The analysis of ettringite in hardened cement paste

CEMENT and CONCRETE RESEARCH. Vol. 4, pp. 821-834, 1974. Printed in the United States.

THE ANALYSIS HARDENED

OF E T T R I N G I T E

Pergamon Press, Inc.

IN

CEMENT P A S T E

H. U c h i k a w a and S. U c h i d a Central R e s e a r c h Laboratory, O n o d a Cement l-l-7, Yoyosu, Koto-ku, Tokyo, J a p a n

Co.

(Communicated by R. Kondo) (Received June 24, 1974)

ABSTRACT The s o l u b i l i t i e s of pure h y d r a t e s and the m i x t u r e of h y d r a t e s e x i s t i n g in h a r d e n e d cement paste to the e t h y l e n e g l y c o l - m e t h a n o l solution, the effects of coe x i s t i n g Ca(0H)2 u p o n the s o l u b i l i t y and rate of diss o l u t i o n of e a c h hydrate, s u i t a b l e c o n c e n t r a t i o n of ethylene glycol, and the limit o[ the amount of e t t r i n g i t e capable of b e i n g a n a l y s e d in paste were investigated. F r o m the results obtained, the reliable a n a l y t i c a l m e t h o d for the d e t e r m i n a t i o n of e t t r i n g i t e in h a r d e n e d cement paste was established. Die L S s l i c h k e i t g e d i e g e n e r H y d r a t e u n d des G e m i s c h e s y o n d e n Hydraten, das in e r h i r t e t e n Paste auftritt, zum E t h y l e n g l y k o l - M e t h a n o l l S s u n g , die Einflu~ k o e x i s t i e r e n d e s Ca(OH)2 auf die L ~ s l i c h k e i t u n d L S s u n g s g e s c h w i n d i g k e i t jedes H y d r a t e und X t h y l e n g l y k o l s g e h a l t , u n d die B e g r e n z u n g y o n a n a l y s i e r e n f ~ h i g E t t r i n g i t in Paste wurde u n t e r s u c h t . Aus die Ergebnisse, die v e r l a s s i g e a n a l y t i s c h e M e t h o d e zur Bestim m u n g des E t t r i n g i t e in Z e m e n t m a s s e n wurde aufgestellt.

821

822

Vol. 4, ~o. 5 H. Uchikawa, S. Uchida Introduction The

cement

is k n o w n

beneficial Midgley and K.

of ettringite d u r i n g

formation

to be

phenomena

and K.

responsible

Tsu/
(I),

(2) s h o w e d

tributed

to the d e v e l o p m e n t

hydrated

cement

properties sulfate

at e a r l y

of c e m e n t

hydrate (jet

cement

cement

paste,

opment

and e x p a n s i o n

and

the q u a n t i t a t i v e in h a r d e n e d H. for

DTA.

used

of c l i n k e r

(4,5)

paste

(6,7),

tive

analysis The

method

and

strongly

con-

strength

to e x p l a i n

of

the

high

early

s~rength

cement)

paste

and e x p a n s i v e

aluminate

of strength d e v e l -

impotent

to d e t e r m i n e

and D. R o s a m a n

method

to d e t e r m i n e

to e s t a b l i s h

ettringite

is not

the m e t h o d

in h y d r a t e d

using

solvent

the m i n e r a l o g i c a l

and the a m o u n t it

(3) p r o p o s e d

of e t t r i n g i t e

of Ca(0H)

still

investigated

ettringite u s i n g dissolution

established

mination

Uchikawa

cement

paste

has b e e n composition

in h y d r a t e d

applicable

cement

to the q u a n t i t a -

of e t t r i n g i t e .

authors

for

selective

but

H.

calcium

it is v e r y

method

H.G.

high

super set

8_nd

paste.

extracting

extensively

In o r d e r

the m e c h a n i s m

of them,

analytical

The

recently

containing

to c l a r i f y

O. M i d g l e y

concretes.

ettringite

stage.

