CM 323
Construction Methods and Materials II
LABORATORY GUIDE
A guide to the experiments in CM 323
University of Washington
Seattle WA 98195
Winter 2017
TABLE OF CONTENTS
LABORATORY SAFETY
3
CHARPY V-NOTCH TEST
4
ROCKWELL HARDNESS TEST
6
TENSION TESTING OF MATERIALS
9
ASPHALT CONCRETE -- BULK SPECIFIC GRAVITY
14
ASPHALT CONCRETE – MAXIMUM SPECIFIC GRAVITY
15
SLUMP TEST
18
AIR CONTENT
19
COMPRESSION TESTING
20
SPLIT TENSILE STRENGTH
21
FLEXURAL STRENGTH OF CONCRETE
23
FLEXURAL STRENGTH OF WOOD
25
WOOD IN FLEXURE – DATA SHEET
26
SAMPLE LAB REPORT
27
-2-
LABORATORY SAFETY
Specific rules and dangers associated with this lab are:
Personal Protective Equipment:

Eye, ear, respiratory, hand and foot protection must be worn where there is danger
of injury.

Safety footwear is mandatory when handling concrete or other heavy items.

Ear protection must be used when noise-generating equipment is in operation. All
personnel in the immediate area must be warned and provided with ear protection
prior to equipment use.

When working with sand, gravel, cement, silica or grinding residues which
produce air borne contaminants, all those exposed must be wearing personal
protective equipment: eye goggles and dust respirators. Adequate ventilation must
be provided; attempts must be made to prevent dust from entering hallways and
office/equipment areas.

Ventilated cabinet must be used for concrete capping.

See details in the Department Safety Manual under Personal Protective
Equipment – Section 4.10.
Housekeeping/Storage of materials:

Waste material must be removed immediately.

Minimize all tripping hazards; keep aisles and passageways as clear as possible.

Keep exit paths clear at all times.

See details in the Department Safety Manual under Housekeeping Hazards –
Section 3.6 and Stack of Stored Materials -- Section 3.4.
Accidents/Injuries:

A First-Aid kit is located on the Room 34 door opposite the classroom portion of
room 34. A First-Aid kit is also located inside the Instructional Technician's
office (across the hall from the classroom end of room 34).

All accidents/injuries must be reported to the Instructional Technician or the
Laboratory Instructor.
-3-
CHARPY V-NOTCH TEST
A.
REFERENCES
1.
B.
C.
D.
ASTM E23 “Standard Method for Notched Bar Impact Testing of Metallic Materials”
OBJECTIVES
1.
Gain an understanding of how temperature can affect the fracture characteristics for
various materials.
2.
Determine the climate zones that can be satisfied by various steels in accordance with
ASTM A709 "Structural Steel For Bridges"
PROCEDURE
1.
Place the notched specimen in the temperature-controlled container provided by the
TA. Read and record the temperature of the liquid in this container. The specimen
must remain in the container for a minimum of five (5) minutes.
2.
Set the energy indicator on the Charpy apparatus to the appropriate scale setting and
position the recording needle for testing.
3.
Raise the hammer to the locked position. Special care should be taken to insure the
path of swing is clear
4.
Take the notched specimen from its cooling (or heating) container and place it on the
Charpy anvils with the notch facing away from the hammer and then release the
pendulum. Be sure the specimen is firmly in place before testing (see TA for
information). THE COMPLETE TESTING SEQUENCE MUST TAKE LESS THAN FIVE SECONDS.
a.
If any specimen fails to break, do not repeat the test on that specific specimen.
Record this observation.
b.
The amount of energy required to fracture the specimen is read directly from the
machine in ft-lbs.
c.
The Charpy apparatus is to be operated by only one member of each group and
an instructor/TA at all times.
CALCULATIONS
1.
Record temperature, time before impact, and energy absorbed.
2.
Estimate the percent shear in the fractured sample from the following figure.
-4-
Figure 1Approximate shear from Charpy specimen.
E.
REPORT
1.
Plot absorbed energy vs. temperature for each material tested using the combined data
from other groups in all the lab sections. Be sure to note the ductile-brittle transition
zone on the figures, where appropriate. This is the area where a dramatic increase in
energy absorption occurs with a relatively small increase in temperature.
2.
Follow the following guidelines when making graphs:
3.
A.
The graph is numbered and has a label that describes the contents of the graph.
Note – Figure labels are placed below the figure in a report.
B.
Data points should appear as symbols or “markers” on the graphs. Lines or curves
that are used to show the general trend of the data may require that a separate
series be plotted (you can’t always just “add trendline” and have it come out
correctly). The only “markers” that appear on the graph should be those of
actually measured values.
C.
Relevant points on the graphs should be clearly and neatly marked.
D.
In general, the page has a neat, uncluttered appearance. It is undesirable to
include irrelevant items on a graph. The purpose of a graph is to convey
information in a simple, easy-to-read fashion.
For your Metals lab report scenario, consider the climate zones that can be satisfied by
each type of metal in accordance with ASTM A709 "Structural Steel for Bridges". This
specification establishes minimum energy absorption for fracture critical members as
25 ft-lb and 15 ft-lb for non-fracture critical members. After plotting absorbed energy
vs. temperature, the absorbed energy exhibited for each climate zone can be determined
based on the laboratory test temperatures. Recommendations can then be made
regarding the use of the material in the corresponding minimum expected service
temperatures. Don't get confused: the test temperatures apply to the lab, the service
temperatures apply to field construction.
laboratory test
temperature
minimum ambient
service temperature
zone 1
70°F
above 0°F
zone 2
40°F
0°F to -30°F
zone 3
10°F
-30°F to -60°F
-5-
ROCKWELL HARDNESS TEST
A.
REFERENCES
1.
B.
C.
ASTM E18 "Standard Test Methods for Rockwell Hardness and Rockwell Superficial
Hardness of Metallic Materials"
OBJECTIVES
1.
Determine the hardness and estimate the tensile strength of various materials.
2.
Understand the purpose and value of hardness testing in general.
3.
Experience the specific procedures associated with the Rockwell Hardness Test.
