investigations of the hydration expansion characteristics of portland cements
TRANSCRIPT
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Research and Development Laboratories
of the
Portland Cement Association
RESEARCH DEPARTMENT
BULLETIN 45
Investigations of the HydrationExpansion Characteristics
of Portland Cements
BY
I-L F. GONNERM, WILLIAM LERCHand THOMAS M. WHITESIDE
Jum 1953
,
Publhhsd byPORTLAND CEMENT ASSOCIATION
33 West Grand Ave., Chicago Io, IIL
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I
Research and Development Laboratoriesof the
,
Portland Cement Association
RESEARCH DEPARTMENT
BULLETIN 45
Investigations of the Hydration
Expansion Characteristics
of Portland Cements
By
H. F. GONNERMAN, WILLIAM LERCH,
and THOMAS M. WHITESIDE
,JUNE 1953CHIC.iGO
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COPYRIGHT,1%53BY PORTLANDCEhmN!cASSOCIATION
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CONTENTS
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HISTORY OF SOUNDLESS TESTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CAUSES OF UNSOUNDNESS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PREVIOUS STUDIES OF THE AUTOCL~VETEST . . . . . . . . . . . . . . . . . . . . . . . . . . . .INVESTIGATIONSBY THE PORTL~XD CEMENT ASSOCIATIONOF L,+BOR.ATORY-
PREP.ARED PORTLANDCEMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .INVESTIGATIONSBY THE PORTLAND CEMENT ASSOCIATIONOF COMMERCML
PORTL.INDCEMENDS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RELATIONSHIPSBETWEEN AUTOCLAVEEXPANSIONOF CEMENT AND STRENGTH
OF MORT.lR AN DCONCRETE.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..4CKNOWLEDGMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..4PPEXDIX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LIST OF TABLESTal>le
1. Comparative Results Obtainecl on ATormal Water Curing and High Pres-sure Steam Curing of Cement Compounds and Certain Mixtures ofCement Compounds (PCAF Investigation C-17) . . . . . . . . . . . . . . . . . . . . .
2. Tests of Three Groups of Laboratory-Prepared Cements of l~aried FreeCaOContent (Series 260): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(A) Length Changes of 1 x 1 x 1Ii-in. Neat Cement Bars and 2 x 2x 9+in. 12 Mortar Bars,
(B) Flexural Strength of 2 x 2 x 9+-in. Mortar Bars, CompressiveStrength of 2-in. Modified Cubes, and Tensile Strength ofBriquets (Before and .4fter Autoclaving at One Day).
3, Tests of Seven Groups of Laboratory-Prepared Cementsof Varied FreeCaO and MgO Contents (Series 260):
(A) Length Changes of 1 x 1 x 11~-in. Neat Cement Bars and 2 x 2x 9&in. l2 Mortar Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(B) Flexural Strength of 2 x 2 x 9+-in. Mortar Bars, CompressiveStrength of 2-in. Modified Cubes, and Tensile Strength ofBriquets (Before and After Autoclaving atOne Day)...,. . . .
-1. Tests of Laboratory-Prepared Cements of Varied MgOandfree CaOCon-tents (Series 260):
(A) Length Changes of 1 x 1 x 11~-in. Neat Cement Bars and 2 x 2x9&in. 1-2 Mortar Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(B) Flexural Strength of 2 x 2 x 9+-in. Mortar Bars, CompressiveStrength of 2-in. Modified Cubes, and Tensile Strength ofBriquets (Before and After Autoclaving atOne Day). . . . . . . .
5, Comparirm of Expansions of lNeat Cement Bars Autoclave at Age of...111
Page1135
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8895969699
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12
14
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24
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One Day and 5 Years with Expansion of Companion Bars DuringStorage in R7ater(Series 230) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3S
6. Comparison of Results of Tests of Cements Ground from Slowly- andQuickly-Cooled Laboratory-Prepared Clinkers of Varied MgO and CS.4Contents (Series 277) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
7. Tests of Cements Ground from Plant-, Quickly-, and Slowly-Cooled Com-mercial Clinkers of Varied Calculated CSA Content (Series 270). . . . . . . . . 44
8, Summary of Autoclave and Length Change Tests of 418 CommercialPortland Cements (Series 263) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9, Summary of Autoclave and 10-Year Length Change Tests of 263 Labora-tory-Prepared Cements (Series 260, 270 and 277). . . . . . . . . . . . . . . . 59
10, Results of Autoclave and Length Change Tests of Miscellaneous Com-mercial Cements (Series 263):
(A) Cements Subjected to Standard ASTM Autoclave Test C151, 60(B) Cements Subjected to a Modified Autoclave Test . . . . . . . . . . . . . . 65
11. Tests of Blends of Portland and Natural Cements (Series 263). . . . . . . . . . 70(.4) Length Changes of 1 x 1 x 11~-in. Neat Cement Bars(B) Chemical Analyses of Cements Used in Blends
12. Tests of ~~ormal and High-Early Strength Cements from 10 Plants (Series263): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
(A) Length Changes of 1 x 1 x 11~-in. Neat Cement Bars(B) Chemical Analyses and Compressive Strengths of Cements
13. Results of Tests of Five Types of Portland Cement (Series 308):(A) Length changes of 1 x 1 x 1ii-in. Neat Cement Bars. . . . . . . . . 74(B) Composition of Concrete Mixes and Length Changes of 3 x 3
xll&in. Concrete Bars..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 ,(C) Chemical and Calculated Compound Composition of Cements . . . 77
14. Results of Autoclave and Length Change Tests of the Long-Time StudyCements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
15. Average Autoclave Expansions and Length Changes for Different Types ofPortland Cement (Data from Tables 13 and 14).. . . . . . . . . . . . . . . . . . . . 81
16, Effect of Duration of Moist Curing on Autoclave Expansion of NeatCement Bars (Series 263 and 271):
(A) Autoclave Expansions and Compressive Strengths. . . . . . . . . . . . . 83(B) Length Changes of Neat Cement Bars Stored in Water, Labo-
ratory Air, or Outdoors Protected from Rain and Snow. . . . . . 84(C) Chemical Analyses and Calculated Compound Composition of
Cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8517. Tests of Mortars and Concretes Made with Laboratory-Prepared Ce-
mentsof Varied MgO Content (Series 230):.... . . .. . . . . . . . . . . . . . . . . . 86(A) Strengths of Mortars and Concretes(B) Burning and Analytical Data of Cements and Length Changes I
of Neat Cement Bars18. Strength Tests of Neat Cement and 1-3 Staiidard Sand Mortar Briquets
Before and After Autoclaving (Series 270). . . . . . . . . . . . . . . . . . . . . . . . . 92LIST OF FIGURES
Fig. Page1. Free CaO in Commercial Portland Cement Clinker. . . . . . . . . . . . . . . . . . . . 42. Free MgO in Commercial Portland Cement Clinker. . . . . . . . . . . . . . . . . . . . 4
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vPage3. Diagrams (Fig. 1 to 9 inclusive) from The Autoclave Test and Inter-
pretations, by R. N, Young, J1. American Concrete Institute Sept. -oct.,1937, p. 13 . . . . . . . . . . . . . . . . . . . . . . .. ~
4. Effect of FreeLime Contentof Cement on Len,gth Changes of Neat Ce-mentand l2 Mortar Prisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5. Length Changes of ~~eat and 1-2 Mortar Bars During 10 YearsJ Storagein Waterat70F. or in Air at70t0800F., and 50Yo Relative Humidity,
insertedbetweenand of Neat Bars During the Autoclave Test. . . . . . . . . . . . . . ~~~e~Z. ~~d~1
6. Effect of Free CaO and MgO Contents of Cements on Length Changes of1 x 1 x 1l$in. Neat Cement Bars and 2 x 2 x 9&in. 1-2 Mortar Bars. . . 22
7, Effect of Free CaO on the Expansion in Water of 1 x 1 x 11~-in. Neat Barsand 2 x 2 x 9~-in. Mortar Prisms Made from Cements of Varied MgOContents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...4 23
8, Effect of MgO Content of Cement on Length Changes of Neat Cementandl2 Mortar Prisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9, Effect of MgO and Free CaO Contents of Cement on Length Changesof 1 x 1 x 11~-in. h-eat Cement and 2 x 2 x 9$in. Mortar Prisms. . . . . . . 29
10. Effect of MgO and Free CaO Contents of Cement on Length Changes of1 x 1 x 11~-in. Neat Cement and 2 x 2 x 9~-in. Mortar Bars During 10Years Storage in WaterorinAir.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
11. Relationships between the Length Changes, the MgO Undissolved (after10 minutes in 2N HhOS Containing 10 ml. of 48% HF), and the MgO -Content of Cements Prepared from Plant-Cooled, Quickly-Cooled andSlowly-Cooled Commercial Clinkers of Varied Composition. . . . . . . . . . 33
12, Comparison of the Length Changes and Undissolved lMgO (after 10 min-ut es in 2N HRTOs Containing 10 ml. 4870 HF) for Cements Preparedfrom Slowly- and Quickly-Cooled Commercial Clinkers of Varied MgOContent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13, Photomicrographs of Clinkers 3Sand3Q. . . . . . . . . . . . . . . . . . . . . . . . . . . .14. Comparison of the Length Changes of Neat Cement and Mortar Bars for
Cements Prepared from Slowly- and Quickly-Cooled Clinkers of VariedMgoC ontent., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15, Relationships between Length Change and Free CaO Content of CementsPrepared from Plant-Cooled, Quickly- and Slowly-Cooled CommercialClinkers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...+. .
