Rate analysis of Concrete

     Hello Everyone, Welcome to "The Civil Engineer", in this article let me tell you how much material like cement, Sand, or M.Sand and Aggregate is required for Concrete Works.

    Before we enter let us see some important facts about cement because they are very crucial for a better understanding of the calculations. Cement is one of the major materials in the construction industry. It gets its name Portland Cement because, after the hydration process, it resembles the color of the building stones from the Isle of Portland off the British Coast. The first person to patent Portland cement was Joseph Aspdin in 1824. With the invention of this new cement, the transport of large-sized rocks were reduced and the speed of the construction was fastened up at the same time since the cement at the beginning can be cast into different shape which is a huge advantage to the stones which takes up more Labour and time-consuming.

How to calculate Cement Bags for Concrete:
    To make you understand, let me take the M20 Grade of Concrete. Let us now calculate the number of bags required to make 1 cup of concrete. Cement is the binding material in the concrete.

    Before we enter further, there are some basic technical terms that you need to understand and that is,

1. Bulkage - See Bulkage is the water that is kept between the particles of the material as water is filled in it. Mostly the Sand which is the finer part or fine aggregate of the concrete retains more water when delivered. Even though it is delivered without any water on site when we make the concrete mix we need to add water to make the chemical reaction work.]
2. The ratio of M20 Grade of Concrete is 1:1.5:3, which means 1 Part is Cement, 1.5 Part of Samd/sand, and 3 parts of Aggregate.
3. Unit of Cement = 1440 Kg/cum.

So to calculate the number of cement bags required for M20 grade follow the steps,

1. Add the Ratio  = 1+1.5+3 = 5.5
2. Use the formula (((1/5.5)*1.5)*1440)/50 = 7.85 bags approx 8 Bags of Cement are required for 1 Cum of Concrete.
3. Here 5.5 denotes the Volume of the concrete, you may wonder why the volume of the concrete is taken as 1.5 instead of 1 because 35% is the maximum bulkage and 20% is added for the wastage while handling the concrete. Hence for casting 1 cum of concrete you need to prepare 1.5 cum of concrete. That's why the Volume of concrete is taken as 1.5cum instead of 1Cum.  

By using this same technique you can easily get the amount of cement required for any grade of concrete. You just need to adjust the ratio according to the grade of the concrete.

How much M.Sand is required

 

    In previous years natural river sands were used but nowadays Manufactured Sand (M Sand) is now being used. The manufacturer's sands were the fine material that was produced by serving and cleaning the dust particles that were produced during the production of course aggregate. We moved on to this type of sand because of environmental concerns. By taking the river sand out of the river we obstruct the river flow and hence we degrade nature. You See M sand or sand is the filling material in concrete.

To Calculate the amount of sand required follow these steps

1. Add the Ratio  = 1+1.5+3 = 5.5
2. Use the formula ((1.5/5.5)*1.5)/35.314  = 14.446 ft if you apply this formula you will get the amount of sand required in CFT.
3. Here first 1.5 denotes the ratio of M sand 5.5 denotes the total ratio of the concrete and 1.5 denotes the volume of the concrete with bulkage.
4. If you don't multiply the obtained value by 35.324 you will get the amount of M sand required in cum.

How much Aggregate is Required

    Aggregates are the strengthening material of the concrete. Aggregates are of different sizes are we need to provide the appropriate size of the appropriate concrete. For Example, mostly the PCC uses 40mm aggregate whereas in concrete we need to use 20mm or a mix of 20mm and 12mm aggregate need to be used.

To Calculate the amount of aggregate required follow these steps

1. Add the Ratio  = 1+1.5+3 = 5.5
2. Use the formula ((3/5.5)*1.5)*35.314 = 28.89cft of aggregate if you apply this formula you will get the amount of sand required in CFT.
3. Here 3 denotes the ratio of M sand 5.5 denotes the total ratio of the concrete and 1.5 denotes the volume of the concrete with bulkage.
4. If you don't multiply the obtained value by 35.324 you will get the amount of M sand required in cum.