Quality Control Tests

QUALITY CONTROL TESTS 1. PREPARATION OF DRY SOIL SAMPLES FOR VARIOUS TESTS (IS: 2720 PART 1 – 1983) SCOPE This standard (Part I) covers the method of preparation of dry samples from the bulk soil sample received from the field for various laboratory tests. APPARATUS 1 Wooden Mallet : For breaking soil clods. 2

Trays : For air drying of soil of suitable size and of non-rusting material.

3 Pulverizing Apparatus: Either mortar and rubber covered pestle or a mechanical device consisting of a mortar and a power driven rubber covered pestle suitable for breaking up the aggregation of soil particles without reducing the size of the individual grains. Pestle and mortar made of soft wood may also be used. 4 Sampler : A suitable riffle sampler or sample splitter for quartering the samples (see IS: 1607-1960† ‘methods for dry sieving’). 5 Sieves : Of sizes 75 mm, 63 mm, 37.5 mm, 19 mm, 13.2 mm, 9.5 mm, 6.7 mm, 4.75 mm, 2.00 mm and 425 micron {see IS: 460(part I)-1978‡ ‘specification for test sieves: part I wire cloth test sieves (second division)’}. 6 Drying Apparatus : a) Drying oven: Thermostatically controlled with interior of non corroding material to maintain the temperature between 1050 to 1100 C. b) Other suitable drying apparatus. 7 Balance:

a) Capacity 10 kg and min. sensitivity 100 g. b) Capacity 1 kg and min. sensitivity 1 g c) Capacity 250 g and min. sensitivity 0.01 g

Preparation of Samples for Tests 1 General : Soil sample as received from the field shall be dried in the air or in the sun. In wet weather, a drying apparatus may be used in which case the temperature of the sample should not exceed 60°C.The clods may be broken with a wooden mallet to hasten drying. The organic matter, like tree roots and pieces of bark should be removed from the sample. Similarly, matter other than soil, like shells should also be separated from the main soil mass. A noting shall be made of such removals and their percentage of the total soil sample noted. When samples are to be taken for estimation of Organic content, lime content etc, total sample should be taken for estimation without removing shells, roots etc. 2 Drying of the sample: The amount of drying depends up on the proposed tests to be conducted on the particular sample. The type, temperature and duration of drying of soil samples for different tests are given in table-I... When oven is used for drying, the temperature in the oven shall not exceed 110°C (see note.). Chemical drying of samples should not be adopted for any tests. Note: Soils containing Organic or Calcareous matter should not be dried at temperature above 60°C.

3 Degree of Pulverization: The big clods may be broken with the help of wooden mallet. Further pulverization may be done in pestle and mortar. The pulverized soil shall be passed through the specified sieve for the particular test and the soil retained on that sieve shall be again pulverized for sieving, this procedure should be repeated until on further attempts at pulverizing very little soil passes through the specified sieve. Care should be taken not to breakup the individual soil particles (see table-I).

67

Table I Quantity of Soil Sample Required for Conducting the Tests. (Clauses 3.2, 3.3 & 4.1) S. NO

TEST

(1) i

(2) Water content

Amount of soil sample required for test. (4) As given in table 2 50 g for fine grained soils 400g for fine, medium and coarse grained soils

Degree of Pulverization (IS Sieve size) (5) --

2 mm

part 3/section 1 part 3/section 2

Air Drying

As given in table 3

--

part 4

do do

270g 60g

425 micron do

part 5 Do

Air Drying

100g

425 micron

part 6

6 kg(15 kg if soil is susceptible to crushing) do

19 mm

part 7

19 mm

part 8

4.75 mm

part 9

Type Temperature and duration of drying. (3) Oven. 24 h

o

ii

iii iv v vi

vii

Specific Gravity

Grain size analysis Liquid Limit Plastic Limit Shrinkage Factors Compaction a) Light Compaction b)Heavy Compaction c)Constant Mass

Oven. 105 to 110 C 24 h

do do do

2 kg

Refer to part of IS 2720. (6) Part 2

viii

Un-confined compressive strength.

Oven 110 C ± 5 C

1 kg

--

part 10

ix

Triaxial compression (Unconsolidated)

Do

1 kg / 5 kg

--

part 11

x

Triaxial compression (Consolidated)

do

do

--

part 12

xi

Direct Shear

Air Drying/Oven o o 110 ± 5 C

1 kg

4.75 mm

part 13

As per size of particle given below 75 mm 45 kg 37.5 mm 12 kg 19 mm 12 kg 9.5 mm 12 kg 4.75 mm 12 kg

--

Part 14

500g

--

part 15

6 kg

19 mm

part 16

xii

xiii xiv

o

o

Density Index (Relative Density)

Oven, 105 to110 C 24 h

Consolidation Properties CBR

Air Drying/Oven o o 110 ± 5 C Air Drying

0

68

xv

Permeability

Oven, 105 to110 C 24 h

2.5 kg (100 mm dia) / 5 kg (200 mm dia)

9.5 mm

part 17

xvi

Field Moisture equivalent

Air Drying

15 g

425 microns

part 18

xvii

Centrifuge moisture equivalent

Do

10 g

do

part 19

xviii

Linear Shrinkage

Do

450 g

do

part 20

2 mm

part 21

do

part 22

5g

--

part 23

80-130 g

--

part 24

---

part 25

425 microns

part 26

--

part 27

0

Chemical Tests a)Total Soluble Solids 0

b)Organic Matter c)Calcium Carbonate xix

d) Cat ion exchange capacity

Oven, 105 to110 C 24 h

10 g

Air Drying

100 g 0

Oven, 105 to110 C 24 h do do

e)silica Sesquioxide ratio

15 g

do

30 g

do

f)pH value

30 g

g)Total soluble Sulphates xx

Vane Shear

Air Drying/Oven o o 110 ± 5 C

250 g

--

part 30

xxi

Negative Pore Water Pressure

Do

1 kg / 5 kg

--

part 35

xxii

Permeability of Granular soils

Air Drying / Oven 0 0 110 C ± 5 C

1 kg / 5 kg

--

part 36

xxiii

sand equivalent value

110 C ± 5 C

1500 g

4.75 mm

part 37

xxiv

Direct Shear

Air Drying

up to 120 g

above 4.75 mm

part 39/ section 1

xxv

Free Swell Index

Oven Dry

20 g

425 microns

part 40

xxvi

Swelling Pressure

Air Drying / Oven Dry

2 kg

2 mm

part 41

o

o

69

Quantity of Sample 1

The quantities of soil sample required for conducting various laboratory tests are given in table-I for guidance.

Note: - For actual quantities corresponding part of IS 2720 shall be referred.

2

When a smaller quantity has to be taken out of a bigger soil mass, representative sampling shall be done by quartering or riffling

Note: - In the case of coarse gravel or gravelly soils, quartering by forming a cone shall not be done. The entire sample shall be thoroughly mixed and spread on a flat surface. The sample so spread shall be divided in to four quadrants and diagonally opposite quadrants mixed. This process shall be repeated till the desired quantity of sample is obtained. Table 2 Quantity of sample required for determination of water content

Table 3 Quantity of Soil required for grain size analysis

Size of Particles more than 90% passing

Minimum quantity of soil specimen to be taken for the test. Mass in Grams.

425 micron IS Sieve

25

2 mm IS Sieve

50

4.75 mm IS Sieve

200

9.50 mm IS Sieve

300

19 mm IS Sieve

500

17.5 mm IS Sieve

1000

Maximum Size of Material Present in Substantial Quantities

Mass to be taken for Test.

mm 75 37.5 19 13.2 9.5 6.7 4.75

Kg 60 25 6.5 3.5 1.5 0.75 0.4

Depending upon the type, 100 to 200 g of the soil fraction passing the 2 mm IS Sieve will be required for the determination of the distribution of particles below 63-micron size.

Determination of Soil Gradation A. Dry Sieve Analysis (for soil fraction retained on 4.75 mm sieve) 1. Prepare the sample by drying it in air or oven and bring it to room temperature. 2. Clean all the sieves to be used (40 mm, 25 mm, 20 mm, 10 mm, 4.75 mm) 3. Weigh the required quantity of material from the prepared sample. 4. Place the sieves over a clean tray one over the other in the ascending order of size. 5. Shake the sieve with a varied motion, backwards and forwards, left to right, circular clockwise and anti clockwise, and with frequent jerking, so that the material is kept moving over the sieve surfaces. 6. Do not force the material through the sieve by hand, except for sizes coarser than 20mm. 7. Break the lumps of fine particles, if any, with fingers against the side of the sieve. 8. Light brushing with a soft brush on the under side of sieve may be done to clear surface. 9. Find the individual weight of material retained on each sieve and record. 10. Calculate the percentage by weight of the total sample passing each sieve and report the results in Form EW- 1.

70

B. Wet Sieve Analysis (for soil fraction passing 4.75 mm sieve and retained on 75 micron sieve) 1. Take a portion of the sample prepared by drying in oven and brought to room temperature. 2. Soak the sample in water and leave it for soaking overnight. 3. Wash out the finer fraction passing through 75 micron sieve. 4. Then dry it in oven for 24 hours and sieve the dry particles and find the percentage of soil passing through each sieve and report the results in form EW-1 SIEVE ANALYSIS OF SOIL Dry sieving I.S. Sieve designation

Weight of soil sample taken in Weight of Sample retained (gm)

Percent of Wt. Retained

Cumulative Percent of Wt. retained (%)

gm

Percentage of Wt. Passing

75 mm 63 mm 37.5 mm 19 mm 13.2 mm 9.5 mm 6.7 mm 4.75 mm 2.00 mm 4.25 micron

Wet sieving I.S. Sieve designation

Weight of soil sample taken in Weight of Sample retained (gm)

Percent of Wt. Retained

2.36 mm 1.18 mm 600 µ 425 µ 75 µ

71

Cumulative Percent of Wt. retained (%)

gm

Percentage of Wt. Passing

Summary of Results Clay / silt (-75 micron) percent Sand (-4.75 mm + 75 micron) percent Gravel (-40 mm + 4.75 mm) percent

