HOW TO CALCULATE CONCRETE VOLUME?

In this post, we are going to discuss "How to calculate concrete volume and it's ingredients?"

How to Calculate Concrete Volume?

If it is a volume, then we know there must be 3 dimensions, Length, Height, Width or Breadth.

For Slab, If we need to calculate the concrete volume,

<sup>Volume = Length x Breadth x Width / Thickness = 5 x 3 x 0.125 = 3.75 cu.m

For Beam,  If we need to calculate the concrete volume,</sup>

<sup>Volume = Length x Breadth x Width = 5 x 0.6 x 0.3 = 0.9 cu.m

For Column, If we need to calculate the concrete volume,</sup>

 <sup>Rectangular Column, Volume = Height x Breadth x Width = 5 x 0.6 x 0.3 = 0.9 cu.m

Circular Column , Volume = 𝛑r˄2h = 3.14 x (0.15)˄2 x 5 = 0.35 cu.m

CONCRETE INGREDIENTS CALCULATION:

For cement, sand and coarse aggregate.

This is a volumetric calculation.

Assuming we need 2 cu.m of concrete for M20 mix,(Mix ratio, M20 = 1:1.5:3)

Total part of the concrete = 1 + 1.5 + 3 = 5.5 parts

Therefore, Cement Quantity = (Cement Part / Concrete Parts) x Concrete Volume

= (1 / 5.5) x Concrete Volume = (1 / 5.5) x 2 = 0.3636 cu.m

Density of Cement = 1440 kg / cu.m = 0.3636 x 1440 = 523 kg = 10.5 approx.bags

Sand Quantity = (Sand Part / Concrete Parts) x Concrete Volume = (1 / 5.5) x 2 = 0.5454 cu.m

Coarse Aggregate = (Coarse aggregate part / Concrete parts) x Concrete Volume = (3 / 5.5) x 2 = 1.09 cu.m

WATER CEMENT RATIO:

According to IS 10262 (2009), Assuming Water-Cement Ratio for the concrete as 0.45

Required amount of water = W/C ratio x Cement volume 

Therefore, Water = 0.45 x 0.3636 = 0.16362 cu.m

[Unit Weight of Water = 1000 liters/cu.m] 

Required amount of water = 0.16362 x 1000 = 163.32 liters

Therefore,we need 10.5 bags of cement , 0.5454 cu.m of sand , 1.09 cu.m of coarse aggregates and 163.62 liters of water.</sup>

DIFFERENCE BETWEEN PLASTERING AND POINTING

DIFFERENCE BETWEEN PLASTERING AND POINTING:

Plastering and pointing or two common terms in building construction. However, both are not same. The difference between plastering and pointing are as follows:

1. The main objective of plastering is to protect the exposed surface of the masonry. That's why motor is applied to the total surface of the masonry. But in pointing only joints are filled with mortar.

2. Cement, sand, lime mortar is used in plastering. But only cement mortar is used in pointing.

3. Plastering is done both the inside and outside surfaces. Pointing is done only on the outside parts.

4. Large amount of materials is required for plastering work. On the other hand less amount of materials is required in pointing work.

5. After plastering the surface becomes smooth and plain. It gives better appearance to the structure. But after Pointing the surface do not become plain as plastering.

6. After plastering the defects of masonry are not visible, but the defects of masonry can be seen in case of pointing.

7. Plastering can be done in all types of brick surface. But pointing is only suitable for first class bricks.

SITE ENGINEER'S CHECKLIST FOR QUALITY BRICKWORK

BRICKWORK CHECKLIST FOR SITE ENGINEERS:

While on site, a site engineer must ensure that the brickwork is going on as per quality requirements. Some of the general requirements of quality of brickwork are mentioned below. Use this as a checklist while executing brickwork.

 1. The thickness of joint in brick masonry should not exceed 1 cm.

 2. The face joints should be raked to a depth of 15mm by raking      tool when the mortar is still green so as to provide proper key for plastering or pointing.

 3.Brick work should be taken up in layers not exceeding one meter height at a time.

 4.Check that the brick work is in plumb.

 5.Check that the brick courses are in level.

 6.Check the quality of bricks with specific reference to

• Strength
• Efflorescence
• Dimensional accuracy
• Water absorption

 

 7.Check that no brick bats are used as queen closer.

 8.Check strength of mortar by scratching with sharp instrument like screw driver.

 9.Check the quality of sand in mortar.(Test for fitness modulus and silt content).

10.Check mixing of  mortar whether done by hand or by machine, whether mixing is done on a proper platform.

11.Check arrangements for curing.

12.Whether raking of green joints done or not.

13.Whether soaking of bricks done or not.

14.Check general quality of works with reference to lines, levels, 
thickness and trueness of the joints.  

15.Whether brick corners are provided properly by a proper brick closer and not by pitting brick bats.

16.Whether top courses in plinth, in window sill and below RCC slab and parapet are provided with brick on edge.

17.Whether joints of brick work are filled with mortar fully, check especially vertical joints.

18.Check type of scaffolding and whether tied and braced properly.

19.Check reinforcement in brick partition wall, whether provided.

20.Check bonding of cross wall with long walls.

21.Whether holes left in the brick work while execution for supporting scaffolding are filled with concrete and not with dry bricks.