Page 74 - HIGHWAY ENGINEERING LABORATORY_FLIP BUILDER

REFERENCE
WORK PROCESS DOCUMENT

4.0 PROCEDURE:

1. Determine the mass of the mold with base plate attached.

2. Prepare 6-7 kg passing sieves 20 mm soil sample. Mix the dry soil with
200ml waterso that themixturehasawatercontentthatis1%below
the optimum moisture content. Prepare around 6 kg of mixture.
Collect required data on soil properties and tabulate into form

3. 10.1.
4. Choose one of six methods for soil compaction. For this test
method No. 5 is recommended for soil compaction. According

to this method, compact the soil in the CBR mold with the
rammer. The soil should be poured into the mold in FIVE layers. Each
layer should be given distributed blows 62times overthe surface.
5. Remove the detachable collar and trim the top of the mold.

6. Measure the mass of the mold with the base plate containing the
specimen.

7. Place the mold with the specimen in the testing machine. Apply
a surcharge over the specimen corresponding to the mass of the
pavement.
8. Seat the plunger on the surface of the specimen under a small

load. Set the load and
9. penetration measuring dial gauges to zero.

10. Apply load to the plunger at a uniform rate of 1.25 mm/min.
11. Record proving ring readings at intervals of penetration of
0.25 mm to a total not exceeding 7.0 mm. Fill data.
12. Take a sample immediately below the penetrated surface

for moisture content determination.
13. Redo the steps listed above for the bottom part of the sample.

Higway Engineering Laboratory page 61