16. Relationships between Length Change, Water Requirement and CSA Con-tent for Cements Prepared from Plant-Cooled, Quickly-Cooled andSlowly-Cooled Commercial Clinkers (MgO Content of Cements Lessthan 2%and Free CaOContent 0.85% or Less) . . . . . . . . . . . . . . . . . . . .
17. Effect of Calculated C~A Content of Cement on Length Changes of NeatCement and Mortar Bars Prepared from Quickly-Cooled and Slowly-Cooled Commercial Clinkers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18. Effect of CIAF Content of Cement on Length Changes of Neat Cementand Mortar Bars During Storage in Water or in Air, and on AutoclaveExpansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19, Comparison of Length(1-mngmof 1 x 1 x 11~-in. Neat Cement Bars withMgO and Free CaO Contents of 34 Commercial High-Early StrengthPortland Cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20. LengthChangesof 1 x 1 x 11~-in. Neat Cement Bars for Cement No. 8(PCA5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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21, Expansion of 1 x 1 x 1I+-in. Neat Cement Bars During .Autoclaving andDuring 16 Years Storage in Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
22. Comparison of Expansion Characteristics of 34 High-Early Strength Ce-ments with Compressive Strength of Concrete and Mortar. . 51
23, Comparison of Length Changes of 1 x 1 x 11~-in. Neat Cement Bars withMgOPlus l?ree CaOContents of Cements. . . . . . . . . . . .. ~. . . . . . . . . . . . 52
24. Length Changes of 1 x 1 x 11~-in. Neat Cement Bars During Autoclavingand During 15 Years Storage in Water or in Air as Influenced by MgOContent of Cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5,3
25, Comparison of the Average Length Changes of N-eat Cement Bars During15 Years Storage in Water at 70 to 75F, and During 10 Years Storagein Air at 70 to 80F. and 5070 R.H, with the Average Length ChangesDuring Autoclave Test (ASTM C151) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
~6. Comparison of the Average Length Changes of Neat Cement and 12Mortar Bars During 10 Years Storage in V7ater with the AverageLength Changes During the Autoclave Test (ASTM C151), . . 58
27. Linear Expansions for Blends of Portland and Natural Cements .. 6928. Relationship between Free CaO Content of Cements and the Flexural
and Compressive Strength of 12 Mortar Bars During Storage in Airor Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
29, Relationship between MgO Content of Cements and the Flexural and Corn-pressive Strength of 12 Mortars During Storage in Air or Water. . . . . . 90
30, Comparison of Strength Ratios of Neat Cement and 13 Mortar Briquetswith the Expansions of 1 x 1 x 11&in. ~~eat Cement Bars in the Auto-clave Test (ASTM C151) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
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,I~w+jTIGATIONs OF THE HYDRATION ExpA~TsK)ATCHARACTERISTICS OF PORTLAND CEMENTS
By H. F, GONNERM.AN1,WILLIAM LERCH2 AND THOMAS M. WHITES[DE3INTRODUCT1O~
l~olume stability is one of the most im-portant characteristics to be desired inportland cement mortars and concretes.Regardless of what other properties itmay possess, unless the mortar or con-crete has a high degree of volume sta-bility, it cannot be expected to producestructures that will be free from objec-tionable volume change and crackingwhich may contribute to gradual deter-ioration. Abnormal expansion of concreteresulting from the use of unsound ce-ment has been a serious cause of suchcracking and deterioration.
The undesirable effects of unsound ce-ment have been recognized in cementspecifications over the years, Specifica-tions in this and other countries havecontained some type of acceleratedsoundness test ever since the inception ofspecifications for cement. The firstASTM specifications for portland cementadopted in 1904 contained the pat testas an accelerated test for soundness andthis test was continued in ASTM spe-cifications until 1940 when the autoclavetest was first adopted,
I Research Consultant.z Head, Performance Tests Group, Portland Cement
~h~a~:ion Research and Development Laboratories,~Ass&iate Research Engineer, Portland Cement
&h~a$;ion Research and Development Laboratories,
Since the adoption of the autoclavetest in 1940 there has not been a reportedcase of abnormal expansion in pavementsor structures that has been attributed tothe use of unsound cement. This 12-yearrecord of experience provides ample justi-fication for the continued use of the auto-clave test, During this 12-year period themaximum limit on autoclave expansionwas 0.50 Y. except that during the 2&yearperiod, August 23, 1942 to November 25,1944, War Production Board LimitationOrder L-1 79 permitted a maximum auto-clave expansion of 1.0 ~o.
This paper summarizes some of thesignificant results of extensive inves- tigations of the volume change char-acteristics of portland. cement pasteswhich have been made by the ResearchLaboratories of the Portland Cement As-sociation and the Portland Cement Asso-ciation Fellowship, The results of thesestudies indicate the primary causes of un-soundness in portland cement and therelationships between the results ob-tained by various accelerated tests, par-ticularly the autoclave test, and thelength change characteristics of neat ce-ment pastes, mortars and concretesstored under controlled laboratory condi-tions.
HISTORY OF SOUNDNESS TESTS
The literature on the testing of cementis extensive and the many different testsfor soundness or constancy of volumecited indicate that the problem of devis-
1
ing suitable tests for soundness has beengiven much attention. In general, sound-ness tests fall into two categories desig-nated as normal or accelerated.
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2
Soundnessstorage and
H. F. GONNERMAN,W. LERCH AND T, M. IVHITESIDE
tests made under normaltemperature conditions re-
quire too long a time to yield significantdata and therefore usually are not wellsuited for acceptance tests of cement.Neverthelessj it is interesting to note that8 countries continue to include the coldwater pat test and 2 countries include theair-stored pat test in their specificationsfor portland cement (Q*.
In considering the relative value ofnormal versus accelerated soundnesstests, it is important to remember thatalthough the final measure of the sound-ness of the cement in service is moreaccurately determined by subjecting thecement paste to normal conditions ofmoisture and temperature for relativelylong periods of time, it is expediencywhich has made the accelerated test morepopular.
The objective of all accelerated sound-ness tests is to speed up the hydration ofthose constituents in the cement that arelikely to give rise to large volume changesafter the cement has been put into ser-vice. Accelerated tests now in general useinvolve subjecting a hardened cementpaste to an elevated temperature in thepresence of moisture for various periodsof time. After the heating period, thespecimen is examined for distortion,cracking and disintegration, or is meas-ured for the quantitative change in VOI-ume. The efficacy of such tests inrevealing unsoundness depends on theage of the cement and the test specimenswhen tested, the temperature to whichthe specimen is subjected, and the timethat it is held at that temperature.
The accelerated tests for soundnessmost frequently used in the testing ofcement are:
(1) The Hot Water or Sieam Test (PatTest). Neat cement pats are keptmoist for 24 hours then exposedto boiling water or steam usually
* ATumbersin parentheses refer to references at end ofpaper.
(2
(3)
from 3 to 5 hours and observed forcracking, etc. This test was in-cluded in ASTM specificationsfrom 1904 to 1940 when it was re-placed by the autoclave test, Atest of this type is included in thespecifications of 10 countries (1},The LeChatelier Test. 30 mm, di-ameter cylindrical neat cementspecimens after curing in coldwater (usually 24 hours) are ex-posed for 3 to 6 hours in boilingwater and the resulting expansionmeasured by means of the Le-Chatelier tongs. This test is re-quired in various forms and with .various limits in the specificationsof 14 clifferent countries (1).Tke Adoclave Test. 1 by l-in. neatbars of 10-in. * effective gage lengthare kept moist for 24 hours thenexposed to steam for 5 hours, 3hours at temperature of 420F. and295 lb. pressure, and measured forlength. This test is used by the U.S. and 7 other countries witha maximum limit on expansionranging from 0.5 to 1.3 Y. (1).
In addition to the above, the followingaccelerated tests for soundness, as de-scribed by Taylor (2) and others, are ofhistorical interest:
(1)
(2)
(3)
The boiling test (first proposedby Michaelis in 1870) ~eat ce-ment balls about 5 Crnl in diam-eter are kept moist for 24 hours,then placed in cold water andraised to boiling,Warm water test (proposed byHenry Faija in 1882)Patsmolded on glasscured moist 6to 7 hours at 105 to 110F. andin water at 115F, for the balanceof the 24 hours.Hot water test (advocated byDeval and others in 1891)Somewhat similar to the warm
*ASTJIspecifications permit the use of 1 by l-in.bars of 5-in. effective gage length in routine tests.
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(4)
(5)
(6)
(7)
water testture raised
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HYDRATIONEXPANSION
except that tempera-to i30 to 200F~and
time increased to 6 days.Maclays tests (suggested by W.IV. Maclay in 1892)Six patssubjected to clifferent tempera-tures and moisture conditions andcompared for cracking, etc.The kiln test (attributed to bothDr. Bohme and Prof. Tetmajerabout 1890)A cake of neat ce-ment, after 24 hours curing nmoist air, is gradually heatedupon a metal plate in dry air to100C. or higher until no moremoisture is evolved (about 3 hr.).In a modification of this test amoist atmosphere was used inplace of dry air.The Heintz ball testA ball ofneat cement, about 2 in. in di-ameter, after setting is heatedover a Bunsen burner,Prussings press cake testA dry
CHARACTERISTICS 3
(8)
(9)
(lo)
mixture of cement and 5 to $ %water is pressed in a mold tomake 2 cakes. After 24 hours inmoist air they are cured inwater--one at normal terrrpera-ture and the other in warm waterat 90 to 100F.Deva\s hot test (recommended in1890)A comparison of tensilestrengths of briquets (l3 mix) atvarious ages, cured either in hotwater or in water at ordinaryroom temperature.Calcium chloride test (suggestedby Candlot)Pat gaged with 4 %CaClz solution then placed in acold 4 % CaClz solution for 24hours and examined for cracks,etc.Bauschingers methodA specialmicrometer and caliper used tomeasure the expansion of 100 by I
22 by 22-mm. prisms after stor- *age in hot water of any desired /.temperature.
