03-BITUMINOUS BASE



BITUMINOUS BASE AND SURFACE COURSES

The bituminous base courses included in the MoRTH Specifications for Road and Bridge works (5th revision 2013) and which are normally used in pavement construction are:

  1. Bituminous macadam
  2. Dense bituminous macadam
  3. Sand bitumen

The bituminous surface courses include: 

  • Surface dressing
  • Open-graded premix surfacing
  • Close-graded premix surfacing/Mixed seal surfacing
  • Seal coat
  • Slurry seal
  • Micro-surfacing
  • Bituminous concrete
  • Stone Matrix Asphalt (SMA)
  • Semi-dense bituminous concrete

For more details, Clause 501 of MoRTH Specifications shall be referred.

1. PRIME COAT AND TACK COAT

1.1 Prime coat over granular base

Prime coat is the application of a single coat low viscosity bituminous material over a granular base or subbase to prevent entry of water into the subgrade. The main function of the prime coat in bituminous pavement is to protect the subgrade from moisture and weathering. The specifications and procedure for applying prime coat is giver under Clause 502 of MoRTH Specifications (5th revision).

1.2 Tack coat

 A tack coat is a very light spray application of a bitumen emulsion to create a bond between the new bituminous layer and the existing surface.

Table: Rate of application of tack coat

Type of surface

Rate of spray in kg/m2

Bituminous surface

0.20-0.30

Primer granular surface

0.25-0.30

Cement concrete pavement

0.30-0.35

2.  BITUMINOUS MACADAM (BM)

Constructing bituminous macadam base shall generally be done as per IRC: 27-1967. The specifications and construction procedure of bituminous macadam is given under Clause 504 of MoRTH Specifications (5th revision).

Table:  Physical requirements for coarse aggregates for BM

Property

Test

Code

Requirement

Cleanliness

Grain size analysis

IS: 2386 (Part 1)

Max 5% passing 75 micron sieve

Particle

shape

Flakiness and elongation indices (Combined)

IS: 2386 (Part 1)

Max 35%

Strength*

Los Angeles Abrasion value

IS: 2386 (Part 4)

Max 40%

Aggregate Impact value

IS: 2386 (Part 5)

Max 30%

Durability

Soundness – Sodium Sulphate

(5 cycles)

IS: 2386 (Part 5)

Max 12%

Soundness – Magnesium Sulphate

(5 cycles)

IS: 2386 (Part 5)

Max 18%

Porosity

Water absorption

IS: 2386 (Part 3)

Max 2%

Bitumen

adhesion

Coating and stripping of bitumen aggregate mixtures

IS: 6241

Minimum 95% coating retained

Water

sensitivity

Retained tensile strength**

AASHTO 283

IS: 6241

Min 80%

Table:  Physical requirements for coarse aggregates for BM

Sl .No

Test prescribed

Code

Minimum test frequency

1

Vescosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3

7

Los Angeles Abrasion

IS: 2386 Part 4

One test per 200 m3

8

Aggregate Impact value

IS: 2386 Part 4

One test per 200 m3

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Plasticity index

IS: 2720 Part 5

One test for each source.

13

Temperature check

-

At regular intervals.

14

Binder content

ASTM D 2172

Two tests per day.

15

Mix grading

IS: 2386 Part 1

Two tests per day.

16

Layer density

-

One test per 700 m3 area

3.  DENSE BITUMINOUS MACADAM (DBM)

The specifications for the design and construction of Dense Bituminous Macadam are giver under Clause 505 of MoRTH Specifications (5th revision 2013).

