Humboldt H-4139 Proctor Penetrometer Set - Manual (Page 2)

General
The Proctor Penetrometer is used in method of test for establishing the
moisture penetration resistance relations of fine-grained soils as determined
by penetration testing.
The Model H-4139, Proctor Penetrometer is furnished with these
interchangeable needles: (in 2 (cm 2 )) 1 (6.45), 3/4 (4.84), 1/2 (3.22), 1/3 (2.15),
1/5 (1.29), 1/10 (.65), 1/20 (0.32), 1/30 (0.22) and 1/40 (0.16). Replacement
needles are available.
H-4139 complies with ASTM D1558 for number and sizes of needles required.
The Penetrometer is furnished with a carrying case. To assemble the apparatus,
place the handle on the graduated handle shaft and tighten in place with the
wing nut. Place the other end of the shaft in the open end of the spring barrel
assembly and tighten the large hexagonal nut finger tight. To install the needles
of various end areas, screw the needle shanks into the tapped hole provided in
the spring barrel assembly.
Sample Preparation
The sample should be prepared in accordance with either method “A” or
method “B” of ASTM D698. After preparation, the fraction passing the #4 sieve
(4.75mm) must have at least 20% passing the 3/8" (9.5mm) sieve.
Test Procedure
1. Compact the soil in the moisture-density mold in accordance with the
procedure described in Section 4 of the ASTM D698.
2. Place the mold containing the soil specimen on a smooth space between
the feet of the test operator.
3. The operator must hold the Penetrometer in a vertical position and control
the rate of penetration by steadying his arms against his legs and at the
same time applying pressure to the Penetrometer handle.
4. Penetrate the soil specimen at the rate of 0.5 inch per second for a distance
of not less than three (3) inches. The penetration needle must be placed
away from the edge of the mold, near the center and the individual
penetrations spaced so as not to interfere with one another.
5. The resistance of the soil to penetration by use of the soil Penetrometer
is determined by the use of the attached needle of known end area. The
needles shall be of such size that the reading will be between 20 and 80.
Take the reading at top as shown in the drawing.
6. Penetrate the soil specimen not less than three times. The average of the
readings must be used. Force readings are indicated at the top of the
sliding ring.
7. The penetration resistance determination must be made on each molded
soil specimen. Penetration resistance determinations cannot be obtained
on very dry molded soil specimens or very granular soils.