PROCEDURE OF TESTING VARIOUS CONSTRUCTION MATERIALS (LABORATORY & ON FIELD TESTS)

(A) Cement:

1. Consistency Test: -
   

   Procedure: - By using Vicat apparatus (IS: 5513-1976) prepare a neat cement paste by gauging the cement with 0.85 times the water required to give a paste of standard consistency. Potable or distilled water shall be used in preparing the paste. The paste shall be gauged in the manner & under the conditions prescribed in IS: 4031 (Part 4)-1988. Start a stopwatch at the instant when the water is added to the cement. Fill the Vicat mould 'E' with cement paste gauged as above, the mould resting on a non-porous plate. Fill the mould completely & smooth off the surface of the paste making it level with the top of the mould. The cement block thus prepared in the mould is the test block.
   

           Immediately after moulding, place the test block in the moist closet or moist room & allow it to remain there except when determinations of time of setting are being made.
   

   
    

To obtained required consistency per 50 kg cement

Shall not be more than 34 liter for 1:3:6 mix

Shall not be more than 30 liter for 1:2:4 mix

Shall not be more than 27 liter for 1:1½:3 mix

 

NOTE 1 – Clean appliances shall be used for gauging.

NOTE 2 – All the appliances shall be free from vibration during the test.

NOTE 3 – Care shall be taken to keep the needle straight.

 

2) Setting Time -

        Determination of I.S.T.: - Place the test block confined in the mould & resting on the non-porous plate, under the rod bearing the needle (C); lower the needle gently until it come in contact with the surface of the test block & quickly release, allowing it to penetrate into the test block. In the beginning, the needle will completely pierce the test block. Repeat the procedure until the needle when brought in contact with the test block & released as described above, fails to pierce the block beyond 5.0 ± 0.5 mm measured from the bottom of the mould. The period elapsing between the time when water is added to the cement & the time at which the needle fails to pierce the test block to a point

5.0 ± 0.5 mm measured from the bottom of the mould shall be the I.S.T.

 

 

 

        Determination of F.S.T.: - Replace the needle (C) of the Vicat apparatus by the needle with annular attachment (F). The cement shall be considered as finally set when, upon applying the needle gently to the surface of the test block, the needles makes an impression thereon, while the attachment fails to do so shall be the final setting time. In the event of a scum forming on the surface of the test block, use the underside of the block for the determination.

 

(B) Aggregates: -

 

1. Aggregate Impact Value –
   

   Apparatus – The apparatus shall be consists of the following.
   

 

(a) An Impact Testing Machine complying with the following:

    (1) Total Wt. not more than 60 kg nor less than 45 kg.

(2) The machine shall have a metal base weighing between 22 & 30 kg with a plane lower surface of not less than 30 cm diameter, & shall be supported on a level & plane concrete or stone block or floor at least 45 cm thick. The machine shall be prevented from rocking either by fixing it to the block or floor or by supporting it on a level & plane metal plate cast into the surface of the block or floor.

(3) A cylindrical steel cup of internal dimensions:

Diameter: 102 mm; Depth: 50 mm.

And not less than 6.3 mm thick with it's inner surface case-hardened, that can be rigidly fastened at the centre of the base & easily removed for emptying.

(4) A metal tub or hammer weighing 13.5 to 14.0 kg, the lower end of which shall be cylindrical in shape, 100 mm in diameter & 50 mm long, with 2 mm chamfer at the lower edge, & case-hardened. The hammer shall slide freely vertical guides so arranged that the lower (Cylindrical) part of the hammer is above & concentric with the cup.

(5) Means for raising the hammer & allowing it to fall freely between the vertical guides from a height of 380 ± 5.0 mm on to the test sample in the cup, & means for adjusting the height of fall within 5 mm.

(6) Means for supporting the hammer whilst fastening or removing the cup.

(b) Sieves – The IS Sieves of sizes 12.5, 10 & 2.36 mm.

(c) Measure – A cylindrical metal measure, tarred to the nearest gram, of sufficient rigidity to retain its form under rough usage, & of the following internal dimensions:

Diameter: 75 mm; Depth: 50 mm.

(d) Tamping Rod – A straight metal Tamping rod of circular cross section

10 mm in diameter & 230 mm long, rounded at one end.

(e) Balance – A balance of capacity not less than 500 gm, readable & accurate to 0.1 gm.