II. Test for the Determination of Liquid Limit By Cone Penetration Method-One Point Method IS: 2720 (Part 5)-1985 Apparatus 1 Cone Penetrometer – It shall consist of a metallic cone with half angle of 150-30’±15’ and 30.5 mm coned length. It shall be fixed at the end of a metallic rod with a disc at the top of the rod so as to have a total sliding weight of 80 ± 0.5 g. The rod shall pass through two guides (to ensure vertical movement), fixed to a stand as indicated in Fig. It shall confirm to IS: 111961985. Suitable provision shall be made for clamping the vertical rod at any desired height above the surface of the soil paste in the trough. A trough 50 mm in diameter and 50 mm high internally shall be provided. 2 Balance – sensitive to 0.01 g. 3 Containers – non-corrodible and air-tight for moisture determination. 4 Oven – thermostatically controlled with interior of non-corroding material to maintain the temperature between 1050C and 1100C. Soil Sample – A soil sample weighing about 150 g from the thoroughly mixed portion of the soil passing 425 micron IS Sieve obtained in accordance with IS: 2720 (Part -1) – 1983 shall be taken. Procedure – About 150 g of the soil specimen obtained as in 3.2 shall be taken and worked into a paste with addition of distilled water. In case of clayey soils, it is recommended that the soil is kept wet and allowed to stand for a sufficient time (24 hours) to ensure uniform distribution of moisture. The wet soil paste shall then be transferred to the cylindrical trough of the cone Penetrometer apparatus and leveled up to the top of the trough. The Penetrometer shall be so adjusted that the cone point just touches the surface of the soil paste in the trough. The scale of the Penetrometer shall then be adjusted to zero and the vertical rod released so that the cone is allowed to penetrate into the soil paste under its weight. The penetration shall be noted after 5 seconds from the release of the cone. If the penetration is less than 16 mm, the wet soil from the trough shall be taken out and more water added and thoroughly mixed. The test shall then be repeated again till a penetration between 16 mm and 26 mm is obtained. The exact depth of penetration between these two values obtained during the test shall be noted. The moisture content of the corresponding soil paste shall be determined in accordance with IS: 2720 (Part -2) - 1973. Computations – The water content is determined for the accepted trial. The liquid limit is computed from the following relationship WL = W c + 0.01 (25 – D) (W c + 15) Where W L = liquid limit of the soil, W c = moisture content of soil paste corresponding to penetration of D and D = depth penetration of cone obtained in mm.

72

Report 1 The results of observations of the test shall be recorded suitably. 2 The liquid limit should be reported to the nearest whole number. The history of the soil sample, that is, natural state, air-dried, oven dried or unknown, the method used for the test and the period of soaking allowed after mixing of water to the soil shall also be reported.

III. Determination of Atterberg Limits of Soil Liquid Limit (LL) 1. Take 120 gm of soil passing IS: 425 micron sieve. 2. Mix it with distilled water to form a paste. 3. Place a portion of the paste in the cup of the apparatus. 4. Level the specimen to half the cup. 5. Cut the paste with the standard grooving tool along the centre line. 6. Start rotating the handle at 2 revolutions per second. 7. Count number of blows till two parts of the sample come into contact at the bottom of the groove (along a distance of 12 mm). 8. Record the number of blows and determine m.c. of the sample taken near the closed groove. 9. Repeat the test by changing the m.c. so that number of blows to close the groove is from 35 to 10. 10. Plot a graph between log (number of blows) and moisture content and fit a straight line. 11. Read the m.c. corresponding to 25 number of blows from the graph. This gives the Liquid Limit of the soil.

IV. Test for the Determination of Plastic Limit Apparatus 1 Porcelain Evaporating Dish – about 12 cm in diameter. Or Flat Glass Plate – 10 mm thick and about 45 cm square or larger. IS: 2720 (Part 5) – 1985 2 Spatula – flexible, with the blade about 8 cm long and 2 cm wide. Or Palette Knives – two, with the blade about 20 cm long and 3 cm wide (for use with flat glass plate for mixing soil and water). 3 Surface for Rolling – ground glass plate about 20 x 15 cm. 4 Containers – airtight to determine moisture content. 5 Balance – sensitive to 0.01 g. 6 Oven – thermostatically controlled with interior of non-corroding material to maintain the temperature between 1050C and 1100C. 7 Rod - 3 mm in diameter and about 10 cm long. Soil Sample – A sample weighing about 20 g from the thoroughly mixed portion of the material passing 425 micron IS Sieve, obtained in accordance with IS: 2720 (Part I)-1983* shall be taken. When both the liquid limit and the plastic limit of a soil are to be determined, a quantity of soil sufficient for both the tests shall be taken for preparation of the soil. At a stage in the process of mixing of soil and water at which the mass becomes plastic enough to be easily shaped into a ball, a portion of the soil sample in the plastic state should be taken for the plastic limit test.

73

Procedure – The soil sample shall be mixed thoroughly with distilled water in an evaporating dish or on the flat glass plate till the soil mass becomes plastic enough to be easily moulded with fingers. In the case of clayey soils, the plastic soil mass shall be left to stand for a sufficient time (24 hours) to ensure uniform distribution of moisture throughout the soil mass(See above Para). A ball shall be formed with about 8 g of this plastic soil mass and rolled between the fingers and the glass plate With just sufficient pressure to roll the mass into a thread of uniform diameter throughout its length. The rate of rolling shall be done till the threads are of 3 mm diameter. The soil shall then be kneaded together to a uniform mass and rolled again. This process of alternate rolling and the soil can no longer be rolled into a thread. The crumbling may occur when the thread has a diameter greater than 3 mm. This shall be considered a satisfactory end point, provided the soil has been rolled into a thread 3 mm in diameter immediately before. At no time shall attempt be made to produce failure at exactly 3 mm diameter by allowing the thread to reach 3 mm, then reducing the rate of rolling or pressure or both, and continuing the rolling without further deformation until the thread falls apart. The pieces of crumbled soil thread shall be collected in an air-tight container and the moisture content determined as described in IS: 2720 (Part II)-1973*. Report 1 The observations of test should be recorded suitably. 2 The moisture content determined as above, is the plastic limit of the soil. The plastic limit shall be determined for at least three portions of the soil passing 425 micron IS Sieve. The average of the results calculated to the nearest whole number shall be reported as the plastic limit of the soil. 3 The history of the soil sample (that is, natural state, air-dried, oven dried or unknown) and the period of soaking allowed after mixing of water to the soil shall also be reported.

Examples of Liquid Limit Tests Sl. No.

Location

(1)

(2) Km1/8 MN Road Km3/6 MN Road Km4/10 MN Road Km6/4 MN Road

1 2 3 4

Penetration in mm (n)

Cup No.

(4)

Wt. of Empty Cup + Wet Soil (5)

Wt. Of Dry Soil + Cup (6)

(3)

90

102.4

22

87

25 24

25

(5 - 6 = 7)

Wt. of Empty cup

Wt. of dry Soil (6 –8 =9)

WL =W N ÷ 0.77 log D

(9)

Moisture Content Wn(%) (7/9 x 100) (10)

(7)

(8)

85.4

17

32.2

53.2

31.95

32.00

109

91.4

17.6

30.7

60.7

29.00

30.00

71

83.2

62.1

21.1

32.2

29.9

70.57

71.00

26

105.4

83.7

21.7

32.5

51.2

42.38

43.00

H2O

(11)

Examples Of Plastic Limit Tests Sl. No. (1) 1 2 3 4

Location (2) Km1/8 MN Road Km3/6 MN Road Km4/10 MN Road Km6/4 MN Road

Cup No. (3)

Wt. Of wet Soil & empty Cup (4)

Wt. Of dry Soil + cup (5)

H2O (4)-(5)=(6) (6)

150

60.4

57

3.4

36.5

20.5

17

154

53.5

50.8

2.7

32.6

18.2

15

103

54.2

48.6

5.6

33.2

15.4

36

188

68.5

64

4.5

43.4

20.6

22

74

Wt. Of Wt. Of Empty cup dry Soil (8) (7)

Plastic Limit ((6)/(8))*100 (9)

V. Plasticity Index Calculation : The plasticity index is calculated as the difference between its liquid limit and plastic limit. Plasticity index (I p) = liquid limit (W L) – plastic limit (Wp). Report : The difference calculated as indicated in 7.1 shall be reported as the plasticity index, except under the following conditions: a) In the case of sandy soils plastic limit should be determined first. When plastic limit cannot be determined, the plasticity index should be reported as Np (non-plastic). b) When the plastic limit is equal to or greater than the liquid limit, the plasticity index shall be reported as zero. Plasticity Index (PI): For above samples:

1). PI = 32 – 17 = 15 2). PI = 30 – 15 = 15 3). PI = 71 – 36 = 35 4). PI = 43 – 22 = 21

VI Determination of Free Swell Index of Soils IS: 2720 (Part 40): 1977 1. Take two samples of dry soil. 10 gm each 2. Take two 100 ml graduated glass cylinders. 3. Pour the soil sample in each cylinder 4. Fill distilled water in one cylinder and kerosene in the other cylinder upto 100 ml marks. 5. Remove the entrapped air by gently shaking or stirring with a glass rod. 6. Leave the samples to settle and allow sufficient time (24 hours or more) for the soil samples to attain equilibrium state of volume. 7. Read the final volume of soil in each cylinder. 8. Determine the differential free swell index Sd using the formula Volume of soil in water - volume of soil in kerosene Sd=

xlOO Volume of soil in kerosene

9. If the value of Sd is 50 percent or more, the soil is expansive and not suitable for use as embankment fill material. (For EW-5(a)) Swell Index Test Sample No.

Final volume of soil in water Vw

Final volume of soil in in Kerosene Vk

Note: permissible Limit…………………Max 50 percent.

75

Free Swell Index Vw – Vk X 100 Sd = Vk

Precautions 1) Pour the soil specimen in both the graduated glass cylinder gently, so that no soil particle remains stuck to the wall of the cylinder. 2) Sufficient time should be given to both the soil specimen to attain the final equilibrium position of volume without any future change in the soil volumes. This may take 24 hours or more. 3) For highly swelling soils, the weight of soil specimen may be taken as 5g or cylinders of 250ml. capacity may be used. A relation between differential free swell (%) and degree of expansiveness of soil is given below: Differential free swell (%)

Degree of expansiveness

< 20

Low

20-35

Moderate

35-50

High

> 50 Very High If the degree of expansiveness of soil at a site is damageable to the structure to be constructed there, it is recommended to take suitable measures for foundation design to the same. In such cases, the foundation should be constructed under the supervision of a geotechnical engineer.