Table: Physical requirements for coarse aggregates for DBM

Property

Test

Code

Specification

  Cleanliness

Grain size analysis

IS: 2386 (Part 1)

Max 5% passing

75 micron sieve

Particle shape

Flakiness and Elongation Indices

(Combined)

 

IS: 2386 (Part 1)

 

Max 35%

   Strength*

Los Angeles Abrasion value

IS: 2386 (Part 4)

Max 35%

Aggregate Impact  value

IS: 2386 (Part 4)

Max 27%

   Durability

Soundness – Sodium Sulphate

(5 cycles)

 

IS: 2386 (Part 5)

 

Max 12%

Soundness – Magnesium

Sulphate (5 cycles)

 

IS: 2386 (Part 5)

 

Max 18%

Porosity

Water absorption

IS: 2386 (Part 3)

Max 2%

 

Bitumen adhesion

Coating and stripping of bitumen aggregate mixtures

 

IS: 6241

 

Minimum 95%

coating retained

Water sensitivity

Retained tensile strength**

AASHTO 283

Min 80%

*Any one of these shall need to be satisfied.

**Anti-stripping agent shall be added if the value falls below 80%.

Table 2300-12: Quality control test on DBM

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Sand equivalent

IS: 2720 Part 37

One test for each source.

13

Plasticity index

IS: 2720 Part 5

One test for each source.

14

Temperature check

-

At regular intervals.

15

Binder content

ASTM D 2172

Two tests per day.

16

Aggregate mix grading

IS: 2386 Part 1

Two tests per day.

17

Marshall test

AASHTO T 245

Three tests per 400 tonnes.

18

Max sp. gravity of mix

AASHTO T 209

Three tests per 400 tonnes.

19

Volumetric analysis

MS-2

Three tests per 400 tonnes.

20

Moisture susceptibility

AASHTO T 283

One test for each mix.

21

Layer density

-

One test per 700 m2 area.

4. SAND BITUMEN MIX

The sand bitumen mix can be used both as subbase and base.

The requirements for sand are prescribed in table 2300-13 (Ref: Table 500-14 of MoRTH Specifications).

Table 2300-13: Grading and physical requirements of sand for sand bitumen mix

Sieve size mm

Cumulative percentage passing by weight of aggregate

9.5

100

2.75

85-100

2.36

80-100

1.18

70-98

0.600

55-95

0.300

30-75

0.150

10-40

0.075

4-10

Plasticity index (PI)

6 (Max)

Sand equivalent (IS:2720 part 37)

30 (Min)

Los Angeles abrasion (IS: 2386 Part4)

40 (Max)

The mix requirements are prescribed in table 2300-14 (Ref: Table 500-15 of  MoRTH Specifications).

Table 2300-14: Requirements for sand base course

Mix parameter

Requirement

Minimum stability (kN at 60°C)

2.0

Minimum flow (mm)

2

Compaction level (Blows)

75 on each face

Air voids in the mix (%)

3-5

Voids in the mineral aggregate (VMA) %

16 (Min)

Percentage voids filled with bitumen (VFB) %

65 - 75

The binder content of the mix shall be determined in the laboratory by Marshall method given in the Asphalt Institute Manual MS-2.

Table 2300-15: Control tests for sand bitumen base / subbase.

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Water absorption

IS: 2386 Part 3

One test for each source.

7

Sand equivalent

IS: 2720 Part 37

One test for each source.

8

Plasticity index

IS: 2720 Part 5

One test for each source.

9

Temperature check

-

At regular intervals.

10

Binder content

ASTM D 2172

Two tests per day.

11

mix grading

IS: 2386 Part 1

Two tests per day.

12

Marshall test

AASHTO T 245

Three tests per 400 tonnes.

13

Max sp. gravity of mix

AASHTO T 209

Three tests per 400 tonnes.

14

Volumetric analysis

MS-2

Three tests per 400 tonnes.

15

Layer density

-

One test per 700 m2 area.

 QC tests on material and work for surface dressing shall be as indicated in table 2300-16 (Ref: Table 900-4 of MoRTH Specifications).

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Temperature check

-

At regular intervals.

13

Binder content

ASTM D 2172

Two tests per day.

14

Moisture susceptibility

AASHTO T 283

One test for each mix.