PROCEDURE
In this lab we will primarily use only the "B" scale, which is one of the most commonly
used scales. Use of this scale requires a steel ball indenter with a 1/16" (1.6 mm) diameter, a
minor load of 10 kg and a major load of 100 kg. The numbers on the inner circle are red these are the ones in which we are interested.
1.
Choose a specimen surface that will accommodate five (5) tests. ASTM E18 specifies
that each indentation must be at least 1 1/2 ball diameters from the edge of the specimen
and at least 3 ball diameters from the other test indentations.
2.
Make sure that the load lever is in the OFF position.
3.
Place the specimen on the anvil.
4.
Turn the wheel clockwise to raise the anvil. If the wheel does not turn easily, STOP,
and make sure that the load lever is in the OFF position.
5.
Continue to slowly raise the anvil until the indenter is in contact with the specimen.
You will see the indicating needles on the dial begin to move counterclockwise. Keep
turning the wheel until the small indicating needle is aligned with the black dot.
NOTE:
IF THE PROPER SETTING IS OVERRUN, REMOVE THE MINOR LOAD AND SELECT A NEW SPOT FOR THE
TEST.
6.
If the large needle is not straight up at this time, adjust the dial face until the gage needle
is aligned with the SET mark. You have just applied the minor (10 kg) load.
7.
Now apply the major load (100 kg) by releasing the load lever. Do not force it to the
ON position; just give it a push and it will fall by itself. Be sure to watch the large
indicating needle during application of the major load.
-6-
8.
D.
As soon as the lever has reached the ON position (the large indicating needle will not
necessarily be stable), return the lever to the OFF position. The indicating needle will
"back up", i.e. move clockwise.
CALCULATIONS
1.
Report the hardness number to the nearest 0.5 HRB directly from the B scale.
2.
Average the five (5) readings. This is the hardness number for this material. Report
the hardness in the form: Hardness = 68 HRB.
NOTE:
3.
HARDNESS VALUES ARE GENERALLY REPORTED AS WHOLE NUMBERS – NO DECIMALS.
If the hardness test is run on a cylindrical specimen, such as the tension specimens, you
will need to correct the hardness for the curvature of the sample:
Corrections for 1/2" Diameter Cylindrical Samples
(from ASTM E18 Tables 6 & 7)
"B" scale
Dial Reading
20
30
40
50
60
70
80
90
100
E.
Add to
Hardness
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
"C" scale
Dial Reading
20
25
30
35
40
45
50
55
60
Add to
Hardness
3.5
3.0
2.5
2.0
2.0
1.5
1.5
1.0
1.0
REPORT
3.
Estimate the tensile strength of the material based on the average hardness.
NOTE:
REMEMBER THIS IS AN ESTIMATE AND YOU CAN ACCURATELY REPORT IT ONLY TO 2
SIGNIFICANT FIGURES (E.G. 42 KSI).
-7-
Approximate Tensile Strength (from ASTM A370 Table 3B)
Rockwell B Scale, Approximate
100 kgf Load
Tensile Strength
1/16" Ball
ksi (MPa)
100
116 (800)
99
114 (785)
98
109 (750)
97
104 (715)
96
102 (705)
95
100 (690)
94
98 (675)
93
94 (650)
92
92 (635)
91
90 (620)
90
89 (615)
89
88 (605)
88
86 (590)
87
84 (580)
86
83 (570)
85
82 (565)
84
81 (560)
83
80 (550)
82
77 (530)
81
73 (505)
80
72 (495)
Rockwell B Scale, Approximate
100 kgf Load
Tensile Strength
1/16" Ball
ksi (MPa)
79
70 (485)
78
69 (475)
77
68 (470)
76
67 (460)
75
66 (455)
74
65 (450)
73
64 (440)
72
63 (435)
71
62 (425)
70
61 (420)
69
60 (415)
68
59 (405)
67
58 (400)
66
57 (395)
65
56 (386)
64
55 (379)
62
54 (372)
61
53 (365)
60
52 (359)
59
51 (352)
57
50 (345)
56
49 (338)
Approximate Tensile Strength (from ASTM A370 Table 3A)
Rockwell C Scale,
Approximate
150 kg Major Load Tensile Strength
Diamond Penetrator
ksi (MPa)
39
177 (1220)
38
171 (1180)
37
166 (1140)
36
161 (1110)
35
156 (1080)
34
152 (1050)
33
149 (1030)
32
146 (1010)
31
141 (970)
30
138 (950)
-8-
Rockwell C Scale,
Approximate
150 kg Major Load Tensile Strength
Diamond Penetrator
ksi (MPa)
29
135 (930)
28
131 (900)
27
128 (880)
26
125 (860)
25
123 (850)
24
119 (820)
23
117 (810)
22
115 (790)
21
112 (770)
20
110 (760)
TENSION TESTING OF MATERIALS
A.
REFERENCES
1.
B.
C.
ASTM E8 “Standard Methods of Tension Testing of Metallic Materials"
OBJECTIVES
1.
Understand the importance of various mechanical properties, and learn how they can
be determined from a stress-strain diagram.
2.
Learn how to construct and interpret a stress-strain diagram for a metal in tension.
3.
Learn how to operate a Universal Testing Machine.
PROCEDURE
Each group will test one specimen. There are two universal testing machines available,
one Instron and one Tinius Olsen (not counting the 2.4 million pound machine). Their
capacities vary, but the following instructions apply to all.
1.
Use the gage punch provided by the instructor, mark the specimen. Push down hard;
it is important to leave definite indentations on the specimen. If necessary, make the
indentations deeper with a center punch. Do not double indent the specimen. Measure
the diameter (d) at the indentations and in the center (three measurements total) and
determine the average diameter of the specimen, and the precision of that measurement.
Also measure the initial gage length (G) by averaging the length on both sides of the
specimen.
d
G
Figure 2. Tensile specimen.
2.
Screw the threaded ends of the specimen into the grips that are attached to the upper
and lower crossheads. Use the UP-DOWN buttons on the crosshead to bring the
crosshead into position.
3.
