H-20 (Ground Floor), Pocket-F, Sector-1,
Bawana (DSIDC), New Delhi - 110039, India
California Bearing Ratio
California Bearing Ratio (CBR)
The California Bearing Ratio Test, (usually called CBR test) is an empirical penetration test for evaluation of mechanical strength of
natural ground, subgrades and base courses beneath new carriageway construction. It is to determine the relative bearing ratio and
expansion characteristics. It was developed by the California department of transportation before World War II.
The test can be performed in the laboratory on prepared samples or in-situ on location. It is important to appreciate that this test, being of an empirical in nature, is valid only for the application for which it was developed i.e., the design of highway base thickness. The basic site test is performed by measuring the pressure required to penetrate soil or aggregate with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material
The test can be performed in the laboratory on prepared samples or in-situ on location. It is important to appreciate that this test, being of an empirical in nature, is valid only for the application for which it was developed i.e., the design of highway base thickness. The basic site test is performed by measuring the pressure required to penetrate soil or aggregate with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material
California Bearing Ratio Apparatus (ASTM Version Mould)
ASTM D 1883 AASHTO T 193
A. CBR mould body complete with collar & perforated base plate. Plated Steel 6 In.(152.4mm) Dia x 7 In. (177.8mm) Height
B. Spacer Disc with T handle 515/16 In. Dia(150.8mm) x 2.416 In. (61.4mm) height
C. Annular surcharge weight 2.27 kg D Slotted surcharge weight 2.27 kg E Filter paper 150 mm dia No 1 Fisherman (Pack of 100 circles)
A. CBR mould body complete with collar & perforated base plate. Plated Steel 6 In.(152.4mm) Dia x 7 In. (177.8mm) Height
B. Spacer Disc with T handle 515/16 In. Dia(150.8mm) x 2.416 In. (61.4mm) height
C. Annular surcharge weight 2.27 kg D Slotted surcharge weight 2.27 kg E Filter paper 150 mm dia No 1 Fisherman (Pack of 100 circles)
California Bearing Ratio Apparatus (BS Version Mould)
BS 1377-4
A. CBR mould body plated steel, with both ends threaded to fit the base or collar, 152 mm ID x 127 mm high
B. Extension collar 152mm ID x 50 mm high
C. Perforated base plate
D. Solid base or top plate
E. Cutting collar
F. C Spanner to mount and dismount the collar from the mould body. Two are required for the operation.
G. Compaction plug with handle 150 mm x 50 mm high
H. Annular surcharge weight 2 kg
I. Split surcharge weight 2 kg
J. Filter paper 150 mm dia No 1 Fisherman(Pack of 100 circles)
A. CBR mould body plated steel, with both ends threaded to fit the base or collar, 152 mm ID x 127 mm high
B. Extension collar 152mm ID x 50 mm high
C. Perforated base plate
D. Solid base or top plate
E. Cutting collar
F. C Spanner to mount and dismount the collar from the mould body. Two are required for the operation.
G. Compaction plug with handle 150 mm x 50 mm high
H. Annular surcharge weight 2 kg
I. Split surcharge weight 2 kg
J. Filter paper 150 mm dia No 1 Fisherman(Pack of 100 circles)
Laboratory California Bearing Ratio Apparatus, Motorised
IS 9669, IS : 2720 (PART XVI)
The Apparatus Consists of :
