Evaluation of Fly Ash Concrete Durability Containing Class II Durability Aggregates · ·...
45
Evaluation of Fly Ash Concrete Durability Containing Class II Durability Aggregates Project No. MLR-85-8 Highway Division July 1986 ----- Iowa Department ----- of Transportation
Transcript of Evaluation of Fly Ash Concrete Durability Containing Class II Durability Aggregates · ·...
Evaluation of Fly Ash ConcreteDurability Containing
Class II Durability Aggregates
Project No. MLR-85-8
Highway DivisionJuly 1986
-----~~ Iowa Department-----~l of Transportation
Evaluation of Fly Ash Concrete DurabilityContaining
Class II Durability Aggregates
Project No. MLR-85-8
BySam G. Moussalli
Cement and Concrete Engineer
Office of MaterialsIowa Department of Transportation
April 1986
DisclaimerThe contents of this report reflectthe views of the author who is responsible for the facts and the accuracyof the data presented herein. Thecontents do not necessarily reflectthe official views or policies of theIowa Department of Transportation.This report does not Constitute astandard, specification or regulation.
TABLE OF CONTENTS
Page
Abstract •••.• ................................................................................................................ .ii
Introduction. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 1
Scope •..•.... .. .. .. .. .. .. .. .. .. .............................. II .. 1
Laboratory Procedures. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 2
Materials ••••••.•. .................................................................................................. 2
Portland Cement.Water ..Air Entraining Agent.Fly Ash •......••.Fine Aggregate •••Coarse Aggregate.
222223
Aggregate Classification Purpose 3
Aggregate Gradation ,. 4
Fly Ash Substitution Rates.................................................................................. 4
Concrete Controls.................................................................................................. 4
Concrete Tests . .. . . .... .... . . . ............ .. . . . ..... 4
Durability (Freeze/Thaw Test) •
................ " .Test Results and Interpretation.
.. . .. " .. .. .. . .. ..............6
6
Table No. 1 physicalTesting
Characteristics of Aggregate Quality. .. .. 7
Table No. 2 Durability of Fly Ash Containing Class II •.•..•••••.• 8Aggregates
Figure No. 1 Durability Factors Class II Aggregates •••• 9
Figure No. 2
Figure No. 3
Durability Factors With and without Fly Ash ....•..•• llMalcom Mine
Durability Factors With and Without Fly Ash .....•••• 12Douds Mine
Figure No. 4 Durability Factors With and Without Fly Ash. .. .. .13
Figure No. 5 Durability Factors With and Without Fly Ash ••....••• 14Nelson Quarry
TABLE OF CONTENTS (continued)
Page
Figure No. 6 - Durability Factors With and Without Fly Ash .. .. .. .. .. .. .. .... 15Garrison Quarry
Figure No. 7 - Durability Factors With and Without Fly Ash ........ .. .. .. .. .. 16Carville/Bunn Quarry
Figure No. S - Durability Factors With and Without Fly Ash ..••.•..• 17Ames Mine
Figure No. 9 - Durability Factors With and Without Fly Ash .................. 18Durham Mine
Figure No. 10 - Expansion Factors with and Without Fly Ash ••••••••• 19Malcom Mine
Figure No. 11 - Expansion Factors With and without Fly Ash •••••.... 20Douds Mine
Figure No. 12 - Expansion Factors With and Without Fly Ash .••..•.•. 21Skyline "Au Quarry
Figure No. 13 - Expansion Factors With and Without Fly Ash .......... .. .. .... 22Nelson Quarry
Figure No. 14 - Expansion Factors With and Without Fly Ash .................. 23Garrison Quarry
Figure No. 15 - Expansion Factors With and Without Fly Ash .•....... 24Carville/Bunn Quarry
Figure No. 16 - Expansion Factors With and without Fly Ash .................. 25Ames Mine
Figure No. 17 - Expansion Factors With and without Fly Ash .•.••.••. 26Durham Mine
Air Content of Fly Ash Concrete .••............•......•.•...•....... 27
Discussion of Results It 28
Conclusion '" 29
Recommendation 29
References " 30
Appendices
Appendix A - Standard Specifications - Mix Proportions ••••••.•••• 32Appendix B - Durability Testing (Freeze/Thaw) •••••••••••••.•••... 34
Abstract
Fly ash was used in this evaluation study to replace 15% of the cement in
Class C-3 concrete paving mixes. One Class "c" ash from Iowa approved
sources was examined in each mix. Substitution rate was based on 1 to 1
basis, for each pound of cement removed 1.0 pound of ash was added.