of

deleterious

of the m e c h a n i c a l

as s p e c i a l

the d e t e r m i n a t i o n

using

and m o r e

- regulated

cement

cement

that

paste

such

cement

for b o t h

in p o r t l a n d

Pettifer

the h y d r a t i o n

a quantitative

the f a v o u r a b l e

of e t t r i n g i t e

a reliable

of e t t r i n g i t e

by

analytical

in h a r d e n e d

analytical

properties

ethylene method

for

of the

glycol

(8),

the d e t e r -

cement

paste.

sample

is e x t r a c t e d

Experimental Outline

of the

experiment

If the ettringite lectively

by

maintaining amount AI203

or CaO

or S03

first

the m i x t u r e

to the

suitable

exactly

of ettringite

So, and

the

ethylene

in h y d r a t e d solvent

as C 3 A - ~ C a S O 4 - 3 2 H 2 0

the stoichiometrical can e a s i l y in the

of all,

be

composition,

estimated

the

by a n a l y s i n g

solvent.

solubili$ies

of h y d r a t e s

se-

existing

glycol-methanol

of e a c h

of pure

in h a r d e n e d

solution,

effect

hydrates

cement

paste

of

coex-

the

Vol. 4, No. 5

823 ETTRINGITE, EXTRACTION, CEMENT PASTE

istence of Ca(0H)2 , suitable c o n c e n t r a t i o n of ethylene glycol and limit of the amount of e t t r i n g i t e

capable of b e i n g

a n a l y s e d in the paste were examined.

Then a n a l y t i c a l pro-

cedure is e s t a b l i s h e d and a n a l y t i c a l results of the ettringite in h a r d e n e d cement paste m e a s u r e d b y the p r o p o s e d m e t h o d was discussed. Sample p r e p a r a t i o n Ettrin~ite

and m o n o s u l f a t e hydrate;

T h e y were p r e p a r e d b y

m i x i n g the solutions

of c a l c i u m hydroxide,

and calcium sulfate,

and b y m i x i n g the solutions of calcium

hydroxide,

a l u m i n a gel and c a l c i u m sulfate

products were r a p i d l y f i l t e r e d and D - d r i e d

a l u m i n u m sulfate

(9)

(i0).

The

to avoid contami-

n a t i o n of c a r b o n dioxide. ~3AH6;

Synthesized

C3A p o w d e r was m i x e d w i t h excess w a t e r

and kept at 50°C for three days w i t h continuous The m a t e r i a l was w a s h e d w i t h alcohol,

stirring.

D-dried and identi-

fied by DTA, X - r a y d i f f r a c t i o n and i n f r a - r e d a b s o r p t i o n spectrtun. H y d r a t e d C3~; The C3S s y n t h e s i z e d f r o m pure reagents was h y d r a t e d in a suspension.

The q u a n t i t i e s

h y d r a t e d C3S d e t e r m i n e d b y chemical m e t h o d

of Ca(0H)2 in (7) was 2 4 . 9 %

A c c o r d i n g to the s t o i c h i o m e t r y p r o p o s e d b y Copeland and coworkers

(ii), the amount of CSH gel in h y d r a t e d C3S was

estimated to be 37.5%. AI(0H)3 gel; A l u m i n a gel is o b t a i n e d b y the precipitation from K A I ( S 0 ~ ) 2

s o l u t i o n b y a m m o n i a water.

Preparation of the h y d r a t e d sample of ordinar~ p o r t l a n d cement and special super h i g h e a r l y s t r e n g t h cement

(jet

cement); E a c h of sample was h y d r a t e d at 20°C w i t h W / C = 0 . 4 0 in o r d i n a r y p o r t l a n d cement and 0.60 in jet cement.

At deter-

m i n i n g age, h y d r a t e d sample was g r o u n d to pass a 200 m e s h sieve and D-dried.