The QC tests on material and work shall be as given in table 2300-19 (Ref: Table 900-4 of MoRTH Specifications).

Table: Quality Control tests for open / close graded premix surfacing

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Temperature check

-

At regular intervals.

13

Binder content

ASTM D 2172

Two tests per day.

14

Moisture susceptibility

AASHTO T 283

One test for each mix.

5.  CLOSE-GRADED PREMIX SURFACING/MIX SEAL SURFACING

The specifications and construction procedure for close-graded premix surfacing are given under Clause 508 of MoRTH Specifications. Close-graded premix surfacing/mix seal surfacing shall be either Type A or Type B and is laid to a thickness of 20 mm. Type A surfacing is recommended for areas where average annual rainfall is more than 1500 mm.

  1. The binder shall be viscosity grade bitumen of the grade specified in the contract conforming to the requirements of IS: 73. For the selection of the grade of binder, table 2300-17 shall be referred.
  2. The coarse aggregates shall satisfy all the physical requirements set for BM except that the water absorption shall be 1% maximum. The polished stone value (PSV) shall not be less than 55% when tested in accordance with BS: 812-114.
  3. Fine aggregates shall be crushed rock, natural sand or a mixture of both which shall be clean, hard, durable, dry and free from soft, friable, flaky particles and organic and deleterious substances.
  4. The coarse and fine aggregates shall be combined to get a grading as stipulated in table 2300-20 (Ref: Table 500-19 of MoRTH Specifications).

6.  SEAL COAT

Clause 511 of MoRTH Specifications provides the details for the application of a seal coat for sealing the voids in the bituminous surface laid to the specified levels, grade and cross fall (Camber). The seal coat shall be either type A (Liquid seal coat) or type B (Premixed seal coat).

Table 2300-21: Physical requirements for stone chips for Type A seal coat.

Test

Code

Specification

Grain size analysis

IS: 2386 (Part 1)

Max 5% passing

75 micron sieve

Flakiness and Elongation Indices

(Combined)

IS: 2386 (Part 1)

Max 35%

Los Angeles Abrasion value

IS: 2386 (Part 4)

Max 35%

Aggregate Impact  value

IS: 2386 (Part 4)

Max 27%

Soundness – Sodium Sulphate (5 cycles)

IS: 2386 (Part 5)

Max 12%

Soundness – Magnesium Sulphate (5 cycles)

IS: 2386 (Part 5)

Max 18%

Water absorption

IS: 2386 (Part 3)

Max 2%

Coating and stripping of bitumen aggregate mixtures

IS: 6241

Minimum 95%

coating retained

Retained tensile strength**

AASHTO 283

Min 80%

7.  SLURRY SEAL

Slurry seal is a mixture of mineral aggregate, slow setting cationic bitumen emulsion, water, additives if required, proportioned, mixed and uniformly spread over a previously prepared surface. The detailed specification and construction procedure for slurry seal is given under Clause 512 of MoRTH Specifications. The three different types of slurry seal and their applications are given in table 2300-22 (Ref: Table 500-25 of MoRTH Specifications).

7.1 Filler

Ordinary Portland Cement (OPC) in the range of 0.5% to 2% by weight of total aggregates shall be incorporated as filler.

8. Mix Design

a) The mix design criteria for slurry seal mix is given in IRC: SP-81.

b) The requirements for the slurry seal mix is given in table 2300-26 (Ref: Table 500-29 of MoRTH Specifications).

Table 2300-26: Mix Design criteria for sluryy seal

Property

Code

Requirement

Mix time

IRC:SP-81, Appendix 1

180 sec (Min)

Consistency

IRC:SP-81, Appendix 3

3 cm (Max)

Wet cohesion

IRC:SP-81, Appendix 4

20 kgcm (Min)

Wet stripping

IRC:SP-81, Appendix 5

90% (Min)

Wet track abrasion loss (1 hour soak)

IRC:SP-81, Appendix 6

800 gm/m2 (Max)

c)   The  design  report  shall  indicate  the  proportion  of  aggregate,  filler,  water  and residual bitumen content based on dry weight of aggregate, additives to be used.

a) The surface finish of construction shall meet the requirements of Clause 2202 (Clause 902 of MoRTH Specifications).

b) Control on the materials and paving shall be done as given in table 2300-28 (Ref: Table 900-4 of MoRTH Specifications).