The freeze/thaw durability of the concrete studied was not adversely af
fected by the presence of fly ash. This study reveals that the durabil
ity of the concrete test specimens made with Class II durability
aggregates was slightly increased in all cases by the substitution of ce
ment with 15% Class "c" fly ash.
In all cases durability factors either remained the same or slightly im
proved except for one case where the durability factor decreased from 36
to 34. The expansion decreased in all cases.
i i
PAGE 1
Introduction
Current Iowa DOT specifications allow the optional use of fly ash as a
partial cement replacement in Class A, Band C concrete paving mixes,
provided a highly frost resistant, coarse aggregate such as Class III du
rability is used.
The basis for this specification is that early durability research indi
cated less frost resistance in fly ash concrete when an aggregate of me
diocre quality was used. Research subsequently has shown that fly ash
concrete with other Class II aggregate may not have reduced freeze/thaw
durability.
Special study and testing where aggregates are salt treated indicates the
addition of fly ash may be beneficial; furthermore, the use of fly ash in
concrete is desirable for economical and environmental reasons.
Therefore, it was the purpose of this study to test durability of con
crete containing several Class II aggregates to establish the effect of
fly ash and further to either substantiate or refute our present posi
tion.
Scope
Eight Class II aggregates were evaluated in concrete in this evaluation
study, with and without fly ash. The aggregate represented a cross
section of carbonate aggregates presently approved for use in Iowa.
PAGE 2
The fly ash studied conformed to ASTM C-618, "Fly Ash and Raw or Calcined
Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Con-
crete". Only one Class "c" fly ash was used in this study from an ap-
proved Iowa source.
Currently Iowa does not have any Class "F" ash approved for use.
This study examines the freeze/thaw durability of Class II aggregates
when used in Class C-3 paving mixes with and without fly ash.
The C-3 paving mix has a cement factor of 604 pounds per cubic yard.
Laboratory Procedures
A. Materials
The following materials were used in this study:
1. Portland Cement: Type I, standard laboratory blend of the tenportland cements commonly available in Iowa, was used to prepare theconcrete specimens.
2. Water: Tap water, City of Ames
3. Air Entraining Agent: Neutralized vinsol resin, Carter-Waters, single strength, Lab No. ACA5-7
4. Fly Ash: Ottumwa Ash, mildly reactive, Class "c" (self cementing)Lab No. ACF5-64
5. Fine Aggregate: Cordova sand (Mississippi River sand), Lab No.AA55-0141
PAGE 3
6. Coarse Aggregates:
Source Name
Malcom MineDouds MineSki line QuarryNelson QuarryGarrison QuarryCarville/Bunn Quarry
Ames MineDurham Mine
B. Aggregate Classification Purpose
Reason for Class II Classification
Durability Factor & PerformanceDurability Factor & PerformanceDurability FactorDurability FactorPerformanceSimilar stone has poorerperformanceDurability FactorDurability Factor & Performance
In view of the fact that Iowa has some concrete aggregates that cause
premature concrete failure, a three-class system has been developed to
denote a portland cement concrete aggregate's expected service life. The
three service life classes are:
Class I - Deterioration in approximately 10 years and a durabilityfactor less than 80.
Class 2 - Deterioration in 10-20 years and a durability factor greaterthan 80.
Class 3 - Deterioration in over 20 years and a durability factor greaterthan 90.
Assignment to one of the service life classes is based on the aggregates
field performance in concrete, or in lieu of that, upon the performance
of concrete containing it in a modification of the ASTM C-666, "Resist-
ance of Concrete to Rapid Freezing and Thawing - Procedure B" test.