At the same time quantities

of Ca(0H)2

and e v a p o r a b l e w a t e r were also determined. S o l u b i l i t y and rate of d i s s o l u t i o n of h y d r a t e s ethylene ~ i y c o l - m e t h a n o l

to

solution

C a l c i u m aluminate h y d r a t e represented by C3AH 6, c a l c i u m aluminate m o n o s u l f a t e h y d r a t e

(C3A.CaS04-12H20),

AI(0H) 3 gel

824

Vol. 4, No. 5 H. Uchikawa, S. Uchida

and hydrated

ettringite

C3S w h i c h

in h a r d e n e d

solubilities

and

CIIA7-CaF2,

reporters

and

CaS04

t h e y are

are

to e t h y l e n e

with

glycol-

s u c h as C3S , C2S,

eliminated

confirmed

the r e s u l t s

of Fig.

i-i

in this

as i n s o l u b l e

and

gel

are h a r d l y

monosulfate

hydrate

are

selectively

glycol

solution.

monosulfate

Ettringite

hydrate.

limitted

hydrate

coexisted

exa/nined t h e i r

compounds

AI(0H)3

the

are

of d i s s o l u t i o n

C}AH6,

ene

to be

ex-

by previous

(2).

From that

paste

Unhydrated

C3A , C~A~

because

considered

cement

the rate

metha/lol s o l u t i o n .

periment

are

The

condition

is m a i n l y

caused by

it is r e a l i z e d

extracted, extracted

is e a s i l i e r

difference

between

1-2,

of the

ettringite

ettringite by

and

the e t h y l -

extracted

than

solubility

under

and m o n o s u l f a t e

the d i f f e r e n c e

of t h e i r

crystal

structures. Dissolved be

Ca(0H)2

from

the

shown

coexisting

analytical

in Fig. Effect

the

i-i

clear

tration

shown

in the

deduction solvent

of e t h y l e n e

the

of e t t r i n g i t e

suitable

of d i s s o l u t i o n

in Fig.

a n d at the

the

case

was

lower

of

solution

aluminum,

1-2

to

is p r o v e d

solution

as

~lycol

concentration

of s o l v e n t

from monosulfate

t h e m are m e a s u r e d having

various

that

i00%.

using

concen-

glycol

and

of sulfur,

reaction

though

dissolution

and

extracted

Same

but

of e t h y l e n e

percentage

tendency

was

ettringite of e x t r a c -

observed

percentage

in

of e x t r a c t i o n

of e t t r i n g i t e . among

sulfur.

to the d i f f e r e n c e

ethylene

of 3:1,

hydrate,

is a d i f f e r e n c e calcium

(e),

of c o n c e n t r a t i o n

compositon

almost

than

(d) a n d

increase

of m o n o s u l f a t e

There

order

This

to e x a m i n e

glycol-methanol

tion attained

is due

of Si02

concentration

increased with

glycol

value

CSH gel.

is c o n s i d e r e d

of s o l v e n t .

As was

with

C3S

separation

hydrate, the rate ethylene

the h y d r a t e d

(c).

of the

In o r d e r for

Ca0 f r o m

they

calcium,

One

rate

combine

ethylene

aluminum

of e x t r a c t i o n

of the r e a s o n s

of the a f f i n i t y

the r e a c t i o n

of e t t r i n g i t e

the

during

is p a r t i a l l y

to the e t h y l e n e

of e a c h glycol

for ions

this to

in the

the p r o c e s s folding. glycol

of

of

The

is p r o m o t e d

Vol.

4,

No.

5

825 ETTRINGITE,

~) A I ( O H ) 3 g e l

Ai~O3 0.~ ~ Z~

o =

~

Pl

20

(b) C3AH6 (c) hydrated C3S

20 40

~ -0.2 ~ ~

z

i

I

I

x

b) C 3 A H ~

~

~o~

~.~.o0

[

0

~ ~

~

-0

soluf~on .

~ ~ ==°" ~ 2~ -~2Z

,.0-

-~

~

0.5" 0.Sq

~

I I

I I I

o

(~)hydrated

I I I

40 2.0"

.~

~

~

m

an --

~-

m

o

~

~

-o~

~

-

~

P~G.