VII. Determination of Field Density and Dry Unit Weight By Sand Replacement Method Object and scope. The object of the test is to determine the dry density of natural or compact soil, in-place, by the sand replacement method. Materials and equipment: (i) Sand pouring cylinder of about 3 litre capacity, mounted above a pouring cone and separated by a shutter cover plate and a shutter, (ii) Cylindrical calibrating container, 10 cm internal diameter and 15 cm internal depth, fitted with flange approximately 5 cm wide and about 5 mm thick (iii) Glass plate, about 45 cm square and 1 cm thick, (iv) Metal tray with a central circular hole of diameter equal to the diameter of the pouring cone, (v) Tools for excavating hole, (vi) Balance accurate to 1 g, (vii) Container for water content determination, (viii) Clean, closely graded natural sand passing the 1mm IS Sieve and retained on the 600-micron IS Sieve. Test Procedure (A) Determination of mass of sand filling the cone 1. Fill the clean closely graded sand in the sand pouring cylinder upto a height 1 cm below the top. Determination the total initial mass of the cylinder plus sand (M1). This total initial mass should be maintained constant throughout the tests for which the calibration is used. 2. Allow the sand of volume equivalent to that of the excavated hole in the soil (or equal to that of the calibrating container), to run out of cylinder by opening the shutter. Close the shutter and place the cylinder on glass plate. 3. Open the shutter and allow the sand to run out. Close the valve when no further movement of sand is observed. Remove the cylinder carefully. Weigh the sand collected on the glass surface. Its mass (M2) will give the mass of sand filling the pouring cone. Repeat this step at least three times and take the mean mass (M2). Put the sand back into the cylinder, to have the same constant mass (M1).

76

(B) Determination of bulk density of sand 4. Determine the volume (V) of the calibrating container by filling it with water full to the brim and finding the mass of water. This volume should be checked by calculating it from the measured internal dimensions of the container. 5. Place the sand-pouring cylinder concentrically on the top of the calibrating container, after being filled to constant mass (M1 ). Open the shutter and permit the sand to run into the container. When no further movement of sand is seen, close the shutter. Remove the pouring cylinder and find its mass (M3) to nearest gram. 6. Repeat step (5) at least thrice and find the mean mass M3. Put the sand into the sandpouring cylinder. (C) Determination of dry density of soil in-place 7. Expose about 45 cm square area of the soil to be tested and trim it down to level surface. Keep the tray on the level surface and excavate a circular hole of approximately 10 cm diameter and 15 cm deep and collect all the excavated soil in the tray. Find the mass (M) of the excavated soil. 8. Remove the tray, and place the sand-pouring cylinder, so that the base of the cylinder concentrically covers the hole. The cylinder should have its constant mass M1. open the shutter and permit the sand to run into the hole. Close the shutter when no further movement of the sand is seen. Remove the cylinder and determine its mass (M4). Keep a representative sample of the excavated soil for water content determination. Tabulation of observations. The observations are tabulated as illustrated in Table 3.10.

TABLE 3.10 Data and Observation Sheet for Determination of Dry Density by Sand Replacement Method (a) Determination of Mass of sand in the cone 1. Mass of sand (+cylinder) before pouring M1 10550 g 2. Mean mass of sand in cone M2 445 g (b) Determination of bulk density of sand 3. Volume of calibrating container V 1000 ml 4. Mean mass of sand (+cylinder) after pouring M3 8655 g 5. Mass of sand filling calibrating container = M1 - M3 - M2 1450 g 1.45 g/cm3 6. Bulk Density of sand γS =1450 / 1000 (c) Bulk density of soil 7. Mass of wet soil from the hole M 2234g 8. Mass of sand (+cylinder) after pouring in the hole M4 8512g 9. Mass of sand in the hole = M1 - M4 - M2 1593g 2.03 g/cm3 10. Bulk density of soil(γ) = 2234 / 1593 X 1.45 (d) Water content determination 11. Container No 11 12. Mass of container + wet soil 62.48 g 13. Mass of container + dry soil 57.76 g 14. Mass of container 21.43 g 15. Mass of dry soil 36.33 g 16. Mass of water 4.72 g 17. Water content (w) Ratio 0.13 18. Dry density γd =_γ_ _2.03_ 3 1.8 g/cm 1+w 1+0.13 Reference to Indian standard: IS: 2720-1974 (Part XXVIII) by sand replacement method):

77

VIII. Determination of Grain Size Distribution by Sieving Object and scope. The object of this experiment is to determine grain-size distribution of coarse grained soil by sieving. The test covers both coarse sieve analysis (for gravel fraction) as well as fine sieve analysis (for sand fraction). Material and equipment. (i) Balances accurate to 1 g and 0.1 g. (ii) Set of IS sieves: 100 mm, 63 mm, 10 mm, 4.75 mm, 2 mm, 1 mm, 600 micron, 425 micron, 300 micron, 212 micron, 150 micron and 75 micron size, (iii) Thermostatically controlled oven, (iv) Two or more large metal or plastic water tight trays, (v) Sieve brushes and a wire brush (vi) Mortar with a rubber covered pestle, (vii) Mechanical sieve-shaker and (viii) Riffler. Test Procedure 1. Using a riffler, take a representative sample of soil received from the field and dry it in the oven. 2. Weigh the required quantity of dried soil, keep it in a tray and soak it with water. Depending on the maximum size of material present in substantial quantities in the soil, the mass of soil sample taken for analysis may be as follows [IS: 2720 (Part IV)-1965]. Maximum Size of Material Present in Substantial Quantities

Mass to be taken for Test

mm

Kg

63

50

20

6.5

10

1.5

4.75

0.375

3. Puddle the sample thoroughly in water and transfer the slurry to the 4.75 mm sieve, which divides the gravel fraction from the sand fraction. Wash the slurry with jet of water. Collect the materials retained on 4.75 mm sieve and the material passing through it in separate containers. Keep the material retained on 4.75 mm sieve in the oven. 4. Wash the material passing through the 4.75 mm sieve through a 75-micron sieve so that silt and clay particles are separated from the sand fraction. Collect the material passing through 75-micron sieve and the material retained on it in separate containers, and keep them in the oven. 5. Sieve the dried material, retained on 4.75 mm sieve (step 3), through the following set of sieves: 63 mm, 20 mm, 10 mm, and 4.75 mm by hand sieving. While sieving through each sieve, the sieve shall be agitated so that the sample rolls in irregular motion over the sieve. The material from the sieve may be rubbed, if necessary, with the rubber pestle in the mortar taking care to see that individual soil particles are not broken and re-sieved to make sure that only individual particles are retained. The mass of material retained on each sieve should be recorded. 6. Sieve the dried material, retained on 75-micron sieve (step 4), through the following set of sieves: 2 mm, 1mm, 600 micron, 425 micron, 300 micron, 212 micron, 150 micron and 75 micron size. The set of sieve should be arranged one above the other and fitted to a mechanical sieve shaker such that the 2 mm sieve is at the top and the 75-micron sieve is at the bottom. A cover should be placed on the top of the 2 mm sieve, and a receiver should be placed below the 75-micron sieve. A minimum of 10 minutes sieving should be used. The soil fraction retained on each sieve should be carefully collected in containers and the mass of each fraction determined and recorded.

78

Alternatively, the material retained on 75 micron sieve (step 4), may not be dried, but be washed through a set of sieves specified in step 6, nested in order of their fineness with the finest (75 micron) at the bottom. Washing should be continued until the water passing through each sieve is substantially clean. The fraction retained on each sieve should be emptied carefully with out loss of material in separate container and oven-dried. The oven-dried fraction should be weighed separate and their mass should be recorded. 7. The material passing 75-micron sieve (step 4) may be used for sedimentation analysis. Tabulation of observations. The test observations and results are recorded as illustrated in Table below. Calculations. The percentage of soil retained on each sieve is calculated on the basis of total mass of soil sample taken and from these results the percent passing through each of the sieve is calculated, as illustrated in Table below.

TABLE : Data and Observation Sheet for Sieve Analysis Sample No. 108 Mass of dry soil sample: 1000g

Mass retained on 4.75 mm sieve: 167 g Mass passing through 75 micron size: 77 g

S.No.

IS Sieve

Particle size D (mm)

Mass retained (g)

% retained

Cumulative % retained

Cumulative % finer (N)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

100 mm 63 mm 20 mm 10 mm 4.75 mm 2 mm 1 mm 600 micron 425 micron 300 micron 212 micron 150 micron 75 micron

100 mm 63 mm 20 mm 10 mm 4.75 mm 2 mm 1 mm 0.6 mm 0.425 mm 0.300 mm 0.212 mm 0.150 mm 0.075 mm

33 49 85 140 160 142 118 82 56 35 23

3.3 4.9 8.5 14.0 16.0 14.2 11.8 8.2 5.6 3.5 2.3

3.3 8.2 16.7 30.7 46.7 60.9 72.7 80.9 86.5 90.0 92.3

100 100 96.7 91.8 83.3 69.3 53.3 39.1 27.3 19.1 13.5 10.0 7.7

Note 1.

Note 2.

Dry Sieve Analysis. If the soil sample contains little or no fines (passing 75 micron sieve), dry sieve analysis may be carried out. Dry sieving through 4.75 mm sieve first separates the gravel fraction and sand fraction. The material retained on 4.75 mm size is further sieved through the following set of sieves: 2mm, 1 mm, 600 micron, 425 micron, 300 micron, 212 micron, 150 micron and 75 micron sizes. The permissible maximum mass of sample on the 200 mm diameter sieves should be as follows: IS Sieve Designation

Maximum mass of sample (g)

600 micron 200 micron 75 micron

160 55 25

Note 3. If the soil contains greater amount of fines (finer than 75 micron size), the dried soil fraction passing through 4.75 mm sieve (step 6) should be soaked in water containing two grams of sodium hexameta phosphate (or one gram of sodium hydroxide and one gram of sodium carbonate) per litre of water. The soaked specimen should then be washed thoroughly over the nest of sieves specified in step 6.