Although the latter test can be definitive in identifying low quality ag
gregates, some aggregates that just pass the test give questionable field
performance. These could appropriately be termed as Class II aggregates.
PAGE 4
C. Aggregate Gradation
The coarse aggregate gradation was:
Sieve No.
1.06"3/4"0.525"3/8"No. 4No. 8
% Passing
10089408.00.80.4
D. Fly Ash Substitution Rates:
Fly ash was substituted for 15%, by weight of the portland cement. The
substitution of Class "c" fly ash was on a pound-for-pound basis. The
change in absolute volumes due to the fly ash substitution, was applied
to each aggregate in its proper ratio. For the C-3 mix, the volumes are
55% coarse aggregate and 45% fine aggregate.
E. Concrete Controls
Concrete mixes were controlled to a slump of 2.0" ± 1/2" and air content
of 6.0% ± 0.5%.
F. Concrete Tests
The investigation of the effects of aggregate and fly ash sources on con-
crete durability was accomplished by preparing test specimens in the lab-
oratory. These specimens were made from a Class C-3 concrete mix with a
cement content of 604 lb./yd 3 as defined in the standard specifications
series of 1984 (1). The variables in the mixes were the aggregate
sources. The specifications referenced above designate the proportions
PAGE 5
of Portland Cement-water-aggregate to be used in the mixes studied. The
specifications also itemize the slump and entrained air content (see Ap
pendix A). The former is achieved by varying the water added and latter
by varying the amount of air entraining agent added.
The actual procedure, as to the preparation and mixing of the ingredi
ents, was as outlined in ASTM C-192 (2) "Making and Curing Concrete Test
Specimens in the Laboratory".
The determination of the durability factor of the concretes containing
the Ottumwa ash and various aggregates was done according to Iowa Test
Method 408A (3) "Method of Test for Determining the Resistance of Con
crete to Rapid Freezing and Thawing" (see Appendix B). This test is a
modification of ASTM C-666, Procedure B (2) in that the 4" x 4" concrete
beams are 18" in length rather than 11" to 16" and 90-day moist room cure
is substituted for the 14-day lime water cure.
A total of three 4" x 4" X 18" beams were cast from each batch and each
combination for the durability testing. The beams were cured for 90 days
in the moisture room.
Upon completion of the appropriate curing period, the beams were sub
jected to cyclic freezing and thawing with periodic sonic modulus and
change in length readings taken twice a week. This was continued until
they had undergone 300 cycles of freezing and thawing or until the speci
men's relative dynamic modulus of elasticity reached 60% of the initial
modulus, whichever occurs first.
PAGE 6
The coarse aggregates used in the concrete currently are approved as
Class II durability aggregates which are associated with no deterioration
of pavements in less than 10 years and only minimal deterioration in
pavements of 10-20 years of age.
Test Results and Interpretation
Durability (Freeze/Thaw Test)
Table No. 1 shows the physical characteristics of the aggregate quality
testing, while Table No.2 shows the concrete mix characteristics and
itemizes the freeze/thaw durability test results for the various aggre
gates. Each durability value indicated is the average of the three
beams. The data is depicted graphically in Figure 1 to point out the re
lationship between the C-3 mixes with and without the substitution of fly
ash for a portion of the cement when Class II and Class III aggregates
are used.
TABLENO.
1
DURABILITYOF
FLYASH
CONTAININGCLASS
IIAGGREGATES
MLR-85-8
AGGREGATESOURCE
COUNTYAGGREGATE
FREEZE-THAWPORE
INDEXABSORPTION
L.A.