(f) Oven – A well-ventilated oven, thermostatically controlled to maintain a temperature of 100°C to 110°C

 

        Preparation of Test sample –

• The test sample shall consists of aggregate the whole of which passes a 12.5 mm IS Sieve and is retained on a 10 mm IS Sieve. The aggregate comprising the test sample shall be dried in an oven for a period of
  

4 hrs. at a temperature of 100°C to 110°C and cooled.

• The measure shall be filled bout 1/3^rd full with the aggregate & tamped with 45 strokes of the rounded end of the tamping rod. A further similar quantity of aggregate shall be added & a further tamping of 25 strokes given. The measure shall finally be filled to overflowing, tamped 25 times & the surplus aggregate struck off, using the tamping rod as a straight edge. The net wt. of aggregate in measure shall determined to the nearest gram (Wt. A) & this wt. of aggregate shall be used for the duplicate test on the same material.
  

 

Test Procedure –

1. The impact machine shall rest without wedging or packing upon the level plate, block or floor, so that it is rigid & the hammer guide columns are vertical.
   
2. The cup shall be fixed firmly in position on the machine & the whole of the test sample placed in it & compacted by a single tamping of 25 strokes of the tamping rod.
   
3. The hammer shall be raised until its lower face is 380 mm above the upper surface of the aggregate in the cup, and allowed fall freely on to the aggregate. The test sample shall be subjected to a total of 15 such blows each being delivered at an interval of not less than 1 sec.
   
4. The crushed aggregate shall then be removed from the cup & the whole of it sieved on the 2.36 mm IS sieve until no further significant amount passes in one minute. The fraction passing the sieve shall be weighed to an accuracy of 0.1 gm (Wt. B). The fraction retained on the sieve shall also be weighed (Wt. C) and, if the total wt. (B+C) is less than the initial weight (Wt. A) by more than 1 gm. The result shall be discarded & a fresh test made. Two tests shall be made.
   

 

 

Calculation: -

The ratio of the wt. of fines formed to the total sample wt. in each test shall be expressed as a percentage (%), The result being recorded to the first decimal place:

 

        Aggregate Impact Value = (B/A) X 100

Where; B = wt. of fraction passing 2.36 mm IS Sieve, and

     A = wt. of oven dried sample.

2) Aggregate Abrasion Value – (Using Los Angeles machine)

 

        Apparatus –

(a) Los Angeles machine: - The Los Angeles abrasion testing machine, confirming in all its essential characteristics to the design shall be used. The machine shall consists of a hollow steel cylinder, closed at both ends having an inside diameter of 700 mm and an inside length of 500 mm. The cylinder shall be mourned on stub shaft attached to the ends of cylinders but not entering it & shall be mounted in such a manner that it may be rotated about its axis in a horizontal position. An opening in the cylinder shall be closed dust tight with a removable cover bolted in place. The cover shall be so designed as to maintain the cylindrical contour of the interior surface unless the shelf is so located that the charge will not fall on the cover or come in the contact with it during the test. A removable steel shelf, projecting radially 88 mm into the cylinder & extending its full length shall be mounted along one element of the interior surface of the cylinder. The shelf shall be of such thickness & so mounted by bolts or other approved means as to be firm & rigid. The position of the shelf shall be such that the distance from the shelf to the opening, measured along the circumference of the cylinder in the direction of rotation, shall be not less than 1250 mm.

 

    The abrasive charge, depending upon the grading of the test sample a described below:

Grading	No. of spheres	Wt. of charge (gm)
A	12	5000 ± 25
B	11	4584 ± 25
C	8	3330 ± 20
D	6	2500 ± 15
E	12	5000 ± 25
F	12	5000 ± 25
G	12	5000 ± 25

 

(b) Test Sample – The test sample shall consists of clean aggregate which has been dried in an oven at 105 to 110°C to substantially constant wt. and shall conform to one of the grading shown in table below. The grading or gradings used shall be those most nearly representing the aggregate furnished for the work.

NOTE – It is recognized that different specification limits may be required for gradings E, F & G than for A, B, C & D. It is urged that investigations be conducted to determine the relationship, if any, which exist between result for these coarse gradings using the

10,000 gm sample & the finer ones using the 5000 gm sample.

 

TABLE – II GRADINGS OF TEST SAMPLE

Sieve Size (Square Hole)		Weight in gm of Test Sample for grade
Passing (mm)	Retained on (mm)	A	B	C	D	E	F	G
80	63	---	---	---	---	2500*	---	---
63	50	---	---	---	---	2500*	---	---
50	40	---	---	---	---	5000*	5000*	---
40	25	1250	---	---	---	---	5000*	5000*
25	20	1250	---	---	---	---	---	5000*
20	12.5	1250	2500	---	---	---	---	---
12.5	10	1250	2500	---	---	---	---	---
10	6.3	---	---	2500	---	---	---	---
6.3	4.75	---	---	2500	---	---	---	---
4.75	2.36	---	---	---	5000	---	---	---

 

* - Tolerance of ±2 percent permitted.

