Practical Lab Manual Plain and Reinforced Concrete - 1

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LIST OF PRACTICALS

1. (a) Determination of standard consistence of cement paste

(b) Determination of soundness of cement

2. Determination of Initial and Final setting of cement

3. (a) To carry out sieve analysis of Fine Aggregate Sample and Determination of Finess Modulus

(b) To carry out the sieve analysis of Coarse Aggregate Sample

4. Test for compressive strength of cement on mortar cubes

5. (a) Determination of crushing value of coarse aggregate

(b) Determination of 10% fine value of coarse aggregate

6. Determination of specific gravity of coarse aggregate

7. Determination of specific gravity of fine aggregate

8. To perform the workability test on fresh concrete

(a) Slump Test

(b) Compacting Factor Test

(c) VeBe Test

9. Determination the compressive strength and tensile strength of concrete

(a) Effect of water cement ratio on strength of concrete

(b) Effect of aging on strength of concrete

10. Determination of modulus of elasticity of concrete

11. Non Destructive testing of concrete

EXPERIMENT 1

(a) TO DETERMINE THE STANDARD CONSISTENCY OF CEMENT PASTE

1. EQPT/MATERIAL Vicat Apparatus, Graduated glass cylinder, Weighing balance, Bowl, Gloves, spatula, water.

2. PROCEDURE a. Make a ball of cement paste in the hands. Toss it six times from one hand to another keeping

them six inches apart. b. At the ball resting in palm of the one hand shall be pressed into larger end of the mould, held in

the other hand, completely filling the mould. The excess paste at the larger end shall be removed be then removed by a single movement of the palm of the hand.

c. Place the mould with larger end on the glass plate and slice off excess paste at the smaller end with the help of the spatula. The top may be smoothed with light touches of end of the spatula. Care should be taken not to compress the paste during this operation.

d. Now bring the plunger rod in contact with the surface of the cement paste and tighten the Set screw, Set the pointer to the zero mark.

e. Release the plunger rod, then after an elapse of 3o second take the reading at the pointer. f. The paste shall be at standard consistence if the plunger settles to a pointer 10 mm below the

original surface or 34 to 36 mm from the above of the scale. Prepare trial pastes by varying the amount of water. Each trial shall be made with fresh cement.

g. The amount of water required for normal consistence is calculated percentage by weight of dry cement.

3. PRECAUTIONS a. All the activities shall be completed within the specified time. b. Mixing of cement shall be done on the non porous plate or steel bowl. c. Plunger shall be cleaned every time before lowering in the cement paste. d. The apparatus should be free of all kind of vibration during the test. e. There should be no friction on the plunger rod.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Type of cement b. Room temperature c. Temperature of the mixing water.

5. THE PERFORMA/FORMAT FOR PREPARATION OF RECORD OF

OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

S/ No. AMOUNT OF WATER

(%)

PENETRATION

(mm)

1

2

3

4

6. INTERPRETATION/ COLLECTION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS

To be done with standard specification of ASTM Designation C 187, C 191 and B.S 12

7. COMMENTS

EXPERIMENT 1

(b) TO DETERMINE THE SOUNDNESS OF CEMENT

1. EQPT/MATERIAL Le-chatlier mould apparatus complete, Cement and water.

2. PROCEDURE a. Take 500 grams of cement sample and find out its standard and normal consistency, as per

practical 1(a). b. Fill the mould with cement paste of standard consistency the mould will be placed on glass plate. c. Cover the upper side of the mould with another glass plate, and the whole assembly is then

immersed in water at 20⁰C for 24 hours. d. At the end of 24 hours the distance between the indicators is measured the mould is immersed in

water again and brought to boil in 25 to 30 minutes. e. After boiling for one hour the assembly is taken out and after cooling the distance between the

indicators is again measured. f. The increase or the difference in distance represents the expansion of cement, and for Portland

cement this expansion should not be more than 10 mm.

3. PRECAUTIONS

Thin oil layer should be applied on mould before filling with cement paste.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Type of cement. b. Room temperature. c. Temperature of the mixing water. d. Room Temperature.

THE PERFORMA/FORMAT FOR PREPARATION OF RECORD OF OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

S/ No.