79

IX. Determination of Compaction Properties Object and scope. The object of the experiment is to determine the relationship between water content and dry density of soil using Standard Proctor Test (light compaction) or Modified Proctor Test (heavy compaction), and then to determine the optimum water content and the corresponding maximum dry density for a soil. The test also covers the determination of relationship between penetration resistance and water content for the compacted soil. (a) Light Compaction (Standard Proctor Test) Materials and Equipment. (i) Cylindrical metal mould of capacity 1000cc, with an internal diameter of 100±0.1 mm and an internal effective height of 127.3±0.1 mm, or mould of capacity 2250 cc, with an internal diameter 150±0.1 mm and an internal effective height of 127.3±0.1 mm, each mould fitted with a detachable base and a removable extension (collar) approximately 60 mm high (ii) Metal rammer, 50 mm diameter circular face, weighing 2.6 kg and having drop of 310 mm (iii) Steel straight edge (iv) 20 mm and 4.75 mm IS sieves (v) Balances, 10 kg capacity sensitive to 1 g, and 200 capacity sensitive to 0.01 g (vi) Thermostatically controlled oven (105 – 1100C) (vii) Water content containers (viii) Mixing equipment, such as mixing pan, spoon, trowel spatula etc. (ix) Measuring cylinder of glass, 100 ml capacity (x) Sample extruder (optional). Test Procedure

1. Take about 18 Kg of air dried sample for 1000 cc mould (40 Kg for 2250 cc mould) . Sieve the soil through 20mm and 4.75mm IS Sieves and calculate the ratio of fraction passing 20mm IS Sieve and retained on 4.75mm IS Sieve. Use 100mm dia mould if percentage retained on 4.75mm sieve is less than 20, and 150mm dia if soil percentage retained on 4.75mm sieve is more than 20. Discard the soil retained on 20mm sieve. Add enough water to bring its water content to about 7 per cent (sandy soils) or 10 percent (clayey soils) less than the estimated optimum moisture content. Keep this soil in an air tight container for about 20 hours, for maturing. 2. Clean the mould and fix it to the base. Take the empty mass of the mould and the base, nearest to 1 g. 3. Attach the collar to the mould. The inside of the mould may be greased thoroughly. 4. Mix the matured soil thoroughly. Take out about 2 ½ kg of the soil and compact it in the mould in three equal layers, each layer being given 25 blows from the rammer weighing 2.6 kg dropping from a height of 310 mm, if 1000 ml mould is used. If however, the 2250 ml mould is used, about 5 kg of soil should be taken and should be compacted in three equal layers, each layer being given 56 blows from the rammer weighing 2.6 kg dropping from a height of 310 mm. The blows should be uniformly distributed over the surface of each layer. Each layer of compacted soil should be scored with a spatula before putting the soil for the succeeding layer. The amount of soil used should be just sufficient to fill the mould leaving about 5 mm to be struck off when collar is removed. Find the penetration resistance of compacted soil, using the Proctor’s needle. 5. Remove the collar, and cut the excess soil with the help of a straight edge. Clean the mould from outside, and weigh it to the nearest gram. Eject out the soil from the mould, cut it in the middle and keep a representative soil specimen for water content determination. 6. Repeat steps 4 and 5 for about five or six times, using a fresh part of the soil specimen and after adding a higher water content than the proceeding specimen.

80

Fig.a

Fig.b

Tabulation of observations. The observations are tabulated as illustrated in Table below.

Table : Data And Observation Sheet For Proctor’s Test (Light Compaction) Determination No.

1

2

3

4

5

6

7

(a) Density Mass of mould + compacted soil (g)

6607

6644

6723

6795

6837

6842

6829

Mass of mould

(g)

4944

4944

4944

4944

4944

4944

4944

Mass of compacted soil

(g)

1663

1720

1779

1851

1893

1898

1885

3

1.76

1.82

1.88

1.96

2.00

2.01

1.99

3

1.55

1.57

1.58

1.64

1.63

1.62

1.58

23

94

8

9

159

71

10

Bulk density (γ) Dry density (γd)

g/cm

g/cm

(b) Water content Container No. Mass of container + wet soil

(g)

45.3

59.9

38.8

52.2

46.8

45.6

44.9

Mass of Container + dry soil

(g)

42.5

54.7

36.2

47.4

42.2

41.3

40.2

Mass of water

(g)

2.8

5.2

2.6

4.8

4.4

4.3

4.7

Mass of container

(g)

22.5

22.9

22.5

22.6

23.1

22.9

22.5

Mass of dry soil

(g)

20.0

31.8

13.7

24.8

19.3

18.4

17.7

Water content (w)

(%)

13.9

16.3

18.8

19.4

22.8

23.4

26.6

Calculations: 1. The dry density of the compacted soil is calculated as follows: γd = γ (1+w) A curve showing the relationship between dry density and water content is plotted. The water content corresponding to the maximum dry density is found from the curve. For the data tabulated above, the optimum water content is found to be 20% corresponding to maximum dry density of 1.64 g/cm 3. The corresponding dry unit weight = 1.64 x 9.81 = 16.09 kN/m3. 2. The voids ratio for each determination is found from the equation: e = G γw - 1 γd 3. On the same plot, a curve is drawn between penetration resistance and water content (Fig. b).

81

(b) Heavy Compaction (Modified Proctor’s Tests) The equipment required for the heavy compaction test is the same as that required for the light compaction except that the rammer has a falling mass of 4.89 kg and has a drop of 45 cm. The soil is compacted in five equal layers, instead, of three. Each layer is given 25 blows of the rammer if the 1000ml mould is used, and 56 blows if 2250cc mould is used.

X. Determination of California Bearing Ratio Value As per IS: 2720 (Part-16) -1979 1. Concept and Significance California Bearing Ratio (CBR) test originally developed by California Division of Highways (U.S.A) is one of the most commonly used methods to evaluate the strength of subgrade soil for design of pavement thickness. CBR value as defined by IS: 2720 (Part XVI)1979 is the ratio of the force per unit area required to penetrate a soil mass with a circular plunger of 50 mm diameter at the rate of 1.25 mm/minute, to that required for corresponding penetration of a standard material. Standard load is that load which has been obtained from tests on a crushed stone whose CBR value is taken to be 100 per cent. The ratio is usually determined for penetration of 2.5 mm and 5.0 mm. The results of this test cannot be related accurately with fundamental properties of the material but are useful in design of flexible pavements. 2. Objective To determine the California Bearing Ratio of the subgrade soil. 3. Apparatus The apparatus as per IS: 2720 (Part XVI) – 1979 comprises of the following: (i) Mould. A metallic cylinder of 150 mm internal diameter and 175 mm height; provided with a detachable metal extension collar 50 mm in height. It also has a detachable perforated base plate of 10 mm thickness. The perforations in the base plate do not exceed 1.5 mm in diameter. (ii) Steel cutting collar, which can fit flush with the mould. (iii) Spacer disc. A metal disc of 148 mm diameter and 47.7 mm in height. (iv) Surcharge weights: One annular metal weight and slotted weights each of 2.5 kg and 147 mm in diameter with a central hole 53 mm in diameter. (v) Dial gauges. Two dial gauges reading to 0.01 mm. (vi) IS sieves of sizes 47.5 mm and 20 mm. (vii) Penetration plunger. A metallic plunger having a diameter of 50 mm and at least 100 mm long. (viii) Loading machine with a capacity of at least 5000 kg and equipped with a platform that can move vertically at a rate of 1.25 mm/min. (ix) Miscellaneous apparatus like mixing bowl, straight edge, scales, soaking tank, drying oven, filter paper, dishes and calibrated measuring jar. Procedure Preparation of test specimen. 1 Preparation of Undisturbed Specimen Fit to the mould, the steel cutting edge of 150 mm internal diameter. Push the mould into the ground as gently as possible till the mould is full of soil. Remove the soil from sides and bottom. Trim the excessive soil from top and bottom. 2 Preparation of Remoulded Specimen Remoulded samples are prepared such that the dry density obtained from proctor compaction tests, the water content of remoulded samples is either the optimum water content or the field moisture as the case may be, the remoulded sample are compacted either statically or dynamically. The test material should pass 20mm IS sieve and retained on 4.75mm IS sieve. If coarser material is retained on 20mm sieve, it should be discarded and an equal amount of material retained on 4.75mm sieve and passing through 20mm sieve should be replaced.

82

3 Statically Compacted Specimen (i) Calculate the amount of soil required such that it fills the mould (excluding collar) at the desired density after compaction. (ii) Calculate the amount of water to be added to give desired water content. (iii) Mix the soil thoroughly with water. (iv) Fix the extension collar to the mould and clamp it to the base plate. (v) Fix the mould with soil, gently pressing it with hands so that it does not spill out of the mould. (vi) Place a coarse filter paper over the leveled soil surface and then insert the space disc. (vii) Place the assembly on the pedestal of compression machine and compact the soil until the top of the spacer disc is flush with the top of the collar. 4 Dynamically compacted specimen (i) Sieve the material through 20 mm IS sieve (ii) Take about 4.5 kg or more of representative sample for fine grained soils and about 5.5 kg for granular soils in a mixing pan. (iii) Add water to the soil in the quantity such that the moisture content of the specimen is either equal to field moisture content or OMC as desired. (iv) Mix together the soil and water uniformly. (v) Clamp the mould along with the extension collar to the base plate. (vi) Place the coarse filter paper on the top of the spacer disc. (vii) Pour soil-water mix in the mould in such a quantity that after compaction about 1/5th of the mould is filled (viii) Give 56 blows with the rammer weighing 2.6 kg dropping through 310 mm in three layers (light compaction) or 4.89 kg dropping through 450 mm in 5 layers (heavy compaction) evenly spread on the surface. (ix) Scratch the top layer of compacted surface. Add more soil and compact in similar fashion. Fill the mould completely in five layers. (x) Remove the extension collar and trim off the excess soil by a straight edge (xi) Remove the base plate, spacer disc and the filter paper and note down the weight of mould and compacted specimen. (xii) Place a coarse filter paper on the perforated base plate. (xiii) Invert the mould containing compacted soil and clamp it to the base plate. 5. Testing the Specimen (i) Place the mould containing the specimen, with base plate in position, on the testing machine. (ii) Place the annular weight of 2.5 kg on the top surface of soil. (iii) Bring the penetration plunger in contact with soil surface and apply a load of 4 kg so that full contact between soil and plunger is established. This should be taken as zero load. (iv) Place the remainder surcharge weight so that total surcharge weight equals to 5 kg. (v) Set the reading of dial gauges to zero. (vi) Apply load so that penetration rate is 1.2 mm per min. Record the load at penetration of 0, 0.5, 1.0, 1.5, 2.0, 2.5, 4.0, 5.0, 7.5, 10.0 and 12.5 mm. The maximum load has to be recorded if it occurs at less than 12.5 mm. (vii) Collect about 20 to 50 g of soil to determine the water content

83

6. CBR Test on Soaked Specimen To perform CBR test on soaked specimen, the sample excluding base plate and spacer disc is weighed. A filter paper is placed on the sample with a perforated plate on it. Over it a surcharge weight 2.5 or 5 kg is placed and the sample is soaked in water tank for 4 days. The sample is then allowed to drain off water in a vertical position for about 15 minutes. The sample is weighed again to calculate the percentage of water absorbed. It is then tested following the normal procedure. 7 Computation of Test Results (i) Plot the load penetration curve with the load as ordinate and penetration as abscissa. Sometimes the initial portion of the curve is concave upwards due to surface irregularities. In such a case apply a correction. Draw tangent at the point of greatest slope. The point where this tangent meets the abscissa is the corrected zero reading of penetration. (ii) From the curve, determine the load value corresponding to the penetration value at which the CBR is desired. (iii) Compute CBR value as follows: Test load corresponding to chosen penetration (PT) CBR value = x 100 Standard load for the same penetration (PS) Usually the CBR value is calculated for 2.5 mm and 5 mm penetration. Generally the CBR value at 2.5 mm penetration will be greater than that at 5 mm and in such a case the former is taken for design purposes. If the 5 mm value is greater the test is repeated, if the same results follow, the CBR value corresponding to 5 mm penetration is adopted for design purposes.

