Page 73 - HIGHWAY ENGINEERING LABORATORY_FLIP BUILDER

Page :
WORK INSTRUCTION
Edition :

CALIFORNIA BEARING Checking No.
RATIO TEST
(Reference Standard: Effective Date:
CIVIL ENGINEERING IS: 2720 (Part 16) 1979)

JKA/ DCC30112/ 2021 Amendment Date:

1.0 OBJECTIVE

TodeterminetheCaliforniabearingratiobyconductingaloadpenetrationtestin
thelaboratory.

2.0 THEORY

The California bearing ratio test is penetration test meant for the evaluation of
subgrade strength of roads and pavements. The results obtained by these tests are used
with the empirical curves to determine the thickness of pavement and its component

layers.Thisisthemostwidely used method for the design of flexible pavement.
This instruction sheet coversthelaboratorymethod forthedetermination of C.B.R. of
undisturbed and remoulded /compacted soil specimens, both in soaked as well as
unsoaked state.

3.0 EQUIPMENTS

1. Cylindrical mould with inside dia 150 mm and height 175 mm,
provided with a detachable extension collar 50 mm height and a

detachable perforated base plate 10 mm thick.
2. Spacerdisc148mmindiaand47.7mminheightalong with handle.
3. Metal rammers. weight 4.5 kg a drop 450 mm. Weights. One annular
metal weight and several slotted weights weighing 2.5 kg each, 147

mm in dia, with a central hole 53 mm in diameter.
4. Loading machine with a capacity of at least 5000 kg and
equipped with a movable head or base that travels at an uniform
rate of 1.25 mm/min. Complete with loading dicatingdevice.

5. Metal penetration piston 50 mm dia and minimum of 100 mm in
length.
6. Two dial gauges reading to 0.01 mm. Sieves 20 mm B.S. Sieves.
7. Miscellaneous apparatus, such as a mixing bowl, straight edge, scales soaking

tankorpan,drying oven, filter paper and containers.

Higway Engineering Laboratory page 60