EXPANSION BEFORE BOILING

(mm)

EXPANSION AFTER

BOILING

(mm)

DIFFERENCE (mm)

RESULT

1

2

3

4

5

6

7

5. INTERPRETATION/ COLLECTION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS

To be done with standard specification of BS 4550 Part 3, Section 3, 7.1978.

6. COMMENTS

EXPERIMENT 2

TO DETERMINE THE INITIAL AND FINAL SETTING TIME OF CEMENT

1. EQPT/MATERIAL Vicat Apparatus with Initial Set Needle, Final Set Attachment, Stop Watch, Portland Cement, Water

2. PROCEDURE a. Neat cement paste shall be formed by mixing cement with the quantity of water required to give a

paste of standard consistence. b. Vicate mould shall be completely tilled and the surfing to the paste shall then be smoothed off,

level with the top of the mould. The temperature of the material and that of the test room, at the time when above operation are being performed, shall be 17.7 to 23.3⁰C.

c. For the determination of the initial setting time the test block confined in the block/mould and resting on the plate shall be placed under the rod bearing needle. This shall then be lowered gently in contact with the surface of the test block and quickly released and allowed to sink in. This process shall be repeated until the needle, when brought to contact with the test block and released as describe above, does not penetrate beyond the point approx. 5±1 mm, from the bottom of the mould (34 to 36 mm penetration from the top).

d. The period elapsing between the time when the water is added to the cement and the time at which needle ceased to pierce the test block is called the Initial setting time.

e. For the determination of final setting time, the same needle shall be used. The cement shall be considered as finally set when, upon applying the needle gently to the surface of the test block, only the needle makes and impression, while the attachment fails to do so.

f. If the scum form on the surface of the test block, then underside of the test block may be used for determining the Final Set.

3. PRECAUTIONS a. The needle should be allowed to touch the surface of cement in the cement paste. b. After every reading the needle should be cleaned.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Type of cement b. Room temperature c. Temperature of the mixing water.

5. THE PERFORMA/FORMAT FOR PREPARATION OF RECORD OF OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

S/ No. AMOUNT OF WATER

(%)

PENETRATION

(mm)

1

2

3

4

5

6. INTERPRETATION/ COLLECTION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with standard specification of ASTM Designation C 150, and B.S 12:1978

7. COMMENTS

EXPERIMENT 3

(a) TO CARRY OUT SIEVE ANALYSIS OF FINE AGGREGATE SAMPLE AND DETERMINATION OF ITS FINESS MODULUS.

1. EQPT/MATERIAL A set of fine sieves, Weighing balance, sieve shaker, Sample of fine aggregates (500 grams) approx, brush for cleaning the sieves.

2. PROCEDURE a. The test is performed on the sample of fine aggregates which has dried. If moisture is present then

dry it at the temperature not exceeding 110 ⁰C. b. Nest the sieve with top lid and bottom pan in approximate order in a sieve shaker. c. Put the material at the top sieve and shake it for the least two minute. If hand shaking is to be

resorted then shaking should done with a varied motion backward and forward, left to right circular clock wise or anti clock wise and with frequent jarring so that the material moves over the sieve surface in frequent changing directions.

d. Continue sieving till more material pass through sieve. e. Weigh the material retained on each sieve. f. Tabulate the observations / readings.

3. PRECAUTIONS a. Sieving should be done properly. b. Quartering should be done before sieving.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Sample No. = b. Source of Supply = c. Total weight sample to be sieved = d. Finess Modulus is equal to the sum of cumulative % retained/100 =

5. THE PERFORMA/FORMAT FOR PREPARED OF RECORD OF

OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

SIEVE NO.

WT. RETAINED

% RETAINED

% PASSING

ACCUMULATIVE % RETAINED

ASTM SPEC

#4 95-100

#8 80-100

#16 50-85

#30 25-60

#50 10-30

#100 02-10

#200 ----------

Total ----------

6. INTERPRETATION/COLLECTION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with standard specification of ASTM Designation C 136.

7. COMMENTS

EXPERIMENT 3

(b) TO CARRY OUT SIEVE ANALYSIS OF COARSE AGGREGATE SAMPLE MODULUS.