Do not seat the specimen tightly with the UP-DOWN buttons. The specimen should
feel loose when you have finished screwing in both ends. The last thread on the
specimen should be flush with the surface of the grip.
4.
Fasten the extensometer to the specimen. Note carefully the following:
-9-
a.
Be sure that all four screw-points are firmly positioned in the gage marks. The
extensometer will not work unless it is so anchored.
b.
Be sure that the extensometer is right side up. Only one of the arms will pivot
vertically; this arm must be the lower one.
c.
Be sure the dial face points in a direction such that it can be seen and read easily.
d.
Be sure the extensometer's arms do not touch the grips. It may be necessary to
slightly unscrew the lower grip.
5.
You may now zero the gage.
6.
Make sure that both the coarse and fine (loading and unloading) valves are shut (turned
fully clockwise). There are a total of four valves.
7.
Select the proper load range. Choose the lowest range that will safely accommodate
the expected ultimate load. Your instructor will advise you.
8.
Zero the load indicator. Use the knob corresponding to the chosen load range.
9.
Position the red indicating needle in front of the black one.
10. Push the START pump button on the console.
11. Open the loading valve (about 1/8 to 1/4 turn). This will raise the working table and
the upper crosshead, thereby firmly seating the grips in the crossheads.
12. As soon as load registers on the dial face, close the valve.
13. Now open the control valve slowly. Gradually adjust the valve until you find a rate of
loading that allows easy reading of the extensometer and loading dials without being
too slow.
14. Take the first 30 readings in the following manner:
1-10 at 6/10,000" per reading (0.0004” actual elongation)
11-20 at 15/10,000" per reading (0.0010” actual elongation)
21-30 at 75/10,000" per reading (0.0050” actual elongation)
17. Continue loading the specimen, but remove the extensometer and use the calipers to
take the remaining readings. Set the calipers for 2/20" over the 2" length and take the
reading when the punch marks reach this length; continue readings at 3/20", 4/20", and
so on.
18. When failure is imminent (evidenced by extreme "necking down"), make no further
measurements.
19. When the specimen fails, close the loading valve. Then open fully the coarse control
of the unloading valve. Leave this valve open until the working table has returned to
- 10 -
its lowest possible position. (This is important. If the working table is left up, oil will
leak out of the cylinder and you will clean it up.)
NOTE:
IF AT ANY TIME DURING LOADING YOU NEED TO UNLOAD IN A HURRY, OPEN THE COARSE
CONTROL OF THE UNLOADING VALVE ALL THE WAY. THIS LOWERS THE UPPER CROSSHEAD AND
THE WORKING TABLE, TAKING THE TENSION OUT OF THE SPECIMEN.
20. Remove the specimen and measure the final length as well as the diameter at the failure
point. Be sure to note the precision of these measurements.
D.
CALCULATIONS
Calculate the engineering stress and strain based on the initial diameter and gage length.
Also calculate the true stress at failure, using the diameter at failure.
Stress (psi) = Load (lb) /Area (in2)
Strain (in / in) = ∆L / L
Yield Strength (offset method – use for aluminum, stainless and cold-rolled)
Draw a line parallel to the elastic portion of the stress - strain curve that has an
initial strain 0.2% (0.002 in/in) greater than that shown by the curve. The stress at
which this line intersects the stress - strain curve is the yield strength. Remember, this
is an estimation from a graph -- two significant figures is the most you can be certain
of. Report the value in the form:
Yield Strength (offset = 0.2%) = 39,000 psi
Yield Point
For a material having a “sharp-kneed” stress - strain curve (hot-rolled plaincarbon steel), the yield point is the stress corresponding to the top of the knee. For
materials not having a well defined yield point, the yield point can be estimated, but
we will not go into the method. The yield strength (offset method, see above) will be
sufficient for analysis of these materials.
Tensile Strength (sometimes called ultimate strength)
This is simply the maximum strength experienced by the sample.
Modulus of Elasticity
This is the slope of the elastic portion of the stress - strain curve.
Elongation
- 11 -
Calculate the percent elongation at failure. Report to the nearest 1%.
E.
REPORT
Elongation % 
length after failure  inital length
 100
initial length
1.
Plot separate stress - strain curves for each of the materials tested. Be sure to label each
of the parameters you calculated clearly on the graph.
2.
Follow the following guidelines when making graphs:
a.
The graph has a figure number and a label.
b.
Plot data as unconnected markers.
c.
Plot a curve that best matches the data. This may require multiple series.
d.
Relevant points on the graphs should be clearly and neatly marked.
e.
As is customary, the elastic portion of the graph is shown separately (in addition
to) from the entire curve. Indicate that the strain is increased by a factor of 10.
f.
In general, the page should have a neat, uncluttered appearance. It is undesirable
to include irrelevant items on a graph. The purpose of a graph is to convey
information in a simple, easy-to-read fashion.
- 12 -
d1=
d2 =
Reading
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Fail load
d3=
Dial Reading
(gage factor = ____)
0.0006
0.0012
0.0018
0.0024
0.0030
0.0036
0.0042
0.0048
0.0054
0.0060
0.0075
0.0090
0.0105
0.0120
0.0135
0.0150
0.0165
0.0180
0.0195
0.0210
0.0285
0.0360
0.0435
0.0510
0.0585
0.0660
0.0735
0.0810
0.0885
0.0960
-
df=
l1i=
Elongation
(∆L)
0.1000
0.1500
0.2000
0.2500
0.3000
0.3500
0.4000
0.4500
0.5000
0.5500
0.6000
0.6500
0.7000
-
- 13 -
l2i=
Approx. Strain
(∆L/L)
0.0002
0.0004
0.0006
0.0008
0.0010
0.0012
0.0014
0.0016
0.0018
0.0020
0.0025
0.0030
0.0035
0.0040
0.0045
0.0050
0.0055
0.0060
0.0065
0.0070
0.0095
0.0120
0.0145
0.0170
0.0195
0.0220
0.0245
0.0270
0.0295
0.0320
0.0500
0.0750
0.1000
0.1250
0.1500
0.1750
0.2000
0.2250
0.2500
0.2750
0.3000
0.3250
0.3500
-
l1f=
Load
(lbs)
l2f=
Stress
(psi)
ASPHALT CONCRETE -- BULK SPECIFIC GRAVITY
ASTM D 1188
Bulk Specific Gravity and Density of Compacted Bituminous Paving
Mixture Using Paraffin-Coated Specimens
Purpose - This test method covers the determination of bulk specific gravity of specimens of
compacted bituminous paving mixtures.