Table : Standard Load for Different Penetration Values Penetration mm 2.5 5.0 7.5 10.0 12.5

Unit standard load kg (f)/cm2 70 105 134 162 183

84

Total standard kg(f) 1370 2055 2630 3180 3600

Note: The test must always be performed on remoulded sample of soils in the laboratory. Where ever possible the test specimen should be prepared by Static Compaction but if not possible Dynamic method may be used as an alternative. In-Situ tests are not recommended for design purpose as it is not possible to satisfactorily simulate the critical conditions of dry density and moisture content in the field.

XI. Determination of Gradation of Aggregates 1. bring the sample to an air dry condition either by drying at room temperature or in oven at a temperature of 100°C to 110°C. Take the weight of the sample. 2. Clean all the sieves and sieve the sample successively on the appropriate sieve starting with the largest. 3.

Shake each sieve separately over a clean tray.

4. On completion of sieving note down the weight of material retained on each sieve. 5. Report the results as cumulative percentage by weight of sample passing each of the sieves. (Form SB - 1) Sieve Analysis of Aggregate I.S. Sieve designation

Weight of Sample retained (gm)

Percent of Wt. Retained

85

Cumulative Percent of Wt. retained (%)

Percentage of Wt. Passing

XII. Determination of Specific Gravity and Water Absorption of Aggregate 1.

Wash a sample of aggregate of not less than 2000 gm to remove dust. Drain and place the sample in the density basket.

2.

Immerse the basket in water at a temperature of 22°C to 32°C with at least 5cm cover of water above the top of the basket.

3.

Immediately after immersion, remove the entrapped air from sample by lifting the basket 25mm above the base of the tank and allow it to drop 25 times, at the rate of one drop per second.

4.

Keep the basket and aggregates completely immersed in water for 24 ± `/~ hours. then weigh in water at temperature of 22°C to 32°C (W 1).

5.

Remove the basket and aggregates from water and allow to drain for few minutes.

6.

Empty the aggregates from basket and return the empty basket into water.

7.

Jolt the basket 25 times and weigh in water

8.

Gently dry the surface of the aggregate by wiping with cloth. Spread the aggregates. expose to atmosphere but away from direct sunlight till they appear dry.

9.

Take the weight of surface dry aggregates (W 3).

10.

Place the aggregates in oven at a temperature of 100°C to 110°C for 24 ± 1/2 hours.

11.

Remove the aggregates in oven, cool in air and weigh (W4).

12. i)

W4 Sp. Gravity = ---------------------W 3 - (W 1 – W 2)

ii)

W4 Apparent Sp. Gravity = ---------------------W 3 - (W 1 – W 2)

W3 – W4 iii) Water absorption (Percent of dry weight) = ---------------- X 100 W4 13.

Report results in Form GB - 5.

86

Water Absorption of Aggregate Test No.

Observations 1

2

Average 3

Wt. of saturated aggregate and basket in water (W 1) gm Wt. of basket in water

(W 2) gm

Wt. of saturated surface dry aggregate in air

(W 3) gm

Wt. of oven dried aggregate in air

(W 4) gm

Specific gravity = W 4 / W 3 - (W 3 – W 4) Apparent Specific gravity = W 4 / W 4 - (W 1 – W 2) Water absorption = (W 3 – W 4) x 100 / W4 (%) Mean value of Specific gravity

=

Mean value of apparent specific gravity = Mean value of Water absorption

=

XIII. Determination of Moisture Content of Aggregates 1. Clean the container thoroughly 2. Dry it and termine its empty weight (W 1) with lid. 3. Take the required quantity of the aggregate sample in the container and place it loosely inside the container. 4. Close the container and determine its weight (W 2) 5. Keep the container with the lid removed in an oven maintained at a temperature of 110°C ± 5°C for 24 hours. 6. After drying. remove the container and allow it to cool to room temperature. 7. Determine weight of the dry sample with lid (W 3) 8. Calculate the water content in percentage using the formula. W2 – W3 W = ---------------- X 100 W2 – W 3 9. Report the results in Form SB - 3. Moisture Content of Aggregates Sample No.

Tin No.

Wt. of Tin (gm) (W1)

Wt. of Tin + wet aggregate (gm) (W2)

Wt. of Tin + dry aggregate (gm) (W3)

Loss of Water(gm) (W2) (W3)

Wt. of dry soil (gm) (W2) - (W1)

(i) (ii) (iii) Average Moisture Content (%)

87

Moisture content (%)

XIV. Determination of Flakiness Index and Elongation Index Values Concept and Significance: Flakiness Index of an aggregate is the percentage by weight of particles in it whose least dimension (thickness)is less than three fifths (3/5th) of their mean dimension. The test is not applicable to sizes smaller than 6.3mm. Object To determine the flakiness of coarse aggregate sample Apparatus 1. Balance should have an accuracy of 0.10% of the weight of test sample 2. Metal gauge confirming to IS 2336 (Part I) 1977 3. I.S Sieves – 63mm, 50mm, 40mm , 31.5mm ,25mm,20mm,16mm, 12.5mm , 10.0mm and 6.3mm. Procedure 1. The sample has to be carefully and properly sieved. 2. Nine fractions are to be collected with the following specifications: Passing through I.S Sieve 60 mm 50 mm 40 mm 31.5 mm 25 mm 20 mm 16 mm 12.5 mm 10 mm

Retained on I.S Sieve 50 mm 40 mm 31.5 mm 25 mm 20 mm 16 mm 12.5 mm 10 mm 6.3 mm

3. Every Piece of each fractional sieve shall be gauged for a minimum thickness with the help of the ISI gauge or in bulk using a set of sieves having standard elongated slots. 4. Thus, each fraction is to be separated into 2 parts: One consisting of pieces which pass through the corresponding slot in the standard gauge and the other consisting of pieces which do not pass through the corresponding slot in the standard gauge. 5. Each part is separately weighed. Sum of both the weights gives the total weight of each fraction. Observations and Calculations:

Flakiness

Index

Wt.of fraction of the sample S.No

Passed Through

1. 2. 3.

63.0 50.0 40.0

Retained On 50.0 40.0 25.0 Total

Weight in gms 4030 11820 21880 37730

Thickness Guage 63.0 - 50.0 50.0 - 40.0 40.0 - 25.0

Wt.of fraction Passing through Thickness guage in gms 383 1217 2341 3941

Flakiness Index:( 3941/37730) x 100 = 10.44 %

88

Allowable Percentage

Not >15 %

ELONGATION INDEX: Elongation Index is weight of elongated particles divided by total nonflaky Particles. The gauge length would be 1.8 times the mean size of aggregate. For an aggregate passing through 50mm sieve but retained on 40mm sieve, the mean size is 45mm and limit for the length of 45, works out to be 1.8 x 45 = 81mm.

Elongation I n d e x S.No 1. 2. 3. Total

Weight of Non-flaky material 3647 10603 19539 33789

Length Guage 63.0 - 50.0 50.0 - 40.0 40.0 - 25.0

Wt. of Fraction Retained on

Allowable Percentage Length gauge in gms

126 273 676 1075

Elongation Index =

1075 x 100 (37730-3941) = 1075/33789 x 100 = 3.18.

Flakiness + Elongation Index = 10.44 + 3.18 = 13.62 % (Not > 30%) The Flakiness Index shall be less than 15% for coarse aggregates for road works (Clause.1007 of MOST Specification.) The Flakiness Index shall be less than 35% for coarse aggregates for concrete works (Clause.1007 of MOST Specification.) The Flakiness Index shall be less than 25% for stone chipping. The Combined Flakiness and Elongation Indices shall be less than 30% for combined mix aggregates (bituminous works)

XV. Determination of Aggregate Impact Value 1. Concept and Significance. The property of a material to resist impact is known as Toughness. Due to movement of vehicles on the road the aggregates are subjected to impact resulting in their breaking down in to smaller pieces. The aggregates should therefore have sufficient toughness to resist their disintegration due to impact. This characteristic is measured by impact value test. The aggregate impact value is a measure of resistance to sudden impact or shock, which may differ from its resistance to gradually applied compressive load. 2. Objective To determine the impact value of the road aggregate

89

3. Apparatus 1. Testing Machine 2. Cylindrical steel cup 3. Metal Hammer 4. Tamping rod 5. Balance. 4. Procedure The test

sample

consists

of

Aggregate size 10.0mm to 12.5 mm .The aggregates should be dried by heating at 100-110° C for a period of 4 hours and cooled. 1. The Aggregates passing through 12.5mm sieve and retained on 10.0mm sieve comprises the test material. 2. Pour the aggregates to fill about just 1/3rd depth of measuring cylinder. 3. Compact the material by giving 25 gentle blows with the rounded end of the tamping rod. 4. Add two more layers in similar manner , so that the cylinder is full. 5. Strike off the surplus aggregates. 6. Determine the net weight of the aggregates to the nearest gram (W 1). 7. Raise the hammer until its lower face is 380mm above the surface of the aggregate sample in the cup and allow it to fall freely on the aggregate sample. Give 15 such blows at an interval of not less than one second between successive falls. 8.

Remove the crushed aggregate from the cup and sieve it through 2.36mm IS sieve until no further significant amount passes in one minute. Weigh the fraction passing the sieve to an accuracy of one gram (W 2). Also weigh the fraction retained on the sieve.

9. Note down the observations in the pro-forma and compute the aggregate impact value. 10. The mean of two observations, rounded to the nearest whole number is reported as the aggregate Impact value. 5. Precautions. 1. In the operation of sieving the aggregates through 2.36mm sieve the sum of weights of fractions retained and passing the sieve should not differ from the original weight of the specimen by more than one gram.

90

6. Record of Observations and Calculations. Example: S.No 1. 2. 3. 4.

TRAIL NUMBER

Details Wt.of Aggregate sample W 1 gms Wt.of Aggregate passing 2,36mm (W 2 gms) Wt.of Aggregate retained on 2.36mm (W 3 gms) Aggregate impact value: W 2/

W 1 x100

1

2

338.00

339.00

69.00

71.00

269.00

268.00

20.41

20.94

Average Aggregate Impact Value

21%

IRC has recommended the following AI values for different types of road construction Sr. No.

Type Of Pavement

Maximum Aggregate Impact Value %

1.

Bituminous surface dressing penetration Macadam, Carpet Concrete, and cement concrete wearing course.

30

2.

Bitumen-bound-Macadam, base course

35

3.

WBM base course with bitumen surfacing

40

4.

Cement Concrete Base Course

45

Tests on Bituminous Material XVI. Determination of Penetration Value of Bitumen (Specification No.136 of APSS) 1. Concepts and Significance. Penetration is a measurement of hardness or consistence of bituminous material. It is vertical distance penetrated by the point of a standard needle into the bituminous material under specific condition of load, time and temperature. This distance is measured in 1/10th of a millimeter. 2. Objectives. 1. To determine the consistency of bituminous material. 2. To assess the suitability of Bitumen for its use under different climatic conditions and type of constructions. 3. Apparatus. 1. Container: A flat-bottomed cylindrical metallic dish 55mm in diameter and 35mm in depth is required. If the penetration is of the order of 225mm or deeper dish of 70mm and 45mm depth is required. 2. Needle: A straight highly polished, cylindrical hard steel rod, as per dimensions given in fig.

