Infrared and Raman spectral studies in cement and concrete (review)

CEMENT and CONCRETERESEARCH. Vol. I0, pp. 771-782, 1980. Printed in the USA 0008-8846/80/060771-12502.00/0. 1980 Pergamon Press, Ltd.

INFRARED AND RAMAN SPECTRAL STUDIES IN CEMENT AND CONCRETE (REVIEW)

S.N. Ghosh and S.K. Handoo Cement Research Institute of India M-tO NDSE-II New Delhi-11no~g India

(Refereed) (Received April 24; in final form July 22, 1980)

ABSTRACT Applications of infrared and Raman spectroscopy in the field of cement and concrete as reported over the years are quite significant. Specific applications in areas such as~ identification of cement phases including different polymorphic and crystal forms, estimation of phases in cement~ cement hydration~ admixture~ concrete-polymer~ alkali-oggregate reactions~ etc, have been recognised with various degree of success. More application of these techniques is envisaged with further advancement in instrumentation and in ~ m p l e preparation~ especially in newer products where organic substances play dominant role.

Les applications de la spectroscopic infrarouge et Raman dane le domaine du ciment/ et du b~ton, ainsi qu~lles ont ~t~ rapportees au cours des annees~ sont d'une grande importance. Les applications J \ sp~cifques ont ~t~ reconnues avec divers degree de succes dans les domaines tels que l' identification des phases du ciment y compris lee formes diverses polymorphiques et cristallinest la d~termination des phases dans le ciment~ l'hydratation du ciment t des adjuvants~ des be~ons-polymeres~ des reactions alcali-agregat t etc. On envisage d'autres applications de ces techniques a mesure que de nouveau× progres seront r~alis~s dane le domaine del instrumentation et dane la preparation des ~chantillons~ surtout dans les nouveaux produits on les substances organiques jouent un role dominant.

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Vol. I0, No. 6 S.N. Ghosh, S.K. Handoo

Introduction The application of infrared (IR) and Raman spectroscopy in the area of building science is rather recent, especially in the latter case. Considerable interest has been shown in the application of IR spectroscopy since the 5th symposium on the Chemistry of Cement, Tokyo (1968). The application of these two spectroscopic techniques in other important branches of science is quite established. The attempts to use these techniques in buildJng science ~ e quii:e understandable ~n view of continuous advancement in instrumentation and also of solving many intricate problems in building science. This review is. intended to give a state-of-art of the experiences gathered during the last ten years or so as published in various journals and proceedings of symposia. Ho,,jnv~ ~t should not be taken as exhaustJveo Anhydrous cement and ~ts..phases Earlier studies on IR of portland cement and ~tn ~heses were reported by launer (1), Roy (2), Hunt (3,4), Lehman and Dutz (5) and Midgley (6). Launer measured the spectrum of ~ - C 2 S from 620 to 5000 cm -I. Roy reportc~d spectra of ~ - C 2 S and ~ - C 2 S and found Y - C 2 S to give an altered spectrum in KBr pellets. Hunt presented IR absorption spectra of compounds of interest. Lehman and Dutz C25 ( ~ & ~ ) , C35 and o~he. ~ presented the spectra of the cement phases and cements. Midgley reported similarly. Apparantly~ the attempts were towards identification of all minerals individual]y and in combination in order to make use of this technique for possible use in quantitative estimation of phases in portland cement as one of major interests for cement chemists. Ghosh and Chatterjee~) presented the IR spectr~, both absorption and reflectance spectra (ATR) of portland cement and its phases (Fig. 1). The spectra of a number of NBS cement samples were reported by these researchers. The spectral regions of interest are the 500 cm-1 and go0 cm -I regions. The spectrum of portland cement is the resultent of all the phases. An attempt has been made to correlate the band intensity ratio (bands around 925 and 850 cm -I) for quantitative estimation of the silicate phases in cement. It appears that a semiquantitetive estimation of the silicate phases is possible in certain cement samples. Butt et al (8) observed that IR absorption spectra of cements are basically similar, consisting of the absorption bands of alite 925, 895-885 and 520 & 465 cm-I. The IR bands of bel~te 965-985 cm-I and 845-850 cm-1 are also present in the spectra ,Ement. The band at 1080-1100 cm-I in clinker spectra is due to sulphateo Butt et al also reported that the band at 770 cm -1 in the spectrum of high alumina cement could be assigned to ~(Al-O) vibrations of aluminate mineral components. They observed that with the help of IR spectroscopy the presence of particular mineral component or an individual compound even if present in very small amount in portland cement can be determined° Spectra of pure phases are still matter of much interest in respect of identification~ structure determination (co-ordination number etc), polymorphic phases~ etc. The spectral investigations on C3A for obtaining structural informations were reported by several investigators (7,9-11). Qualitative interpretations of the spectra of C3 A were put forward. Bensted & Varma (12) in their studies tabulated the spectral data of the cement phases with tentative assignments. Substitution of various ions in the C3 S lattice reduces the sharpness or even causes