Background - This test is useful in calculating the percent air voids and unit weight of a sample.
An additional ASTM (D2726) can be used for dense-graded or nonabsorptive compacted mixes.
Bulk specific gravity is the ratio of the mass of a given volume of material at 25C to the mass of
an equal volume of water at the same temperature. Bulk density is defined as the mass of a
meter cubed (or foot cubed) of a material.
Procedures - The following steps should be followed:
1. Weigh the uncoated specimen with surface water evaporated. Designated this mass
as “A”. (Done for you already)
2. After completely drying the sample, coat the specimen with paraffin wax and let cool.
(Done for you already) Weight the wax coated specimen. Designated mass as “D”.
3. Weigh the coated specimen in the water bath at 25C. Be cautious of the water level
and edges of the basket. Designated mass as “E”.
Calculations - Perform the following calculations:
Bulk Specific Gravity (BSG) =
A
  D  A 
D E 

 F 
where F = specific gravity of the paraffin at 25C. (use 0.92)
Density = BSG x 0.9970 g/cm3
or
Density = BSG x 62.24 lb/ft3
(the multiplicative factors are the density or the unit weight of water)
Sample
Uncoated
Wax Coated in Air
Wax Coated Under Water
- 14 -
Label
A
D
E
Mass
ASPHALT CONCRETE – MAXIMUM SPECIFIC GRAVITY
ASTM D 2041
THEORETICAL MAXIMUM SPECIFIC GRAVITY
OF
BITUMINOUS PAVING MATERIALS
Purpose - The purpose of this test is to determine the theoretical maximum specific gravity of a
bituminous paving material (asphalt concrete). This is accomplished by measuring the
mass of a quantity of un-compacted asphalt concrete along with measuring the mass of
water needed to fill the absolute volume of the asphalt concrete.
Procedure - This procedure assumes that a sample of uncompacted asphalt concrete has already
been obtained, and has been cooled to room temperature. The following steps are
required to perform the test:
1.
Determine the mass of a clean, dry specific gravity jar.
2.
Fill the jar to approximately half full with uncompacted asphalt concrete and
determine the mass of jar plus the asphalt concrete. The difference between this
mass and the mass of the jar alone is “A” in the equation below.
3.
Add enough water (at 25ºC or 77ºF) to cover the asphalt concrete in the jar.
4.
Place the screw-top vacuum lid on the jar and apply a vacuum to the jar. Once the
vacuum has been applied, close the vacuum valve and gently agitate the jar to
remove air bubbles. Every two minutes re-apply the vacuum. Continue this
process for 10-15 minutes.
5.
Release the vacuum and fill the jar as close as possible to the top with 25ºC water.
6.
Dry the outside of the jar and place the jar in a pan on the balance. Apply a thin
film of vacuum grease to the top edge of the jar. Place the volumetric lid on the
jar and fill the jar and lid to the top using a water bottle. Avoid trapping air
bubbles in the jar.
7.
Record the mass of the jar plus lid plus water plus asphalt concrete. This is “E” in
the equation below.
8.
Dump out most of the water and place the sample in a metal pan for drying.
9.
Repeat steps 6 and 7 with no sample in the jar (just water). This is “D” in the
equation below.
10.
Calculate the theoretical maximum specific gravity as:
SGmax 
A
A D  E
- 15 -
CONCRETE MIXING, CASTING, AND CURING
A.
REFERENCES
1.
B.
ASTM C192 “Making and Curing Concrete Test Specimens in the Laboratory"
PROCEDURE
1.
Concrete mixing using electric mixers
a.
Determine and weigh out the necessary batch quantities (adjusted for stockpiled
moisture contents of the aggregates) and also material to make a 1/2 cu. ft.
“buttering batch”. Add any admixtures to be used to the water before mixing.
b.
Prior to starting the mixer, put half of the coarse aggregate, all of the fine
aggregate, and the cement into the drum (IN THAT ORDER!), Turn on the mixer
and add the water. Continue mixing in the following manner:
above ingredients
add remaining coarse aggregate
turn off mixer and rest
re-start and continue mixing
c.
2.
3.
mix 1-1/2 minutes
mix 1-1/2 minutes
rest 3 minutes
mix 2 minutes
At the end of the mixing cycle, discharge concrete into damp, buttered
wheelbarrow for necessary testing of fresh properties.
Concrete mixing by hand
a.
Determine and weigh out the necessary batch quantities (adjusted for stockpiled
moisture contents of the aggregates). Add any admixtures to be used to the water
before mixing.
b.
Put the dry materials (cement and aggregates) into a wheelbarrow and use a hoe
to mix the materials thoroughly.
c.
Add water (with admixtures if used) slowly and continue to mix with the hoe. It
is important to mix from both ends of the wheelbarrow to insure no dry pockets
remain in the mix.
Casting cylinders
a.
Lightly oil the inside of the mold as necessary, and oil one side of a steel plate.
b.
Fill the bottom third of the cylinder with concrete and rod 25 times.
c.
Fill the next third of the cylinder and rod 25 times. Be sure to penetrate the
previous layer by about one inch to avoid a layered effect.
- 16 -
4.
5.
d.
Fill the cylinder until it slightly overflows and rod 25 more times, adding
additional concrete as necessary.
e.
The next morning, remove the mold from the specimen, label the side and end
with the date, section, and group number and place the specimen on its side in the
fog room for curing.
f.
Clean up the area as well as the molds and plates.
Casting beams
a.
Scrub a 6" x 6" x 21" mold with a wire brush to remove old concrete. Dry the
mold and lightly oil it thoroughly before assembly (NOTE: Oil the nuts and bolts
as well)
b.