91

3. Water bath: A water bath maintained at 25.0 + 0.1° C containing not less than 10 Lt. of water, the sample being immersed to a depth not less than 100mm from the top and supported perforated shelf not less than 50mm from the bottom of the bath. 4. Penetration Apparatus: It should be with a calibrated accuracy upto 1/10th of a millimeter. 5. Thermometer: 0 to 44 degrees and readable up to 0.20° C. 6. Time Measuring device: With an accuracy + 0.1 sec.

4. Procedure 1. Preparation of test specimen: Soften the material to a pouring consistency at a temperature not more than 60° C for Tars and 90° C for Bitumen. Stir it thoroughly until it is homogeneous and free from air bubbles and water. Pour the melt into the container to a depth at least 10 mm in excess of the expected penetration and allow it to cool to room temperature. Then place it along with the transfer dish in the water bath at 25.0°C + 0.1 and allow it to remain for 1 to 1 ½ hour. 2. Clean the needle with Benzene, dry it and load with the weight. The total moving load requires is100+0.25gms, including the weight of the needle carrier and super-imposed weights. 3. Adjust the needle to make contact with the surface of the sample. 4. Make the pointer of the dial to read zero or note the initial dial reading. 5. Release the needle for exactly five seconds. 6. Adjust the penetration machine to measure the distance penetrated. 7. Make at least 3 readings at points on the surface of the sample not less than 10mm apart and not less than10mm from the side of the dish. (After each test return the sample and transfer dish to the water bath and wash the needle clean with benzene and dry it). 5. Precautions 1. There should be no movement of the container while needle is penetrating into the sample. 2. The sample should be free from any extraneous matter. 3. The needle should be cleaned with benzene and dried before each penetration.

92

6. Record of observations and calculations: Example: S.No. 1.

Details

Test 1

Test2

Test3

Penetrometer dial reading

2.

(i) Initial

0

0

84

(ii) Final

86

84

171

86

84

87

Penetration value

Mean penetration value = (86+84+87)/3 = 85.67 or Say 86 Penetration at 25 degree C, 100g, 5seconds in 1/100 cm shall be as under for the different grades of materials (as per IS: 73-1961 Table-II). Grade of material

Penetration

S 35

30 – 40

S 45

40 – 50

S 65

60 – 70

S 90

80 – 100

S 200

175 – 225

XVII. Determination of Open Flash Point and Fire Point of Bitumen 1. Concept and Significance The flash point of a material is the lowest temperature at which the application of test flame causes the vapours from the material momentarily catch fire in the form of a flash under specified conditions of test. The fire point is the lowest temperature at which the application of test flame causes the material to ignite and burn at least for 5 seconds under specified conditions of test. 2. Objective To determine flash point and fire point of the bituminous material. 3. Apparatus 1. Cup:- A handle is attached to the flange of the cup. 2. Stove. 3. Thermometer: which is having a range of 90° C to 370° C readable to 2° C. 4. Procedure. 1. Clean and dry all parts of the cup and its accessories thoroughly. 2. Fill the cup with the material to be tested up to the level indicated by the filling mark. 3. Insert the thermometer. 4. Light and adjust the test flame and apply heat such that the temperature rises at a rate of 5 – 6° C per minute.

93

5. Note the temperature at which a flash first appears at any point on the surface of the material. 6. Continue heating until the bitumen ignites and burns for 5 minutes. Record this temperature as fire point. Ex: Test Property

Mean 1

2

3

Flash Point

185

188

179

184

Fire Point

238

240

234

237

Note: Paving bitumen shall not be heated beyond the flash point. For paving bitumen of all the five grades (i.e, S.35 to S.200) the flash point is 175°C. XVIII. Determination of Softening Point of Bitumen 1. Heat the bitumen to a temperature between 125°C and 150°C. 2. Heat the rings at same temperature on a hot plate and place it on a glass plate coated with glycerine. 3. Fill up the rings with bitumen. 4. Cool it for 30 Minutes in air and level the surface with a hot knife. 5. Set the ring in the assembly and place it in the bath containing distilled water at 5°C and maintain that temperature for 15 Minutes. 6. Place the balls on the rings. 7. Raise the temperature uniformly at 5°C per minute till the ball passes, through the ring. 8. Note the temperature at which each of the ball and sample touches the bottom plate of the support. 9. Temperature shall be recorded as the softening point of the bitumen. [Form Bl-1(C)] Softening Point of Bitumen 1

Grade of bitumen

2

Approximate softening point

3

Liquid used in water bath (water I Glycerin)

4

Period of air cooling (minutes)

4.1

Period of cooling in water bath (minutes)

Test Property Temp at which sample o touch bottom plate ( C)

1

Sample No. 1

Sample No. 2

Ball No.

Ball No. 2

3

4

Mean Value, Softening point o

Note: Permissable Limit ………………More than 40 C

94

XIX. Determination of Ductility of Bitumen 1.

The bitumen sample is melted to a temperature of 75°c to 100°c above the approximate softening point until it is fluid. It is strained through IS sieve 30, poured in the mould assembly and placed on a brass plate, after a solution of glycerine and dextrin is applied at all surfaces of the mould exposed to bitumen. Thirty to forty minutes after the sample is poured into the moulds, the plate assembly along with the sample is placed in water bath maintained at 27°C for 30 minutes. The sample and mould assembly are removed from water bath and excess bitumen material is cut off by leveling the surface using hot knife. After trimming the specimen, the mould assembly containing sample is replaced in water bath maintained at 27°c for 85 to 95 minutes. The sides of the mould are then removed and the clips are carefully hooked on the machine without causing any initial strain. The pointer is set to read Zero. The machine is started and the two clips are thus pulled apart horizontally. While the test is in operation, it is checked whether the sample is immersed in water in depth of at least 10mm. The distance at which the bitumen thread breaks is recorded (in cm.) and reported as ductility value. [Form BL-1(b)] Ductility of Bitumen

2.

3. 4. 5. 6. 7. 8. 9. 10.

1

Grade of bitumen

2

Pouring temperature, C

3

Test temperature, C

4

Period of air cooling, (minutes)

o

o

4.1

In Air

4.2

In water bath before trimming

4.3

In water bath after trimming

Briquette number

Test Property (a)

(b)

Mean Value (c)

Ductivity value (cm) Note: Permissable Limit ………………More than 75 Units

XX. ELASTIC RECOVERY TEST AS PER APPENDIX – 1 OF IRC: 53 – 2002 Prepare 3 test specimens for 1 sample as prescribed in IS: 1208 at 15ºC. Elongate the test specimen to 10cm at the rate of ± 0.25 cm per minute. Immediately cut the test specimen in to 2 halves at the mid point using scissors, Keep the test specimen in water bath in an undisturbed condition For one hour at specified temperature, Move the elongated half of the test specimen back in to position near the fixed half to just touch. Record combined length as X Elastic Recovery (%) = (10-X)/10x100

95

XXI. Determination of Rate of Spread of Binder I.

Cut the cotton pads to a size of 203 x 102 mm. making sure that. each pad is as uniform in size as possible.

2.

Attach the cut cotton pads to heavy wrapping paper using suitable adhesive, the amount of adhesive applied, being the same on each pad. Leave sufficient area of wrapping paper on the four sides uncovered.

3.

Number the pads on the underside of the paper.

4.

Attach pieces of masking tape to the wrapping paper and tape, to the nearest 0.1 gm.

5.

Weigh the cotton pads complete with wrapping paper and tape, to the nearest 0.1 gm.

6.

Attach the pads to the metal sheets. Fold the uncovered paper under the metal sheet and secure with tape. such that no uncovered paper is exposed.

7.

Place the metal sheets with test pads. on the road way at such locations, that the tyres of the distributor will not run over the pads.

8.

As soon as the bitumen distributor has passed. Remove the metal sheet and test pad from the pavement. Remove the absorbent pads and wrapping paper. Including masking tape from metal sheet,

9.

Weigh each pad. Including wrapping paper and masking tape to nearest 0.1g.

Rate of Spread of Binder Tray No.

Wt. of Bitumen on tray

96

Rate of spread

XXII Determination of Bitumen Content by Centrifuge Extractor 1. Concept and significance The Centrifuge Extractor is used for the quantitative determination of bitumen in hotmixed paving mixtures and pavement samples, essentially as a field test to exercise quality control and ensure that the specified amount of bitumen has been used. The bitumen content is calculated by difference of the weight of the extract aggregate, moisture content and ash from the weight of the sample taken for the test. 02. Objective To determine quantity of bitumen in hot-mix paving mixtures and pavement samples. 3. Apparatus 1. The centrifuge Extractor consists of a revolving bowl inside housing. The bowl is provided with a cover plate and it is secured in position by tightening the nuts. 2. The bowl housing is provided with an outlet, the housing is mounted on an enclosed gearbox. A cover is clamped to housing. 3. The gears are splash lubricated and the system is operated manually with the handle.

4. Procedure a) Percentage basis (for SDBC, DBM, BM etc.,) 1 Weigh about 500 gm sample of asphalt mix and record the same. 2. Place the sample in the bowl and cover the sample (i.e. immersed with Benzene) and allow it to soak for one day. 3. Next day cut the filter paper to size, weigh it and place it in position. Pour the Benzene soaked mixes in the centrifuge and fix it. 4. Place a beaker under the outlet.

97

5. Rotate the centrifuge gradually to increase the speed to 3600 rpm. Rotate until the solvent ceases to flow from the outlet. 6. Repeat the procedure, till the solvent coming out of outlet is same that of Benzene without any sediments or colour. 7. Remove the filter, dry it in air, and brush the loose particles into the centrifuge. 8. Dry the filter and contents in the centrifuge in an oven to 98° to 105° C. 9. Obtain the weight of filter and dry aggregates separately. Record of observations: Wt. of sample

= w1 g

Initial wt. of filter paper

= w2 g

Final wt. of filter Paper

= w3 g

Wt.of retained fines(filter paper)

= (w3-w2) g

Wt. of aggregates after BT.Extraction

= w4 g

Total Wt. of aggregates + fines

= (w3-w2) + w4 g

Wt. of bitumen (W b)

= w1- ((w3-w2) + w4) g

Bitumen content %

= W b/w1 x 100

b) Area basis (for BTWC,BTSD, MSS etc.,) 1. In the field, cut the bitumen carpet of a standard size ie. say 15x15 cm, simultaneously recording the thickness(X mm). 2.

