. Giving preference to measurement box instead of mortar pan (ghamela) for the concrete mix.

Ghamela.

When we use ghamela, the volume contained in it differs for every laborer involved in this concreting process, as it largely depends upon his will. There is also a greater chance of missing the count of one or two ghamela, of any raw material poured in the concrete mixer, which results in the concrete of lower quality. 

Although it is a volume batching, we prefer to classify it as a random batching 😃.

b.  Weight batching.

Here, the raw materials for the preparation of the concrete are taken by weight, using a concrete weigh batcher . We can produce concrete of higher quality with more precision in the weight batching process.

Concrete weigh batcher.

Every material that is added is taken by weight, so there a less chance of missing out, (as in the case of volume batching) producing high strength, compact, and long-lasting concrete. For this reason, weight batching is always a preferred method of batching for precision and accuracy in quality control.

In weight batching, the calculation of the bulking of sand, and bulk density of aggregates is not taken into account, as they affect the volume of the materials, but not the weight.

2. What is the importance of batching?

When we produce the concrete in the construction field, it becomes mandatory to control segregation and bleeding of the concrete to achieve a designed strength and quality of the required grade. Maintaining the correct w/c ratio also plays a big role to maintain the concrete quality. 

As the construction field is largely dependent on laborers, maintaining the quality of work can be achieved only by proper discipline and planning. 

Batching helps us to smoothen the tedious task of concreting and provides us a cohesive concrete of required quality by controlling all the above-said factors with good accuracy. 

3.  What is the standard dimension of the measuring box/farma in concrete?

The standard dimension of the measuring box or pharma in concrete is 1ft. × 1ft. ×1.25 ft. The volume of this box comes to 35.39 liters, which is nearer to the volume of cement, i.e. 35 liters.

Measurement box.

They are usually made up of MS or plywood material with handles on either side(see fig.), to lift and transport the material conveniently by two workers. The weight of the material contained in the box is such that two laborers can handle it properly without much shoulder pressure.

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Thank you for going through this article😄.

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