Friday, July 4, 2014

Garsa Stone -A Construction Material found in Kullu

Hi,
Garsa is a place near to Bajaura, Bhunter at a distance of about 8 km from Bajaura. Recently I was nearby to this place and was told about the mine, a source of the famous Garsa stone.
This stone can be extracted in the form of layers, both sides finished in a perfect manner suitable to use as the wall surfaces.
Vinod, my neighbour cum friend is the resident of the nearby village, has used this stone on the walls of his home.

Garsa Stone used on the walls of house
His home looks quite beautiful with these stone finished surfaced walls. While coming back from Bhunter to Sunder Nagar I observed a number of houses which used the same stone as a surface finish material for the walls of their houses.
I was told by Vinod that the main advantage of using this stone is that its color doesn't fade away with time, so you don't have to replace it with time. Another great advantage is its natural aesthetic appearance.

Here is the photo showing the wall finished with the Garsa Stone available only at Garsa in Kullu district of Himachal Pradesh.

Thanks for your kind visit!

Thursday, June 12, 2014

Timber

Hi, How you doing?

Why Timber is obsolete these days? what are the conditions under which timber is desirable to be used?
Well, timber is one of the building materials known to the mankind. Before man realized the other materials, timber was used throughout the world as the construction material, perhaps the few of materials known to man. Today timber is used as for beams, columns, piles, roofings, bridges, trusses, doors and windows.
In places like Kashmir, where timber is available in abundance, it is widely used for almost every construction work, but now-a-days for important construction works, use of timber has become obsolete due to the following reasons:

  1. Steel components are cheaper.
  2. Timber components require often frequent renewal. 
  3. There is often difficulty and considerable delay in securing the desired quality, sizes and lengths of timber.
  4. Timber components are liable to be caught by fire. In this regard steel has the maximum advantage.
Inspite of the disadvantages listed above, there are certain conditions under which use of timber may be felt desirable. In places which always remain wet and are not liable to drying and wetting, timber piles have been found satisfactory. Regarding bridges, timber bridges involve low first cost.
Bridges are rarely constructed entirely of timber, in many cases, the compression members are made of timber and tensile members are made of steel. Such bridges are called combination bridges. 
timber trusses are also used in jobs of a temporary character- for example, false work needed for supporting workmen and materials or in some cases to support a temporary road around a site on which a permanent steel structure if being erected.
Thanks for you kind visit!

Monday, January 20, 2014

Classification of Aggregates

Hello There,

Aggregates are classified into two categories according to their size:

  1. Coarse Aggregates These are the aggregates which has size more than 4.75 mm. In laboratories they are separated as the aggregates which are retained on the BIS test sieve no. 480. Generally broken stones are used as the coarse aggregates.
  2. Fine Aggregates These are the aggregates which has size less than 4.75 mm. In laboratory they are classified as the aggregates which passes through the BIS sieve no. 480. In general, Natural river sand is used as a fine aggregate.
Now we will discuss the characteristics of the coarse aggregates:
  • As per IS:383-1963 shape of the particles of the aggregates may be round, angular and flaky.. Rounded particles do not have good interlocking, where as irregular and angular particles show very good inter-locking properties. Rounded particles show good workability.
  • They should have a rough surface to get better bond between particles and cement paste.
  • Porosity and water absorption should be less.
  • Harmful ingredients such as iron pyrites, coal, mica, shale, clay, alkali and organic impurities should be avoided. These materials should not be present in such quantities that they may effect strength and durability of the concrete. Total amount of deleterious materials in aggregates should not exceed 5%.
Thanks for visit!

Friday, December 6, 2013

Fly Ash as a Road Material

What is Fly ash?
Fly ash is a waste material obtained from the furnaces, which use the coal as a fuel for energy. Fly ash particles are spherical in shape and they fly from the plant and if not captured will pollute the surroundings. So, this is not only waste material but a pollutant.

Can we use Fly ash for useful works?
It was hoped that fly ash will make a good material because it has cementing properties when mixed with right proportions of different materials and can be used as a road material for the stabilization of the sub-grade and to replace the cement in cement concrete roads.
Tests were conducted at Civil Engineering department, NIT Hamirpur in the year 2009 by three final year students under their major project and a very big report was prepared to give you the detailed report.

How to get the report?
Well, just contact me through the email or leave a comment and I will tell you the procedure for that.

Monday, November 18, 2013

Compaction Factor Test for Fresh Concrete

Hello,
How you doing?
Here is what you searched for:

  • Aim: To find out the compaction factor for the given fresh mix of concrete.
  • Theory: Work-ability of concrete is the ability/ease with which concrete can be mixed, transported and placed. This is a major factor which contributes to the other properties of concrete also. If concrete is workable enough then it can be compacted with less compacting effort. So there is a relation between the amount of work required to compact a given fresh concrete and the work-ability of the concrete. This relation is well suited for the concrete of the low water cement ratio. Slump cone test is also used to find out the work-ability of the concrete but only recommended for the concrete of higher work-ability. For less workable concrete(having less water cement ratio), compaction is standardized by various standards. 
  • Apparatus: Compaction factor apparatus/machine, weighing balance, cow/mixing tray.