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IR SPECTRA, RAMAN, CEMENT, HYDRATES, CONCRETE

~

disappearance of some of silicate bands and broadening of bands, Alite contains discrete 5i044- tetrahedra which are very much affected by the proximity of other ions present in the lattice° However~ such effects are weaker in belite. C3A shows discrete bands in its spectrum in contrast to the ferrite phase (C4AF) which is somewhat glasslike,

S

Boikova et al (13) recently reported the IR spectra of the different crystal forms of C3A. The band positions are given in Table-I. Thus~ considerable differences in band position and in band number were observed for different crystal forms of C3A o Factor group analysis was performed to explain the spectra of the different crystal forms of C3A. The spectral data of C3A were earlier reported by Bensted and Varma (12) & others (7,10,11)o The polymorphs of C2S were studied by Bensted and Varma (14). The spectral data are listed in Table II. The spectra (Fig. 2) are characteristic° The spectra of the high temperature polymorphs ( ~ O C / ) art quite similer,

tte

The IR study of polymorphs of C3S appears to be not reported so far° Conjeand and Boyer (15) observed an extra band at 832 cm-1 in the Raman spectra of monoclinic alite but this band was found to be absent in the spectrum of synthetic monoclinic alite° I

Solid Solution

I

I

1200 1000

I

I

800

I

I

600

I

J

400~ Cm-i)

Tarte (16-17) while studying IR FIG. 1 spectra of solid solution C2Ap-FI_ p observed increase in wave number but Reflection spectra of cement above C2Ao.7Fo. 3 no change in spectra minerals and cement (ref. 7) until higher alumina content up to C2A8.85Fo.15. The position of certain lines changes again apparently due to the appearance of new phases such as C3A and C12A7° An interesting comparison of spectral absorption characteristics was made in the case of C2F solid solution (vitreous and crystal.line phases) and of C4AF phase. The isomorphous replacement of A1-Fe was also studied by Tarte (18) and this accompanied by change of position of bands and the appearence of a new band which was assigned to tetrahedral FeO 4 group. Sakurai et al (19) reported the IR spectra of Cr substituted ferrite phase in the C2F-C2Cr system and observed that the absorption peaks at 1160~ 950 and 710 cm-I became stronger with increasing substitution wh±le the bands in the 640 - 580 cm-I region became ueaker° Similar phenomenon was observed in the CaAF-C?Cr system~ i.e. thm

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S.N. Ghosh, S.K. Handoo TABLE - I IR bands of different 'Cl'A

--

crystal

Ch~mica'l Composition~.) CaO A1203 Na20

forms of C3A (Ref. 13)

---900 - 700 cm -1

below 700 cm -1

Cubic

60.57

37.40

2.42

894~862~842,816~ 804,788~742t710

626,593~52b~512~ 460~431,415

Orthorhombic

59.04

37°50

3.80

g04,861,824~801~ 745~716

592,540,510~ 473,431~a17

Tetragonal

57.52

37.22

4.83

879~862~790~732~ 723

597~537~523~494~ 4309~16

Monoclinic

56.30

37.38

5.70

870~794~733p724p

510~596~537~523~ 493~432~a16

C3A ( C u b i c )

