Table 1: grading of test samples, Calculation, Maintenance – Humboldt H-3860A Los Angeles Abrasion Machine User Manual
Page 4: Weight of indicated sizes, g, Ab c d
Test Sample
The test sample shall consist of clean aggregate that has been dried in an oven at
105°C to 110°C (221°F to 230°F) substantially to constant weight and shall conform to
a grading shown in Table 1. The grading used shall be the most nearly representing the
aggregate furnished for the work.
TABLE 1: Grading of Test Samples
Sieve Size (Square Openings)
Weight of Indicated Sizes, g
Passing
Retained On
Grading
A
B
C
D
37.5 mm (1 ½")
25.0 mm (1.0")
1 250 ± 25
...
...
...
25.0 mm (1")
19.0 mm (3/4")
1 250 ± 25
...
...
...
19.0 mm (3/4")
12.5 mm (1/2")
1 250 ± 10
2 500 ± 10
...
...
12.5 mm (1/2")
9.5 mm (3/8")
1 250 ± 10
2 500 ± 10
...
...
9.5 mm (3/8")
6.3 mm (1/4")
...
...
2 500 ± 10
...
6.3 mm (1/4")
4.75 mm (No. 4)
...
...
2 500 ± 10
...
4.75 mm (No. 4)
2.36 mm (No. 8)
...
...
...
5 000 ± 10
Total
5 000 ± 10
5 000 ± 10
5 000 ± 10
5 000 ± 10
Test Procedure
Place the test sample and the abrasive charge in the Los Angeles Abrasion Testing
Machine and rotate the machine at a speed of 30 to 33 rpm for 500 revolutions. The
machine shall be so driven and so counter balanced as to maintain a substantially
uniform peripheral speed. After the prescribed number of revolutions, discharge the
material from the machine and make a preliminary separation of the sample on a sieve
coarser than the No. 12 (1.70mm). Sieve the finer portion to a No. 12 sieve in a manner
conforming to section 5.2 of ASTM Method C136. Test for sieve or screen analysis of
fine and coarse aggregates. Wash the material coarser than the No. 12 sieve, oven dry
at 221°F to 230°F (105°C to 110°C) to substantially constant weight and weigh to the
nearest 1-G.
Calculation
The difference between the original weight and the final weight of the test sample shall
be expressed as a percentage of the original weight of the test sample. This value shall
be reported as the percentage of wear.
Maintenance
Keep the assembly as clean as possible.
Lubricate necessary parts regularly. Use heavy transmission oil-40 weight, for the speed
reducer (AGMA lubricant class 8 COMP). Some examples are as follows:
Oil Recommended for H-3860 Los Angeles Abrasion Machine:
•
Gulf Oil
Senate 680
•
Shell Oil
Omala 680
•
Texaco
Honor 680
•
Mobil
Extra Helica Super Cylinder Oil