SPECIFICCLASS
METHODA
%ABRASION
GRAVITY%
%
Ma1com;'
MinePow
eshiekII
1.016.0
2.8030.0
2.597(D
olomite)
Douds
Mine
VanB
urenII
2.018.0
5.0435.0
2.525(D
olo mite2Skyl
tne
Quarry
Winneshiek
II1.0
20.01.39
25.02.654
(Dolom
ite/Lim
estone)
Nelson
Quarry
Henry
II2.0
10.00.70
46.02.667
(Lim
estone2G
arrisonQ
uarryB
entonII
1.013.0
2.7026.0
2.653(D
olomite2
----------_......._
----_
.•------------_
...~----_
..-----------
------
--
--------
---_..•...-
Carville/B
unnQ
uarryFloyd
II1.0
18.02.99
30.02.630
(Dolom
iteL_
__
__~
__
__
__
__
__
__
__
__
__
__
_v:P-
Ames
Mine
StoryII
2.018.0
2.7541.0
2.584a:en
(Dolom
ite)-..J
Durham
Mine
Marion
II1.0
24.02.2
28.02.614
(Dolom
ite)
TABL
ENO
.2
DURA
BILI
TYOF
FLY
ASH
CONT
AINI
NGCL
ASS
IIAG
GREG
ATES
MLR
-85-
8
AGGR
EGAT
ESO
URCE
FLY
ASH
FLY
ASH
W/C
RATI
OAI
RSL
UMP
DURA
BILI
TYEX
PANS
ION
SOUR
CECL
ASS
CEM
ENT
CEM
ENT
%(IN
CH)
FACT
OR%
ONLY
&%
FLY
ASH
Malc
omM
ine
Con
tro1
--0.
427
----
-6.
42.
2568
0.07
7M
alco
mM
ine
Ottu
mw
aC
0.46
60.
395
6.5
2.50
860.
039
Dou
dsM
ine
Con
trol
--0.
414
----
-6.
41.
7587
0.04
2D
ouds
Mine
Ottu
mw
aC
0.47
40.
401
6.5
2.25
930.
014
Skyl
ine
Qua
rry
Con
trol
--0.
420
----
-6.
01.
7597
0.01
4Sk
ylin
eQ
uarr
yO
ttum
wa
C0.
481
0.40
86.
32.
5097
0.01
3
Ne1s
onQ
uarr
yC
ontr
ol--
0.42
0--
---
6.1
2.00
770.
072
Nel
son
Qua
rry
Ottu
mw
aC
0.45
90.
388
6.5
2.25
840.
048
Gar
riso
nQ
uarr
yC
ontro
1--
0.43
9--
---
6.0
1.75
860.
026
Gar
riso
nQ
uarr
yO
ttum
wa
C0.
489
0.41
46.
12.
0095
0.01
8"J> G
> .,., 00
Car
vill
e/B
unn
Qua
rry
Con
trol
--0.
420
----
-6.
22.
0064
0.10
6C
arvi
lle/
Bun
nQ
uarr
yO
ttum
wa
C0.
496
0.42
06.
02.
0073
0.09
7
Ames
Min
eC
ontr
o1--
0.40
8--
---
6.1
2.50
360.
167
Ames
Min
eO
ttum
wa
C0.
474
0.41
46.
42.
5034
0.12
2
Dur
ham
Min
eC
ontr
o1--
0.47
7--
---
6.0
2.00
770.
098
Dur
ham
Min
eO
ttum
wa
C0.
519
0.43
96.
02.
5078
0.12
6
-- ~
.
Fig
ure
#1
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PAGE 10
While the durability of concrete test specimens was slightly increased in
most cases by the substitution of 15% of the cement with fly ash, the ex
pansion was decreased in all cases. The results of the durability fac
tors in combination with the fly ash used in this evaluation study are
shown in Figures 2-9. The expansion factors of the same combinations are
graphically presented in Figures 10-17.