62.50

37°23

922~87a~794,735 t 724

60g,598~537~ 50°~a92~432,416

-

TABLE - II IR spectral data of C25 (Ref. 14) c~

Y

510 s 550 sh

500 sh 515 s 550 m

840 sh

850 sh

440 m 455 sh 49 5 S 515 S 565 S 81 5 W 855 VS

930 vs~b

935 vstb

1000 sh 1150 w

980 s 1150 w

500 sh 529 s 540 sh 845 870 890 920 1000 1170

vs sh vs sh s vw

g20 930 950 1150

w sh s vw

1160 and 720 cm -I bands became stronger with increasing substitution of Cr203 whereas the strong absorption spectra at 780 and 430 cm-1 became weaker. The bands in 720 - 780 cm -I and 430 cm -1 belong to AlO 4 tetrahedra and the 610-660 cm -I to FeO 4 tetrahedra. Toropov (20) studied the IR spectra of solid solution of Ca35iO 5 Ca3GeO 5 in the range 700 - 1200 cm-1 and observed differences in intensity and position of 930 and 780 cm -1 bands. Singh (21) did not notice any change of C3S spectrum when C35 was doped with NiO and he concluded that Ni might not replace Si. Also~ the liberation of free lime was observed to increase with the addition of NiO~ which could indicate that probably Ni substitutes for Ca. Shchetkina et al (22) also failed to notice any change in band position in the IR spectra of C35 doped with Cr203 (0.8~). However~ a drop in intensity of the absorption bands at 825~ 450 and 410 cm -I was observed by them.

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775 IR SPECTRA, RAMAN, CEMENT, HYDRATES, CONCRETE 10

12

14

18

1

I

I

I

Z4

I

WAVE LENGTH MICRONS (:~- C25

vJ~,

I

1200

1000

I

800 WAVE NUMBER (Cm -1) FIG. 2

I

600

Infrared spectra of different C2S polymorphs as KBr discs

400

( ref. 14 )

Between the IR spectra of the cubic C3A (pure) and cubic C3A (2.4% Na2 O) some shifts of frequencies and redistribution of intensities in 460 cm-I region occured, which was assigned to the structure disordering as a result of Ca - Na substitution (13).

Hydration studies Hunt (3) reported studies of hydrated products of cement phases. He observed the spectral details in the 700 to 1200 cm -I was lost when C3S was hydrated. Lehman & Dutz (5) discussed the IR spectral characteristics

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during progress of hydr~tion, fixation of water and absorption of carbon dio-.. xide and nature of the hydration products of cement minerals. They also reported the spectra of h~drated ~ - C 2 5 and ~ - C 2 5 and observed spectral changes in 1000 - 800 cm-- . They referred to rapid changes in spectral lines (lowering of intensity, etc.) for C3S (1 day hydr~Jted) and C12A7 (1 hour hydrated). The spectral changes for hydrated CA, 03A etc were noted. Midgley (6) reported the spectrum of C4AH13 and ettringite and he also made an attempt to assign bands in the spectrum of portland cement. Bensted (23) studied the IR spectra of hydrated ~ - , o(~, ~ and ~ - C 2 5 samples. He observed the 930 cm -I band in thespectrum of anhydrous o~-phase shifting to higher frequency. Similarly in o(~ and ~-C25 spectra~ significant changes were observed in the spectra of hydrated materials compared to these of anhydrous material. Slow hydraulic behaviour of ~-phase was also observed in IR study. Raman study of hydrated cement materials were a]so reported(24)~ Kiriyana et al (25) reported IR studies of C3AH 6. 5chwiete and Ludwig (26) also reported spectra of C3AH6, and C4AH13 among other compounds. C-S-H and other hydrates A number of researchers reported the spectra of C-S-H (3-6)° Taylor (27) published IR spectra of plombierite C-S-H(1), techaranite and tobermorite - they are al) relatively similar to one another but different from those of fairly closely related phase, such as xonotlite. Taylor inferred a fair degree of structural similarity in all four cases though the X-ray diffraction evidence indicates that techaranite and plombierite differ from tobermorite and C-S-H(I) in more than the relative degree of crystallin~ order. Hunt (3) presented the spectra of Okernite, gyrolite, Lock Eynort tobermorite, afwillite, hil]ebrandite and a synthetic Xonotlite. Midgley (6~ also reported spectra of C3SH2 , tobermorite and afwillite as well as flints, CSH(A), C 2 S ~ H t C2S ~H and C 2 S ~ H . These spectra in general are good for identification purposes. Raman studies of C-S-H and other hydrated products were reported by Bensted (23). For identification of C-S-H in hydrating cement material, the band at g70 cm -I (~35i04) was designated by Bens~.ed & Varma (13). Conjeand and Boyer (15) reported the Raman spectra of C-S-H (1) and found only one characteristic broad line at 670 cm-1; the spectrum of C-S-H (II) was also presented° The main products of hydration, calcium hydroxysilicate of the 02SH2 and CSH(B) types were detected in the IR spectra from the ~3(Si-O) absorption band at g65 - g75 cm -1 and calcium hydroxide from ~ ( O H ) absorption band at 3640 cm -1. Progressive hydration of portland cement is accompanied by increase of the intensities of these absorption bands and simultaneous decrease of the intensities of the absorption bands of the constituent mineral phases in portland cement. In the case of amorphous hydration products (especially formed at lower temperatures) IR spectrum is useful in identification. Butt et al (8) conducted IR studies of forms in which water is bound in hydrated binders. They discussed the possibility of using IR spectroscopy in determining the presence of water in absorbed and capillary liquid form as well as bound H20 in the hydrated clinker minerals as water of crystallization or bound OH. Ettrinqite and other compounds The study of ettringite and monosulphate by IR received m11ch