 

Procedure –

1. The test sample & the abrasive charge shall be placed in the Los Angeles Abrasion testing machine & the machine rotated at a speed of 20 to 33 rev/min. For gradings A, B, C & D, the machine shall be rotated for 500 revolutions; for gradings E, F & G, it shall be rotated for 1000 revolutions. The machine shall be so driven & so counter balanced as to maintain a substantially uniform peripheral speed. If an angle is used as the shelf, the machine shall be rotated in such a direction that the charge is caught on the outside surface of the angle. At the completion of the test, the material shall be discharged from the machine & a preliminary separation of the sample made on a sieve coarser than the 1.7 mm IS Sieve. The finer portion shall then be sieved on a 1.7 mm IS Sieve in the manner described in 2.3 Part I of this standard.
   
2. The material coarser than the 1.7 mm IS Sieve shall be washed dried in an oven at 105°C to 110°C to a substantially constant weight & accurately weighed to the nearest gram.
   

NOTE – Attention is called to the fact that valuable information concerning the uniformity of the sample under test may be obtained by determining the loss after 100 revolutions. When this determination is made, care should be taken to avoid loss of any part of the sample; the entire sample; including the dust of abrasion, shall be returned to the testing machine for the completion of the test.

 

Reporting of result –

The difference between the original weight & the final weight of the test sample shall be expressed as a percentage of the original weight of the test sample. This value shall be reported as the percentage of wear.

 

(C) Natural Sand: -

DETERMINATION OF MATERIALS FINER THAN 75 MICRON

IS: 2386 (Part – I) – 1963.

Object –

This method of test deals with the procedure for determining the total quantity of material finer than 75 micron IS Sieve in aggregates by washing.

 

NOTE – Clay particles that are disposed by wash water as well as water soluble materials will be removed from the aggregate during the test.

 

Apparatus –

(a) Balance – The balance or scale shall be of sufficient capacity & sensitivity and shall have an accuracy of 0.1% of the weight of the test sample.

(b) Sieve – A nest of two sieves, the lower being 75 micron IS Sieve and the upper approximately 1.18 mm IS Sieve [see IS : 460-1962 Specification for test Sieves (Revised)].

(c) Container – A pan or vessel of size sufficient to contain the sample covered with water & to permit of vigorous agitation without inadvertent loss of any part of the sample or water.

(d) Oven – An oven of sufficient size capable of maintaining an uniform temperature of 110°C ± 5°C.

Sample –

The test sample shall be selected from material which has been thoroughly mixed & which contains sufficient moisture to prevent segregation. A representative sample, sufficient to sample, sufficient to yield not less than the appropriate weight of dried material, as shown below, shall be selected:

Maximum Nominal size of aggregate In (mm)	Approximate minimum weight of sample in (gm)
4.75	500
10.0	2000
20	2500
40 or over	5000

 

Procedure –

(1) The test sample shall be dried to constant weight at a temperature of 110°C ± 5°C & weighed to the nearest 0.1%.

(2) The test sample after being dried & weighed shall be placed in the container & sufficient water added to cover it. The contents of the container shall be agitated vigorously.

(3) The agitation shall be sufficiently vigorous to result in the complete separation from the coarse particles of all particles finer than 75 micron & bring the fine material into suspension.

    Care should be taken to avoid, as much as possible, the decantation of the coarse particles of the sample. The operation shall be repeated until the wash water is clear.

(4) The wash water containing the suspended & dissolve solids shall be immediately poured over the nested sieves arranged with the coarser sieve on the top.

(5) All material retained on the nested sieves shall be returned to the wash sample. The wash aggregate shall dried to constant weight at a temperature not exceeding 110°C and weighed to the nearest 0.1%.

 

Calculation –

The amount of material passing the 75 micron IS Sieve shall be calculated as follows:

 

A = [(B-C) / B] X 100

Where,

    A = percentage of material finer than 75 micron.

    B = original dry weight, and

    C = dry weight after washing.