Fill the mold in two equal layers, and rod once for every two square inches of
surface area (this works out to a total of 63 times per lift).
c.
Finish the top surface and cover with plastic.
d.
Strip the beam the following morning and put it in the fog room. (NOTE: To strip
the specimen, remove the bolts and hammer upward on the horizontal lips of the
long sides). Scrub the mold, then dry, oil and reassemble it.
Curing
Specimens will be cured in the fog room for the specified amount of time (generally
7, 14, or 28 days). The fog room maintains 100% relative humidity at a constant
temperature of 73°F per ASTM standards.
- 17 -
SLUMP TEST
A.
REFERENCES
1.
B.
C.
ASTM C143 “Standard Test Method for Slump of Portland Cement Concrete"
OBJECTIVES
1.
Become familiar with the amount of workability indicated by different slumps.
2.
Learn to perform this very common test.
PROCEDURE
1.
Scrub the inside of the cone to remove any hardened concrete, dampen it with water
and place it on a clean damp surface.
2.
Fill the bottom third of the cone and rod 25 times.
3.
Fill the next third of the cone, and rod 25 times. Be sure to penetrate the previous layer
by about one inch to avoid a layered effect.
4.
Fill the cone until it slightly overflows and rod 25 more times, adding additional
concrete as necessary to keep the cone slightly overflowing.
5.
Strike off the concrete level with the top of the cone.
6.
Remove the cone by lifting straight up without twisting.
5 ± 2 seconds.
7.
Measure the drop in height of the slumped concrete to the nearest 1/4". (Measure to
the displaced original center of the top surface as shown:
Figure 3. Slump test.
- 18 -
This should take
AIR CONTENT TEST
A.
REFERENCES
1.
B.
C.
ASTM C231 “Standard Test Method for Air Content of Freshly Mixed Concrete by
the Pressure Method" (using Type-B Meter)
OBJECTIVES
1.
Become familiar with the air content of various concrete mixtures.
2.
Learn to perform this very common test.
PROCEDURE
1. Dampen the inside of the measuring bowl as well as the underside of the cover
assembly.
2. Fill the bottom third of the measuring bowl and rod 25 times. Tap the sides of the bowl
with a rubber mallet 10 to 15 times to close the rod holes.
3. Fill the next third of the measuring bowl, and rod 25 times. Be sure to penetrate the
previous layer by about one inch to avoid a layered effect. Tap the sides of the bowl
with a rubber mallet 10 to 15 times to close the rod holes.
4. Fill the measuring bowl until it slightly overflows and rod 25 more times. Tap the sides
of the bowl with a rubber mallet 10 to 15 times to close the rod holes.
5. Strike off the concrete level with the top of the measurement bowl. The concrete should
not extend above the top of the bowl rim. A small amount of additional concrete can
be added on top if the bowl is not completely full.
6. Thoroughly clean the top flange/rim of the measurement bowl using a wet cloth. Be
sure that there are no sand particles on the top rim.
7. Place to cover assembly onto the measurement bowl, being careful to avoid disturbing
the surface of the concrete. Latch the cover assembly down with the four latches. All
four latches should require some resistance to close.
8. Make sure that both petcocks are open, and fill the space between the top surface of the
concrete and the inside of the cover assembly by using a syringe to insert water into
one of the petcocks. Add the water gently to avoid disturbing the concrete surface, and
continue adding water until clear water comes out the other petcock.
9. Pressurize the upper chamber using the air pump until the needle reaches the line
indicated on the calibration tag. Gently tap the pressure gage, and pump as necessary
to reach the proper calibration line. If too much pressure is applied, the pressure can
be released by opening the hexagonal cap.
9. Close the petcocks and release the pressure into the measuring bowl by pressing the
pressurization lever. Tap the gage and press the lever a few times until the gage reading
stabilizes.
10. Read the air content from the gage to the precision given by the smallest divisions on
that portion of the gage.
- 19 -
COMPRESSION TESTING
A.
REFERENCES
1.
B.
C.
ASTM C39 “Standard Test Method for Compressive Strength of Cylindrical Concrete
Specimens"
OBJECTIVES
1.
Determine the compressive strength of concrete (f’c).
2.
Learn to use the Forney compression-testing machine.
PROCEDURE
1.
Center the capped cylinder in the Forney compression-testing machine and close the
doors.
2.
Turn on the machine; press the "auto tare" and then the "peak hold" buttons on the
console. Be sure the lights for these buttons illuminate.
3.
Turn the load lever to "full advance" until a load is registered and then turn back to
"metered advance".
4.
Adjust the metering valve so that the rate of loading is between 34,000 and 86,000
pounds per minute (between the white arrows on the display).
NOTE:
D.
AS THE CYLINDER BEGINS TO FAIL, THE RATE OF LOADING WILL BEGIN TO STEADILY DECREASE.
DO NOT CONTINUE TO OPEN THE VALVE TO KEEP UP WITH IT.
5.
When the "max peak" light illuminates, the ultimate load has been reached. Continue
metered loading until failure.
6.
Remove the cylinder and debris from the testing cage.
7.
Observe the fracture surface to see if failure occurred in the bond between paste and
aggregate or if the aggregate fractured, or if some other mechanism was at work.
CALCULATIONS
P
failure load
compressive S trength f c =
=
A
cross sectional area
NOTE:
THE FAILURE STRENGTH IS GENERALLY REPORTED TO THE NEAREST 25 PSI
- 20 -
SPLIT TENSILE STRENGTH
A.
REFERENCES
1.
B.
C.
ASTM C496 "Standard Test Method for Splitting Tensile Strength of Cylindrical
Concrete Specimens"
OBJECTIVES
1.
Learn the basic procedures associated with the split tension testing of standard concrete
cylinders, and to observe the failure behavior of concrete under tension.
2.
Compare actual split tensile strength to estimate based on compressive strength.
PROCEDURE
1.
Cast and cure a cylindrical specimen, just as for compression testing, but do not cap
the cylinder.
2.
Place a plywood strip on the lower surface of the jig and place the cylinder on top of
the wood. Place a second plywood strip along the top surface of the specimen, and put
the steel bar in place as shown in the figure.