CAUSES OF UNSOUNDNESS
Uncombined or free CaO in portlandcement can lead to unsoundness; and ex-cessive volume change. The presence offree CaO in cement may be the result ofeither incorrect proportioning of the rawmaterials which introduces an excess ofC2CI into the mix over that needed forproper combination, insufficient grindingof the raw materials, or of the underburn-ing of a properly-proportioned, properly-ground raw mixture. The free CaO in theclinker from a well-burned, over-limed orcoarsely ground raw mixture is likely tobe harder burned and to hydrate moreslowly and thereby cause greater expan-sion than that in an under-burned mix-ture.
Insley ancl McMurdie (s) state that:Free Cao usually occurs as rounded
grains, either singly or in aggregates (Fig. 1).-aggregates appear to be the result of imper-
fect batch mixing. Single grains, which areoften located at the centers of C&, are evi-
{dently the result of imperfect diffusion dur-ing reaction to form CZS and C$.
Hard-burned, crystalline MgO (peri-clase) when present in cement in exces-sive amounts also has been found toproduce large expansions which may not
-.
develop for a considerable period of timebecause hard-burned MgO reacts S1OW1ywith water. Insley and McMurdie (3)have reported that free MgO occurs incommerical clinker almost without ex-ception as separate grains in the intersti-tial constituents (Fig.2).
Bogue (4) has shown that the3Ca0 AIZOScontent of the cement has
t!.
a significant effect on the autoclave ex-pansion. He found that for slowly-cooledclinker, where the 3Ca0 oAIzOawas crys- !.
tallized, the autoclave expansion in- i:
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.I@.
. . .
Fig. 1. (Left.) Free CaO in commercial portlanrl cement clinker.Polished specimen, etched with 1:1 alcohol-water solution for 2 minutes. Reflected light. Magnification 1,000X. (Insley and McMurdie).
Fig. 2.(Right.) Free MgO in commercial portlancf cement clinker.Polished specimen, unetched. Reflected light. Magnification SOOX.(Insley and McMurdie).
.
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HYDRATION EXPANSION CHARACTERISTICS 5
creased when the calculated or potential3CaO AlzOt content exceeded about 6to 8 per cent. With quickly-cooledclinker, where the CaO and A1203 in theglass are not present as the simple com-pound 3Ca0 .AIZOS,the potential or cal-culated 3Ca0 oAIZ03 has no significanteffect on expansion.
According to Lea and Desch ($ Lerch(6), and others, calcium sulfate whenpresent in large amounts may cause ex-
PREVIOUS STUDIES OF
During the period 1932-1940, muchresearch work on the question of sound-ness was carried out by the Portland Ce-ment .4ssociation and other agencies andmuch valuable inforrnat ion on this sub-ject became available. Most of this workclealt with the autoclave test, which atthat time had not been adopted as astandard method of test in any nationalspecifications for portland cement, butwhich had been adopted by some statehighway departments and was used as acontrol test by most manufacturers ofportlan~ cement in this country and inseveral foreign countries.
Probably the first investigator to usethe autoclave in testing cement was Dr.L, Erdmenger (@ of Germany, who usedit in his studies of the effect ot MgO onunsoundness in portland cement, ancl asearly as 1881 recommended it in Ger-many for testing the constancy of vol-ume. This test next attracted attentionin 1912 when H. J. Force, Chemist andEngineer of Tests of the D. L. & W.Rai.road, published an article (!)) rec-ommending an autoclave test for cement..4t the .4STM Convention at AtlanticCity in June 1913, Force presented apaper 110) which illustrated the appara-tus, described the test, and presented re-sults of tests of cements from a numberof plants. The test data included tensilestrengths of neat briquets at 24 hours andof companion briq~-lets autoclave at the
cessive expansion after setting and hard-ening owing to the continued formationof calcium sulfo-aluminate. Expansiondue to this cause is not common in com-mercial cements since specifications re-strict the SOS content to values below thepoint of possible danger. Lerch (6) andMeissner (7) have shown that the expan-sion caused by large additions of gypsumis not detected by either the pat test orthe autoclave test for soundness.
THE AUTOCLAVETEST
age of 24 hours and then tested for tensilestrength, the autoclave expansion of 1 by1 by 6-in. neat bars, the tensile strengthof standard sand briquets cured in wat,erup to 6 months, and a limited amount ofinformation on the chemical compositionof the cements. The method of conduct-ing the autoclave test and the specifica-tion limits used by the D. L. & }V. Rail-road are given in the following extractfrom their specifications for portland ce-ment (10),
Sowtdness: Force -Autoclave TestThree neat briquets to be made up in theusual manner and allowed to remain in thedamp closet for 24 hours. .4t the expirationof that time, the briquets are to be removedfrom the molds and placed in the autoclave,sufficient water being added to partly orwholly cover the briquets. The autoclave isthen closed, the burners being of sufficientsize to raise the pressure to 295 lb. in notmore than 1 hour. The pressure of 295 lb.shall be maintained for 1 hour longer, or atotal time of 2 hours. The pressure is thengradually released, the briquets taken outand placed in the moist closet, where theyshall be allowed to remain for 1 hour. At theend of that time they are to be broken in thestandard cement testing machine in theusual manner. The average tensile strengthof the three briquets taken from the auto-clave must show a tensile strength of notless than 500 lb. per sq. in. They must alsoshow an increase of not less than 25 percent over the average tensile strength ofthree briquets broken at the age of 24 hours.
-
6 H. F. GONNERMAN,W. LERCH AND T, M. WHITESIDE
A bar of neat cement, 6 in. long by l-in.square shall be made up at the same time thebriquets are made. This expansion bar toremain in the moist closet for 24 hours andto be removed along with the briquets andtested with the briquets in the autoclave,as indicated above. After 1 hour in the moistcloset, this expansion bar shall not show anexpansion greater than 0,5 per cent.
I% a few years following the publica-tion of Forces paper, the autoclave testwas given some study, notably by \17igand Davis (11), but was never adoptedby the ASTM as a standard until 19-N,Since about 1926, and particularly since1934, the autoclave test in various forms,was given serious attention by a numberof agencies including ASTM CommitteeC-1, manufacturers of portland cement,and the Portland Cement Association. Aresum6 of some of the published articlesalong with the results of some laterstudies of this test will now be presented.
Autoclave Tests by R. N. Young. In1937, R. AT.Young presented data (12)correlating the results of autoclave testson neat cement bars with the expansionsand contractions of similar bars whenstored for long periods as follows:
(1) Continuously in water,(2) In air outdoors protected from di-
rect sunshine and rain,(3) In the laboratory at 70F. and 50
per cent relative humidity.Youngs tests included data on 186 com-mercial normal portland cements gath-ered from various parts of the country,All except one of these 186 cements weresound in the ASTM pat test over boiling~,ater, but 18 of them showed autoclaveexpansions above 1 per cent by Youngsmethod of test which Young stated pro-duced expansions equivalent to about 60per cent of those produced by ASTMMethod C151. The expansion of these 18cements in water at 4 years averagedabout 0,32 per cent as compared withabout 0.20 per cent for the remaining 168cements. Young considered that cements
showing a hydration expansion of 0.3 percent, or less, in neat cemint specimensduring 4 years storage in water wereacceptable.
In air storage at 50 per cent relativehumidity, or in storage outdoors, the ce-ments of high autoclave expansionshowed a distinct tendency first to con-tract for 6 to 12 months and then to ex-pand until in many cases disintegrationoccurred. The diagrams in Fig. 3 takenfrom Youngs paper illustrate this be-havior. Young also pointed out that theeffect of CS.A content was to increaseautoclave expansion and above about 11per cent to increase the contraction in airand in outdoor storage, He found thatthe expansions under wet storage werenot influenced by the CSA content.
Studies by L, S, Brown and M. A.Swayze. In a paper (13) published in 1938,Brown and Swayze reported the resultsof their studies of the action of:
(1) Water at 70F.,(2) The ASTM steam test, and(3) The autoclave test,
on the degree of hydration of free CaOand crystalline MgO in cement andpointed out that it is the reaction ofthese oxides with water to form Ca(OH)zand Mg(OH)z which is accompanied byvolume increases of 97 and 118 To re-spectively, that causes excessive expan-sion and cracking of concrete,
These authors reported finding threeforms of free CaO in portland cementwhich they designated as:
(1)
(2)
(3)
Lig~t-bur~ed lime (quicklime);hydrates rapidly,Hard-burned lime; hydrates slowlyand is the most dangerous form,Air-slaked hard-burned lime;found in cements originally con-taining free CaO that have beenheld in open storage for more thana few hours.
Brown and Swayze imply that thegrains of CaO and MgO found in cementwill, in general, be more or less sur-
-
HYDRATION EXPANSION CHARACTERISTICS7
,uents 01 me Illillcu , *Vtheir hyclra- unhydrateu ua~
Magnesia arthe ~o;l t~~t. In
sins entmely exposed, attacked, with size limits for separate grams
:-.~. .~[e have been unable to find anYrounded by the other constit
-~ coO in autoclave specimens,cement which tend to delay ~tion. They state that:
>pears to be unaffected by,. ,,,. .. . _.1 the autoclave it is rapidly
For free Cao W- - .. i
7:~.
n
~
4%T0rTTl
.......