% Passing w.e.f. IS Sieve (Grading zones)

 

Designation	Grading Zones
	Zone I	Zone II	Zone III	Zone IV
10 mm	100%	100%	100%	100%
4.75 mm	90%-100%	90%-100%	90%-100%	95%-100%
2.36 mm	60%-95%	75%-100%	85%-100%	95%-100%
1.18 mm	30%-70%	55%-90%	75%-100%	90%-100%
600µ	15%-34%	35%-59%	60%-79%	15%-50%
300 µ	5%-20%	8%-30%	12%-40%	15%-50%
150 µ	0%-10%	0%-10%	0%-10%	0%-10%

NOTE – Grade - IV shall not be used in RCC.

 

(D) Concrete -

Workability of concrete (Slump Test)

 

Placing conditions	Degree of Workability	Slump in (mm)
Blinding concrete; Shallow sections; Pavement using pavers	Very low	IS 1199
Mass concrete; Lightly reinforced sections in slabs, beams, walls, columns; Floors; Hand placed pavements; Canal lining; Strip footings	Low	25 – 75
Heavily reinforced sections in slabs, beams, walls, columns; Slip form work; Pumped concrete	Medium	50 – 100   75 – 100
Trench fill; In situ piling Tremie concrete	High   Very high	100 – 150   IS 9103

 

 

 

 

Description	Slump in (mm)
	With vibrator	Without vibrator
Plain Cement Concrete Mass concrete in foundation, footings, retaining walls & pavements   Thin section of flooring less than 75 mm thick	10 – 25       25 – 40	50 – 75       75 – 100
Reinforced Cement Concrete Mass concrete in RCC foundations, footings, retaining walls   Beams, slabs, & columns Simply reinforced   Thin RCC section or section with congested steel	10 – 25       25 – 40     40 – 50	80       100 – 125     125 – 150

 

(E) Bricks: -

 

TYPES OF BURNT BRICKS AND THEIR USES

 

Class	Nature	Surface	Hardness	Uses
First Class	Sound, Well Burnt, Rectangular	Clean, Smooth, no cracks	Very Hard	Face – worked structures
Second class	Well burnt but with irregular shape	Spots on surface	Hard	Ordinary structure
Third class	Under Burnt	Rough & distorted edges	Slightly soft	Buildings not subjected to heavy rains
Fourth class	Over Burnt	Irregular	Very Hard	Concrete for foundations

 

 

 

Compressive strength of Bricks: -

        The compressive strength of Brick is measure of its ability to withstand compressive strength.

        The brick is placed between thin plywood sheets & inserted between the plates of the testing machine. The upper plate is screwed by hand wheel provided at the top of the machine. The load is applied beneath the plate by pumping oil to a hydraulic ram. The amount of pressure is read on the dial of the machine.

        The compressive strength of engineering bricks, building bricks & good clay bricks are 7000 to 10,000; 2000 to 4000; 4000 lbs. per sq. ft.

 

Water absorption test –

        It is the measure of the quantity of water absorbed by a brick when immersed in water.

        The brick is weighed in room temperature when completely dry. Let the weight be 'W₁'. Next the brick is kept immersed in water for 24 hrs. again at room temperature & then weighed. Let the weight be 'W₂'. After this, the brick is boiled in water for 5 hrs. & cooled in water overnight & weighed. Let the weight be 'W₃'.

        Saturation coefficient is given by:

    

(W₂ – W₁)

(W₃ – W₁)

Water absorption, percent by weight is given by

 

(W₂ – W₁) X 100

W

 

Efflorescence Test for Bricks:

        The end of the specimen is immersed in water contained in a dish up to a depth of 2.5 cm & allowed to remain in this condition. Part of water is absorbed by the brick & the remaining is evaporated. The brick is taken out & when it appears dry, the same procedure is repeated. After second evaporation the brick is examined for efflorescence & the conclusions are drawn as follows:

(a) No efflorescence in absence of any visible deposit.

(b) Slight efflorescence, moderate efflorescence, heavy efflorescence are indicated by deposit cover 10%, 25% & 50% of the covered area of the brick surface, respectively.

 

 

CPVC – Chlorinated Polyvinyl Chloride.

    It is a thermoplastic pipe & fitting material made of compounds.

CPVC products are specifically used for potable water distribution & corrosive fluid handling industry etc. It is a very cost-effective system.

 

MICROSILICA – It is found from natural deposit in New Zealand. It is a highly reactive pozzolan. Like silica fume, it is very fine amorphous product.

        When MICROSILICA is added with Portland cement, it gives better performance such that it provides very low chloride iron diffusion & it gives better performance such that it provides very low chloride iron diffusion & it increases the compressive strength.