Table 2300-28: Quality control tests for slurry seal/micro-surfacing

Test prescribed

Code

Minimum test frequency

Quality of emulsion

IS: 8887

One test per lot of 20 tonnes.

Aggregate moisture

IS: 2386 Part 3

Two tests at site per day.

Water absorption

IS: 2386 Part 3

One test for each source/site.

Soundness

IS: 2386 Part 5

One test for each source/site.

Sand equivalent

IS: 2720 Part 37

One test for each source/site.

Binder content

ASTM D 2172

Two tests per lane/km.

Aggregate grading

IS: 2386 Part 1

Two tests at site per day.

Calibration of machine

-

Once per project.

Quantity of slurry

(By weight of aggregate)

-

Daily (Travel time of machine).

9.  MICRO-SURFACING

Micro-surfacing is provided for surface treatment of pavements in accordance with the procedure given in Clause 514 of MoRTH Specifications.

The micro-surfacing is applied to an existing pavement surface which is structurally sound but the surface showing signs of premature ageing, aggregate loss, cracking, higher degree of polishing. The types of micro-surfacing and rates of application are given in table 2300-29 (Ref: Table 500-31 of MoRTH Specification).

9.1 Material

9.1.1 Bitumen

The bitumen emulsion shall be a modified bitumen emulsion conforming to requirements specified in table 2300-30 (Ref: Table 500-32 of MoRTH Specifications).

Table 2300-30: Requirement for modified bitumen emulsion for micro-surfacing

Property

Code

Requirement

Residue on 600 mic sieve (% by mass)

IS: 8887

0.05 (Max)

Saybolt Furol viscosity at 250C

IS: 8887

20-100 sec

Coagulation of emulsion at low temperature

 

 

Storage stability after 24 hrs (168 hrs)

IS: 8887

2 (4) % (Max)

Particle charge

IS: 8887

+ve

a) Paving bitumen complying with IS: 73 shall be used for designing BC mix.

b) Coarse aggregates shall be crushed rock retained on 2.36 mm sieve. The source of aggregate shall be approved only after testing for stripping. The physical requirements for coarse aggregates specified in table 2300-33 (Ref: Table 500-16 of MoRTH Specifications) shall be achieved.

Table 2300-33: Physical requirements for coarse aggregate for BC

Property

Test

Code

Specification

Cleanliness (Dust)

Grain size analysis

IS: 2386 

(Part 1)

Max 5% passing

75 micron sieve

Particle shape

Flakiness and Elongation Indices

(Combined)

IS: 2386 

(Part 1)

Max 35%

Strength

Los Angeles Abrasion value

Or Aggregate Impact  value

IS: 2386 

(Part 4)

Max 35%

Durability

Soundness –

Sodium Sulphate

IS: 2386

(Part 5)

Max 12%

Soundness –

Magnesium Sulphate

IS: 2386 

(Part 5)

Max 18%

Polishing

Polished stone value

BS: 812-114

      Min 55

Porosity

Water absorption

IS: 2386 

(Part 3)

Max 2%

Bitumen adhesion

Coating and stripping of bitumen aggregate mixtures

      IS: 6241

Minimum 95%

coating retained

Water sensitivity

Retained tensile strength**

AASHTO 283

Min 80%

recommended to meet the requirement.

10. Quality control

a) The control of alignment, level and surface regularity shall be as given in Clause 2202 (Clause 902 of MoRTH Specifications).

b) The control tests and their minimum frequencies for BC work shall be as given in table 2300-37 (Ref: Table 900-4 of MoRTH Specifications).