Figure 4. Split Tensile Strength Jig
3.
Place the assembly on the working table of the Baldwin. Turn it so that the round face
of the specimen points outwards, and center the apparatus beneath the bearing surface
suspended from the lower crosshead.
4.
Operate the Baldwin machine as for previous tests. Let the load steadily increase until
the specimen fails and then stop the loading.
- 21 -
SAFETY NOTE:
5.
D.
THE BROKEN SPECIMENS HAVE A TENDENCY TO ROLL TOWARDS THE EDGE OF THE
WORKING TABLE. KEEP YOUR FEET OUT OF THE WAY.
Remember to let the working table settle to its lowest position. Clean up your mess,
and dump broken specimens in the dumpster.
CALCULATIONS
split tensile strength T =
2P
Ld
T = split tensile strength (psi)
P = maximum load (lb)
L = length of specimen (12 in)
d = diameter of specimen (6 in)
ASTM specifies the rate of stress increase must be between 100 to 200 psi / min.
Since our area (Ld) is 72 in2, we apply the load at 7,000 to 14,000 lb / min.
E.
REPORT
You can also gain an approximation of split tensile strength by knowing how it
relates to compressive strength. Split tensile strength is approximately nine to fourteen
percent of the compressive strength for the same mix under similar curing conditions.
split tensile strength T ≈ 9% to 14% fc
- 22 -
FLEXURAL STRENGTH OF CONCRETE
A.
REFERENCES
1.
B.
C.
ASTM C78 “Standard Test Method for Flexural Strength of Concrete Specimens
(Using Simple Beam with Third-Point Loading)"
OBJECTIVES
1.
Learn the basic procedures associated with the flexural testing of concrete, and to
observe the failure behavior of concrete under flexure.
2.
Compare actual modulus of rupture to the estimated value based on the relationship
with compressive strength.
PROCEDURE
1.
Turn the beam on its side and assemble the apparatus as shown
Figure 5. Flexural Strength of Concrete Apparatus
2.
Center the beam on the working table of the Baldwin.
3.
Using the loading jig provided, load the beam to failure. ASTM specifies the rate of
stress increase must be between 125 and 175 psi / minute. Since our area (bd2/L) is
12 in2, we must use a load rate between 1,500 and 2,100 lb / minute.
- 23 -
D.
CALCULATIONS
σflex
=
PL
bd
2
σflex = modulus of rupture (psi)
P = maximum load (lbs)
L = length of span (18 in)
b = width of beam (6 in)
d = depth of beam (6 in)
If the fracture does not occur between the loads, then calculate σflex as follows
a = distance from fracture to the nearest
support measured on the tension face
σflex = 3Pa/bd2
If the fracture occurs in the tension surface outside of the middle third of the span
length by more than 5% of the span length, discard the results of the test.
E.
REPORT
You can also gain an approximation of the modulus of rupture by knowing how
it relates to compressive strength. Modulus of rupture is approximately eight to ten
times the square root of the compressive strength for the same mix under similar curing
conditions.
σflex ≈ k
fc
- 24 -
where k  8 to 10
FLEXURAL STRENGTH OF WOOD
A.
B.
OBJECTIVES
1.
Gain some rudimentary exposure to the process of visually grading lumber.
2.
Observe directly the statistical nature of the strength of wood.
3.
Observe the various failure modes in wood and the interplay between them.
OVERVIEW
Since wood is essentially a non-manufactured material, a primary concern in using
wood is identifying how a given piece of wood will behave. Historically this has been
done by means of visual grading, i.e. visually examining the wood and judging its
strength based on this examination. This lab will give you experience at this process.
As a material wood has many interesting properties, including a variety of failure
modes related to its anisotropic structure. This simple flexure test will allow you to
observe several such failure modes.
This lab report is to be completed during the lab session. Record your observations
and perform your calculations such that they will be suitable to hand in at the end of
class. Use the form provided on the next page for this purpose.
C.
PROCEDURE
1.
Your group will be given a short section of standard 2x4 lumber to be tested in flexure.
Prior to performing the test, do the following:
a.
Measure and record the actual dimensions of the specimen.
b.
Observe and note any strength reducers contained in the specimen (the TA or
instructor will explain this).
c.
Compare your observations with those of the other groups in your section. Predict
the relative strength of each specimen.
2.
Use the universal testing machine to load the specimen to failure; a simple apparatus
will be provided to maintain lateral stability. The failure will occur in a progressive
manner. If possible, record the loads at which different failure phenomena are
observed. Think about the nature of the failure in terms of relative ductility.
3.
Record the final failure load.
4.
Examine the broken specimen and list the various failure modes you observe. For each
failure mode calculate the corresponding failure stress acting in that mode.
5.
When all groups have completed their testing compare the actual strength rankings with
the predicted rankings. Comment on any discrepancies.
- 25 -
WOOD IN FLEXURE – DATA SHEET
name: ____________________________
group: ____________________________
date:
1.
____________________________
Preliminary Data
a.
b.
Dimensions
Length = L =
Test length = l =
Width = b =
Depth = h =
Strength Reducers (include reduction factors and underline the most critical reduction factors)
• knots (size and location)
• slope of grain
• shakes, checks, and splits (size and location)
• other
c.
Moisture adjustment
2.
Predicted Strength (in psi)
3.
Test Results
4.
a.
Failure Load =
Failure Stress =
b.
Observed Failure Mode(s)
Laboratory Summary
Group
Failure Mode(s)
Observed Strength
1
2
3
4
- 26 -
Predicted Strength
SAMPLE LAB REPORT
- 27 -
Bituminous Laboratory
245 Bitumen Dr.
Seattle, WA 98195
February 17, 1992
Jack Brown, President
Joe Asphalt Paving
555 Black Top Rd.
Seattle, WA 98105
Dear Mr. Brown:
Bituminous Laboratory has completed the testing requested pursuant to you letter dated
February 10, 1992. Testing was performed to determine an appropriate mix design for use on the
Highway 99 overlay project in north Seattle. Based on the tests performed on the samples of
asphalt and aggregate submitted by your firm, we recommend an asphalt content of 5.3% by weight
of aggregate be used on your project. However, due to the magnitude and importance of this
project, we feel that further testing may provide you with a more economical and durable project.