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interest. Schwiete and Ludwig (26)t Bensted and Varma (12) reported IR spectra of thesc~ materials and Raman study of ettringite was reported by Bensted (25). There is little difference among the spectra of substituted ettr~ngites (Ti, Cr, Mn or Fe) as reported by Bensted and Varma (28); however there is considerable difference between the spectra (Fig, 3) of monosulphate and ettringite (29) (Table-Ill). Hydration studies under different conditions Gouda and Roy (30) used IR spectroscopy in studying hot-pressed cement materials. They observed anhydrous C2S present in the hot pressed compound. They also observed shifting of bands (Al-O and Fe-O stretchings), An absorption peak at~J3500 cm -I (free hydroxyl stretch) was found in all hot-pressed and water cured materials. The presence of CO 2 (1440 cm-I) was observed in some of the compounds. It was also noted that all the standard and hot pressed Ca- silicate or cement paste studied have absorption maximum more similar to one another (in the 1025 to 775 cm-1). Ariizumi (31) reported the spectral characteristics of gehlenite (C2AS H8) at different temperatures (200, lO00°C and room temperature). Baird et al (32) studied the effect of carbonation on C-S-H produced by refluxing slurries of Ca(OH)2 ~nd silica gel by IR spectroscopy as one of the methods. Nell (33) reported the influence of alkali carbonates on the hydration of cement by using IR spectroscopic method. He used extinction values for obtaining quantitative result. Bensted (34) used IR spectroscopy in the hydration of OPC in the presence of CaC12 and Ca-formate and observed that C-S-H gel was more in the case of CaC12 additive. Turriziani and Rio (35) used IR spectroscopy in high chemical resistance pozzolanic cements. Bensted (36) studied the effect of various gypsum set-retarders (byproduct gypsump ferrogypsum~ phosphogypsum) on hydration of cement° McCall and Mannone (37) used IR spectroscopy in determining concentration of tr~ethanolam~ne in cement hydration. The bands at 1030 and 900 cm-1 were used for such purpose. Connally and Hime (38) worked in similar line and observed that IR method as quite adequate, Singh et al (3g) concluded from IR study that mixes of C3A and sulphanilic acid that strong bonding exists between them. 8en-dor and Rubinste~n (40) observed lowering intensity of OH band with increasing amount of P205 in hydrated C3 S sample, Studies in the concrete field Sugama and Kukacka (41) studied the effect of 02S and C3S on the thermal stability of vinyl-type polymer concrete. The most significant changes in the spectra are in the absorption band of the - CH2- group vibration in the region 3020 to 2900 cm -I of PMMA containing the C-S system and cement. These absorption bands were f3und to be much weaker in intensity than that of bulk PMMAo They inferred that the reaction occured between the calcium oxide in the filler and the - CH 2- groups in the polymer, Berry et al (42) made use of Raman spectroscopy in their study of sulphur infiltrated concrete sample. They pos,tulated the presence of Sn 2- species in lecchate obtained from sulphur-infiltrated concrete by observing IR band positions of its spectrum with those of N2S 4 in aqueous solution. Hirche(43) observed from his studies of reactive aggregates that cement aggregates with high infrared absorption bands in 3800 and 2800 cm-1 regions were alkali reactive. He suggested that all alkali aggregates with total absorption greater than 8xi05 cm/mol would be dangerous.