.,!ndllll,. -
,0.2t-/
o
;mLL..lJ~c~?=iUr-l-I IA L {
.,,!.!,.....-0.40,\~~56
I
AqeatTest. yearaP,. 0, (.,,,. #,, ,,8,,,.!! .aam,d Imk.. W..IO. !0 *I.,0,... MU* ,,,,, ,4,,,,,.,.,,,,,, 10 d.> .114 out~..,.,. !.,,.-.
EmI I I I ~L-l I I I 1 I 1661012146 16\-Al 2345 r.A c.hn+ - Derten+
-
qeatTea+- years-, .. .. .
l?ig, 3.Dittgrams (Fig. 1 to 9 incluslve) :romThe Autoclave Test and Interpretations by R.
X. Young. Journal American Concrete Institute Sept.-OctQ,1937, p. 13.
the maximum size that will be completelyin the vicinity of 20 microns. In general the
hydrated in the boil testis approximately 20grains of magnesia found in cements will be
microns. Grains exceeding 20 microns areconsiderably under 20 microns.
not uncommon in commercial products. TheMoreover, the autoclave t~st is much
maximum size that can be hydrated in themore effective than the boil test m hydrating
autoclave treatment has not been deter-rement minerals, thus diminishing the like-
.
-
8 H. I?. GONNERMAN)\Y. LERCH AND T. M, \\-H~~ESIDE
.
Iihood that enclosed lime or magnesia grainscan survive the treatment unaffected. Ithas been shown that it is possible for freeCaO to remain unhydrated through the boiltest, and magnesia is quite untouched; onthe other hand, the autoclave treatment isfound to hydrate nearly, if not quite com-pletely, free CaO and magnesia as theyusually occur in portland cement.
The conclusions drawn by Brown andSwayze were:
First, that the present ASTM steamtest is entirely inadequate as an indicatorof the tendency toward delayed expansion.Not only is crystalline magnesia completelyunaffected by the steam treatment, but thelarger free CaO grains are incompletelyattacked by the test. Small grains of limeinside the clinker particles remain essentiallyunchanged.
fjecond, the 5-hour autoclave test at-120F. (14) furnishes a reliable index forthis type of unsoundness. In only the coars-est of cement particles can lime and crystal-line magnesia escape the complete actionof the high pressure treatment.
Discussion of the A uioclave Test by J.J. Fox. J. J. Fox made the following sig-nificant statements in the July 1937issue of Pit and Quarry (15):
The expansion undergone by neat ce-ment bars when subjected to the autoclavetest may be due to either free lime or mag-nesia or to a combination of the two, Theamount of expansion contributed by eachdepends largely upon the physical charac-teristics oi the clinker which are influencedby the burning temperature and the rateof cooling.
The same percentages of free CaO in dif-ferent cements do not always produce the
same degree of expansion. This is accountedfor by the degree of burning and the densityof the clinker. In cements made of porous,underburned clinker the free CaO is moreaccessible to water and is more fully hy-drated before the cement sets, thereby re-ducing the expansive force. Increasing thefineness of cement also reduces expansionfor the same reason.
Mr. Fox also discussed the autoclavetest with respect to its value for controlof burning at the plant and indicatedthe measures to be taken at the plantin order to avoid high autoclave expan-sions caused by either free CaO or MgO.
Discussion of Magnesia and the A zdo-clave Tesi by H. H. Vaughan. In a. pam-phlet (16) published in 1938, H. H.Vaughan raised a number of importantquestions regarding the significance ofthe autoclave test with respect to MgOin cement although he seemed convincedof its usefulness in detecting free CaO.
From extensive study of a number ofinvestigations and some additional testsof his own, as well as from his experienceover a period of years with a rather highmagnesia portland cement in Brazil,Vaughan concluded that:
There is no experimental evidence sup-porting the theory of abnormal delayed ex-pansion caused by magnesia and high expan-sion in the autoclave test does not determinethat the cement is of unsatisfactory qual-ity. The autoclave test determines the pre-sence of free lime that remains unhydratedafter the preparation of the specimen.
Additional data have been obtainedwhich throw further light on the ques-tions he raises. These will be presentedlater in this paper,
INVESTIGATIONS BY THE PORTLAND CEMENT ASSOCTIATION OFLABORATORY-PREPARED PORTLAND CEMENTS
Since 1932 the PCA Fellowship at the mercial and laboratory-prepared cementsNational Bureau of Standards and the in an effort to determine what constitu-Research Laboratory at Chicago ha~~e ents of the cement produce high expan-conducted numerous tests of both corrl- tiions in the autoclave test and to
-
1HYDRATION EXPAXSION (k.kR.$cTERrsrlcs 9
1
compare the autoclave expansions withthe length changes of corresponding spec-imens stored in water and in air. Inone of the first groups of tests at theFellowship, specimens made with thepure compounds C&, CzS, CW4, C4AF,and mixtures of these compounds, weretested in the autoclave and during stor-age in water and in air. In one case 5 percent of crystalline MgO was added to asynthetic mixture of C3S and C2S.The re-sults are given in Table 1, which is fromPaper 55 of the Fellowship (Ii). It willbe noted that both when tested alone andin synthetic mixtures, the compoundsC3S, C2Sand CAAF showed slight con-tractions in the autoclave test. C3A whentested alone disintegrated in the auto-clave and when added in the amount of15 YOto a synthetic mixture of C$ andCZS the mixture showed an expansion ofabout 1 Y. in the autoclave test. An ex-pansion of about 1 % also occurred when5 Y. of crystalline MgO (periclase) wasadded to a synthetic mixture of pure C&and C2S, The principal value of theseresults is in showing the possible effectsof these various compounds on the auto-clave expansions of commercial cements.
Other series of tests conducted by thePortland Ce~ent Association on the vol-ume change characteristics of portlandcement are listed as follows:
series 2.?o (Fellowship InvestigationK-2) :
Influence of Composition on theQualities of Portland Cement
5
laboratory-prepared cements withMgO added; C3S constant,laboratory-prepared cements withMgO substituted for CaO; C$ de-creases.
255 (Fellowship Investigation C-.Series8-9) :
.s
1- ;, Investigation of 34 High-EarlyStrength Commercial Portland Ce-i~.
to ments
Initial tests made in cooperationwith the Sponsoring Committeeon High-Early Strength of ASTMCommittee C-1 and reported bythe Working Committee on Vol-ume Change and Soundness ofPortland Cement in the 1936 Pro-ceedings of the ASTM, v. 36, I,page 225. (18)
.Series 260 (Fellowship InvestigationK-2) :
Effect of Fineness, Composition andClinker Burning Temperature onStrength and Volume Change Charac-teristics of Portland Cement
79 laboratory-prepared cements.
Series 263:Autoclave and Length Change Testsof 418 Commercial Portland Cementsand 213 Special and MiscellaneousCommercial Portland Cements.
Series 270 (Fellowship InvestigationK-4) :
Tests of Heat-Treated CommercialClinkers
116 cements prepared from 26 com-mercial clinkers before and after heat treatment in laboratory.
,$cries 271: Cooperative Autoclave Tests of Port-land Cements
Initially reported by the WorkingCommittee on Volume Changeand Soundness in the 1938 Pro-ceedings of the ASTM, v. 38, page280, Part I. (19).
35 commercial cements.
Series 276:Tests for Grindability and Clinker
Properties of Quickly-and Slowly-Co~led Grab Samples from Comm&--cial Kilns
61 cements ground in the laboratory
-
TABL
EI.
COM
PARA
TIV
ER
ESU
LTS
OBT
AIN
EDO
NN
ORn
~ALW
ATE
RCU
RIN
GA
ND
HIG
HpR
ESSU
REsT
EA~I
CURI
NG
OF
CE~f
ENT
CO~~
pOU
ND
SAN
DCE
RTA
INM
LYTf
JRES
OF
CEM
ENT
COM
1O
UN
DS
(Test
sby
Portl
and
Cem
ent
Ass
n.Fe
llow
ship
)G
ypsu
ma{
idedt
ogi
ve1.
8%S
03an
dgr
ound
toab
out
2200
sq.
cm.
pmgm
._
.
.
_
.
..
..
.
.
1 2
E3
4 5 6 7 8,.
Com
posit
ion
BCZ
S
C,s
C,A
C4A
F
p;50
]
(C3S
42.5
)(C
,S42
.5)
(CaA
15.0
)(C
,S42
.5)
C,S
42.5
)(C
4AF
15.0
)(C
,s47
.5)
(C,s
47.5
)(it
rgo5.
0)
Com
pres
sive
Stre
rs@
ho
fN
eat
Cem
ent
Past
esin
Seai
cdV
ials,
l-in.
13M
orta
rCu
bes,
ib.
per
sq.
in.
4070
Wat
er
_..
Curin
gCo
nditi
onSt
oreA/5%d
0.~ +0,4 lb .S36
u I
.G -m san
+ 0.10 IG 0 ICO Curves Represent Ce~ent: Wit~ Less than 1.5/% Free CaO
o6 I
11.6 ,
1.z
0.8(
0.4
234.5MgO
, * +094 , fe..owu
o
0
() o 0( 10
:00
0n o
0
o00
& &() -0
0
012345
W,
ll
;2) l
ll
/
012345Content of Cements - percent
Fig, 1I.Relationships between the length changes, the MgO undissolved (After 10 minutes in2N HN03 containing 10 ml. of 48~o HF), and the MgO content of cements prepared from plant-coolecl, quickly-cooled and slowly-cooled commercial clinkers of varied composition.
-
c.-
f12~ /0
0
10-0
0
/0
8S/ow/y -Coded clinker-
-;6.
//
4 I/
2
AS7M Lim~
;Q u~kiy-cwledClinke. _
o -~ -+-* . .