Thank you for allowing Bituminous Laboratory to serve your testing needs. I look forward
to working with you again in the future. If you have any questions or comments, please don't
hesitate to call us at 555-9387.
Sincerely,
Tim Tester, Chief Technician
Bituminous Laboratory
enclosures
- 28 -
ASPHALT LAB REPORT
prepared for
Jack Brown, President
Joe Asphalt Paving
555 Black Top Rd.
Seattle, WA 98105
prepared by
Tim and Tammy Tester
Bituminous Laboratory
245 Bitumen Dr.
Seattle, WA 98195
submitted
February 17, 1992
TABLE OF CONTENTS
Introduction
1
Background
1
Stability
2
Durability
2
Flexibility
2
Materials
3
Procedures
3
Results
4
Analysis
4
Conclusions
7
References
8
Appendix A Calculations (not included)
9
Appendix B Raw Data (not included)
15
LIST OF FIGURES
Figure 1 – Standard Marshall Specimen
4
Figure 2 – Marshall Mix Design Results Graphs
6
LIST OF TABLES
Table 1 – Marshall Mix Design Results
5
Table 2 – ASTM Requirements
5
- ii -
INTRODUCTION
Testing of the materials to be used in the overlay on Highway 99 in north Seattle was
conducted by Bituminous Laboratory at the request of Jack Brown, President of Joe Asphalt
Paving Company. Testing was performed to establish an optimum asphalt cement content by use
of the Marshall Mix Design Method. [Asphalt Institute] All testing was completed during the
week of February 10, 1992 at Bituminous Laboratory in Seattle, WA.
BACKGROUND
The primary use of bituminous material is in road and highway construction. Asphalt
cement concrete is comprised of asphalt cement, coarse aggregate, fine aggregate, and other
materials, depending on the type of asphalt cement concrete. [Garber and Hoel] Asphalt cement
can be obtained from natural deposits or can be refined from crude petroleum.
Natural deposits of asphaltic materials occur as native asphalts or as rock asphalts. Native
asphalts, such as the La Brea asphalt pits in Los Angeles, California must be softened by petroleum
fluxes before use. Rock Asphalts are natural deposits of sandstone or limestone filled with asphalt.
Neither native nor rock asphalts are primary sources of asphalt cement due to the low levels of
usable asphalt contained.
The primary source of asphalt cement is from the distillation of crude petroleum. [Garber
and Hoel] Crude petroleum is composed of a variety of products, including asphalt. The refining
process involves the heating of the petroleum to vaporize the lighter fractions which are cooled
and refined into fuels such as gasoline and kerosene. The heavier crude that remains can be refined
into a number of products, including asphalt cement. Depending on the particular refining process
used, asphalt cements of very high consistencies or low consistencies are produced. These
materials can then be blended in appropriate amounts to produce asphalt cements of any desired
consistency. [Asphalt Institute]
Asphalt cements are semisolid hydrocarbons which have certain physiochemical
characteristics that make them good cementing agents. [Garber and Hoel] They are also very
viscous, and when used as a binder for aggregates in pavement construction, it is necessary to heat
both the aggregates and the asphalt cement prior to mixing the two materials. For several decades
the particular grade of asphalt cement has been designated by its penetration and viscosity, both of
which give an indication of the consistency of the material at a given temperature. The penetration
is the distance in 1/10 of mm that a standard needle will penetrate a given sample, under specific
conditions of loading, time, and temperature. The softest grade used for highway construction has
a penetration value of 200-300 and the hardest has a penetration value of 60-70. Recently,
however, viscosity has been used more often than penetration to grade asphalt cements.
There are two series of viscosity grades by which asphalt cement is available. [Asphalt
Institute] One consists of grades AC-2.5, AC-5, AC-10, AC-20, and AC-40, with the numerical
values indicating the viscosity in hundreds of poises at 140°F. The other consists of grades AR1000, AR-2000, AR-4000, AR-8000, and AR-16000 with the numerical values indicating the
viscosity in poises after the asphalt has been through the rolling thin film oven test. This series is
referred to as the "Aged Residue" series.
Asphalt cement concrete is comprised of proportionate amounts of aggregate and asphalt
cement. By varying the amounts and the physical characteristics of these materials, it is possible
to alter the behavior of the asphalt cement concrete. The critical properties of an asphalt paving
mixture are stability, durability, and flexibility. [Asphalt Institute]
Stability is the ability of an asphalt paving mixture to resist deformation under loaded
conditions. High stability can be obtained by utilizing angular aggregates to provide more particle
interlock, well graded aggregates, higher viscosity asphalts, optimum asphalt content, and
maximum compaction. Optimum asphalt content is that percent of asphalt cement in the sample
that will adequately coat all aggregate particles providing maximum cohesion. Insufficient asphalt
will not coat all the aggregate particles and excessive asphalt will tend to lubricate and separate
the aggregate particles thereby decreasing stability. An indication of the stability of the asphalt
paving mixture can be obtained from the Marshall test.
Durability describes the ability of the asphalt cement concrete to resist disintegration by
weathering and traffic. [Asphalt Institute] This includes the oxidation and volatilization of the
asphalt cement and the action of water in stripping and freeze thaw action. Durability is not
directly measured; however, it is enhanced by higher asphalt contents, densely graded aggregates,
and adequate compaction. Higher asphalt contents tend to reduce stability; therefore, a
compromise may be required in the stability to develop adequate durability.
Flexibility is the ability of asphalt cement concrete pavements to conform to gradual
settlements and movements of the base and the subgrade. Settlement occurs in every construction
application; therefore, it is imperative to have a flexible pavement that will resist cracking.
Flexibility can be increased by higher asphalt contents and relatively open graded aggregates. An
indication of the flexibility of an asphalt cement concrete pavement is given by the flow values
obtained from the Marshall test.