1. EQPT/MATERIAL A set of coarse sieves, Weighing balance, sieve shaker, Set of coarse aggregates, weighing balance, brush for cleaning the sieves.

2. PROCEDURE a. The test is performed on the sample of fine aggregates which has dried. If moisture is present then

dry it at the temperature not exceeding 110 ⁰C. b. Nest the sieve with top lid and bottom pan in approximate order in a sieve shaker. c. Put the material at the top sieve and shake it for the least two minute. If hand shaking is to be

resorted then shaking should done with a varied motion backward and forward, left to right circular clock wise or anti clock wise and with frequent jarring so that the material moves over the sieve surface in frequent changing directions.

d. Continue sieving till more material pass through sieve. e. Weigh the material retained on each sieve. f. Tabulate the observations / readings.

3. PRECAUTIONS a. Sieving should be done properly. b. Quartering should be done before sieving.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Sample No = b. Source of Supply = c. Total weight sample to be sieved =

5. THE PERFORMA/FORMAT FOR PREP OF RECORD OF OBSERVATIONS/DATA

WITH NOTES TO HELP COMPLETION

6. INTERPRETATION/COLLATION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with standard specification of ASTM Designation C 136

7. COMMENTS

SIEVE SIZES (in)

WT. RETAINED

% RETAINED % PASSING

EXPERIMENT 4

TEST FOR COMPRESSIVE STRENGTH OF CEMENT ON MORTAR CUBES

1. EQPT/MATERIAL Compression Testing Machine, Weighing balance, glass cylinder, trowel/spatula, cube mould 2”* 2”* 2”, cement, sand passing Us sieve # 20 and retained on US sieve # 30, distilled water.

2. PROCEDURE a. Take one part of cement and three parts of sand and add 10% of the water of total dry material. b. For one mould the amount of water and the quantity of dry material that will be mixed at one time

will be calculated as follows. 1. 70 grams of cement. 2. 210 grams of sand. 3. 28 cc of water. c. After preparation of mix, the required no. of mould should be filled. The tamping pressure shall

be just sufficient to ensure uniform filling of mould. The layer of mortar about 1 inch is first placed in the mould and tamp 20 times with the tamper. Then fill the mould with mortar and tamp as specified for the first layer.

d. After completion of filling place the moulds in moist air for 24 hours. e. After 24 hours de-mould the specimens and immersed into the water for the required age. f. After three days take out three specimens of the same type of cement, and keep them in open air,

wiped to surface dry condition before test. g. Apply the load to the specimen faces that were in contact with the plane surfaces of the mould.

Carefully place the specimen in tile testing machine below the center of the upper bearing block. h. Record the total maximum load indicated by the testing machine and calculate the compressive

strengths in pounds per square inch.

3. COMMENTS

EXPERIMENT 5 (a) TO DETERMINE THE CRUSHING VALUE OF COARSE AGGREGATE

1. EQPT/MATERIAL

Crushing value apparatus complete compression testing machine, BS sieves of size ½ inch, 3/8 inch and #7, sample of coarse aggregate.

2. PROCEDURE a. Take the sample from the site and sieve it through ½ inch and retained on 3/8 inch sieve. b. Place the aggregate in three layers in cylindrical mould (measure) and each layer should be

tamped 23 times by tamping rod. c. Take out the material from the measure and weigh it, then put the measure in crushing value

apparatus on base plate in three equal layers and each layer should be tamped 25 times. d. After this place the plunger in the cylinder and subject it in the compression testing machine. e. Apply the load of 40 tons at the rate of 4 ton per minutes in 10 minutes. f. Remove the apparatus from the machine and unload the plunger from the cylinder. g. Then remove the aggregate from the cylinder and sieve it through #7 and weigh the material

retained on #7 or pass from #7. h. The results are expressed in percentage of original weight called crushing value.

3. PRECAUTIONS a. Aggregate should be in dry condition. b. Load should be given according to the specified rate.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Type of aggregate = b. Source of Supply = c. Total weight sample =

d. Weight retained or passes from # 7 sieve =

5. THE PERFORMA/FORMAT FOR PREPARATION OF RECORD OF OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

S/ No.