The weight of the above sample is to be found and recorded.

3.

Further the procedure is same as that of % process. Accordingly the experiment is continued.

Record of observations: Wt. of sample

= w1 g

Initial wt. of filter paper

= w2 g

Final wt. of filter Paper

= w3 g

Wt. of retained fines (filter paper)

= (w3-w2) g

Wt. of aggregates after BT. Extraction

= w4 g

Total Wt. of aggregates + fines

= (w3-w2) + w4 g

Wt. of bitumen (W b)

= w1- ((w3-w2) + w4) g

(for x mm thick observed) Wt. of bitumen for 20mm thick (W c)

= (W b x 20) / X

Wt. of bitumen in Kgs/10sqm (of 20mm thick) = W c / 2.25 X 100

98

Examples of Bitumen extraction test Results

S. No

1

Location Description of of Sample Sample

2

3

Filter Paper Weight

Initial Weight of Sample (gms)

Initial weight (gms)

Final Weight (gms)

Rtd. Wt. of Fines (gms)

Weight of chips after Test (gms)

4

5

6

7

8

Total Wt. of Chips (7)+(8) (gms) 9

Weight of Bitumen with Sample 0.15x0.15 (4)-(9)

Thickn ess in mm

10

11

Proportional Wt of Bitumen for 20mm (gms) 12

Weight of Bitumen Used Kg/10m2

Required Quantity of Bitumen Kgs/10m2

13

14

1.

1.756

BTSD+S C

1001

4.82

6.22

1.40

946

947.40

53.60

20

53.60

23.82

23.80 Kgs/10m2

2.

0.064

MSS

1048

4.35

5.27

0.92

1000

1000.92

47.07

22

42.79

19.02

19.00 Kgs/10m2

3.

4.075

SDBC

838

4.61

5.99

1.38

801

802.38

35.62

-

-

4.25

4.50+0.3%

4.

4.075

B.M

680

4.67

5.91

1.24

657

658.24

21.76

-

-

3.20

3.25+0.3%

99

XXIII. Determination of Stripping Value of Road Aggregate 1. Concept and Significance This test is conducted to determine the effects of moisture upon the adhesion of the bituminous film to the surface particles of the aggregate. This test is of significant value to ascertain the suitability of the two materials viz., bitumen (binder) and aggregates, because one particular aggregate may be satisfactory with one binder and unsatisfactory with another and the same being true for the binders. 2. Objectives: 1. To determine the stripping value of aggregates used in road construction. 2. To ascertain the suitability of road aggregates for bituminous road construction. 3. Apparatus: 1. Thermostatically controlled water bath. 2. Beakers of capacity 500 ml. 4. Procedure: The aggregate sample: The test sample consists of aggregate of size passing 25mm sieve and retained on 12.5 mm sieve. 1. Obtain the material that passes through 25-mm sieve and is retained on 12.5-mm sieve. 2. Dry, clean and heat the binder and aggregates to 150-175°C and 120 –150°C respectively and mix with 5 per cent binder by weight of aggregate. 3. After complete coating, allow the mixture to cool at room temperature in clean dry beaker. 4. Add distilled water to immerse the coated aggregates. 5. Cover the beaker and keep it undisturbed in a thermostatic water bath at a temperature of 40°C for a period 24 hours. 6. Estimate the extent of stripping by visual examination while the specimen is still under water and express as the average percent area of aggregate surface uncoated. Note:

Three samples may be tested simultaneously so as to arrive at an average value. The stripping value is expressed to the nearest whole number.

5. Precautions: 1. The aggregates should be thoroughly dried before mixing with binder. 2. Distilled water should be used for the test. 3. Mix-up of the two separate samples should be uniform. 6. Record of observations and calculations: S.No 1.

Details

Sample 1

Percentage of area of aggregate uncoated by immersion in water

15 %

Samlple 2 20 %

Sample 3 15%

Average stripping value = (15+20+15)/3 = 16.67 or 17% 7. Interpretation of results: The results of the stripping test give an indication regarding susceptibility of aggregates to the action of water, or moisture. The more the stripping value, the poorer are the aggregates from point of view of adhesion. APSS Table: 1508-8 has specified the maximum stripping value of 25 % for aggregates to be used in bituminous road construction. MOST Tables 500.8 has specified minimum retained coating 95%.

100

XXIV. Determination of Marshall Stability Value 1.Concept and Significance The test procedure is used in designing and evaluating bituminous paving mixes, and is widely applied in routine test programs for the paving jobs, The major features of the Marshall method of designing mixes are to determine the two important properties of strength and flexibility. Strength is measured in terms of the ‘Marshall Stability’ of the mix which is defined as the maximum load carried by a compacted specimen at a standard test temperature of 60° C. This temperature represents the weakest condition for a bituminous pavement in use. The flexibility is measured in terms of the ‘Flow value’ which is measured by the change in diameter of the sample in the direction of load application between the start of loading and the time of maximum load. In this test an attempt is made to obtain optimum binder content for the aggregate mix type and traffic intensity. 2. Objectives 1. To determine the density - voids analysis for the given bituminous mixture; 2. To determine the strength (Marshall’s Stability Value)and flexibility (flow value) for the given bituminous mixture; 3. To determine the suitability of the bituminous mixture to meet the specified criteria for the surface course. 3. Apparatus 1. Specimen Mould Assembly comprising mould cylinders 10cm diameter by 7.5 cm height, base plate and extension collars. They are designed to be interchanged with either end of cylindrical mould. Three mould cylinders are recommended.

101

2. Specimen extractor for extracting the compacted specimen from the mould. A suitable bar is required to transfer load from the extension collar to the upper proving ring attachment while extracting the specimen. 3. Water bath with thermostatic control. 4. Thermometers of range up to 200° C with sensitivity of 2.5° C and 5. Miscellaneous equipment like containers, mixing and handling tools etc. 4. Preparation of Test Specimen 1. Measure out 1200 gm of aggregates blended in the desired proportions. Heat the aggregates in the oven to the mixing temperature (155° –165° C). 2. Add pre-determined quantity of bitumen at the mixing temperature (130°-150° C) and mix the materials in a heated pan with heated mixing tools. 3. Return the mixture to the oven and reheat it to the compacting temperature (120°C). 4. At no time shall the difference in temperature between the aggregates and the binder exceed 15°C. 5. Place the mixture in a heated Marshall mould with a collar and base. Spade the mixture around the sides of the mould. Place filter papers under the sample and on top of the sample. 6. Place the mould in the Marshall Compaction pedestal. 7. Compact the material with 75 blows of the hammer (or as specified), invert the sample. and compact the other face with the same number of blows. 8. After compaction, invert the mould with the collar on the bottom. Remove the base and extract the sample by pushing it out the extractor. 9. Allow the sample to stand for a few hours to cool at room temperature. 5.Test Procedure 1. The aggregates are tested and their apparent specific gravites, Aggregates Impact values and Flakiness and Elongation Index water absorption values are recorded. 2. Bitumen 80/100 grade is tested for its grade, from penetration test. A 80/100 grade bitumen indicates that its penetration value lies between 80 and 100. 3. Take approximately 4 Kg of each aggregate and conduct gradation test individually. 4. Normally the weight of sample to be prepared is about 1200 gm in practice. So in a sample of 1200 gm weight, the weight of mix aggregate and bitumen will be 1152 and 48 gm, for a bitumen content of 4 %. 5. Conduct mix gradation trials in various proportions, till MOST table 500-20 & 500-22 Satisfied. 6. With the attained suitable mix gradation of aggregate, take mix gradation of aggregate sample as detailed below for different binder contents (1200gm - W1).

S.No 1 2 3

Binder Content (W 2) 4.00% (48gms) 4.50% (54gms) 5.00% (60gms)

102

Mix aggregate Weight (W 1-W 2) 1152gm 1146gm 1140gm

7. At least three specimens for each combination of aggregates and bitumen should be prepared. 8. After preparation of the specimen it has to be weighed first in air and then in water. 9. The differences of the weight are the volume of the specimen (or) take the thickness of the specimen on four sides and take the average and calculate the volume of the specimen. 10. The specimen is then immersed in hot water bath at a testing temperature of 60° C for 30minutes. 11. The specimen is then removed, fixed in the breaking head assembly and mounted on the testing machine. 12. Place the flow meter over one of the posts and adjust it to read zero. And also the dial gauge in proving ring is set to read zero. 13. The machine is set to operation by applying load, until the maximum load reading is obtained. 14. Record the maximum load reading. At the same instant, obtain the flow meter reading. Reverse the machine and remove the specimen tested. 15. Care must be taken to ensure that the elapsed time from the water bath to the maximum load determination should not generally exceed 30 seconds. 16. The stability values obtained above are correlated if the height of specimen tested is other than 63.50 mm or by its volume using correlation factors as shown below.

Marshall Stability correlation values: S. No

Vol.Of Specimen (Cm3)

Appox. Thickness of Specimen (mm)

Correlation ratio

S. No

Vol.Of Specimen (Cm3)

Appox. Thickness of Specimen (mm)

Correlation ratio

1

200-213

25.4

5.50

18

421-431

52.4

1.39

2

214-225

27.0

5.00

19

432-443

54.0

1.32

3

226-237

28.6

4.55

20

444-456

55.6

1.25

4

238-250

30.2

4.17

21

457-470

57.2

1.19

5

251-264

31.8

3.825

22

471-482

58.0

1.14

6

265-276

33.3

3.57

23

483-495

60.3

1.09

7

277-289

34.9

3.33

24

496-508

61.9

1.04

8

290-201

36.5

3.03

25

509-522

63.5

1.00

9

302-316

38.1

2.78

26

523-535

65.1

0.96

10

317-328

39.7

2.50

27

536-546

66.7

0.93

11

329-340

41.3

2.27

28

547-559

68.3

0.89

12

341-353

42.9

2.08

29

560-573

69.9

0.86

13

354-367

44.9

1.92

30

574-585

71.5

0.83

14

368-379

46.0

1.79

31

586-596

73.0

0.81

15

380-392

47.6

1.67

32

597-610

74.6

0.78

16

393-405

49.2

1.56

33

611-625

76.2

0.76

17

406-420

50.8

1.47

103

Example: Semi-Dense Bituminous Concrete 25mm thick (MOST: 511) 1) Individual sieve analysis of aggregates: i)Sample :-11.2 mm Table 500-20 (Grading-I) Sieve size 13.2 mm 11.20 mm 5.60 mm 2.80 mm 710 Micron 355 Micron 180 Micron 90 Micron Total Weight.