Table 2300-37: Quality Control tests for bituminous concrete (BC)

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Sand equivalent

IS: 2720 Part 37

One test for each source.

13

Plasticity index

IS: 2720 Part 5

One test for each source.

14

Temperature check

-

At regular intervals.

15

Binder content

ASTM D 2172

Two tests per day.

16

Mix grading

IS: 2386 Part 1

Two tests per day.

17

Marshall test

AASHTO T 245

Three tests per 400 tonnes.

18

Max sp. gravity of mix

AASHTO T 209

Three tests per 400 tonnes.

19

Volumetric analysis

MS-2

Three tests per 400 tonnes.

20

Moisture susceptibility

AASHTO T 283

One test for each mix.

21

Layer density

-

One test per 700 m2 area.

Table 2300-38: Physical requirements of aggregates for SMA

Property

Test

Code

Specification

Cleanliness

Grain size analysis

IS: 2386 (Part 1)

<2% passing

0.075 mm sieve

Particle shape

Flakiness and Elongation Indices

(Combined)

IS: 2386  (Part 1)

<30%

Strength

Los Angeles Abrasion value

IS: 2386  (Part 4)

<25%

Aggregate Impact  value

IS: 2386  (Part 4)

<18%

Polishing*

Polished stone value

BS: 812-114

      <55%

Durability

Soundness 

Either sodium or magnesium ( 5 Cycles)

Sodium Sulphate

IS: 2386 (Part 5)

<12%

Magnesium Sulphate

IS: 2386  (Part 5)

<18%

Water absorption

Water absorption

IS: 2386  (Part 3)

<2%

12.1. Mix requirements

  1. The SMA mix shall be designed using AASHTO MP8 - Standard Specification for designing Stone Matrix Asphalt and AASHTO PP41 - Standard Practice for designing SMA.
  2. Compaction of the mix shall be carried with 50 blows on each side using Marshall Method given in Asphalt Institute Manual MS-2.

Table: 2300-43: Quality Control tests for SMA

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Sand equivalent

IS: 2720 Part 37

One test for each source.

13

Plasticity index

IS: 2720 Part 5

One test for each source.

14

Temperature check

-

At regular intervals.

15

Binder content

ASTM D 2172

Two tests per day.

16

Mix grading

IS: 2386 Part 1

Two tests per day.

17

Marshall test

AASHTO T 245

Three tests per 400 tonnes.

18

Max sp. gravity of mix

AASHTO T 209

Three tests per 400 tonnes.

19

Volumetric analysis

MS-2

Three tests per 400 tonnes.

20

Moisture susceptibility

AASHTO T 283

One test for each mix.

21

Layer density

-

One test per 700 m2 area.

13. SEMI-DENSE BITUMINOUS CONCRETE

The specifications for SDBC are more or less similar to dense bituminous macadam (DBM). This item is not included in the 5th revision published in 2013. Hence for the detailed specifications and construction procedures of Semi-dense Bituminous Concrete (SDBC) wearing and profile corrective courses (PCC) Clause 508 of MoRTH Specifications for Road and Bridge works (4th revision 2001) shall be referred.

13.1 Materials

a) Paving bitumen complying with IS: 73 shall be used for designing SDBC mix.

b) Coarse aggregates shall be crushed rock retained on 2.36 mm sieve. The source of aggregate shall be approved only after testing for stripping. The physical requirements for coarse aggregates are specified in table 2300-44 (Ref: Table 500-14 of MoRTH Specifications - 4th revision).