TOTAL WEIGHT OF DRY SAMPLE

(W1)

WEIGHT RETAINED

ON SIEVE # 7

(W2)

AGGREGATE CRUSHING VALUE

[(W1-W2)/W1 ]*100

1

2

3

4

5

6

7

6. INTERPRETATION/COLLATION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with standard specification of BS 882:1965 and B.S 812:1967

7. COMMENTS

EXPERIMENT 5

(b)TO DETERMINE THE 10% FINE VALUE OF FINE AGGREGATE

1. EQPT/MATERIAL Crushing value apparatus complete, compression testing machine, sieves, sample of coarse aggregate, weighing balance.

2. PROCEDURE a. Make all arrangements according to the procedure as stated in crushing value experiment. b. Place the cylinder with plunger over aggregate in compression machine and apply the load of 40

tons at the rate of 4 tons/minute. c. Unload the plunger and remove it from the compression testing machine. d. Remove the sample from the cylinder and sieve it through # 7. The material passing or retained

are collected and weighed. This weight expressed as the percentage of total weight gives crushing value of aggregate.

e. Take the mean of the load (Z tons) and % of fines (Y %) and work out 10 % finess value = [(14*Z)/4] + Y%

3. PRECAUTIONS a. Aggregate should be in dry condition. b. Load should be given according to the specified rate.

4. DETAILS OF READINGS/OBSERVATIONS/DATA TO BE RECORDED/COLLECTED a. Type of aggregate = b. Source of Supply =

c. Total weight sample = d. Weight retained or passes from # 7 sieve =

5. THE PERFORMA/FORMAT FOR PREPARATION OF RECORD OF

OBSERVATIONS/DATA WITH NOTES TO HELP COMPLETION

OBSERVATION TEST NO 1 TEST NO 2

Wt. Of sample

Penetration of plunger

Load (t)

Wt. Passing #7

% Passing

Mean % Passing = Y%

Mean Load = Z (T)

10% Fines Value = [(14*Z)/4] + Y%

6. INTERPRETATION/COLLECTION OF THE OBSERVE READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with standard specification of BS 882:1965 and B.S 812:1967

7. COMMENTS

EXPERIMENT 6

TO DETERMINE THE SPECIFIC GRAVITY AND ABSORPTION OF THE COARSE AGGREGATE

1. EQPT/MATERIAL Buoyancy balance, bowl, sample of coarse aggregate, oven, distilled water.

2. PROCEDURE a) Take an aggregate sample through wash and oven dried. b) Immersed aggregate sample in distill water for 24 hours. c) Take the weight of aggregate in water. d) Remove the sample from water and role it in a large absorbent cloth until all visible film of

water are removed. e) Take S.S.D. (saturated surface dry) weight. f) Dry that sample in oven and take the dry wt of sample.

3. PRECAUTION

Take all the weights with care.

4. DETAILS OF READINGS/OBSNS/DATA TO BE RECORDED/COLLECTED a) Wt of oven dry sample in air = A = grams. b) Wt of S.S.D sample in air = B = grams. c) Wt of saturated sample in water = C = grams.

5. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

S / No BULK SPEC GR. APPARENT SPEC GR.

ABSORPTION

%1. Oven dry = A/B-C A/A-C

B-A/Ax 100 2. S.S.D=B/B-C

6. INTERPRETATION/COLLATION OF THE OBSN READINGS, GRAPHS, ETC

LEADING LO RESULTS. To be done with the standard specification of ASTM Standard C 127

7. COMMENTS

EXPERIMENT 7

TO DETERMINE THE SPECIFIC GRAVITY AND ABSORPTION OF THE FINE AGGREGATE

1. EQPT/MATERIAL Weighing balance, Volumetric Flask of capacity 500ml, Conical mould made from metal sheet, base dia 3-1/2 in top dia l-l/2 in, height 2-7/8 in, tamping rod, sample of sand (l000gms).