Wt.Retained(g) Nil 1490 2110 435 725 4760

Wt. of Passing(g) 4760 3270 1160 725 -

% Wt.of Passing 100.00 68.70 24.37 15.23 -

Wt.Retained(g) Nil 70 2400 1115 560 90 82 25 8 4350

Wt. of Passing(g) 4350 4280 1880 765 205 115 33 8 -

% Wt.of Passing 100.00 98.39 43.22 17.59 4.72 2.64 0.76 0.18 -

Wt. of Passing(g) 2730 2730 2730 1870 1150 805 525 260 -

% Wt.of Passing 100 100 100 68.50 42.12 29.49 19.23 9.52 -

ii) Sample :-6.70 mm Sieve size 13.2mm 11.20 mm 5.60 mm 2.80 mm 710 Micron 355 Micron 180 Micron 90 Micron (-)90 Total Weight.

iii) Sample :-2.80 mm Stone dust Sieve size 13.2mm 11.20 mm 5.60 mm 2.80 mm 710 Micron 355 Micron 180 Micron 90 Micron (-)90 Total Weight.

2. Mix Aggregate: Trail No:1

Sieve size 13.2mm 11.20 mm 5.60 mm 2.80 mm 710 Micron 355 Micron 180 Micron 90 Micron (-)90

Wt.Retained(g) Nil Nil Nil 860 720 345 280 265 260 2730

Specimen Wt. =1200 gm Bitumen Wt = 54 gm --------Wt. of aggregate 1146 gm Wt.Retained (g) Nil 103 417 236 192 99 42 27 30

Wt.of Passing(g) 1146 1043 626 390 198 99 57 30 -

104

11.2 mm 6.70 mm 2.80stone dust Total %Wt.of Passing (g) 100 91.01 54.62 34.03 17.28 8.64 4.97 2.62 -

(30%) = 344 gms (45%) = 516 gms (25%) = 286 gms 1146 gms Limits 100 88-100 42-64 22-38 11-24 7-18 5-13 3-9 -

Remarks

Total Weight.

1146

Trail No:2.

-

-

Specimen Wt. =1200 g Bitumen Wt = 54 g ---------Wt. of aggregate 1146 g

Sieve size 13.2mm 11.20 mm 5.60 mm 2.80 mm 710 Micron 355 Micron 180 Micron 90 Micron (-)90 Total Weight.

Wt.Retained (gm) Nil 83 417 280 195 55 45 32 38 1145

Wt.of Passing(gm) 1145 1062 645 365 170 115 70 38 -

-

11.2 mm (20%) = 229 g 6.70 mm (50%) = 573 g 2.80stone dust (30%) = 344 g Total 1146 g

% Wt.of Passing (gms) 100 92.75 56.33 31.88 14.85 10.04 6.11 3.32 -

Limits 100 88-100 42-64 22-38 11-24 7-18 5-13 3-9 -

Remarks

Satisfied O.K

3. Specific gravity:S.No.

Details

1.

Wt. of Jar

2.

Wt. of Jar + Sample (w2) Wt. of Jar + Sample + Water (w3) Wt. of Jar + Water (w4)

3. 4.

(w1)

11.20 mm 168 gm

Sample Size 6.7mm 2.8mmStone Dust 168 gm 168 g

731 gm

709 gm

435 g

1022 gm

1006 gm

838 g

664 gm

664 gm

664 g

(w1-w2) Specific Gravity :- ------------------------- = (w4-w1)- (w3-w2)

2.746

2.718

The theoretical specific gravity of mix (Gt) is calculated as below: Gt =

100 ---------------------------------------W2 W3 W4 W1 ------ + ------ + ------ + ------g1 g2 g3 g4

Where W 1 = % by weight of coarse aggregate (11.2 mm) w2 = % by weight of fine aggregate (6.7 mm) w3 = % by weight of fines (dust) w4 = % by weight of bitumen in total mix g1 g2 g3 g4

= = = =

Apparent specific gravity of coarse aggregate Apparent specific gravity of fine aggregate Apparent specific gravity of fines (dust) Density of bitumen

105

2.871

Size

%of Sample

11.20 mm

20

229

Sp.Gravity 2.746

6.70 mm

50

573

2.718

2.80 mm

30

344

2.871

B.T

4.50

54

0.98

Wt.of Sample (gm)

Sp.GR. of Mix(GT) 100 --------------------------------------20 50 30 4.50 ----- + ------ + ------- + ------2.746 2.718 2.871 0.98 =2.456

Density and voids determination for “SDBC” requirement as per MOST:511, Table No:500-21 Trail No

Date of Casting/T esting

Sp.Gr of mix

Binder Content %

Height of Specimen ‘cm’

Wt.of Specimen ‘gms’

Bulk Density Gb

1.

11-06-01

2.456

4.50

6.38

1183

2.360

Vol. of Bitumen Vb = Gbxw4 G4 10.84

2.

-do-

2.456

4.50

6.39

1188

2.366

10.86

AVG

2.363

% of voids in the mix Vv= (Gt-Gb) x 100 Gb

% of voids in mineral aggt. VMA= Vv+Vb

% of voids in the Aggt. filled with Bitumen VFB = Vb/VMAx 100

4.07

14.91

72.70

3.80

14.66

74.08

3.93

14.78

73.39

Marshall Test Observations Trail No Specimen

Date of Casting

Date of Testing

Binder Content

1. 2.

11-6-01 10-6-01

11-6-2K 11-6-2K

4.50 % 4.50 %

Maximum Proving ring 330 355

Marshall Stability Value Measured 959 1036

Correction 1.04 1.04

Corrected 997 1077 AVG:1037

Flow Value 3.10 3.50 3.30

Tests On Sand. I. Determination of Bulkage of Sand (APSS 110). Object:- This test covers the procedure of determining in the field, the amount surface moisture or Bulking in fine aggregates by displacement in water. Bulking of sand:- Increase in bulk volume of a quantity of sand in moist condition over the volume of the same quantity of sand when completely inundated. Procedure: In a 250ml measuring cylinder pour the damp sand (consolidating by shaking) until it reaches 200ml mark. Then fill the cylinder with water and stir the sand well.(The water shall be sufficient to submerge the sand fully). It will be seen the sand surface is now below its original level. Suppose the surface is at the mark y ml, the percentage of bulking of the sand shall be calculated from the following formula; Bulking % = 100(200-y)/y Note: The percentage of bulking of sand shall be rounded off to the nearest whole number.

106

Therefore the volume of sand used shall be more than the quoted volume by above % in the specification.

II. Determination Of Silt Content (APSS 110). Object: To determine the percentage of silt content. Sand shall be durable and free from adherent coatings and organic matter and shall not contain any appreciable amount of clay balls or pellets. Procedure: A sample of sand to be tested shall be placed without drying in a200ml measuring cylinder. The size of sample shall be such that it fills the cylinder up to 100ml mark. Clean water shall be added over it up to 150ml mark. The mixture then shall be shaken vigorously and the contents allowed to settle for 3 hours. The height of silt visible as settled layer above the sand shall be expressed as percentage of the height of sand below. Limits: Clay, Fine Silt & Fine dust in natural sand or crushed gravel sand should not more than 4% by weight.

III. Determination of Fineness Modulus (APSS 110) An empirical factor obtained by adding total percentages of a sample of the aggregates retained on each of the following series of sieves divided by 100. Object: To determine the fineness modulus of sand The sieves used are 150,300,600 Microns, 1.18, 2.36, 4.75, 10.0, 20.0, 40.0 mm and larger increasing in the ratio of 2 to 1. Ex: Sl. No 1 2 3 4 5 6 7 8

Sieve Designation 10mm 4.75mm 2.36mm 1.18mm 600µ 300µ 150µ (-)150µ

Weight Retained(g) 1 45 583 1935 1407 334 37

Cum. Wt. Retained(g) 1 46 629 2564 3971 4305 4342

TOTAL

Cum Wt. Retained In % 0.02 1.06 14.49 59.05 91.45 99.14 -

Cum Wt. Passing In % 100 99.98 98.94 85.51 40.95 8.55 0.86 -

265.21

Fineness Modulus = Total Cum. Wt. Retained % : 265.21/100 = 2.65% 100 Allowable Limits: 2.00 to 3.50 % TESTS ON BRICKS First Class Bricks: The tolerance on the specified dimensions shall not exceed + 3% Second Class Bricks: The tolerance on the specified dimensions shall not exceed + 8% Physical Characteristics: When tested in accordance with IS: 3495 – 1966 the Bricks shall conform to the requirements as follows:

107

Sl. No

Characteristics

Requirements

1. 2. 3.

Compressive strength Absorption after 24 hr immersion in cold water Efflorescence

2

Not less than 40 Kg/Cm Not more than 20% by wt. Not more than ‘moderate’

XXV. Determination of Crushing Strength of Bricks Object: To determine the crushing strength of Bricks (APSS 102) Preconditioning: Remove the unevenness observed in the bed faces to provide two smooth and parallel faces by grinding. Immerse in water at room temperature for 24 hours. Remove the specimen and drain out any surplus moisture, at room temperature. Fill the frog (Where provided) and all voids in the bed face, flush the cement mortar of grade (1 cement, 1 clean coarse sand). Then cover it with wet jute bags for 24 hrs followed by immersion in clean water for 3 days. Remove and wipe out any traces of moisture. Procedure: Place the specimen with flat faces horizontal and mortar filled face, facing upward between two 3- ply plywood sheets each of 3mm thickness and carefully centered between the plates of the testing machine. Apply load axially at a uniform rate of 140 Kgs/Cm2 per minute till the maximum load at which the specimen fails to produce any further increase in the indicator reading on the testing machine. Ex: Load at failure Area Compression Average Compression Sl. No. (Kg) (Cm2) Strength (Kgs/Cm2) Strength (Kgs/Cm2) 1. 10,450 253 41.30 41.40 2. 10,600 253 41.50 Note: The strength of a Brick decreases by about 25% when soaked in water.

XXVII.

Determination of Water Absorption

Object: To determine water absorption of Bricks (APSS 102). Pre-conditioning: Dry the specimen in a ventilated oven at a temperature of 100°-110°C till a constant weight is obtained. Cool the specimen to room temperature and obtain its dry weight (W 1). Procedure: Immerse completely the dried specimen in clean water at temperature of 27 + 5° C for 24 hr. Remove the specimen and wipe out any traces of water with a damp cloth and weigh the specimen (W 2). Complete the weighing in 3 minutes after the removal of specimen from water. Water absorption: (W 2 – W 1) x 100 W1 Ex: S.No 1. 2. 3.

Size of Brick (Cm) 23x11x7 23x11x7 23x11x7

Dry weight (g) 2047 2236 1974

Wet weight (g) 2431 2643 2310

Weight of water (g) 384 407 336 Average =

% of water Absorption 18.76 18.20 17.02 17.99 %

Note: Water absorption of Bricks after 24hr. immersion shall not be more than 20% by weight.

108