1-1

Zo-

~

~e rate of dissolution of h y d r a t e s to the e t h y l ene glycol-me th~ol solution

_

~ i = = ~

0

I 2 3 4 5

Time

action

is

in Fig.

o~ing

co~i~ed

1-2

ent

the

~e hydrate

of

~der

of

the

the

were

the

soluvation with

(12,13)

that

calculated

glycol-meth~ol

calculated

Ettringite r~ge

to its

ettringite

from

coexistence

extraction

the p a s t e

(hr.) of w h i c h

of e t h ~ o l

as

sho~

(e).

that

Effect

5

comparing

ethylene

from

34

for extraction

Estimated into

~ ~ ~ ~ I 012

the m e t h ~ o l

~ ~

1.0

0

by

I

;

~

C3S

o

~ = ~

]

,

~

~

o

--

~

-o I ~=

~

~

~ ~

g2

=

0~

~

--

1.5-

;

> _~

and agilated with 20Oral of ( I , l )

~ ~ ~

~

~~

g of s~mple containing i ner t m o t e r ~ t ( g ~ s s powder} wos sh~ked

~-

~

coo?

~ ~

~

~ ~

-0.1

~

= I

conten~' (%)

0 0.4~ -=

0

(note)

"13 (o ~ ~

(a)AI(OH)~ gel

o 0.2 ~ ~

0.1

0 0 ~

u

O"

CEMENT PASTE

=~ ~ -=', 0,6~ ~ ~ -0.5 ~

0.2-

~

~

~

EXTRACTION,

curves

was

~ounts

in Fig. almost of

S03

dissolved

is q u i t e

differ-

A1203. of

Ca(OH)2 ~d

of C a ( O H ) 2 2 ~d

just

monosulfate like

as

in

3.

compeletely

it ~ d

the

solution

of e t t r i n g i t e

coexistence

sho~

from

added

extracted Ca(0H)2

even

in wider i n the

826

Vol. H.

Uchikawa,

l dl monosulfate

"~~

S.

hydrate

~o

~

c~o /A

/

zo ~o~, ]-

~..

~o ] ~ ~

~

~

•~-

~

=

~

~o

I0 4-

. ~ ~

~

2-

o

0

111

,4

I

0

I

~ I

I

I

~0 ~

e) e f f r i n g i f e

~

~

AI203

2

~

~a

_

--

>

20 ~

:t

5

0

.o I0

~ ~ ;

I

~

0

50"

C~O

~

SO 3

~

~o- ~

4o

;~ •~ ~

~~

30-

~o

~ ~

,~8-

~

~

~

~

~~

ZO

4

~

0

~ o ~

o

~ I 1 ~ t ~ 2345

o

~ I I I ~z s4s

Time ( note ) ~ (3:1)et~ylen~ o

( I :1)

=

C I :3)

•

( I:l)et~ylene

for

glycol-methanol

I

~

I00

o

extraction solution

', solution

~EG.

of

Ig

dissolution

of

hydrates

•~

~

~;

~

70'

~ ~ ~ e

~

t

~0

The amount of in s a m p l e (note)

1

40 ettringite

I

I

50

60

to

(I,I) (I,5) FIG.

ettrin~ite containi~

of in

2

Ca(OH)2

solvent

10'

~:,,

I0

20

30

40

T h e amount o f m o n o sulf0fe hydrot~ mixed in s a m p l e (~/~) Ca(OH)2 content

,~ o ~

extraction the s~ple

the

~

20% 5

FIG. 3 of extraction of monosulfate hydrate the s~ple containin~

Percentage

/

Percentage

wit~ t~e

2o

0

mixed (~/~)

ethylene glycol-methanol solution

.........

and ~ g i t a t e d

.~

e0:

I

20e/o of

or e t t r i n g i t e

1

~z

20

0

30~

~

I

hydrate

saa~ed

~

I0

~~

~

$-2

90-

0

~

2s

~

o~

~ S

solution.