2. PROCEDURE a) Take approximate 500 grams of sand sample in a pan and dry it in oven to constant weight. b) Cover the sample with distilled water and let it stay immerse for 24 hours. c) After 24 hours decant the water and spread the sample on a flat smooth surface. d) Expose the sample to a gentle current of warm air. Take S.S.D weight. e) Fine aggregate is then packed loosely in the conical mould, the surface lightly tamped 25

times with the tamping rod and mould lifted vertically up. If free moisture is present then the cone of time aggregate will retain its shape.

f) Drying with constant stirring is continued and the test made at frequent interval until the cone of fine aggregate slumps upon removal of the mould.

g) This stage indicates that fine aggregate has reached a surface dry condition. h) Now take approx 500 grams sample prepared above and introduce it into the volumetric

flask. Fill it to 500ml mark with water at 20 °C. i) Roll the flask on a flat surface to remove air bubbles. After this keep the flask at 20 °C in j) oven for one hour then fill it up to 500ml mark and weigh it: k) Now remove fine aggregate from flask, dry it in oven to a constant weight, allow it to cool

to room temperature and weigh.

3. PRECAUTION a) Take all the weights with care. b) Roll the flask gently.

4. DETAILS.OF READINES/OBSNS/DATA TO BE RECORDED/COLLECTED a) Wt of saturated surface dry sample = (A) grams b) Wt -of oven dried sample = (B) grams c) Wt of bottle filled water = (C) grams d) Wt of bottle + sample (SSD) + water = (D) grams

5. THE PERFORMA/FORMAT FOR PREP WITH RECORD OF OBSNS, DATA, WITH NOTES TO HELP COMPLETION

S/No BULK SPEC

GR. S.S.D

BULK SPEC

GR. OVEN

ABSORPTION

%

1.

A/A=C-D

B/A=C-D [A-B/B]x 100

2.

3

4

5

6

7

8

9

10

11

6. INTERPRETATION/COLLATION OF THE OBSN READINGS, GRAPHS, ETC LEADING TO RESULTS To be done with the standard specification of ASTM Standard C 128

7. COMMENTS

EXPERIMENT 8

(a) TO STUDY THE EFFECT OF WATER CEMENT RATIO ON THE SLUMP OF CONCRETE

1. EQPT/ MATERIAL Slump cone with base dia 8", top dia 4" and height 12" with foot pieces and handle for lifting, metal plate. tamping rod, steel rule, towel, aggregate, water and cement

2. PROCEDURE a. Place the slump cone on the metal plate and prepare the concrete mix. b. Hold the mold on the metal surface firmly from the sample of concrete fill the mould in

three layers each approx 1/3 of the volume of the mould. c. Ensure symmetrical distribution of concrete while placing concrete inside the mould. d. Give 25 strokes of tamping rod uniformly distributed over the entire cross-section

penetration into the underlying layer. The bottom layer shall b rodded throughout its depth.

e. The mould is then immediately removed by raising it carefully in vertical direction. f. Measure the slump by the determining the difference between the height of mould and the

specimen after subsidence.

3. PRECAUTION The mould should be removed by raising it carefully in vertical direction without any jerk.

4. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Concrete mix proportions = b. water cement ratio = c. Type of slump (1) True slump (2) Collapse slump (3) Shear slump

5. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

S/NO SLUMP

( in ) WATER CEMENT RATIO

1.

2.

6. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC

LENDING TO THE RESULTS To be done with the standard specification of ASTM C 143-78

7. COMMENTS

EXPERIMENT 8

(b) TO DETERMINE THE VE BE TIME OF FRESH CONCRETE BY VE BE APPARATUS

1. EQPT/ MATERIAL Ve Be apparatus complete fresh concrete, scoop

2. PROCEDURE a. Place the slump cone in the container on the vibrating table and firmly clamp the

assembly. b. Swing the funnel over the slump cone and clamp it in position. c. Fill the slump cone in three layers tamping each layer 25 times with the tamping rod, d. After filling the cone, carefully remove the funnel holding the slump cone to avoid its

being lifted up. Trowel off the top surface of the concrete to level it with the top of the slump.

e. Now carefully remove the cone from the concrete. f. Release the measuring head so that the plastic disk rests on the concrete cone (cake). g. Simultaneously start the vibrator and stop watch. h. Observe the re-moulding of concrete until the under side of the plastic disc is completely

covered with cement grout. Immediately slop the watch and vibrator, i. The time taken to cover the plastic disc is recorded as the Ve Be time.

3. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Water cement ratio = b. Concrete mix proportion = c. Ve Be time should be 4 or 5 seconds or less or more than that.

4. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

5. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC LENDING TO THE RESULTS To be done with the standard specification of ASTM and B.S

6. COMMENTS

S/No VE BE TIME (SECONDS)

AVERAGE VE BE TIME

1.

2

3.

EXPERIMENT 8

(c) DETERMINATION OF COMPACTING FACTOR OF FRESH CONCRETE BY C.F APPARATUS TO MEASURE THE WORKABILITY OF CONCRETE.

1. EQPT/ MATERIAL The compacting factor apparatus complete steel trowels, scoop, tamping rod or vibrating machine, weighing balance.

2. PROCEDURE a. The sample of concrete to be tested shall be placed gently in the upper hopper using the

scoop until the hopper is filled. b. Then the trap door shall be opened immediately after the filling, so that the concrete falls

into the lower hopper c. The trap door of lower hopper is opened and the concrete is allowed to fall into the

cylinder d. The weight of concrete in the cylinder shall then be determined to the nearest of 10

grams This weight shall be known as the “weight of partially compacted concrete”.

e. Now put the cylinder on the vibrating machine and start vibration. f. The cylinder shall then be filled with concrete from the same sample, so as to obtain full

compaction g. The weight of concrete in the cylinder shall again be determine to the nearest of 10

grams. This weight shall be known as “The weight of fully compacted concrete”

h. Calculate the compacting factor from :- CF = partially compacted concrete / fully compacted concrete

3. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Water cement ratio = b. Mix proportion = c. Weight of cylindrical Mold = d. Volume of cylindrical Mold =

4. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

S/No

WT OF CYLINDER

BEFORE COMPACTION

LOOSE DENSITY

WT OF CYLINDER

AFTER COMPACTION

COMPACTED DENSITY

C.F=

LOSE DENSITY

COMPACTED DENSITY

1

2

3

5. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC

LENDING TO THE RESULTS To be done with the standard specification of ASTM and B.S

6. COMMENTS

EXPERIMENT 9

(d) TO DETERMINE SPLIT TENSILE STRENGTH OF CONCRETE

1. EQPT/ MATERIAL Cylinder molds, cone mixer, concrete making materials, vibrating table, bearing strips, compression testing machine, weighing machine, trays.

2. PROCEDURE a. Prepare the specimen of 6" dia and 12" length 5 numbers. b. Cast the cylinder by prepared mixed in three layers with the help of vibrating table. c. De-mold the specimens after 24 - hrs and keep them in curing tank for curing. d. After 28 days curing, take out all the specimens from the tank. e. Place concrete cylinders between two plywood bearing strip of 1/8" width and 13"

length on the platen of machine along generetrix.

f. Apply the load without shock at a constant rate and with the range of 1 1300 to 22600 lbs per minute till failure. Note the load at failure.

3. PRECAUTIONS a. All molds should be oiled before filling, b. All should be casted in three proper layers and vibrating. c. Bearing strips should not be reused. d. Load should be applied gradually and without shock and at a

specified rate

4. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Specimen identification number = b. Dimension of specimen= c. Date of casting = d. Area of cylinder= e. Age of testing= f. If the load is applied along the generatrix, then an element on vertical diameter of the

cylinder is subjected to vertical compressive stress of 2P/LD * D2 /r (D-r)-l. and the horizontal tensile stress of 2P/nLD where P Compressive load, L = Length of cylinder, D= Diameter of cylinder

5. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

S/No DIA OF CYLINDER

LENGTH OF CYLINDER

LOAD AT FAILURE

SPLIT TENSIL STRENGTH

AVG STR

1. 2. 3. 4. 5. 6.

6. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC LENDING TO THE RESULTS To be done with the standard specification of ASTM C 496-96

7. COMMENTS

EXPERIMENT 9

(b) TO DETERMINE THE EFFECT OF AGE ON THE COMPRESSIVE STRENGTH OF CONCRETE

1. EQPT/ MATERIAL Cylinder/cubes molds, concrete mixer machine, concrete making materials, vibrating table, comp testing machine, weighing balance, mixing trays etc.

