Commonwealth of Pennsylvania
Department of Transportation
PA Test Method No. 130
January 2016
8 Pages
LABORATORY TESTING SECTION
Method of Test for
EVALUATION OF POTENTIAL EXPANSION OF STEEL SLAGS
1.
SCOPE
1.1
This method of test covers the determination of the rate of expansion of steel slags
where compacted and tested in the laboratory. Steel slags, produced in steel making processes
such as open hearth, open oxygen, and electric arc furnaces are generally expansive with volume
changes of up to 10% attributable to the hydration of calcium and magnesium oxides.
1.2
This method is also applicable to any particulate material suspected of having
expansive characteristics.
2.
APPARATUS
2.1
Mold - The mold (see Fig. 1) shall be of metal, cylindrical in shape, with an inside
diameter of 6 ± 0.026", and a height of 7 ± 0.018". It shall be provided with a metal extension
collar 2.0" in. in height, and a perforated metal base plate 3/8" in height. The perforations in the
base plate shall not exceed 1/16" in diameter. The mold apparatus shall be well coated with a rust
preventative or constructed of stainless steel.
2.2
Spacer Disk - A circular metal spacer disk (see Figure 1) 5 15/16" in diameter and
2.416" in height.
2.3
Rammer - A metal rammer as specified in Section 2.2, PTM 106.
2.4
Expansion Measuring Apparatus- An adjustable metal stem and perforated plate,
with perforations in the plate not exceeding 1/16" in diameter, and a metal tripod to support the
dial gage for measuring the amount of vertical expansion (see Figure 1).
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2.5
Weight - Two annular metal weights or four slotted metal weights totaling
10 lbs., 5 7/8" in diameter, with a center hole 2 1/8" in diameter (see Figure 1).
2.6
Gauge - Dial gauge reading to 0.001".
2.7
Miscellaneous Apparatus - Other general apparatus such as a mixing bowl,
straightedge, scale, submersion tank or bucket, filter paper, dishes, and a 160 ± 5ºF oven.
3.
STOCKPILE SAMPLING
3.1
Three representative samples, two sample bags or approximately 100 pounds of
material per sample, shall be obtained from each stockpile or sublot. One sample shall be
obtained at a random location from each of three separate faces of the stockpile.
3.2
Since aggregate segregation usually occurs when the material is stockpiled, with
the coarser particles rolling to the outside base of the pile, it is necessary to excavate into the
base of the stockpile with power equipment to obtain a representative sample. At least two scoop
loads of the representative material shall be thoroughly mixed on a separate pile by the power
equipment and then "backbladed" to form a level surface. The sample shall then be obtained by
channeling in one direction across the middle of the level surface. If additional material is
needed, another channel may be made at approximately right angles to the first near the middle
of the level surface.
3.3
Identification
3.3.1
The following identification shall accompany each sample:
3.3.1.1 Sample number - each sampled stockpile shall have three separate
samples numbered 1, 2 and 3
3.3.1.2 Name of owner or seller
3.3.1.3 Stockpile identification or designation
3.3.1.4 Date the stockpile was sealed to start the cure period
3.3.1.5 Approximate quantity available in the stockpile
4.
SAMPLE PREPARATION FOR DENSITY
4.1
Prepare the sample in accordance with PTM 106, Section 4 (Method B).
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4.2
Select and maintain separate representative samples of slag passing the No. 4
sieve and the 3/4" sieve but retained on the No. 4 sieve so that the total sample will weigh
approximately 14 lbs. or more for the moisture-density relationship and 12 lbs. or more for the
molding of the test specimen. Set aside the portion of the sample to be used in the expansion test
and store so as to minimize loss of natural moisture. The percentage, by oven-dry mass, of
aggregate passing the 3/4" sieve and retained on the No. 4 sieve shall be the same as the total
percentage larger than the No. 4 sieve in the original sample when the material is recombined at
the time the moisture-density curve is determined.
4.3
Determine the optimum moisture content and maximum dry density in accordance
with PTM 106, Section 5 except that the 6" diameter mold depicted in Figure 1, with the spacer
disc in place, is used and that the soil shall be compacted in 3 equal layers with 56 blows per
layer. That portion of material passing the 3/4" sieve and retained on the No. 4 sieve is used in
the surface-dry condition.
5.
