By going through this exclusive construction video tutorial, you will learn how to work out the quantity of cement & sand (cement mortar) in a concrete block.

Suppose, the length of the block wall is 6 meter and height is 3 meter. The dimension of a single block without mortar is given as follow:-

Length = 405 mm

Height = 200 mm

Breadth = 152 mm = 0.152 meter

Initially, it is required to determine the volume of the block wall.

So, volume = Length x Breadth x Height = 6 x 0.152 x 3 = 2.736 cubic meter

Volume of the block wall = 2.736 cubic meter

Now, it is required to determine the volume of one block without mortar.

Volume = Length x Breadth x Height = 0.405 x 0.152 x 0.200 (after converting to meter) = 0.012312 cum

So, volume of one block without mortar = 0.012312 cubic meter

Now, it is required to determine the volume of one block with mortar.

(If mortar is applied, the length and height will be changed. The thickness of mortar is taken as 1 inch or 25 mm)

So, the height will be changed to 200 + 25 = 225 mm

The length will be changed to 405 + 25 = 430 mm

After converting to meter, we get the following value for volume calculation:-

Volume = 0.430 x 0.152 x 0.225 = 0.014706 cum

So, volume of one block with mortar = 0.014706 cum

To determine the number of blocks, the following formula will be used:-

Volume of wall / volume of one block with mortar

After putting all the values, we get the following result:-

2.736 / 0.014706 cum = 186 numbers

So, the number of blocks = 186

Now, it is required to determine the volume of total blocks with the following formula:-

No. of blocks x volume of 1 block without mortar

After putting all the values, we get the following result:-

186 x 0.012312 cum = 2.290032 cum

So, volume of total blocks without mortar = 2.290032 cum

To determine volume of mortar, the following formula will be used:-

Volume of mortar = Total volume - Volume of blocks

After putting all the values, we get the following result:-

Volume of mortar = 2.736 - 2.290032 = 0.445968 cum

The above volume of wet volume and it should be converted to dry volume as follow:-

Dry volume = Wet volume x 1.27 = 0.445968 x 1.27 = 0.56637936 cum

(Initially, the cement and sand remain in dry condition)

Now, it is required to find out the quantity of cement and sand.

Suppose, the ratio of cement mortar = 1:6 i.e. one part cement & 6 part sand.

The quantity of cement = Ratio of cement x dry volume / sum of ratio

After putting all the values, we get the following result:-

= 1 x 0.56637936 / 7 = 0.08091134 cum

To convert it to bags, 0.08091134 / 0.035 = 2.31 bags (as 1 cubic meter = 0.035)

The quantity of sand = Ratio of sand x dry volume / sum of ratio

After putting all the values, we get the following result:-

= 6 x 0.56637936 / 7 = 0.48546802 cum or 0.5 cum

Video Courtesy : Civil Study