Figure
#2
PERCENTO
RIGIN
AL
MODULUS
EAGLECITY
LEDGEFROM
THEMALCOM
MINE
LABNUM
BERA
AC
5-428
STANDARDOTTUM
WA
FLYASH
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19861-515-239-1339
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Figure
#3
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AS
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'QUARRY
LABNUM
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LEDGEFROM
THENELSON
QUARRYLAB
NUMBER
AA
C5-523
OTTUMW
AFLYASH
~4
i~
u:
TC
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Figure
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RIGIN
AL
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FROMTHE
CARVILLE/BUNNQUARRY
LABNUM
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AMES
MINE
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Figure
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RIGIN
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1-515-239-1339CODE:
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PAGE 27
Air Content of Fly Ash Concrete
It should be noted that one of the common problems which has been en
countered with the use of fly ash in concrete is the effect on entrained
air content. Failure to increase the amount of air entraining agent to
compensate for the negative effect of the presence of fly ash can produce
concrete with a lower than desired air content. This can then result in
the premature failure of concrete due to the action of freezing and
thawing processes.
PAGE 28
Discussion of Results
1. This study reveals that the durability of concrete test specimens
made with Class II durability aggregates were either slightly in
creased or remained the same when 15% of the cement was substituted
with fly ash. However, fly ash is not expected to materially affect,
either favorably or unfavorably the freeze/thaw behavior of concrete
in which it is used, and the general use of Class II aggregate in fly
ash concrete may not insure satisfactory laboratory durability.
2. The slightly improved durability test results shown with the fly ash
mixes are not regarded as significant, and can be attributed to the
lower water cement ratios. The cause for the lower durability fac
tors of Class II aggregate - fly ash concrete in past studies cannot
be related directly to Class II aggregates as a whole nor is it
likely to be an aggregate - fly ash reaction. It is more likely due
to combination of a particular Class II aggregate with a freeze/thaw
susceptible pore system. Research studies in the past have shown
that some of Iowa's Class II aggregate possess a pore system that has
a need to expel water during freezing if they are to retain their
structural integrity.
Some Iowa pavements, however, have undergone deterioration associated
with coarse aggregates that is primarily caused by adverse chemical
reactivity rather than freeze/thaw susceptibility. Other coarse ag
gregate do not become affected and the addition of fly ash to the
concrete may restore the durability properties.
PAGE 29
Conclusion
Based on the laboratory test data gathered in this study, the addition of
fly ash as a partical cement replacement in the concrete mix can be ac
complished without detrimental effects to the freeze/thaw durability of
concrete. Therefore, portland cement concrete containing Class II dura
bility aggregates should either remain largely unaffected with respect to
durability or, in a few isolated cases, exhibit improved long term per
formance with 15% replacement of the cement with quality fly ash.
Recommendation
It is recommended that the substitution of fly ash from approved sources
for up to 15% of the portland cement in concrete paving mixes containing
Class II aggregates be allowed in the specifications.
PAGE 30
References
1. Iowa Department of Transportation, Standard Specifications for High
way and Bridge Construction, Series of 1984, Iowa Department of
Transportation, Section 2301 "Portland Cement Concrete Pavement".
2. ASTM (American Society for Testing and Materials), Annual Book of
Standards, Section 4, Volume 04.02, Concrete and Mineral Aggregates
ASTM 1984.
3. Iowa Department of Transportation, Office of Materials, Laboratory
Manual.
APPENCICES
PAGE 31
PAGE 32
APPENDIX ASTANDARD SPECIFICATIONS
MIX PROPORTIONS
PAGE 33
Proportions for Pavement ConcreteSection 2301.04
Class C ConcreteBasic Absolute Volumes of Materials Per
Unit Volume of Concrete
Mix Cement Water Entr. Fine CoarseNo. Minimum Air Aggregate Aggregate
C-2 0.110202 0.148144 0.06 0.272662 0.408992C-3 .114172 .153840 .06 .301895 .370093C-4 .118330 .159808 .06 .330931 .330931C-5 .122867 .166318 .06 .358448 .292367C-6 .127782 .173371 .06 .384308 .254539
Approximate Quantity of Dry Materials PerCubic Yard of Concrete *
Fine CoarseMix Cement Aggregate AggregateNo. Pounds Tons Tons
C-2 583 0.6087 0.9130C-3 604 .6739 .8262C-4 626 .7388 .7388C-5 650 .8002 .6527C-6 676 .8579 .5682
*These quantities are based on the following assumptions: Specific gravity of cement 3.14; specific gravity of aggregate 2.65, water cement ratio 0.430 pound of water per pound of cement, air voids 6.0 percent.