Slowly-Cmled Clinker -- Av. Free CaO Content -02 %Quickly II i, Mill, ,,
-0:6%
1 I I I
.,
--
-. . ,- -. .
I1
-1I
4 1---
t
--- 1 07d--- +-. ---- Ned Ce ents
.
I 2 3 4 5MgO Content - percent
Fig. 12.Com~arison of the length changes and undissolved MgO (after 10 min. in 2N HN03containing 10 ml. 4870HF) for cements prepared from slowly-and quickly-cooledcommercialclinkersof varied MgO content,
34
-
_-..
..
Fig.
13.
Phot
omic
rogr
aphs
ofc
linke
rs3S
and
3Q(L
eft.)
Phot
omic
rogr
aph
of
rlis
hed
sect
ion
of
clin
ker
no
.3S
sele
cted
tosh
owgr
ains
of
peric
lase
aso
bser
ved
inslo
wly
coo
led
clin
kers
.N
oet
ch.
Mag
nific
atio
n.llO
ooX
.(W
ard)
(Righ
t.)Ph
otor
nicr
ogra
pho
polis
hed
sect
ion
of
clin
ker
no
.3Q
sele
cted
tosh
owgr
ains
of
peric
lase
aso
bser
ved
inqu
ickl
yco
ole
dcl
inke
rs.
No
etch
.M
agni
ficat
ion
1000
X.(
Ward
)
-
,, ..,,, ,, .. . ~,.,.,,.
36 H. F. GONNERMAN,W. LERCH AND T. M. WKtTESIDE
autoclave expansions whereas the sameamount of magnesia when partly dis-solved in glass, or when present in smallergrains does not cause high expansion inthe autoclave. Measurements with themicroscop~ made by Dr. G. W. Ward ofthe PCA Fellowship of the size of themagnesia grains in the 10-minute insol-uble residues of the clinkers representedin Fig, 13 showed the following values:
Size of MgOCrystals-microns
Clinker Treatment
Average Maximum
Reheated and slowly cooled. . . . . . . 22 35Clinker as received from plant. . . . 15 fiReheated and rapidly cooled. . . . . . 10
These values are probably too lowsince some of the grains would probablybe broken down in the grinding processand also some solution would occur dur-ing the ten minutes in the acid. The meas-urements indicate that the magnesiagrains present in the clinker may befaklY large and that they are hard anddense since they are not rapidly dissolvedin 2A7HN03.
In view of the results just describedthe length changes of specimens madewith cements of varied MgO contentwhen stored continuously in water wereexamined to see what significance maybe attached to the large differencein autoclave expansion of the slowly- andquickly-cooled clinkers containing over2,5 per cent MgO.
In Fig. 14 the autoclave and lengthchange results obtained with the cementsfrom the slowly- and quickly-cooled re-heated commercial clinkers, as shown inFig. 12, are compared with the resultsobtained with the cements fromthe quickly-cooled laboratory-preparedclinkers shown in Fig. 8. These compari-sons are based on cements of low freeCaO content thus eliminating so far asis possible the effect of free CaO.
It is seen from the upper diagram at
the right inFig. 14 that when quick cool-ing is employed, and the cements arelow in free CaO, a total MgO content of6 to 7 per cent is attained b~fore thereis a sharp increase in the autoclave ex-pansion, This is a much higher MgO con-tent than the value of 2.5 to 3 per centabove which a similar sharp increase inautoclave expansion occurred with ce-ments prepared from the reheated,slowly-cooled clinkers of low free CaOcontent, as shown by the upper diagramat the left in Fig, 14. Therefore whenquick cooling is employed, a much highertotal MgO content can be tolerated be-fore high expansions (above about 1 percent) in the autoclave occur. On the otherhand, the marked difference in autoclaveexpansion between the slowly- andquickly-cooled clinker, where the totalMgO content is above 2.5 to 3 per cent,has not yet been reflected in the expan-sions of the neat cement and mortar barsduring continuous storage in water for10 years. This may be seen by compar-ing the average expansion curves in thelower diagrams of Fig. 14 which as statedpreviously are based on clinkers of lowfree CaO content in order to eliminatethe effect of that factor from the expan-sion curves. Thus the bars fromthe slowly-cooled commercial clinkershave not shown to date any tendencytoward greater expansion in water thanthose from quickly-cooled clinker of simi-lar MgO content but of low autoclaveexpansion.
It appears from these results that upto the 10-year period, the coarser grainsof MgO in the slowly-cooled clinkers, be-cause of the larger size and greater sur-face of the individual grains, have nothydrated sufficiently to cause excessiveand disruptive expansions during con-tinuous water storage. Whether such ex-pansions wiil occur at some later periodcannot be predicted. However, the pos-sibility remains that abnormal expansionmay eventually occur when these coarser
-
HYDRATION EXPANSION CHARACTERISTICS 37
I
L
I
grains of MgO reach a higher degree of surface, the individual MgO grains in de-hydration. That the MgO ,grains, even ment from slowly-cooled clinker, wouldin cements from quickly-cooled clinker not be expected to hydrate as rapidly asmay not be completely hydrated during the smaller grains in cement from the
20- 4
,8 CementsPrepared tiomCommercial ClinkersReheated in Loborotory and
16 Slowly. or @ick& Cooled
14
12 - //
10 - {
I8
16 ;
Slowly .Cm!ed 1Cl;nk er -[
4 - I
2ASTM Limit QutcklyCcvled
_/ Ciinker.-
0 =
//
Labor.iory Cemenfs prepored t./from Quick~ -Cooled Clinkers
AK Free CaO= 0.3% L, 10 ;
/y(i
/
I
I
IASTM Limit
~,+q_ 1 ~- . .. . +. -.
/II I 1
I
Neat Cemen i Prisms: 1 bg I bg [IA -in, 1A0.5 1-2 Mortur Pri$ms : Zby2.5y 93-in. -
Morfar: I-2 by Weight;0.4- /
Sbwly-Cooled --- 0-No, 4 tt$(gin SendQuickly- II
0.3- /INeof
/l-2 fVortor
o,? AV,Free CaO 0.6%/
0, I //~
~
o/-2 /.fortur_
-0.1 -- -
-0,2 ~ +. .
---
~s~ Mg O Content of Cement per cent
Fig. 14.Comparisonof the length changes of neat cement and mortar bars for cements pre-pared from sIowly- and quickly-cooled clinkers of varied MgO content.
5 years in water, is shown by the auto- quickly-cooled clinker, but might be ex-clave results in Table 5 obtained at the petted to exert a greater expansive effectFellowship using neat cement bars which when they have hydrated appreciably.were made from cements from quickly- Professor A. H. White (22) whosecooled clinker and tested at 1 day and studies of volume changes of cements ex-also after 5 years storage in water. tended over many years, has shown that
Because of their larger size and greater 3 and 4 per cent of finely ground hard-
-
58 H, F. GONNERMAN, W, LERCH AND T. M. WHITESIDE
burned MgO added to aground cement length changes of neat cement and nlor-containing 1,.9 per cent MgO originally tar bars made with commercial cementscan produce excessive expansions in neat manufactured in three different plants.cement bars after 3 or 4 years storage The principal data f~om these tests arein water and that the added MgO was plotted in Fig. 15.not completely hydrated in the neat ce- From Fig. 15 which shows relation-ment bars during 40 years storage in ships between length changes and freewater, In this case the water has more CaO content for commercial cements, itready access to the individual grains of is seen that the autoclave expansionsadded MgO whereas in the case of cement (upper diagrams) for all three plants are
TABLE 5COMPARISON OF EXPANSIONS OF NEAT CEJIENT BARS AUTOCLAVE AT AGE OF 1 DAY AN D5 YE.ARS WITH EXPANTSIOhl OF COMPANION BARS DURING STORAGE IN WATER-SERIES 230
Tests made by Portland Cement Association Fellowship at Washington, except the 5-hour autoclave tests which weremade by the Research Laboratory at Chicago.
Calculated Compound Composition~. ~ Expansion of I by 1 by 6-in. Neat Cement Bars-z1
K-2 jNo ;; C&II
I / ~ I ~ In Autoclave after iWhen Auto-1I I 1 day in Molds1 , In Water Con- claved after
C2S~ C,A ; G.4F i MgO Free ! tinuously Sy. in Water*I I I ,.,Cao jhfa&O?#mpi a&~~mp
! hf~~o~~mp,
1
~lj~~sh
I I I24h. I 72h. ly. I Sy, I Ioy. 24h. ~ 72h.
hIgO SUBSTITUTEDFOR CaO IN THE RAW MIX; CA DECREASES
the grains of MgO are surrounded by theother constituents and therefore do nothydrate so readily. Moreover, because ofthe impermeability of the neat cementand rich 1-2 mortar bars, it is diflicultfor water to penetrate to the MgO grainsand as a result they hydrate very slowly,Hence, very long storage in water mayberequired to reveal the ultimate effects ofthe MgO.
Plant and Laboratory Studies of Eject ojRate oj Clinker CoolingTables L, M and NTof the Appendix
give additional data on the effect of rateof cooling on autoclave expansion and on
highest for the slowly-cooled clinkers,and lowest for the plant- and quickly-cooled clinkers. It may. also be seen thatthe autoclave expansions for the plant-and quickly-cooled clinkers were notgreatly different, indicating that theseclinkers were cooled at approximately thesame rate. Even though the slowly-cooledclinkers were as low, or lower, in freeCaO content than the plant- and quickly-cooled clinkers, they showed a muchwider range in autoclave expansion. Sincethese cements all contained 2.7 per centor less MgO, it appears that the higherexpansions are due to the presence ofcrystalline CSA in the slowly-cooled
-
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nt
of
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23.0
22.0
23.0
21.5
23.0
22.5
24.0
21.0
27.0
23.0
.04
8.13
5
.07
9.18
2
.040
.098
.063
.138
.038
.121
.058
.136
.041
.116
.050
.131
.055
.139
.044
.133
.23
0.27
6.01
6.04
4.06
6.09
0.22
1.28
0
.28
4
.02
1.05
2.07
3.09
1.24
8.29
0
,
,
l
,
,
.15
5.18
1.01
1.03
6.05
4.06
6.16
3
.19
9.22
6.01
5.04
7.05
9.07
0.18
0
.