~00

~

-=

~

75 50

o~

o f the s~m~le c o n t a i n i n g

was

glyool-eth~nol

~

-

(hr.)

monosulfdte

"

The rate solution

I ~ t i ~ zs45

~

M ~

-~oo ~

o. ~ ~ ~ 5

5o~

o

~

~ ~"

"~ ~

~o

o

=

~ ~ ~5o ~ g

,.-

I0-

o

~

~m ~ ~

zoo~.

zo-

<

e

0

~_ - I 0

0 ~

Z ~6-

o~

~~ --

~ ~ E ~

~

~

~

~

15

~ &7

No.

~ =r~

~s~~--

~

m

4,

Uchida

of

Ca[OH)2

k

in

5

Vol.

4, No. 5

827

ETTRINGITE, EXTRACTION, CEMENT PASTE case w h e n used. the

dilute

This

ethylene

result

case w i t h o u t On the

traction out

Ca(0H)2

Fig.

3.

curves

is q u i t e

little

comparing

clear

present,

with

effect

was

Fig.

extracted

of

to the

ethylene

this

glycol

~

140-

~

130-

ethylene

glycol

solution

its

tendency

even

was

diminished

in the case

A1203

of

in

from

ettringite,

value

near

100%

excepting

dissolves

is

sample by

(14).

come

as b e f o r e

in the

to the f o r m a t i o n

varying their m i x i n g

ettringite

content

at

in the m i x t u r e

a small

(see Fig.

the d i l u t i o n

of h i g h m o n o s u l f a t e

are

to be

becomes

ex-

over

lower. of e t h y l e n e

hydrate

ethylene ~lycal -methanol solution

and

amount

hydrate tend

in

lower

mentioned

and m o n o s u l f a t e

and

can be made

the m e a s u r e d

constant

hydrate

on the

and B. T r i m i l l o n

of e t t r i n g i t e

ettringite

when

glycol

solution

showed

Monosulfate

3),

of C a ( O H ) 2

related

all

(d) and

in the e x t r a c t i o n

ettringite

that

and w i t h -

Ca(0H)2.

hydrate-Ca(OH)2

simultaneously

estimated

A

by

the a m o u n t

side.

tracted

gel w i t h

the e s t i m a t e d

ettringite

(d) and

observed

Charlot

higher

But

1-2

glycol-methanol

range

in

in the ex-

of Fig.

of the role

On the a s s u m p t i o n

observed

the r e s u l t

as s h o w n b y G.

A shows

the e t h y l e n e

was

obtained

with

to be

ettringite-monosulfate ratio.

was

it is c o n s i d e r e d

of C a - c o m p l e x

that

between

also

explanation

of e t t r i n g i t e

but

from

(1:3)

hydrate

of C 3 A H 6 and A I ( 0 H ) 3

extraction

1-2

effect

of m o n o s u l f a t e

Little

No

wider

different

solution

Ca(0H)2.

contrary,

curve

glycol-methanol

content.

Content

. - -

~ ~ ~

©

120II0

% ~oo-

Z

90-

~

80-

=® O The

I

I0

20

amount

mixed

i

in

30 of

I

4O

,

50

ettringife

sample

(1:3)

(1:5)

manosulfate Ca(OH) 2

o

•

a

~0 %

•

•

•

30

hydrate

(%)

20 % 5

~EG.

\ I

I,I)

~

2ercentage of extraction of ettringite in tAe s a_rP,p l e containing monosulfate hydrate El_tld C a ( O ~ ) 2

828

Vol. 4, No. 5 H. Uchikawa, S. Uchida There

hardened a~nount

exists

cement

calcium

ethylene

over

paste,

of e t t r i n g i t e

solutions the

generally it

a calcium

is u n s u i t a b l e

from

the

hydroxide

value

dissolves

solution

in

the

to e s t i m a t e

analytical

fairly

glycol-methanol

and

the

of C a 0

easily

there

is

in

when

calcium

accelerated crystal

SO 3 is

by

such

the

as

CSH

ethylene

reason

estimated

of SO

oned

specimen

these

reliable

value

mixture as

shown

experimental

into a risk

is

the

able

of

facts,

M

C3AH 6 gel

i

0.80

0.20

2

0.70

0.20

3

0.50

~

0.65

minute

remarkable

we

analytical in

compounds 1 and

the h a r d -

and

in

2.

