Quantity of Cement and Sand Calculation in Mortar

Quantity of cement mortar is required for rate analysis of brickwork and plaster or estimation of masonry work for a building or structure. Cement mortar is used in various proportions, i.e. 1:1, 1:2, 1:3, 1:4, 1:6, 1:8 etc.

Calculation of quantity of cement mortar in brickwork and plaster:

For the calculation of cement mortar, let us assume that we use 1m3 of cement mortar. Procedure for calculation is:



1. Calculate the dry volume of materials required for 1m3 cement mortar. Considering voids in sands, we assume that materials consists of 60% voids. That is, for 1m3 of wet cement mortar, 1.6m3 of materials are required.

2. Now we calculate the volume of materials used in cement mortar based on its proportions.

Let’s say, the proportion of cement and sand in mortar is 1:X, where X is the volume of sand required.

Then, the volume of sand required for 1:X proportion of 1m3 cement mortar will be

1.6 x X divided by (1+X)

3. Volume of cement will be calculated as:

1x 1.6/(1+X)

Since the volume of 1 bag of cement is 0.0347 m3, so the number of bag of cement will be calculated as:
[1x1.6/(1+X)]/0.0347

Example:

For cement mortar of 1:6, the quantity calculated will be as below:

Sand quantity:
1.6 x6/(1+6)=1.371cubic meters

Quantity of cement (in bags):

Volume of cement = 1.6/(1+6)=0.22857

The number of bags required = 0.22857/0.0347 = 6.58 bags.

The number of cement required is 6.58bags in a 1cubic meters of 1:6 mortar.

segzy14:
[b]Plastic shrinkage of concrete:

Cracks appearing on the surface of concrete before setting of concrete is due to plastic shrinkage of concrete. The cause of shrinkage cracks in concrete is due to settlement of heavy aggregates at the bottom of concrete and rise of water to the surface. This process continues till the concrete has set and it is called as bleeding of concrete.

As long as the rate of evaporation is lower than the rate of bleeding, there is a continuous layer of water at the surface known as “water sheen”, and shrinkage does not occur. When the concrete surface looses water faster than the bleeding action bring it to the top, shrinkage of top layer takes place, and since the concrete in plastic state can’t resist any tension, cracks develops on the surface. These cracks are common in slabs.

The extent of plastic shrinkage in concrete depends on:

Temperature of concrete,
Exposure to the heat from sun radiation,
Relative humidity of ambient air and velocity of wind.[/b]

Nice job sir. What can be done to avoid this?

charlesadeoye:



Nice job sir. What can be done to avoid this?

Start curing the concrete as soon as possible, and keep it continuously moist for a minimum of 3 days.

Hi

Happy xmas in arrears and a new year in advance

Good morning

Happy new year

How many tonnes do you have in a 10tyres truck and 6tyres also.

dearpiriye:
This is after adding the 1 coach that brought it to 11

did you later do the German floor ? What alternative did you use?

Segzy14 (Sam)
You have no integrity, you are a thief and a liar.
Beware (new members on property section) everyone and DO NOT let him handle your project.
He is a one-chance engineer.