Table: 2300-44: Physical requirements for coarse aggregate for SDBC

Property

Test

Code

Specification

Cleanliness (Dust)

Grain size analysis

IS: 2386 

(Part 1)

Max 5% passing

0.075 mm sieve

Particle shape

Combined flakiness and elongation indices

IS: 2386 

(Part 1)

Max 30%

Strength

Los Angeles Abrasion value

Or Aggregate Impact  value

IS: 2386 

(Part 4)

Max 30%

Max 27%

Durability

Soundness –

Sodium Sulphate

IS: 2386

(Part 5)

Max 12%

Soundness –

Magnesium Sulphate

IS: 2386 

(Part 5)

Max 18%

Polishing

Polished stone value

BS: 812-114

        Min 55

Porosity

Water absorption

IS: 2386 

(Part 3)

Max 2%

Stripping

Coating and stripping of bitumen aggregate mix*

      IS: 6241

Retained Coating 

95% Min

 

Water sensitivity

Retained tensile strength**

AASHTO 283

Min 80%

The aggregate may satisfy one of the requirements.

If the minimum coating retained is ≥95%, the water sensitivity test need not be carried ou

If the minimum retained tensile strength falls below 80%, use of anti-stripping agent is recommended to meet the requirement.

  1. The variations in quantities of the ingredients from the approved job mix formula shall not exceed the prescribed limits (Ref: Table 500-13 of MoRTH Specifications-4th revision).
  2. The temperature requirement for bituminous mixes shall be as given in table 2300-36 (Ref: Table 500-2 of MoRTH Specifications – 5th revision).
  3. The difference in temperature between the binder and the aggregate should at no time exceed      14 0C.
  4. The control of alignment, level and surface regularity shall be as given in Clause 2202 (Clause 902 of MoRTH Specifications).
  5. The QC tests and their minimum frequencies for SDBC work shall be as given in table 2300-49.

 Table: 2300-49:  Control tests for SDBC

Sl. No

Test prescribed

Code

Minimum test frequency

1

Viscosity of binder

IS: 73, IS: 15462

One test for each supply.

2

Ductility

IS: 73, IS: 15462

One test for each supply.

3

Penetration

IS: 73, IS: 15462

One test for each supply.

4

Softening point

IS: 73, IS: 15462

One test for each supply.

5

Grain size analysis

IS: 2386 Part 1

Two tests per day.

6

Flakiness & elongation

IS: 2386 Part 1

One test per 350 m3 .

7

Los Angeles abrasion

IS: 2386 Part 4

One test per 350 m3 .

8

Aggregate impact

IS: 2386 Part 4

One test per 350 m3 .

9

Water absorption

IS: 2386 Part 3

One test for each source.

10

Stripping

IS: 6241

One test for each source.

11

Soundness

IS: 2386 Part 5

One test for each source.

12

Sand equivalent

IS: 2720 Part 37

One test for each source.

13

Plasticity index

IS: 2720 Part 5

One test for each source.

14

Temperature check

-

At regular intervals.

15

Binder content

ASTM D 2172

Two tests per day.

16

Mix grading

IS: 2386 Part 1

Two tests per day.

17

Marshall test

AASHTO T 245

Three tests per 400 tonnes.

18

Max sp. gravity of mix

AASHTO T 209

Three tests per 400 tonnes.

19

Volumetric analysis

MS-2

Three tests per 400 tonnes.

20

Moisture susceptibility

AASHTO T 283

One test for each mix.

21

Layer density

-

One test per 700 m2 area.

RELATED CODES :

1.         MoRTH           Specifications for Road and Bridge Works, 5th Edition 2013 -Published by IRC, New Delhi.

2.         MoRTH           Specifications for Road and Bridge Works, 4th Edition 2001 -Published by IRC, New Delhi.

3.         MoRTH           Manual for construction and supervision of bituminous works, Edition 2001 – Published by IRC, New Delhi.

4.         IRC SP: 11      Quality Control for the Construction of Roads and Runways -Published by IRC, New Delhi.

5.         MS-2               Marshall method of mix design for asphalt concrete and other hot mix types – Asphalt Institute Manual Series No. 2 (MS-2) - Published by Asphalt Institute (USA).

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