.19
2.23
2.01
6.04
0.05
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9.15
6
.19
0.21
4.01
3.04
0.05
4.07
2.16
9.
.
.
.19
2.22
8.01
5.04
2.06
2.08
2.18
2
.18
5,20
7.01
6.04
6.04
8.06
4.19
0
.
.23
0.27
4.02
2.05
6.08
4.10
8.23
3
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9.22
8.01
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7
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9
.24
0
.165
.180
.25
5
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.33
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1
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8
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.18
+
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.22
0
.38
0
.29
5
.34
7.06
0
.35
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3
.30
2.05
8
.29
4.05
0
.
.20
8.06
4
.23
4.06
8
.35
1.07
6
.24
2.07
4
.08
4.09
8.10
4
.07
7.08
4.08
8
.07
4.07
4.07
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5.07
4.07
1
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2
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2
,
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8
.11
6
.101
.11
4
.101
IF
-
4/2 H. F. GONNERMAN, W. LERCH AND T, M. lliHITESIDE
clinkers whereas with quick cooling therewas little opportunity for the formationof crystalline CSA. The effect of crystal-line C3A on autoclave expansion is dis-cussed below.
For each set of diagrams in Fig. 15there is a trend toward increased auto-clave expansion with increasing free CaOcontent. In general there is a trend to-ward increased expansion of the neat andmortar bars during storage in water withincreasing autoclave expansion. The con-tractions in air at the 10-year periodtended to decrease with increasing auto-clave expansion.
Results of tests made to show the effectof slow and quick cooling on cementsmade from laboratory-prepared clinkersof both high and low MgO content andof varied CSA content are given in TablesO, P and Q of the Appendix. Some ofthe signticant results for these labora-tory-prepared cements are summarizedin Table 6.
Table 6 compares the expansions andcontractions of neat cement and mortarbars for pairs of laboratory-prepared ce-ments which were made from slowly- andquickly-cooled clinker of a given compo-sition. In one of the groups of cementsthe MgO content varied from 0.8 to 1.5per cent and in the other group from 4.8to 6,1 per cent. The cements in bothgroups were low in free CaO, The re~i.d~in Table 6 for the cements of a givencomposition in the group low both inMgO and free CaO show that up to theage of 10 years the expansions of thebars during storage in water were gen-erally of about the same order of magni-tude for both slow and quick cooling.Also for these cements the autoclave ex-pansions, except in one case, were lessthan about 1.0 per cent.
In the case of the cements in the groupof high MgO content and low free CaO,the autoclave expansions were high (7 percent to 21 per cent) for the slowly-cooledclinkers, and much lower (0.2 to 9.4) for
,.
the quickly-cooled clinkers. In spite ofthe wide differences in autoclave _expan-sion, the expansions of the neat cementand mortar bars duri~g storage in waterwere for a given clinker composition,about the same for the slowly- as for thequickly-cooled clinkers. However, the ex-pansions during water storage for thisgroup of cements of high MgO contentwere considerably higher than those forthe cements in the group low-in MgOcontent. These results are in agreementwith those in Fig, 14 in showing thatwhile slow-cooling of the clinker greatlyincreased the autoclave expansion in thelaboratory-prepared cements of highMgO content, it has not to date generallyresulted in higher expansions than quickcooling for specimens stored continuouslyin water.
Influence oj CSA and C4AF on AutoclaveExpansion and Length Changes asAffected by Clinker CooliI~gIn the discussion of the autoclave tests
of the pure cement compounds (Table 1),it was stated that C3A when tested alonedisintegrated in the autoclave and thatwhen added in the amount of 15 per centto a synthetic mixture of C3S and CZS themixture showed an expansion of about1 per cent in the autoclave test, Theinfluence of C3A on autoclave expansionof cements made from commercialclinkers is brought out in Fig, 16, Thisfigure shows relationships between auto-clave expansion, expansion in water andcontraction in air, water requirement ofneat cement paste and 12 mortar, andthe calculated CSA content of cementsground from plant-cooled, and from re-heated and slowly- and quickly-cooledcommercial clinkers. The data in this fig-ure are from Table H of the Appendixand are summarized in Table 7. Theclinkers represented in Fig. 16 containedless than 2 per cent MgO and 0.85 percent or less free CaO. Hence these con-stituents should have exerted little if any
-
HYDRATION EXP.4NSJON CHARACTERISTICS 43
influence on the results shown in this comparison. The curves for the slowly-figure. cooled clinkers are based on clinkers in
The effect of C3A may best be seen which the free CaO content did not ex-,
+0.3, 1, r 1
2 10!+ ~+oz -,Ccm I~tm n
k%+o,l-u 1 0,
-
44 H. F, GONNERMAN, W. LERCH AND T. M. WHITESIDE
effect on expansion of crystalline MgO increasing the autoclave expansion butand free CaO were reduced to negligible when crystalline C3A is not formed be-values. Because of the low glass content, cause of rapid cooling of the clinker, thethe actual C3A of these slowly-cooled autoclave expansion is not affected.clinkers, except as influenced by the The expansions and contractions ofminor constituents, may be assumed to neat cement and mortar bars from thesebe close to that indicated by the calcu- clinkers, during 10 years storage in water
TABLE 7.mwrs oF CEMENTSGROUNDFROMPLANT.,QUlCKLY-,ANDSLOWLY-COOLEDCOMMERCIAL CLINKERS OF VARIED CALCULATED CsA CONTENTSERIES 270
Cements in each grou arranged in ascending order of calculated CgA content.Data compiled from l!ables H and I of Appendix.
I II1
Length Changes During 10 Years
~ Calcula- 1 A&c \vat~~ I ;;(!2 Neat Cement $% I 2 Mortar?%Cement No. {Free CaOI ted%CsA , MgO % / %I I E~
, for#c ~ ;:;::: In , ;n ,n1
Air 1 M&erIlllli
Air(-) , (-l-) (-) I Y?Y
SLOWLY-COOLEDCLIiSKER
6S , 10.917s 1 11.920s 13.521s ~ 15.0
II::1.71.31.3
1.41.3l.O1.3
,04.08.06.31.18
,2!.33.05
,006I
21.5-.006 22.5
.027 I 21.5
.137 23.0
.158 23.5
.112 23.0
.308 25,0
.318 24,5
.840 26.5
3.91 .2103.91 .2203.91 .2483.91 .2963.91 ( .256
QUICKLY-COOLEDCLINKER
.122
.076
.123
.150
.110
.110
.105
.098
.125
.081 .054
.083 ,040
.097 .042
.088 .049
.088 .047
.088 .043
.106
.096 i.026.043
.147 .031
I
1:: :::1:6 ~ A; ~ -:$O; 22.5 ~ ~.91391 .230 .132 .088 .049
268
I ;.; ~ 3: I ::.: 1.204 .104 .064 .054
2 ~ ::! ..097 ,- 3:91 .293 .211 .083 .052
10.9 ::; ] :;:!? I ::;i.098 .202
,47.054 .066
1% j 11.9 ;:; ~ ,52.193 .131
.042.081
22.0.044
21Q I 15.03.91
1.3.220
.36.137 .090 .042
1 I I 038 I23,5 3,91 .244 .138 .102 .039
PLAATT-COOLEDCLIISKER
5P I 15 I 16 ~ .33 ~ -.oo3 22.5 3.91 1 .214::; i ::: 1 04411P i 4.4 .
2P ; 6.2:039
26P ~ !:! I :1 :;: ;;:; ;::; ;;[ ::# I ;;; ::!;1::! ~ 1.4 I ,36 .084 22.5
1!;3.91 .188 .136 .085 .043I
~ ;::: ::;.40 .096 23.0 I 3.91
21P.220
.38 .374.114 ,088 .039
24.5 1 4.06 .290 .132 .108 .029
lated CSA. The curve for the slowly-cooled clinkers shows that above about8 per cent of calculated CSA the autoclaveexpansion tends to increase moderatelywith increasing C3A, On the other hand,the curve for the quickly-cooled clinkersof the same compositions and having freeCaO contents of 0.85 per cent or lessshows that the autoclave expansions areconsistently low. From these results it isseen that crystalline CSA is capable of
and in air are shown in the upper dia-grams of Fig. 17. The curves do not showany effect on expansion in water due tothe presence or absence of crystallineC3A. R. hT. Young also found no relationbetween calculated CSA content and ex-pansion in water (See diagram labelledFig. 9 of Fig, 3).
For the slowly-cooled clinkers the con-tractions of the neat and mortar bars inair tended to increase when the C3A con-
-
HYDRATION EXPANSION CHARACTERISTICS 45
I
(
-0.1
-0.2
-0.3
-0.4
-0.5+0;
+ 0,2
+0,1
o
+1.o
I-- -_
. ___
---- -
-- -
- >, A!euf
\\\
-- Slowly-Cooled clinker Quickly- II II \
INeaf ~AK free CaO= .5%
I I \--. - - . ~
- - ,
/I
IS/ow/y - Cooled /
Ar/
/
//
//-
//~ Quickly-Cooled
--. -1
2 4 6 8 [() ,2 ,~ ,6Calculated C3A Gntent of Cement - per Cent
.