PREPARATION OF TEST SPECIMEN FOR EXPANSION
5.1
Using the 12 lbs. or more portion of unprepared sample at approximately the
natural stockpile moisture (undried), compensate for the aggregate larger than 3/4" as stated in
Section 4.2 except the weights of the plus No. 4 sieve and minus No. 4 sieve material used in the
procedure shall be adjusted for their respective natural moisture.
5.2
Clamp the well-lubricated mold (with extension collar attached) to the base plate.
Insert the spacer disc over the base plate and place a disc of coarse filter paper on top of the
spacer disc. Compact the slag-water mixture into the mold in accordance with Section 4.3 above,
except the amount of water added shall be adjusted downward to compensate for the
approximate natural moisture content. Compact the sample at maximum density and optimum
moisture as determined in Section 4.3. If other densities and moisture contents are desired, they
may be used if indicated in the report.
5.3
Remove the extension collar and carefully trim the compacted soil even with the
top of the mold by means of a straightedge. Patch with smaller size material any holes that may
have developed in the surface by the removal of coarse material. Remove the perforated base
plate and spacer disc, weigh and record the weight of the mold and compacted slag. Place a disc
of coarse filter paper on the perforated base plate, invert the mold and compacted slag, and clamp
the perforated base plate to the mold with the compacted slag in contact with the filter paper.
5.4
Place the adjustable stem and perforated plate on the compacted slag specimen in
the mold and apply weights to produce a 10 lb. surcharge. Submerge the mold and weights in
water, which have been preheated to approximately 100ºF, allowing free access of water to the
top and bottom of the specimen.
5.5
Place the submerged sample in a level position in a controlled oven at 160 ± 5ºF.
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5.6
Seat the tripod on the extension collar and adjust the dial gage to a zero reading.
The dial gage shall be set so that its piston is not fully extended. This will allow for measurement
of initial sample settlement or consolidation.
6.
PROCEDURE
6.1
Record an initial gage measurement taken 30 minutes after the sample was placed
in the 160 ± 5ºF oven. This measurement is the base reading and allows for thermal expansion of
the test apparatus.
6.2
Dial measurements shall be recorded a minimum of once daily (preferably the
same time each day) thereafter for a period of at least one week.
6.3
Sufficient water shall be added each day so that the test specimen remains fully
submerged. Water shall not be added within 2 hrs. of the time for dial measurement readings.
6.4
After a period of one week, the test specimen shall be removed from the tank or
bucket and placed in the 160 ± 5ºF oven in an unsubmerged but saturated condition for an
additional one week period.
6.5
Dial measurements for the unsubmerged sample shall be continued as stated in
Section 6.2. Measurements shall not be obtained within 2 hours of the time of addition of water
to the specimen.
6.6
A minimum of 500 milliliter (500 cc) of water shall be added to the top of the
sample each day so that the test specimen remains fully saturated.
6.7
Carefully dismantle the test specimen after the two-week expansion period, and
visually inspect it for crystalline growth on the slag particle surfaces.
7.
CALCULATIONS
7.1
Percent Volumetric Expansion - Calculate the percent expansion by dividing the
dial gage measurement (A) minus the base gage measurement (B) by the initial sample height of
4.584".
(𝐴 − 𝐵)
𝑋 100
4.584
7.2
Rate of Expansion - The rate of expansion is the slope of the plot of time in days
(x-axis) versus the percent expansion (y-axis) shown in Fig. 3. Those parts of the curve
developed during submerged and unsubmerged conditions shall be clearly indicated and separate
rates of expansion shall be calculated for each of the two parts.
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7.3
Percent Total Volumetric Expansion - The dial gage measurement after fourteen
days of combined submerged and unsubmerged conditions (A¹) minus the base dial gage
measurement (B) divided by the initial sample height of 4.584".
(𝐴1 − 𝐵)
𝑋 100
4.584
8.
REPORT
8.1
The report shall include the following:
8.1.1
Particle size distribution curve of the original sample
8.1.2
Particle size distribution curve of the prepared sample before testing
8.1.3 The optimum moisture content and maximum dry density of the slag
specimens as per Section 4.3 herein.
8.1.4
expansion tests.
The moisture content and dry density of the molded specimens used in the
8.1.5 The expansion curve as depicted in Figure 3 to include the total percent
volumetric (one dimensional) expansion after 14 days and rate(s) of expansion.
8.1.6 The average of the 3 total volumetric expansions for the 3 material
samples representing each stockpile.
8.1.7 Determination of the pH of the sample leachate and x-ray diffraction of
the sample, if specified
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