A. Load Frame, 50kn ( 5000 kgf) Capacity, 3 Speeds
B. Mould 150mm ID x 175mm high
C. Perforated Base Plate for - 2 Mould
D. Extension Collar, 150mm ID x 50mm high
E. Penetration Piston, 50mm face dia
F. Adjustable Bracket, for Penetration Dial Gauge
G. Circular Metal Spacer Disc. With detachable handle, 148 mm dia x 47.7 mm high time.
H. Annular Metal Weight, 2.5kg, 147mm dia with 53 mm dia central hole
I. Perforated Metal Weight 2.5 kg. 147mm dia, with 53mm dia soft
J. Perforated Plate, 148mm dia, with adjustable stem and lock nut
K. Metal Tripod for Dial Gauge
L. Cutting Collar
M. Rammer 2.6kg, 310mm controlled drop
N. Rammer 4.9kg, 450mm controlled drop
O. Proving Ring Capacity 50 KN
P. Dial Gauge, 25 mm travel, 0.01mm least count
Optional Extras:
Q. Annular Metal Weight 5 kg, 147mm dia with 53 mm dia central hole
R. Slotted Metal Weight 5 kg 147mm dia with 53mm dia slot
The Apparatus Consists of :
A. Load Frame, 50kn ( 5000 kgf) Capacity, 3 Speeds
B. Mould 150mm ID x 175mm high
C. Perforated Base Plate for - 2 Mould
D. Extension Collar, 150mm ID x 50mm high
E. Penetration Piston, 50mm face dia
F. Adjustable Bracket, for Penetration Dial Gauge
G. Circular Metal Spacer Disc. With detachable handle, 148 mm dia x 47.7 mm high time.
H. Annular Metal Weight, 2.5kg, 147mm dia with 53 mm dia central hole
I. Perforated Metal Weight 2.5 kg. 147mm dia, with 53mm dia soft
J. Perforated Plate, 148mm dia, with adjustable stem and lock nut
K. Metal Tripod for Dial Gauge
L. Cutting Collar
M. Rammer 2.6kg, 310mm controlled drop
N. Rammer 4.9kg, 450mm controlled drop
O. Proving Ring Capacity 50 KN
P. Dial Gauge, 25 mm travel, 0.01mm least count
Optional Extras:
Q. Annular Metal Weight 5 kg, 147mm dia with 53 mm dia central hole
R. Slotted Metal Weight 5 kg 147mm dia with 53mm dia slot
Automatic CBR Test Apparatus
EN 13286-47; BS 1377:4; ASTM D1883; AASHTO T193; NF P94-078; UNI CNR 10009
The automatic CBR test machine is designed for performing laboratory evaluation of the CBR value of highway sub- bases and subgrade, and determination of the strength of cohesive materials which have maximum particle sizes less than 19 mm (3/4"). This CBR apparatus is composed of a robust and compact two column frame with adjustable upper crossbeam driven by an electromechanical ram with a maximum capacity of 50 kn and a data acquisition and processing system.
The machine is designed to load the penetration piston into the soil sample at a constant rate to measure the applied load and piston penetration at predetermined intervals. The ram speed can be set between 0.5 mm/min to 5 mm/min by using the digital readout unit. This main feature allows the user to perform tests complying to BS, EN, ASTM or AASHTO standards with the same machine.
Rapid adjustment of the platen is also provided by up and down buttons which are located on the front panel of the machine. The machine is supplied complete with a 50 kN load cell, penetration piston, linear potentiometric displacement transducer (25 mm x 0.001 mm), computer software and connection cable. PC is optional.
The automatic CBR test machine is designed for performing laboratory evaluation of the CBR value of highway sub- bases and subgrade, and determination of the strength of cohesive materials which have maximum particle sizes less than 19 mm (3/4"). This CBR apparatus is composed of a robust and compact two column frame with adjustable upper crossbeam driven by an electromechanical ram with a maximum capacity of 50 kn and a data acquisition and processing system.
The machine is designed to load the penetration piston into the soil sample at a constant rate to measure the applied load and piston penetration at predetermined intervals. The ram speed can be set between 0.5 mm/min to 5 mm/min by using the digital readout unit. This main feature allows the user to perform tests complying to BS, EN, ASTM or AASHTO standards with the same machine.
Rapid adjustment of the platen is also provided by up and down buttons which are located on the front panel of the machine. The machine is supplied complete with a 50 kN load cell, penetration piston, linear potentiometric displacement transducer (25 mm x 0.001 mm), computer software and connection cable. PC is optional.
California Bearing Ratio Test (Field Type)
IS 2720 (PART XXXI) 1969.