-2-
In order to develop the proper combination of asphalt cement and aggregate, tests must be
run to determine the amount of asphalt required. One commonly used method was originally
developed by Bruce Marshall, a former bituminous engineer with the Mississippi State Highway
Department, and is now referred to as the Marshall method of mix design. The original features
have been improved by the U.S. Corps of Engineers, and the test is now standardized and described
in detail in ASTM D1559. [ASTM] The objective of the Marshall mix Design is to determine the
optimum blend of the different components that will provide the following [Garber and Hoel]:
• An adequate amount of asphalt to ensure a durable pavement
• An adequate mix stability to prevent unacceptable distortion and displacement when
traffic load is applied
• Adequate voids in the total compacted mixture to permit a small amount of compaction
when traffic load is applied without loss of stability, blushing, and bleeding, but at the
same time low enough to prevent harmful penetration of air and moisture into the
compacted mixture
• Adequate workability to facilitate placement of the mix without segregation
MATERIALS
The materials used in the evaluation of the optimum asphalt content were submitted by
Jack Brown, President of Joe Asphalt Paving Company. The aggregate was a unwashed, angular,
crushed gravel having a maximum particle size of 3/8". The asphalt cement was an AR-4000
originally supplied by Witco. Tests were performed for asphalt contents of 4.5%, 5.0%, 5.5%,
6.0%, and 6.5%.
PROCEDURES
All tests were performed in strict accordance to American Society for Testing and
MaterialsASTM) standards. [ASTM] Any exceptions to prescribed methods are noted below.
• ASTM D1559 “Standard Test Method for Resistance to Plastic Flow Of Bituminous
Mixtures Using Marshall Apparatus"
This test is used to determine the stability and flow of a particular asphalt paving
mixture. By testing specially prepared 4" diameter and 2.5" thick samples , Figure 1, at
a constant rate of loading, the stability and flow can be established. By testing various
different asphalt contents, this data can be used to establish the optimum asphalt content.
-3-
2 1/2"
Marshall Compaction Specimen
used for stability and flow tes ting
4"
Figure 1. Standard Marshall specimen.
• ASTM D2041 "Standard Test Method for Theoretical Maximum Specific Gravity of
Bituminous Paving Mixtures"
This test is performed by breaking up the warm sample used in determining the stability
and flow, and subjecting it to a partial vacuum under water. With the air removed from
the sample, the maximum specific gravity can be calculated from the different weights
that are recorded.
• ASTM D2726 "Standard Test Method for Bulk Specific Gravity and Density of
Compacted Bituminous Mixtures Using Saturated Surface-Dry Specimens"
This test used the same sample as prepared for testing stability and flow, but this test is
performed before the stability and flow testing. The sample is weighed in air and then
saturated and weighed in a surface dry condition, and then is weighed submerged. The
data are then used to calculate the bulk specific gravity of the sample.
• ASTM D3203 "Standard Test Method for Percent Air Voids in Compacted Dense and
Open Bituminous Paving Mixtures"
This test simply uses data gained from ASTM D2726 and ASTM D2726 to calculate
the percent air voids in the compacted mixture.
RESULTS
A graphical presentation of the results is given in Figure 2.
ANALYSIS
Figure 2 gives graphical representations of the results of the Marshall mix design. Several
trends that exist in the figures are important to discuss. It can be seen from the first plot (1A) that
the unit weight increases with increases in asphalt content up to a point and then begins to decrease.
This would tend to indicate that once the asphalt has completely filled all of the voids, additional
asphalt only decreases the unit weight because of the asphalt cements lower unit weight with
respect to the aggregates. It can also be seen that an increase in asphalt content tends to fill the
-4-
voids in the compacted mixture and thus reduces the percentage of air voids in the mix (1B).
Additionally, stability tends to increase with increasing asphalt content up to a point and then
decreases in a similar fashion to the unit weight graph (1C). This is likely due to the fact that a
deficiency of asphalt cement in a mix reduces the amount of cohesion, while an excess tends to
lubricate the particles, which both tend to reduce the amount of stability in the mix. Also, the
percent voids in the mineral aggregate (%VMA) decreases with increased asphalt content and rises
after a certain point (1D). This is because at lower asphalt contents adequate compaction is not
possible, and at higher asphalt contents, much of the volume is occupied by asphalt cement. These
both tend to increase the percent of the mix not occupied by aggregate causing greater expense
and/or a lower durability. Finally it can be seen that an increase in asphalt content tends to lubricate
the particles and thus increase the flow (1E).
Table 1 shows the results derived from Figure 2. As can be seen the asphalt content at the
maximum unit weight is 5.7%, at the average allowable air voids (4%) is 5.0%, and at the
maximum stability is 5.4%. This results in an optimum asphalt content of 5.3% by weight of
aggregate. Table 2 indicates that an asphalt content of 5.3% meets or exceeds all of the
requirements set forth by the American Society for Testing and Materials.
Table 1. Marshall Mix Design Results
Asphalt content at maximum unit weight
5.7%
Asphalt content at 4% air voids
5.0%
Asphalt content at maximum stability
5.4%
Average asphalt content
5.3%
Table 2. ASTM Requirements.
Criteria
5.3% asphalt content
ASTM Specifications
Stability
2300 lbs
min 750 lbs
14
8-18
Air Voids
3.3%
3%-5%
Percent VMA
17%
16%
Flow
-5-
Figure 2. Marshall Mix Design Results Graphs.
-6-
CONCLUSIONS
Based on the results of the Marshall mix design performed on the materials submitted by
Joe Asphalt Paving Company, we recommend using an asphalt content of 5.3% by weight of
aggregate. The use of this asphalt content meets or exceeds all of the requirements set forth by
ASTM, however, it is possible that an alternative source of aggregate or a different grade of asphalt
cement will provide a better performing, more economical mix.
-7-
REFERENCES
1)
Asphalt Institute (1983), Asphalt Technology and Construction Practices. The
Asphalt Institute, College, Park, Maryland.
2)
Garber, Nicholas J. and Lester A. Hoel (1988), Traffic and Highway Engineering,
West Publishing Co., St. Paul, Minnesota, pp. 727-781..
3)
ASTM (1988), Book of ASTM Standards. Volume 4.03
-8-