APPENDIX BDURABILITY TESTING
(Freeze/Thaw Testing)
PAGE 34
Page 1 of 5
PAGE 35
Test gethod No. Iowa 40B-AApril 1980
IOWA DEPARTMENT OF TRANSPORTATIONHIGHWAY DIVISION
0ffice of Materials
METHOD OF TEST FOR DETERMINING.THE RESISTANCEOF CONCRETE TO RAPID FREEZING AND THAWING
(CONCRETE DURABILITY)
This method covers the determination ofthe resistance of concrete beam specimens(4 11x4"x18") to rapidly repeated cyclesof freezing in air and thawing in water.The Procedure is a slight modificationto ASTM C-666 Procedure B.
Procedure
2. A polished brass button shall becast into each end of each prismfor the purpose of providing asmooth reference surface forlength measurements.
3. Three specimens shall be cast foreach variable under study.
E. Test Procedure
2. Twenty-four hours prior to placement in the freeze-thaw apparatus tthe specimens shall be placed inthe tempering tank.
D. Curing
1. Upon removal from their molds thetest specimens shall be placed inthe moist room for a period of notless than 89 days or not more than128 days.
A. Apparatus
1. Freezing and thawing Apparatus, Temperature MeasuringEquipment, Dynamic TestingApparatus, Scales.
The freezing and thawingapparatus t temperaturemeasuring equipment t dynamic testing apparatus,and scales shall conformto ASTM C-666 Procedure B.
2. Length Comparator
The length comparator fordetermining the lengthchange of the specimensshall be accurate to 0.0001".An invar steel reference baris provided' for calibratingthe comparator.
3. Tempering Tank
The tempering tank is temperature controlled at 40 + 2 QF.
It is to be used for coolingspecimens prior to placementinto the freezing chamber.
B. Freeze-Thaw Cycle
1. The freezing and thawingcycle shall be identical toASTM C-666 Procedure B.
C. Test Specimens
1. Unless otherwise specifiedthe test specimens shall be4 1x4"x18" prisms.
1. Beam Rotation
Prepare the order for random rotation of the specimens as follows:
a. Prepare paper slips with thespecimen identification numbers for each specimen in thefreezing chamber.
b. Place all the paper slips ina pan.
c. Draw out the ·slips one at atime and record the resultingrandom sequence.
Rotate the beams in the followingmanner:
a. Withdraw the first specimenin the sequence and place itto one side.
b. Move each successive specimenin the sequence into the position of the specimen precedingit.
Test Method No. Iowa 408-AApril 1980
c. When the last specimen inthe sequence has been moved,replace it with the firstspecimen.
2. Length Measurements
a. Before any length measurement is taken, calibratethe beam comparator to0.0200 using the Invarsteel reference bar. Thisbar should be cooled forapproximately 30 minutesin water to 40°F. Adjustthe comparator dial ifneeded.
b. Remove the specimen fromthe tempering tank or thefreezer depending uponwhether the beam is a newone or one with severalcycles on it.
c. Place the specimen in thecomparator with the identification numbers facing upat the left end of the comparator. Care should beexercised to insure thatthe specimen is firmlyagainst the back stopsand the right end of thecomparator.
d. Allow the dial indicatorto come to rest on thebrass button on the endof the specimen. Readthis value on the indicator to the nearest 0.0001 11
•
Record this value. Repeatthe measurement by completely removing the specimen from the comparator,replacing it, and remeasuring it until two successivereadings are equal.
e. If measuring three specimens at once, -cove r thosespecimens immediately afterremoving from the sub-zerounit with a towel soaked inthe thawing water.
3. Weight Measurement
Weigh the beam on the scale tothe nearest ~ 'g~ams. Recordthe value obta~ne .