Compaction Factor apparatus

  • Procedure:
1. Oil the inner sides of the top and bottom cone frustum.
2. Prepare a M15 concrete mix(1:2:4) using a water content of about 0.4-0.6 by weight of cement.
3. Fill the top cone frustum with the fresh mix of concrete and then open the gate and let the concrete fall on the second frustum.
4. Open the gate of second frustum and let it fall on the cylinder to fill up to top of cylinder. 
5. Measure the weight of the cylinder filled with the concrete(partially compacted) and then empty this.
6. Again fill the cylinder with the same sample of the concrete but this time, do the compaction using the mechanical vibrator to do the compaction. 
7. Again measure the weight of the cylinder filled with the concrete(Fully compacted).
8. Clean all the apparatus and put them at their places as before.

  • Calculations: 
Let weight of the empty cylinder = W1
Let weight of the cylinder with the partially compacted concrete = W2
Let weight of the fully compacted(Using mechanical vibrator) concrete with cylinder = W3
Compaction Factor = Weight of the partially compacted concrete/ Weight of the fully compacted concrete
i.e., Compaction factor = (W2-W1)/(W3-W1)


  • Result: The compaction factor of the given fresh concrete mix is .....
(Note: Relation between the compaction factor and work-ability is that higher the compaction factor higher is the work-ability. Theoretical maximum value of the compaction factor can be 0.96 to 1.0)


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Saturday, November 9, 2013

Concrete Slump Test


Aim: 

To determine the slump of a given fresh concrete mix sample.

Theory:

 Work-ability is the ease with which the given concrete mix can be mixed together, transported to the application place and can be placed/applied/compacted their within the initial setting time of cement. This property depends largely on the amount of water added i.e. water cement ratio of the concrete mix and kind of aggregates used. Generally work-ability increases with the addition of the water, however it results in the less strength of concrete. So we have to settle for an intermediate value of water cement ratio at which it may have the sufficient work-ability as well as sufficient strength.

Apparatus: 

Slump cone apparatus, cow tray

Slump Cone Apparatus:
This is the standard apparatus used to determine the slump of the  given fresh concrete. This is a metallic, conical shaped, of height 30 cm, 20 cm, and 10 cm as the larger and smaller diameters respectively at the far two ends. This is provided with two handles to lift it above the base.
Cow tray: This is used to mix the given materials in the given proportions (Water, Cement, Sand and coarse aggregates).


Procedure: 


  •  Oil the inner side of the slump cone apparatus(so that concrete do not stick to its sides)  and put it on the table/floor with the larger diameter base at bottom. 
  • After mixing the concrete,fill the slump cone with the freshly prepared concrete mix, compacting this in 3 layers, each layers tamped with the tamping rod giving 25 no. of blow. 
  • Remove the extra concrete overflowing from the top edge of the cone with the help of a strike.
  • Hold the two handles of the cone in hand and then lift the cone up leaving the concrete on the base. 
  • After the cone support is removed, concrete will fall under its own weight. The initial height of the concrete cone was 30 cm and after the fall, you have to measure the amount of fall from its top with the help of a scale.


Calculations: 

Initial height of the concrete = 30 cm
     Height after lifting the cone = h2.
 slump = 30 - h2 (cm)


Interpretations of Results: 

Types of slumps

  • Slump of concrete is interpreted as collapse slump, shear slump and true slump. 
  • If it is collapse slump then the concrete is too wet, and shear slump also indicates a poor mix, concrete of true slump is of value. 
  • A concrete of slump value 0 to 25 mm is used in the road mixes, 10-40 mm mixes are used in the foundations with light reinforcement, and 50-90 mm used for normal concrete works compacted with vibrations, slumps .10 cm are considered of higher work-ability.

Thank you!

Tuesday, October 29, 2013

Le-Chatelier's Apparatus- Soundness Test of Cement

Hello,


  • Aim: To find out the Soundness of Cement.
  • Apparatus: Le- Ch-atelier's Apparatus, Weighing balance, measuring cylinder, trowel, mixing pans heater, thermometer.
  • Standard Reference:  Test is performed as per IS: 4031 (Part - 1) - 1988,
  • Theory: 
Cement of good quality does not contain the impurities like free lime, magnesia and sulphates, so this should be checked before use.

When it contains the impurities named above, it can expand after reacted with the water, which will result in the unwanted results like, cracking, unwanted expansion of the dimensions and lower strength. 
Le-Ch-atelier's Apparatus is the standard apparatus prescribed as per IS:5514 -1969 to check the presence of the impurities in cement.  Cement is said to be sound when the expansion is below 10 mm.


  • Procedure: 

Prepare a cement paste of 78% of standard consistency of the cement, and fill it into the split brass cylinder.

Cover the top and bottom of the cylinder and put it in water at 27 degrees Celsius for 24 hours.

After 24 hours, measure the separation between the two indicators at their pointed ends.

Then heat the whole water and immersed cylinder with paste up to a boiling temperature in 30-35 minutes and then boiling  for 3 hours.

After cooling it down, again measure the separation between the two pointers.

  • Calculations: 

Let the reading before putting the cement paste into the boiling temperature  = L1
                         After three hours of hot water immersion = L2
                  Expansion = L2-L1

  • Result: As the value of expansion is (Less/More)..... than 10 mm so the cement is .........(Sound/Unsound).

Thanks for visit!
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