2. PROCEDURE a. Prepare concrete mix (1.50 kg approx) b. Prepare 9 specimens in the proscribed manner and at a constant workability/vibration. c. De-mold the specimens after 24 hours and place them in curing tank. d. After 3 days take out 3 specimens from the tank and place one specimen on the lower

platen of the machine and apply the load with specified rate of loading, until the specimen fails. Note the reading of the machine. Test the remaining specimens in the same way.

e. After 7 and 27 days take out remaining 3specimens and test them. f. Find out the strength of specimens at different ages plot the graph age vs compressive

strength.

3. PRECAUTIONS a. Molds should be oiled before filling. b. Cylinders should be capped by suitable material, c. Specimens should be placed such that they are concentrically loaded. d. Specimens should be tested in SSD condition, e. Load should be applied

gradually and at a specified rate.

4. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Identification mark

= b. Dates of casting and resting = c. Age of the specimens = d. Cross-sectional area of the specimen =

5. THE PERFORMA/FORMAT FOR THE PREP WITH THE RECORD OF OBSNS, DATA, WITH THE NOTES TO HELP ITS COMPLETION

S/No AGE LOAD(T)

AREA ( 2)

COMP STRENGTH(PSI)

MEAN STR

1

3 Days

2

3

1

7 Days

2

3

1 28 Days

2 3

6. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC LENDING TO THE RESULTS To be done with the standard specification of ASTM

7. COMMENTS

EXPERIMENT 10

TO DETERMINE THE MODULUS OF ELASTICITY OF CONCRETE BY EXTENSIVE METER

1. EQPT/MATERIAL Compressive Extensive Meter, compression testing machine, concrete mixer, cylinder molds, concrete making materials, trays, float, graduated glass cylinder etc.

2. PROCEDURE a. Prepare the specimens of 6 inch dia and 12 inch length 5 numbers. b. Cast the cylinder by prepared mix in three layers with the help of vibrating table. c. De-mold the specimens after 24 hours and keep then in curing tank for curing. d. After 28 days take out all the specimens from the tank and cap them with capping material. e. Three cylinders are tested to determine the compressive strength of concrete. Remaining two

cylinders are used for Modulus of Elasticity. f. Clamp the metal ring of compressive extensive meter on a specimen such that equal distances

are left below and above the rings. Attach the dial gauge with the least count of at least 0.001 inch.

g. Place the specimen with strain measuring equipment and attach the lower plate of testing machine.

h. Align the axis of specimen with the centre of thrust of upper plate. Note the dial reading and gently obtain the uniform seating of upper plate,

i. Now load and unload the specimen twice and do not record any data. Loading is done to obtain 50% to 40% of compressive strength of concrete.

j. Now apply the load continuously and without shock at the rate with the range 35= psi/min. k. Load the specimen twice about 50% of its strength and record the data. 3. DETAILS.OF READINES/OBSNS/DATA TO BE RECORDED/COLLECTED a. Area of specimen = b. W/C = c. Date of casting = d. Gauge length = e. Least count of dial =

4. THE PERFORMA/FORMAT FOR PREP WITH RECORD OF OBSNS, DATA, WITH NOTES TO HELP COMPLETION

S/No. LOAD (T)

STRESS,

(PSI) P/AX2240

DIAL READING MEAN X

0.0001"

STRAIN

∆L/L

1 2 3

E = (S2 -S1)L -0.000050

• E = Chord modulus of elasticity. • S2 = Stress corresponding to max applied load, psi • S1 = Stress corresponding to a longitudinal strain of 50 in-psi • L = Longitudinal strain produced by S2

5. INTERPRETATION/COLLATION OF THE OBSN READINGS, GRAPHS, ETC

LEADING TO RESULTS To be done with the standard specification of ASTM Standard C 128

6. COMMENTS

EXPERIMENT 11

(a) TO DETERMINE THE COMPRESSIVE STRENGTH OF HARDENED CONCRETE BY USING THE SCHMIDT HAMMER

1. EQPT/ MATERIAL Rebound hammer, carborundum stone, Mass of concrete

2. PROCEDURE a. Selection of test surface

Concrete members to be tested shall be at least 4 in thick and fixed with a structure. Smaller specimens must be rigidly supported. Area exhibiting honey combing, scaling rough texture high porosity should be avoided. Concrete should be approximately the same age and moisture. Dry concrete give high rebound numbers than the wet concrete.