4. Dynamic Modulus
a. Place the specimen on thesupport such that the
PAGE 36
Page 2 of 5
driving oscillator is midwaybetween the end of the specimen. Make sure the specimenis firmly against the backstops of the support.
b. Place the tone arm pickup onthe end of the specimen aboutmidway between the sides.
c. On the oscilloscope, rotatethe large knob slowly backand forth until an elipseshape is formed on the cathoderay tube of the oscilloscope.
d. Set the nOse. Frequencyll knobto II 1011 and read the frequencyfrornXthe indicator on the oscil-"loscope. Add 1000 to this valueand record the number obtained.
5. Replace the specimen in the freezechamber inverted from its originalposition.
6. Repeat steps 2 through 5 for allof the speoimens.
7. Continue each specimen in the testuntil it has been SUbjected to 300cycles or until its relative dynamic modulus reaches 60% of theinitial modulus! whichever occursfirst.
F. Calculations
1. Record all the required data onthe "P.C. Concrete nurab Ll.Lt.y" labworksheet.
2. From the recording charts, obtainthe number of cycles completedsince the specimens were lastmeasured. (Mark the date read andthe number of cycles to that pointon the recording chart.) Add tothis number the number of cyclesat which the specimens were lastmeasured. Record this cumulativevalue in the column labeled "Cycles".
3. Subtract the" dial reading at zerocycles from the latest dial reading.Record this value in the columnlabeled tlGro. In".
4. Calculate the relative dynamic modulus of elasticity using the formula:
where:
PAGE 37
Page 3 of 5 Test Method No. Iowa 40B-AApril 1980
n
relative dynamic modulusof elasticity after ccycles of freezing andthawing, percent
fundamental transversefrequency at 0 cycles offreezing and thawing
N number of cycles at whichP reaches the specifiedminimum value for discontinuing the test or thespecified number of cyclesat which the exposure is tobe terminated, whichever isless
8. Report. The final report (worksheet) should be submitted to theGeology Section, and it shouldinclude all data pertinent to thevariables or combination of variables studied in the evaluation.Also, any defects in each specimen which develop during testingand the number of cycles at whichsuch defects were noted should bedocumented on the worksheet.
fundamental transverseafter c cycles of freezing and thawing
Record this value in the'columnlabeled '1% of Orig."
5. When all of the above calculations have been made for asimilar set of specimens, compute the average for the setfor the items "% of Orig.",'IGro. %", and "Gro. In".Compute "Gro. %" using theformula:
M specified number of cyclesat which exposure is to beterminated. (Three-hundredcycles in most cases.)
G s x 100iflT8T
where:
G = average growth for the setof specimens in %.
S the sum of the growths foreach specimen.
T the total number of specimens in the set.
DF = the durability factor ofthe specimen
6. Repeat the preceding steps foreach specimen.
Record these values in theappropriate columns on theworksheet.
PN11
DF
where:
"T" should include only numberof specimens which showeda normal reading
7. Should it be desired to handcalcul~te the'durability factor,use the following formula:
P the relative dynamic modulus of elasticity at Ncycles, percent
Specimens in theFreezing & Thawing Apparatus
Page 4 of 5
Freezing & Thawing Apparatus"Cincinnati"
PAGE 38
Test Method No. Iowa 408-AApril 1980
Freezing & Thawing Apparatus"Con r ad"
Beam Comparator Dynamic Testing Apparatus
Page 5 of 5orm 8212'88·75
PAGE 39Test Method No. Iowa 408-A
P.C. CONCRETE DURABILITY
w/c: Mix:
Lab. No.:
Date Made:
Cejl1. Content:
Beam No. ----------
3sklyd
Fine Agg. :
Coarse Agg.:
Lab. No.:
Lab. No.:
Sp. Gr.:
sp , Gr.:
Date Weight
Slujl1p: Air: Grams--------
AEA @ fl. oz./sComments:
Admixture @ flo oz·/s...._..._. ---_.._--
I._-- Set Average
I--
Date Dlal Gro. % of % ·of Gro. Gro.
CYcles Rdq. In. F~ Oriq. Remarks Orig. % In.,
Read
I
I,I
k.
k .