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S.N. Ghosh, S.K. Handoo

3 1

6

7

8

I

I

I

L

10

12

I

I

WAVELENGTH MICRONS

X 2

X L

3800

3500

3000 1750

1500

i

I

1250

1000

750

WAVE NUMBER Cm-1 FIG. 3 Infra, red spectra of (1) mon~JsLJlphate (2) eti~rtngits in nujo! m,Jl]_ X = bands due to nujol ( ref. 29 )

TABLE-

III

IR spectral data of monosulphate

and ettrinoite

.--. .iMi~s'~- .~-~"2-2:1i-:-- 11-2: 1121i:i-:~12,22~-21'-:21..22.2<~-r2C~:(e2Z i i 850 vw 1100 vs 11'70 s~sh 1600 w 3100-3500 vs~b 3S40 vs . . . . . . 367_~ .~. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85:, 1120 1640 1675 2190 3420 .363 5

vw vs b,m b,s vw b~vs m

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779 IR SPECTRA, RAMAN, CEMENT, HYDRATES, CONCRETE

Qua i i t y_ _c2jit2~ol in cemen_t,s~aw m a t e r ia l The IR and Raman studies of gypsum, hemihydrate and anhydrate wero repotted by 8ensted and Varma (12) and Bensted (23) as shown in Table-IV. TABLE - IV IR & Raman spectral bands for various calcium sulphate

IR

Raman

IR

414 mw

Raman

IR

438 mw 494 mw

sg3 s

fgrms

Raman Soluble

(cm -1)

Raman Insolub I~

438 mw

420 mw

498 mw

500 mw

604 w

611 w

602 s

494 mw

602 s

602 w

612 s

667 s

622 w

660 s

636 w

675 s

1004 vw

624 w

1008 m

676 w

636 w

630 w

1120 vs

676 w

1094 s

1018 vs

678 w

679 w

1010 vs

1115 vs

1132 w

1130 s

1020 vs

1020 vs

1148 vs

1114 w

1155 vs

1150 w

1158 vs

1131 w

1116 vw

1623 s

1138 w

1623 s

1174 w

1150 w

1134 w

1638 m

1144 w

1172 w

1165 vw

3410 s 3500 w

3560 w

3555 w

361 6 s

The spectroscopic data are quite important to analyse a given sample quickly. Ghosh et al (44) suggested simple IR method for evaluating cement raw meals Dolomite content in limestone can be analysed ouickly with the help of 711 (calcite) and 727 cm -1 (dolomite) bands in limestone. Ghosh (45) published IR spectra of rocks~ minerals and products of industrial importance (principally to cement industry). The spectra can be used as standards for rapid identification and characterisation of these materials. An attempt to correlate crushing strength of concrete aggregate with the IR spectra of these materials was reported (46)~ The changes in composition of cement raw meal upon heating (in a vertical shaft kiln) was studied by IR (47)° The studies are more or less qualitative but are useful for characterization. Conclusion The IR and Raman spectra of the anhydrous phases of portland cement are characteristic for identification and other purposes. The spectral changes (intensity of bands~ etc) with introduction of foreign

780

Vol. lO, No. 6 S.N. Ghosh, S.K. Handoo

ions in the cement phases are marked in general though qualitative in natur~~. In the study of polymorphic or different crystal forms of the phases, the spectral characteristics are useful and complimentary to X-ray. The estimation of cement phases in portland cement by I R is more or less qualitative and possibly the method's value would increase if applied after the separation of phases. The spectral studies in the area of hydration of cement phases are limited to qualltative estimation of hydratlont formation of hydrated compounds~ e.go C-S-H~ ettringite etc. The studies on pressure effects during hydration and on admixtures in cement hydration~ etc are quite interesting. The identification of reactive aggregate (Quartz) by IR is quite rapid but more data are yet to oomee

The studies of IR spectroscopy in the identification and analysis of minerals/rocks in cement making are quite useful for rapidity and are complimentary to X-ray diffraction. References le

P.J. Launer, Am. Mineralogist.

2.

DoM.

3.

CoM. Hunt~ 5th Symp. on Chemistry of Cement, I, Tokyo, 297 (1958).

4,

C.M. Hunt, Ph.D dissertation, University of Maryland (1959).

5.

Roy~ JoAm. Ceram. Soc.

37, 764 (1952). 41, 293 (1~58)o

H. Lehman and H. Dutz, 5th Symp. on Chemistry of Cement, I, Tokyo, 513

(1968).

6e

H.G. Midgley, 5th Syrup. on Chemistry of Cement, I, Tokyo, a79 (1968).

7.

5.N. Ghosh and A.K. Chatterjee, 3. Mater, Sci. 9, 1577 (1974) ~ , 1454 (1975).

8o

Yuo M. Butt, Jo Appl,

9.

P. Tarte, Spectrochim Acts, 23A, 2127 (1967).

Chem. (USSR), 48, 1046 (1975).

10.

V.L. Burdick and D.E. Day, JoAm. Ceram. 5oc. 50, 97 (lO67).

11e

R.A. 5chroeder and L.L. Lyons~ 3. Inorg. NUcl. Chem. 28, 1155 (1966).