Fig, 17.Effectof calculated CSAcontent of cement on length changes of neat cement and mo:tar[Jars prepared from quickly-cooled and slowly-cooledcommercial clinkers.
(MgO content of cement less than 2% and free CaO content 0,85% or less; see Table 7.)
-.
-
46 H, F. GONNERMAN, W. LERCH .4ND T. M. WHITESIDE
tent was more than about 11 per cent quired for the corresponding cementsbut the quickly-cooled clinkers showed from quickly-cooled clinker (See Fig. 16),no such tendency. In this connection It is probable therefore th?t the higher
Cement No,-221, 223, 225, 226,227 228, 229, 230MgO Content of Cements: 2.98 to 3,42%Free CaO II II II : 0 tO 0.3 %C3A II II II :4.6 t06.6%
Cement No,233, 235, 236, 23? 238, 239, 240MgOContent of Cements: 2.73 to 3.44%FreeCaO II II II : 0 to 0.4%C3A M u : fo.8to 12.1%
All Cements Prepared from Qu~y-Cooled Clinker
.. _
0.
0~0 0
cf
0I -.
,- ?; l%%l%;;~%;~~ & ilk-i..Z 2 +i3.3(U:k>cc) \
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0J ~
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000000000000 l() l******.*.****o ***** . . . . . . . . . . . . . . .
PCA W2313KM 9~ll%ti Y@1228K~311961S 3Z177~18?44 120292135RSTM31230 9S5B193n>3 llZ411?4ZZ 161017~B 6~WB73l526~28
Cement Number
Fig. 19.Comparisonof length changes of 1 by 1 by 11~-in.neat cement bars withfree CaO contents of 34 commercial high-early strength portland cements.
Cementsarrangedin ascendingorderof expansion during 16 years stora e in water.8?
These cements were supplied by the Sponsoring Committee on Hi h-Ear y Strength, ASTM CommitteeTeats made on the cements are reported in the 1936ASTM Procee ings, page ZM, Part I,
MgO
c-l.
and
-
HYDRATION EXPANSION CHARACTERISTICS 49
acteristic of cements of high free CaO as the expansions of the cement in watercontent. As was pointed out previously, increased. The increase in expansion innone of the other cements showed expan- water with increase in MgO content ofsion during air storage, the cement is particularly noteworthy.
0.6
I 0.2
Eo
l-
V)
L0
0.2
0.1
0
0.1
, #
Fret? COO Confenf Of Cempn+ _ 6.5%72 hK Aufockwe Expunsion,(Mux Temp.d50E) L 2/%
* 1 , 1 ,A .-0.2 u. a 12 15lge - y~ars
Fig. 20.Length changes in 1 by 1 by Ill-in. neat cement bars for cement No. 8 (P.C.A. No. 5.)
At the top of Fig. 19 the sum of the The relationships between the MgOMgO plus free CaO for each of the 34 content of these cements and their ex-cements is shown by bar diagrams. A pansions in the autoclave and in waterdistinct trend toward increasing values are brought out more clearly in the dia-of the MgO and free CaO may be noted grams of Fig. 21, The diagrams at the
-
50 H, F, GONNERNIAN, W. LERCH AND T, M. WHITESIDE
right in this figure, which show the auto- Fig. 10 for cements having free CaO con-clave expansions and the expansions in tents of 2.2 to 3.5 per ce;t.water for cements having free CaO con- Fig. 22 compares the expansions oftents greater than 1.5 per cent, are strik- neat cement bars made with the 34 ce-ingly similar to those for the curves in ments during 16 years storage in water
,
I
-1
0.8
0,6-
0.4
0.20
~o
o
0 0
I Il.? ~xponsion During_ ? Ha. in u
r - TA;V(Mffx Temp 504 Group/)
free Coo Z L 5 %LO Free (fao > L5,Y
free &O COn&ntsOin Porenthesb
[2.23)
0(/ 83) 0(265) (> G.20)
&
(2 /2)(/ 62)
(/ 76)
0.5 ! IQ
I I I I 1 I Expansion During /6 kors in Wufer of 700-73ET~ .
0.4 free COO,2 /.5% free CaO *15% I
0.3o 0 *
/Oo 00
>
0 00.2 0 0
0
0.1~ NO Autoc/ove Tesf
001 2 3 40 I 2 3 4
MgO Content of Cement - percentFig. 21,Expansion of 1 by 1 by 11,+-in,neat cement bars during autoclaving and during 16
years storage in water.Bars made with 34 high-early strength cements of varying MgO and free CaO contents,
,
-
HYDRATION EXPANSION CHARACTERISTICS 51
I!
with the corresponding strengths of 6 by sion in the autoclave and in water com-12-in. concrete cylinders and 1-2.77, 2-in. pare favorably with the strengths ofmortar cubes at age of 10 and 15 years those made with the cements showing
,
0000
7000
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0 m0- (5gz)
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00 0 00 0 0 0
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!-2.72-4.32 Cmrefe CylindersStored Moisi Lhfll Tested of/0 Edrs
[ o I8 7000 ou /-2. 77 Mor7i7r Cubes in WoferL o
Unii/ fisfed of /5 Yeurs?/j 6000 - 0 00 Oo 00 0 (4yn)7
o 0 000
5000. oo 0 0
0 0000 00 0
00
4000 0h as21 i
+0,4 - 1 L5~VJby/1~-in Neat Cemenf Bars h 0.493 ijj Z Waler d 70E - 73Ku o
LO.3.0,
0s/6 years
LQ.
: +0.2 oo8@z:n.9U8U8:::8$**G
; +0,1I
c.-
-1
PC A-oM 231314349281125263310122 81622311961532177271824412029 2135 4
ASTM -31 UB9345H 193027331 12411242Z 321610172118628 KK73E26m 28
Cement Number
,,
,
,,
.!
1,,,
..
Fig. 22.Comparison of expansion characteristics of 34 high-early strength cements with Icompressivestrength of concrete and mortar. I
respectively. No relationship exists be- the lowest expansions k the autoclavetween strength and expansion in the and in water, and the cements appear !autoclave or in water. The compressive to have suffered no impairment of Istrengths of the specimens made with strength up to the present. Ithe cements showing the highest expan- Cooperative Auotclave Tests of Conwner- (
-
H. F. GONNERMAN, W. LERCH AND T. M. WEUTESIDE
ROpen areas indicate Free CaO content
-o:=Contraction during 15 years Storage1 l* ll . l*-0.2 l o 0 1
00z oaJ
-0.3. OQQQ ov o
0.L~
I-0.4 c Normal portlando -0.5. , 1 , 1 1 , 1 ,.-
5L
g +1.0vL
0 +0.5?co 0
,-
In
I , I 1 1 , 1 1 I 1Expansion during .5 hr.sin oAutoclave (Max.Temp,.420CF] 1)
ASTM Limit- 00----- ______ ___
o
0 OQQQ OQO oboo? 1
m1116217120191521249141018617 3
* ***
t 1 (in Air
l
l
o
00
D
gh EarlKZj7i.
30.___00709$0 QOQl* *
I//// I
Willo190l333
Cement NumberFig. 23,Comparison of length changes of 1 by 1 by 11+-in.neat cement bars with MgO
plus free CaO contents of cements.*lhese cements contained additionsCements arranged m ascending order of expansion during 15 ears storage in water. Normal Portland Ce.
fments hTo.s 8 and 13 are not listed since their expansion data are lmited to one year in water.These cements were included in a cooperative autoclave test sponsored by the Working Co~ittee on VolumeChange and Soundness, ASTM C-1, the results of which were reported in the 1938ASTM Proceedings, Part I, page280.
I
-
HYDRATION EXPANSION CHARACTERISTICS
c;al ~o~~luJz~ Ce~ett~~.~e~~e~ ,271. Tables cements used in the
53
cooperative tests re-J and K of the Appendix give chemical ported by the Working Committe on Vol-analyses and results of autoclave and ume Change and Soundne~s, ASTMlength change tests on the 35 commercial Committee C-1, in 1938 (19). The auto-
1-ic
L
-E8
Tc0.-
vlc
(uQd
+ 1.2
+1.0
+ ().8
+ ().6
+().4
+(3.2
o
~ansion During 5 Hours in Autoclave(Max. Temp. 420 E )
(w) I0/
/
I I t 0(.57)free COO content in F&rentheses //
I/
(:05)(/:9]
(RP
+0.4E~xmsion During 15Years in Water at 70 E
I I I+(3
-
J-k H. F. GONNERMAN, W. LERCH AND T. M, WHITESIDE
clave tests of these cements were madein accordance with the normal 5-hr. testcycle (3 hr. at max. temp. of 420F.).
Data from these tests are presented inFig. 23 and 24. In Fig, 23 the lengthchanges of neat cement bars are com-pared with the MgO plus free CaO con-tent of the cements which are groupedaccording to type and arranged in as-cending order of expansion of their cor-responding neat cement bars during 15years storage in water.
The expansions during 15 years inwater for the 21 normal portland (TypeI) cements ranged from 0.1 to 0.3 percent. The increase in the expansions forthe various cements between the 28-dayand 1-year periods and between 1 and10 years was relatively large comparedto that between 10 and 15 years. Threeof the four cements showing the highestexpansions at 15 years also showed thehighest autoclave expansions. Only fiveof the cements showed an autoclave ex-pansion in excess of 0.5 per cent, Thehighest autoclave expansion was 1.1 percent. The contractions of the neat barsstored in air of laboratory showed noconsistent trend with respect to the ex-pansions in water but the contractionsof the bars stored out-of-doors undercover for 15 years showed a tendency todecrease with increase in expansion ofthe companion bars stored in water.There was a distinct trend toward in-crease in the expansion of the neat ce-ment bars during 16 years storage inwater with increase in the per cent MgOplus the per cent free CaO.
