CHAPTER 13
MATERIALS TESTING
As you know by now, materials testing is a major
part of an EAs responsibilities, especially for those
EAs assigned to the Seabee construction battalions.
The EA3 TRAMAN introduced you to the subject of
materials testing. In that TRAMAN, you learned
many of the basic soils and concrete tests that an EA
performs. This chapter furthers your knowledge of the
subject area.
In this chapter you will be introduced to several
soils tests that the EA2 is expected to perform. You
will study the constituent ingredients used in the
production of concrete and will be introduced to many
different procedures for testing those ingredients. You
will learn about the tests used for concrete mixture
design purposes and for determining the strength of
concrete. Also, you will study bituminous materials,
learn about methods used to test those materials, and
will be introduced to various tests used in the design
of bituminous pavement mixtures.
Although some of the tests discussed in this
chapter are covered in seemingly thorough detail, it is
not the intent of this TRAMAN to teach you how to
perform the tests; instead, you will learn the purpose
and principles of the tests, but only the fundamental
procedures. For each test, the discussion identifies an
authoritative source that you should refer to for
detailed procedural guidance. Always use those
sources when actually performing any of the materials
tests.
SOILS TESTING
Soil compaction and density testing are two of the
most common and important soils tests that an EA
must learn to perform. Those tests, as well as the
California bearing ratio test and hydrometer analysis,
are discussed in this section.
COMPACTION TEST
Compaction is the process of increasing the density
(amount of solids per unit volume) of soil by mechanical
means to improve such soil properties as strength,
permeability, and compressibility. Compaction is a
standard procedure used in the construction of earth
structures, such as embankments, subgrades, and
bases for road and airfield pavement.
In the field, compaction is accomplished by
rolling or tamping the soil with special construction
equipment. In the laboratory, compaction can be
accomplished by the impact of hammer blows,
vibration, static loading, or any other method that
does not alter the water content of the soil. Usually,
however, laboratory compaction is accomplished by
placing the soil into a cylinder of known volume and
dropping a tamper of known weight onto the soil from
a known height for a given number of blows. The
amount of work done to the soil per unit volume of
soil is called compactive effort.
For most soils and for a given compactive effort,
the density of the soil will increase to a certain point,
as the moisture content is increased. That point is
called the maximum density. After that point, the
density will start to decrease with any further increase
in moisture content. The moisture content at which
maximum density occurs is called the optimum
moisture content (OMC). Each compactive effort for
a given soil has its own OMC. As the compactive
effort is increased, the maximum density generally
increases and the OMC decreases.
The following discussion briefly describes the
equipment and procedures of the ASTM compaction test
that determines the OMC and the maximum density
obtainable under a given compactive effort. You can find
a full discussion of the test in Materials Testing,
NAVFAC MO-330.
Equipment
The principal equipment used for the compaction
test is the compaction cylinders and the compaction
tamper that are shown in figure 13-1.
There are two compaction cylinders. The smaller
cylinder (Proctor mold) is 4 inches in diameter and has
a volume of 1/30 (0.0333) cubic feet. It is used for
materials passing the No. 4 sieve. The Proctor mold is
13-1
