road construction activity
Construction & Quality
Control of Flexible
Pavements
BITUMINOUS PAVEMENT
CONSTRUCTION
Bituminous construction are classified into four categories
• Interface Treatments
• Thin Bituminous surface Courses
• Bituminous Surface Courses
• Bituminous Binder Courses
INTERFACE TREATMENTS
Prime Coat
Tack Coat
Crack Prevention Courses
SAM and SAMI
Purpose Of Priming:
To plug the capillary voids
To coat and bond loose materials on the surface
To harden or toughen the surface
To promote adhesion between granular and the bituminous layer
Choice of Primer
–
The primer shall be bitumen emulsion, complying with IS 8887 of a type and grade as specified (SS-1)
–
The use of medium curing cutback as per IS 217 shall be restricted only for sites at sub-zero temperatures or for emergency applications
REQUIREMENT FOR PRIMING
MATERIAL
Porosity
Type of
Surface
Viscosity at Quantity
600 C per 10 m2
(Kg)
(centistokes)
30-60
6-9
Low
WMM,
WBM
Medium
Gravel base 70-140
9-12
Cement
Stabilised
soil base
250-500
12-15
High
TACK COAT
Purpose of Tack Coat:
To ensure a bond between the new construction and the old surface
Material for Tack Coat:
The primer shall be bitumen emulsion, complying with IS 8887 of a type and grade as specified (RS-1)
Use of Cutback:
It should be restricted for sites at subzero temperatures or for emergency applications
RECOMMENDED QUANTITIES OF
MATERIAL FOR TACK COAT
Type of Surface
Bituminous Surface
Quantity in kg per m2 area
0.20 to 0.25
Dry and hungry bituminous surfaces Primed granular surface
0.25 to 0.30
Unprimed granular base
0.35 to 0.40
Cement concrete pavement
0.30 to 0.35
0.25 to 0.30
WRONG PRACTICE OF TACK COAT
INSUFFICIENT TACK COAT
MECHANICAL PRESSURE
SPRAYER FOR PRIME/TACK COAT
MECHANICAL PRESURE HAND
SPRAYER FOR PRIME/TACK COAT
Properly Done Tack Coat
20-30% more quantity of tack
Control of Flexible
Pavements
BITUMINOUS PAVEMENT
CONSTRUCTION
Bituminous construction are classified into four categories
• Interface Treatments
• Thin Bituminous surface Courses
• Bituminous Surface Courses
• Bituminous Binder Courses
INTERFACE TREATMENTS
Prime Coat
Tack Coat
Crack Prevention Courses
SAM and SAMI
Purpose Of Priming:
To plug the capillary voids
To coat and bond loose materials on the surface
To harden or toughen the surface
To promote adhesion between granular and the bituminous layer
Choice of Primer
–
The primer shall be bitumen emulsion, complying with IS 8887 of a type and grade as specified (SS-1)
–
The use of medium curing cutback as per IS 217 shall be restricted only for sites at sub-zero temperatures or for emergency applications
REQUIREMENT FOR PRIMING
MATERIAL
Porosity
Type of
Surface
Viscosity at Quantity
600 C per 10 m2
(Kg)
(centistokes)
30-60
6-9
Low
WMM,
WBM
Medium
Gravel base 70-140
9-12
Cement
Stabilised
soil base
250-500
12-15
High
TACK COAT
Purpose of Tack Coat:
To ensure a bond between the new construction and the old surface
Material for Tack Coat:
The primer shall be bitumen emulsion, complying with IS 8887 of a type and grade as specified (RS-1)
Use of Cutback:
It should be restricted for sites at subzero temperatures or for emergency applications
RECOMMENDED QUANTITIES OF
MATERIAL FOR TACK COAT
Type of Surface
Bituminous Surface
Quantity in kg per m2 area
0.20 to 0.25
Dry and hungry bituminous surfaces Primed granular surface
0.25 to 0.30
Unprimed granular base
0.35 to 0.40
Cement concrete pavement
0.30 to 0.35
0.25 to 0.30
WRONG PRACTICE OF TACK COAT
INSUFFICIENT TACK COAT
MECHANICAL PRESSURE
SPRAYER FOR PRIME/TACK COAT
MECHANICAL PRESURE HAND
SPRAYER FOR PRIME/TACK COAT
Properly Done Tack Coat
20-30% more quantity of tack