Calculation, Moisture-penetration resistance relationship – Humboldt H-4139 Proctor Penetrometer Set User Manual
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Calculation
Divide the average Penetrometer reading by the end area of the penetration
needle (the marked needle size) and record the resulting value as the
penetration resistance of the soil expressed in pounds (force) per square
inch. The moisture content of the soil must be calculated in accordance
with ASTM D2216.
Moisture-Penetration Resistance Relationship
Plot the penetration resistance and the corresponding moisture content as
calculated in accordance with the small letters for the series of determinations
with the corresponding moisture-density relations data. Plot the penetration
resistance determinations as ordinates with their corresponding moisture
contents as abscissas. The moisture-penetration resistance relationship curve
must be established by not less than three determinations.
Penetration Resistance Needles for H-4139/H-4137
Replacement Resistance Needle Set
H-4143N
1/40 sq. in. (0.16 cm
2
) needle
H-4143.025
1/30 sq. in. (0.22 cm
2
) needle
H-4143.033
1/20 sq. in. (0.32 cm
2
) needle
H-4143.05
1/10 sq. in. (0.65 cm
2
) needle
H-4143.10
1/3 sq. in. (1.29 cm
2
) needle
H-4143.33
1/4 sq. in. (1.61 cm
2
) needle
H-4143.75
1/5 sq. in. (2.15 cm
2
) needle
H-4143.20
1/2 sq. in. (3.22 cm
2
) needle
H-4143.50
3/4 sq. in. (4.84 cm
2
) needle
H-4143.75
1 sq. in. (6.45 cm
2
) needle
H-4143.1