In recent years i t has become important to know C.B.R. values in situ. It is useful in determining the load carrying capacity in the field when in place density and water contents are such that the degree of saturation is 80% of greater, when material is cohesionless and coarse grained, such that it is not effective by changes in water contents and when the material has been in place for considerable the loading is effected by means of a mechanical load frames which can be fixed to the under side of a truck
Specification :
Mechanical screw loading jack, 10,000 kg. Capacity with u-bracket and swivel head. Penetration piston, 50mm dia. Threaded at the upper end. Extension rods consisting of 2 lengths 5 cm. g lengths 10cm. 1 length 30 cm., 1 length 50 cm. and 1 length 100 cm. used as spacers between the proving ring and penetration piston. The lengths are machined from steel tubing. Connector set, has eight connectors for coupling the penetration piston and proving ring assembly either directly or through extension pieces. Dial gauge support of seamless pipe constructions. It stands 30 cm high and 45 cm. Wide at the base. Provided with a quick release screw type clamp capable of sliding and locking anywhere along 2 meter length of the bridge. Supplied with annular metal weight 5 kg., 250mm dia with 53 mm dia central hole, slotted metal weight 5 kg., 215mm to 250mm dia with 53 dia slot 2 nos.
In recent years i t has become important to know C.B.R. values in situ. It is useful in determining the load carrying capacity in the field when in place density and water contents are such that the degree of saturation is 80% of greater, when material is cohesionless and coarse grained, such that it is not effective by changes in water contents and when the material has been in place for considerable the loading is effected by means of a mechanical load frames which can be fixed to the under side of a truck
Specification :
Mechanical screw loading jack, 10,000 kg. Capacity with u-bracket and swivel head. Penetration piston, 50mm dia. Threaded at the upper end. Extension rods consisting of 2 lengths 5 cm. g lengths 10cm. 1 length 30 cm., 1 length 50 cm. and 1 length 100 cm. used as spacers between the proving ring and penetration piston. The lengths are machined from steel tubing. Connector set, has eight connectors for coupling the penetration piston and proving ring assembly either directly or through extension pieces. Dial gauge support of seamless pipe constructions. It stands 30 cm high and 45 cm. Wide at the base. Provided with a quick release screw type clamp capable of sliding and locking anywhere along 2 meter length of the bridge. Supplied with annular metal weight 5 kg., 250mm dia with 53 mm dia central hole, slotted metal weight 5 kg., 215mm to 250mm dia with 53 dia slot 2 nos.
Swell Test Apparatus
Specification :
It is designed to determine the swelling pressure developed by soil specimens moulded to desired densities at knows moisture contents when soaked in water. The load applied to restrain the swelling is transferred to a load measuring proving ring through a perforated swell plate and a load transfer bar. The proving ring is attached to the lead screw of hand operated load frame. A soaking tank is provided for saturating the specimen and the base of the mould has channels and radial grooves with connecting holes it consists one each of :
It is designed to determine the swelling pressure developed by soil specimens moulded to desired densities at knows moisture contents when soaked in water. The load applied to restrain the swelling is transferred to a load measuring proving ring through a perforated swell plate and a load transfer bar. The proving ring is attached to the lead screw of hand operated load frame. A soaking tank is provided for saturating the specimen and the base of the mould has channels and radial grooves with connecting holes it consists one each of :
- Load Frame, Hand Operated, Capacity 50 KN (5,000 kgf)
- Mould, 100mm dia x 127.3mm height (1,000ml volume) with base plate and collar
- Proving Ring, with integral boss, high sensitivity 2.5KN (250 Kgf) capacity
- Dial Gauge , 25 mm travel, 0.01mm least count Lid & receiver in G.I. frame for 300 mm dia x 450 mm dia sieves
- Spencer, 100 mm dia x 12.7 mm thick
- Pair of Porous stones, 100 mm dia x 12.7 mm thick
- Load Transfer Bar
- Steel Ball
- Soaking Tank, 250 mm dia x 210 mm high
