Dear Readers ,
We are meeting after a long gap .
I was occupied in some different priorities during this time.
When one of the students ( who is also a follower to this blog ) asked me about no new post for a long time , I thought I shall immediately post something interesting today.
In our previous articles, we have already covered the basic theory behind using the AAC blocks. [ Read the article here ]
As you know , these blocks , Autoclaved Aerated concrete blocks are quite light in weight.
When you compare the unit weight of AAC blocks @ 600 Kg/cum with that of the red bricks @1900 Kg/Cum, we find that these blocks reduce the dead weight of the building.
These are also faster to build . Whereas we need 510 bricks for 1 cum of brick work, we need only 42 Blocks for 1 CuM of AAC block masonry. Thus, the mason needs to handle only 42 AAC blocks as against 510 bricks.
The mortar quantity is also reduced from 25% in brick work to 4.5 % in AAC block masonry.
Now let us solve one practical example from the site.
Find out the total material needed to construct a wall using AAC blocks with the following details :
- Size of AAC block : 625 mm x 240 mm x 150 mm
- Cement mortar mix ; CM ( 1:4 )
- Thickness of the joint : 5 mm
4.Wall dimensions : 5.5 m x 2.9 m x 0.15 m
Step 01 : Volume of the masonry wall : 5.5 m x 2.9 m x 0.15 m = 2.3925 Cum.
Step 02 : Materials needed for the Cement mortar CM 1:4 :
Cement : 1.52*28.8 /( 1+4 ) = 8.76 Bags
Sand : 1.52*4 /( 1+4 ) = 1.216 Cu M.* 0.3529 = 0.429 Brass
Step 03 : Volume of 1 block of size 625 mm x 240 mm x 150 mm :
0.625 m x 0.240 m x 0.150 m = 0.0225 cum.
Step 04 : No of blocks in 1 Cum = 1/0.0225 = 44.44 Nos.
Step 05 : Increased dimensions of 1 block due to 5 mm mortar joint :
( 625 +5 ) mm x ( 240 +5 )mm x ( 150+5 ) mm :
= 630 mm x 245mm x 155 mm
Step 06 : Volume of block with mortar :
0.63 m x 0.245 m x 0.155 m = 0.0239 cum.
Step 07 : No of blocks in 1 Cum = 1/0.0239 = 41.84 Nos.= 42 blocks.
Step 08 : Difference in no of blocks due to mortar : 44 -42 = 2 blocks.
Step 09 : Volume of mortar in 1 Cum = volume of 2 blocks = 2 * 0.0225 = 0.045 Cum.
Note : this means 0.045 x 100 = 4.5 % mortar.
Step 10 : Calculate the materials needed for 1 Cum of block masonry :
Blocks : 42 Nos
Cement : 8.76 Bags * 0.045 Cum. = 0.39 bags.
Sand : = 0.429 Brass* 0.045 Cum. = 0.019 Brass
Step 11 : Total material needed for 2.3925 Cum. of masonry :
Blocks : 42 Nos * 2.3925 Cum = 100.485 Blocks = 105 Blocks
Cement : 0.39 bags. x 2.3925 Cum = 0.93 Bags = 1 bag
Sand : 0.019 Brass x 2.3925 Cum =0.045 Brass =0.046 Brass
With this much information , it is also easy to find out the cost of the materials .
Step 12 :
Blocks : 105 Blocks@ 72 per block = Rs.7560
Note :The cost of AAC block is considered @ Rs.3300 per Cum.
Cement : 1 bag@ 300 Rs/bag = Rs.300
Sand : 0.046 Brass@4200 Rs/Brass Rs. 193
Total cost : Rs.7560 + Rs.300 + Rs. 193 = Rs.8053
Cost per Cum = 8053/2.3925 = Rs.3366
Cost per CFt : Rs.3366/35.29 = Rs.95
Hope you are able to follow these steps.
In case of any doubt , please let me know.
All the best !