One of the cooperating laboratoriesmade chemical analyses of the cementsand reported that several contained ad-mixtures. These cements are indicatedby an asterisk in Fig. 23. It will be notedthat several of the cements reported tocontain admixtures showed greater con-tractions than the others in their respec-tive groups.
The expansions of the neat cement barsmade with the six high-early strength
cements during 15 years in water wereof the same order of magnitude as thosefor the normal portland cements showingthe highest expansions in water, but werein no case higher than 0.3 per cent, Theautoclave expansions for the high-earlystrength cements were less than about0.25 per cent except for one cement (No.23) which showed an autoclave expan-sion of 0.58 per cent. This cement showednext to the lowest expansion in water ofthe six high-early strength cements.-
The autoclave expansions and the ex-pansions of neat cement bars in watermade with the three moderate heat, thetwo sulfate-resisting, and the three port-land-pozzolan cements were low but theircontractions in air and in outdoor storagewere relatively high in some cases.
In Fig. 24 the length changes of neatcement bars made from the various typesof cement during autoclaving and during15 years storage in water or in air areplotted against the MgO content of thecements. The relationship between ex-pansion in water and MgO content (mid-dle diagram of Fig. 24) is good consider-ing that the indicated free CaO contentof the cements varied over a wide range.The relation between autoclave expan-sion and MgO content is uncertain be-cause of the variation in free CaO contentof the cements and lack of knowledgeas to the method and rate of coolingernpioyed in the various plants in whichthey were made. While it appears fromthe autoclave tests that most of theclinkers from which these cements weremade had been rapidly cooled it alsoappears that in some cases where theMgO content was relatively high theymay have been cooled slowly. In theupper diagram of Fig. 24 the dash-linecurve is intended to represent clinkersthat appear to have been slowly cooledand the solid line curve clinkers thatappear to have been quickly cooled, Bothcurves are similar to those shown in themiddle diagram of Fig. 12.
The contractions of neat bars during.
-
HYDR..ITION EXP.+NSION CH.IR.\CTERISTICS 5.?
15 years storage in air of laboratory andoutdoors under cover are shown in thelower diagram of Fig. 24. The contrac-tions of the neat bars stored in air oflaboratory show considerable scatteringwhereas those for bars stored outdoorsunder cover show much less scatteringand their contractions are approximatelyone-half those of the bars stored in thelaboratory. R. N. Young (12) also re-ported lower contractions for neat ce-ment bars stored outdoors, but protectedfrom direct sunshine and rain, than forbars stored in the laboratory at 50 percent relative humidity and 70F.
Tests of 418 Commercial Portland C~-ment.sSeries 263: Tables R, S, T andU of the Appendix give results of auto-clave tests, length change determinationsof neat cement bars at ages of 28 daysto 15 years, and chemical analyses for3 groups of commercial portland cementscomprising a total of 418 cements. In thefirst group were 103 cements purchasedin 1934 and tested in 1936. The secondgroup comprised 122 cements purchasedin 1936 and 1937 and tested in 1937. The225 cements in these two groups repre-sented virtually every plant east of theRocky Mountains. They were obtainedin the open market and furnished by amember company of the Association fortest. These cements were stored in sealedmetal ccmtainers until tested. The third
group included 193 cements from plants
throughout the United States which were
received by the Research Laboratory at
various times during 1936 to 1938 and
tested as received. Since the A18 cements
were manufactured before the adoption
in 19A0 of the ASTM specifications cov-
ering j types of cement, virtually all of
them were 0$ Type I classification.In Table R, to facilitate study of the
:Iutoclave and length change data, the-118cernent,s are listed in ascending orderof their expansions in the autoclave tesi(5 hour cycle, 3 hours at maximum tem-perature of 420F) and are arranged ingroups according to the magnitude of
their expansions in the autoclave test,the range of autoclave expansion for eachgroup being restricted to narrow limitsas follows: O per cent or l~s (negativeexpansion), 0.01 to 0.10 per cent, O.11to 0,20 per cent, 0.21 to 0.30 per cent,etc.). In Table R the averages of theresults of the tests on the cements in thevarious groups and the high and lowvalues for each group are also shown.The autoclave tests were made on 1 by 1by 11~-in. neat cement bars at age of 1clay.
Table S gives the oxide analysis andthe calculated compound composition formany of the cements. In this table thecements are listed in the same order asin Table R.
Tables T and U contain the same dataas Tables R and S, respectively, exceptthat in these two tables the cements arehsted in ascending order of their expan-sions in neat cement bars during 15 yearssiorage in zvaier and are arranged ingroups according to the magnitude oftheir expansions during the 15 yearsstorage in water, the range in expansionfor each group being restricted to thefollowing close limits: 0.100 to 0.125 percent, 0,125 to 0.150 per cent, 0.150 to0.175 per cent, 0.175 to 0.200 per cent,etc. These four tables permit the datato be studied on the basis of the magni-tude, within relatively close limits, ofeither the autoclave expansion, or theexpansion of the neat cement bars during15 years storage in water.
The average results from Tables R, S,T and U are summarized in Table 8where it will be noted that the expansionsduring storage in water tend to increasewith increase in autoclave expansion.
The contractions in air also tend toincrease with increase in autoclave ex-pansion but at the higher autoclave ex-pansions they tend to decrease. The prin-cipal chemical constituents of the cementwhich appear to correlate with both auto-clave expansion and expansion duringstorage in water are the MgO and free
-
TAB
LE
(I.-S
UM
MAR
Y O
F A
UTO
CLA
VE
AND
LE
NG
TH
CffA
NG
E TE
STS
01
418
CO
MM
ERC
IAL
POR
TLA
ND
C
EMEN
TS-S
ERIE
S 26
3 Tw
o hu
ndre
d an
d tw
ent
-live
of
the
418
cem
ents
wer
e pu
rcha
sed
in t
he o
pen
mar
ket
and
furn
ishe
d fo
r te
st b
y a
mem
ber
com
pany
of
the
Port
land
C
emen
t A
ssoc
iatio
n.
Of
thes
e 22
5 ce
men
ts, 1
03 wer
e pu
rcha
se cr
. rn 1
934 a
nd a
utoc
lave
d in
193
6; 12
2 wer
e pu
rcha
sed
in 1
936-
1937
and
auto
clav
ed i
n 19
37; 1
93 of
the
418
cem
ents
wer
e re
ceiv
ed d
urin
g 19
36-1
938 a
nd a
utoc
lave
d as
rec
eive
d. S
mce
the
cem
ents
wer
e m
anuf
actu
red
befo
re t
he A
STM
Te
ntat
ive
Spec
ilica
tion
for
5 ty
pes
was
ado
pted
in
1940
, virt
ually
ai
l of
the
418
cem
ents
wer
e of
Typ
e I
clas
silic
atio
n.
Auto
clav
e ex
pans
ions
det
erm
ined
in
acco
rdan
ce w
ith A
STM
C
-151
(5 h
r. i
n au
tocl
ave,
3 h
r. a
t m
ax.
tem
p. o
f 42
0F.
).
Leng
th c
hang
e m
easu
rem
ents
mad
e on
1 b
y 1
by 1
1%~
in. n
eat
cem
ent
bars
of
ASTM
no
rmal
con
sist
ency
. Af
ter
24 h
ours
in
mol
ds i
n m
oist
air
the
bars
wer
e st
ored
in
air
at 5
0% r
eia-
tiv
e hu
mid
ity a
nd 7
0 to
8O
F.,
or i
n w
ater
at
70 to
75
F.,
or o
utdo
ors
prot
ecte
d fr
om r
ain
and
snow
. (S
ee T
able
s R
,
S
T
and
U
of A
ppen
dix)
. A
ll of
the
cem
ents
wer
e so
und
whe
n te
sted
in
acco
rdan
ce w
ith
ASTM
C-
189,
Te
st
for
Soun
dnes
s of
H
ydra
ulic
Ce
mcn
; ov
er
Boili
ng
Wat
er
(Pat
Te
st).
%:p
;,,
I
I I
I
sen t
ed
Expa
nsio
n-%
I
Aver
age
Con
trac
tion
or
Expa
nsio
n-%
I
Aver
age
Oxi
de A
naly
sis-
%
-~-
____
--.-
_-
Cal
cula
ted
Pote
ntia
l C
ompo
und
Com
posi
tion
[No.
T!
ta
l
Auto
clav
e
Av.
Ran
ge
, --.
.-
___-
-__
~_-
-..~
..--.
-..-
..-.-
_.. ,
_.
15 .$
2;fs
r in
I In
Wat
er a
t 75
F.
(+)
I In
A
ir 50
% R
.H..
7O-8
0F.
C
-1
I
AV.
I I
Ran
ge
28d.
ly.
2y
. 4y
. 1O
y. 1
.5~
. 28d.
ly.
2y
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5~.
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k --
7
0 i! --
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v)
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AR
RAN
GED
IN
AS
CEN
DIN
G
URD
ER
OF
r;XP
ANSI
ON
IN
AU
IOCL
AVE
--
2 43
0.:
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.03
.06
.08
.08,
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-13 I
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3 .1
2 .1
6 -1
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7 -2
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5 .2
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7 .2
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7 -3
0 22
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63.6
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1.14
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1.76
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51
94
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8 .2
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7 89
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369
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