b. Preparation of test surface A test area should be at least 6" in diameter. Heavily textured, soft or surface with loose mortar shall be ground smooth with the carborudum stone.

c. Testing method a. Firmly hold the instrument in a position that allows the plunger to strike

perpendicular to the surface tested. b. Gradually increase the pressure on the plunger until the hammer impacts. c. After impact, record the rebound number from the graduated scale given on the

hammer. d. Take ten readings from each test area, and take the mean. e. Strength of concrete can be known by reading the rebound numbers from abscissa and

drawing the line which cut the curve at some ordinate, which will give the comp strength.

3. PRECAUTION a. To avoid load; variation take 12 to 14 readings at different places. b. Discard maximum and minimum no of readings. c. Test should be done against smooth surface.

4. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Structure identification b. Location of testing area in structure, e.g. 3" from bottom of column 2 bent 3 or one meter

from the north end etc. c. Description of testing area, e.g. wood, floated surface, dry, ground with abrasion stone etc. d. Proportion of concrete if known. e. Average rebound number for each test area.

S/No DIRECTION OF

HAMMER USED

REBOUND NUMBER

AVG COMP

STR (N/MM2)

COMP STR (PSI)

1 2 3 4 5 6 7 8 9

5. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC LENDING TO THE RESULTS To be done with standard specification of ASTM C 805-97

6. COMMENTS

EXPERIMENT 11

(b) TO CARRY OUT THE ULTRA SONIC PULSE VELOCITY TEST.

1. EQPT/ MATERIAL PUNDIT (Portable Ultrasonic Non- Destructive Digital Indicating Test) and concrete surface to be tested.

2. PROCEDURE

a. Determination of calibration correction Check the accuracy of the transmit time measurements against their calibration device. The difference between the readings taken on the calibration correction, m which must he included in the determination of transmit time. Check the calibration over a range of transit time that includes the transit times anticipated.

b. Determination of zero correction Apply zero time correction to the measured transit time. The zero correction is equal to the travel time between the transmitting and receiving transfuses with zero thickness of concrete between the two. Measure it directly by pressing the two transducers together using a coupling agent apply the same pressure used in the actual measurement, and measure the transit time with digital unit it may be preferable to make zero adjustments by coupling the two transducers to opposite ends of a reference bar for which the transit time is accurately known.   

c. Determination of transit time Apply an appropriate coupling agent (such as water oil, petroleum jelly, grease or other viscous materials) to the transducer diaphragms, the test surface or both, to avoid entrapped air between the contact surface of the diaphragms of the transducers and the surface of the concrete. Press the faces of the transducers against the surface of the concrete assuring good contact between the two, and measure the transit time. Measure the length of the shortest direct path between the centers of the diaphragms. 

3. PRECAUTION The mould should be removed by raising it carefully in vertical direction without any jerk.

4. DETAILS OF READINGS AND OBSNS/DATA TO BE RECORDED a. Location of test out identification of test. . b. Distance between transducers, slated to greater precision than 0.5% of distance. c. Transit lime. d. Location of transducers. e. Effective transit time, scaled to greater precision than 0.5%. f. Pulse velocity,

Calculate the pulse velocity as follows:

V = L/T where V= Pulse velocity m/s (ft/s).

L = Distance between Transducers m (ft).

T = Effective transit time

(Measured time minus zero time correction and corrected for calibration errors).

Classification of quality of concrete on the basis of pulse, velocity;

Longitudinal pulse Velocity KM/S

Longitudinal pulse Velocity 10

ft/

Quality of concrete

> 4 . 5 > 1 5 Excellent 3 . 5 - 4 . 5 12-15 Good 3.0-3.5 30-12 Doubtful 2.0-3.0 7-10 Poor < 2 . 0 < 7 . 0 Very poor

5. INTERPRETATION/COLLECTION OF OBSNS. READINGS, GRAPH ETC LENDING

TO THE RESULTS To be done with the standard specification of ASTM C 597-97

6. COMMENTS