Harvard Miniature Compaction Apparatus (H-4165) Page 3 of 7
Instruction Manual Rev.0; August 01, 2003
Copyright 2003 Humboldt Mfg. Co., Norridge, IL. 60706, U.S.A.
All rights reserved. Printed in U.S.A.
1. General
This test determines the relationship between the moisture content of soils and resulting
densities (oven-dry weight per cubic foot) when the soil is compacted in the laboratory
with this apparatus. Selection of the most appropriate number of layers, number of tamps
per layer and tamping force depends on the type of material and the intended use to
which the compacted material will be put. In general, at least five layers and ten tamps
per layer are required to produce homogeneous test specimens.
2. Unpacking
In shipment, all of the parts are packed carefully to prevent damage. It is suggested that
all packing material be carefully checked to ascertain that no parts are overlooked. The
apparatus consists of the following:
2.1 Specimen ejector and collar remover with spacer plate.
2.2 Mold holder.
2.3 1/454 cu. ft. (129 m3)-volume mold & collar.
2.4 Compaction tamper with 20 lb. (9.07kg), 37.5lb. (17kg) & 40lb (18.2kg) spring.
3. Assembly
Very little assembly is required since the collar remover and specimen ejector is shipped
completely assembled.
To assemble the mold, place collar on the mold. Set in center of base plate with top of
mold collar fitted into recess in top plate. Tighten knurled nuts.
The tamper is supplied with 20-pound compaction spring in place. To change springs,
remove the two lock nuts and remove insert in lower end by loosening the two set
screws.
4. Operation
4.1 Sample Preparation:
Air-dry to a slight to slightly damp condition a 2 to 3 lb. sample of soil taken
from a portion of the material passing the No. 4 (4760-micron) sieve. Mix
thoroughly to break up the lumps and insure a homogeneous mixture. Then
divide into six to eight portions, such that each portion contains slightly more
than enough material for one test. To each portion add approximately the
required amount of water to obtain the desired range of moisture contents. After
thorough mixing, place each portion in a small glass jar with tight fitting cover
and store overnight or until ready for testing. For soils that mix readily with
water and have low dry strengths, it is satisfactory to add water and mix the
