California Bearing Ratio Test - Soil Properties: Testing, Measurement, and Evaluation - page 399

(3) Apply the load on the penetration piston so that the rate of pen-
etration is approximately 0.05 in. (1.27 mm)/min. Record the load
readings at penetrations of 0.025 in. (0.64 mm), 0.050 in. (1.27 mm),
0.075 in. (1.91 mm), 0.100 in. (2.54 mm), 0.125 in. (3.18 mm), 0.150 in.
(3.81 mm), 0.175 in. (4.45 mm), 0.200 in. (5.08 mm), 0.300 in.
(7.62 mm), 0.400 in. (10.16 mm), and 0.500 in. (12.70 mm). Note
the maximum load and penetration if it occurs for a penetration
of less than 0.500 in. (12.70 mm). With manually operated loading
devices, it may be necessary to take load readings at closer inter-
vals to control the rate of penetration. Measure the depth of piston
penetration into the soil by putting a ruler into the indentation and
measuring the difference from the top of the soil to the bottom of
the indentation. If the depth does not closely match the depth of
penetration gage, determine the cause and test a new sample.

(4) Remove the soil from the mold and determine the water con-
tent of the top 1-in. (25.4-mm) layer. Take a water content sample
in accordance with ASTM Test Methods D 698 or D 1557 if the
average water content is desired. Each moisture content sample
shall weigh not less than 100 g for fine-grained soils nor less than
500 g for granular soils.

Note 5 —The load readings at penetrations of more than 0.300
in. (7.6 mm) may be omitted if the testing machine's capacity
has been reached.

The following data should be collected during a CBR test:

DATA

[A] Water Content Determination

Mass of wet soil plus can (g)
Mass of dry soil plus can (g)
Mass of can (g)

Note —These data must be obtained for each of four specimens: (1) before
compaction, (2) after compaction, (3) top 1 in. after soaking, (4) average
moisture content after soaking.

[B] Density Determination

Mass of mold plus compacted soil specimen (g)
Mass of mold (g)
Diameter of mold (in.)
Height of soil specimen (in.)

Note —These data must be obtained for each of two specimens: (1) before
soaking, (2) after soaking.