12.

3. Bensted and S.P. Varma, Cement Tech. 5t 378 (1974).

13o

A.I. Boikova, A.I. Domansky, V.A. Paramonova, G.P. Stavitskaja and VoM. Nikushchsnko, Cement and Concrete Research, 7, 483 (1977).

14.

J. Bensted and S.P. Varma, Cement Tech., 5, 256 (1974).

15.

M. Conjeand and H. Boyer, Cement and Concrete Research, 10, 51 (1980).

16e

P. Tarts, Nature.

207t No. 500~ 973 (1965).

Vol. I0, No. 6

781 IR SPECTRA, RAMAN, CEMENT, HYDRATES, CONCRETE

17.

P. Tarte, Silicates Industriclsj 31, 343 (1952).

18.

P. Tart,, Revo Chim. Miner. 1, 425 (1964).

qco

T. Sakurai, T. Sato and A. Yoshinage, 5th Symp. on Chemistry of Cement~ I~ Tokyo~ 300 (1968).

20.

N.A. Torpov, 5th Syrup. on Chemistry of Cement, I v Tokyo, 49~ (1£68).

21.

N.B. Singh, Cement and Concrete Research~ 6~ 409 (lO76).

22.

T.Y. Shchetkina~ L.N. Skrynnik and PoA. Strarominskaya 9 6th Symp. on Chemistry of Cement~ Moscow (1 774).

23e

J. Bensted t Cement and Concrete Researchj

24.

Jo Bensted, J. Am. Ceram. Soc. 59, 140 (1976).

25.

Ro Kiriyama~ H. Kiriyama and M. Takagawa t 5th Symp. on Chemistry of Cement~ II~ Tokyo t 98 (1968)o

26.

HeE. Schwiete and U. Ludwig~ 5th Symp. on Chemistry of Cement~ II, Tokyo, 37 (I 968)o

27o

HeF.W. Taylor, 6th Int. Symp. on Chemistry of Cement~ Moscow (I£74).

28°

J. Bensted and S.P. Varma, Cement Tech, 2, 73 (1£71).

29°

3. Bensted and S.P. Varma, Cement Tecl., 4, 112 (I£73).

30.

GeR. Gouda and DoM. Royt J. Am. Ceramo Soc.~ 59, 412 (1976).

31.

Ao Ariizumi~ 5th Symp. on Chemistry of Cement~ I]~ Tokyo, 138 (I068).

32.

T. Bairdt A.G. Calrnes-Smith and D.S. Snell, J. Coll.

8, 73 (I£78)~ ~, 97 (19797.

Interface

sci. so, 3s7 (197s). 33o

E.~IoM.G° Niell~ 5th Syrup. on Chemiatry of Cement~ II~ Tokyo, 472

(1968). 34°

J. Bensted, Silicates Industriels, 4.3, 117 (lO78).

35.

R. Turriziani and A. Rio~ 4th Syrup° on Chemistry of Cement~ Washington~ Vol. II~ 1067 (1960).

36.

3. Bensted~ W. Cement Tech. I0~ 404 (I£79).

~7.

MoT. McCall and J. Mannone, Cement and Concrete Research, 5, 489 (1975).

38.

J.D. Connally and W.G. Hime~ Cement and Concrete Research~

6, 741, (1976). 39.

V.K. Singh~ M.M. All and K.K. Narang, Ind. Ceramics, 20 t 305 (1977).

782

Vol. I0, No. 6 S.N. Ghosh, S.K. Handoo

40.

L. Ben-dor and Y. Rubinstein, J. Mater. 5ci., 14, 365 (1979).

41•

T. Sugama and L.E. Kukacka~ Cement and Concrete Research, ~t 69 (1979).

42.

E.E. Berry~ J.A. Soles and U.M. Malhotra~ Cement and Concrete Research~ 7~ IB5 (1977).

43.

D. Hirche~ Symp, on Alkali Aggregate Reaction, Reykjavik, 205, August (1975).

44e

S.N. Ghosh, V.N. Vishwanathan and A.K. Chatterjee, 3. Mater, Sci. 11~ 1167 (1976).

45.

S.N. Ghosh, J. Mater. Sci., 1~ t 1877 (1978).

46.

S.N. Ghosh and S. Das, Ind. Conc. 3. 52~ 241 (1978).

47,

S.N. Ghosh and A.K. Chatterjeet Trans. Ind. Ceram. Soc°~ 37~ 18 ( 1 ~ 8 ) .