conclude from

that the

the analytical

1

-

-

0.I0

-

-

0.I0

0.30

-

-

O.lO

0.i0

0.i0

0.25

0,i0

-

ettringite f r o m cement

ratio

estimated

ordinary CaSO 4 portlsund cement clinker

s p e c i a l super high early s t r e n g t h cement clinker

based

0.25

0.i0

0.i0

-

-

0.05

0.60

0.05

-

(~)

on b a s e d

503

{12.6 15.~ 2.3"

20.5

13.4

on

CaO

,33.0 '32.6 25.3* 32.4

12.3 i0.4"

7.5 I. I*

20.3 lb.2*

ii.0

7.1

18.4

-

24.8

24.~

29.6

0.60

23. (24.75

~25-3 23.8

,28,7 <27.5

0.05 -

ettringite

on b a s e d

AI203

19.5 (18.6

O.i0

the

clinkers

18.8"

5

For

is used.

the

obtained

of the e x t r a c t i o n of of p u r e h y d r a t e s a n d

AI(0H) 3 E

coexisting

solution.

mixing hydrated C3 S

is

estimated

in T a b l e

sulfate

precipitation

becomes

on

cement

to be

the

calcium

solution

based

Table Results mixture

of

is u n d e r of

as

this

tendency

ettringite

paste

of A I 2 0 3 in

effect

T~is

solution

the

datum

and

glycol-methanol

the

of

cement

From most

in

is p r e s e n t

gel.

dilute

value

to p r e c i p i t a t e

nucleation

this

hardened

tend

hydroxide

when

6

the

estimation. Dissolved

No.

hydroxide

(note) E

: ettringite

M: m o n o s u l f a t e

o lg of m i x e d sample was s h a k e d s o l u t i o n for two hours. o Parenthesis

in the

table

hydrate

* : (l:D)

and a g i t a t e d

indicates

with

repetition

E~hylene

20Oml

of

of a n a l y s i s .

glycol-methanol

(i:l)

ethylene

solution

was

glycol-meths-nol

used.

Vol. 4, No. 5

829 ETTRINGITE, EXTRACTION, CEMENT PASTE

Referring cement

paste

methanol volume

these results,

is able

ettringite

to be e s t i m a t e d

solution by selecting

of solvent,

sample

in the h a r d e n e d

using ethylene

suitable

quantity

glycol-

concentration

to be a n a l y s e d

and

and time

for extraction. Determination cement

of e t t r i n g i t e

in the m i x t u r e

paste

The a n a l y t i c a l five h y d r a t e s cement

paste

showed

results

are s h o w n in Table ettringite

good coincidence

data malculated resulted

from

from

cement)

the e t t r i n g i t e

cement

small

estimated

as small

mixed,

of cement

time

A

B

*sample weight (g)

amount

strength

portland

A1203

portland

cement

cement

of e t t r i n g i t e

amount

of o r d i n a r y

(jet

2. paste

is tend

of m o n o s u l f a t e

c o m p o s i t i o n of extracting analytical value solution v o t u m e ratio

(EG:M)

the

d a t a of ettringite

(g)~ f

hydrate

CaO

SI)3

CaO O ~$O \ the a m o u n t of - "~ 3~ evaporable (~) AI203 /

/~'--~,,'

containing

to be over

Table 2 R e s u l t s of the e x t r a c t i o n of e t t r i n g i t e h a r d e n e d cement pastes

curlng

but

respectively.

paste

super h i g h e a r l y

in o r d i n a r y

generally

in the' s o l u t i o n

of the a n a l y t i c a l

are shown in Table

Ettringite

in the h a r d e n e d

the S03 and the Ca0 in the s o l u t i o n

the h a r d e n e d

and special

of

1.

in u n d e r and over e s t i m a t i o n

obtained

in the m i x t u r e

existing

f r o m the A 1 2 0 3

with

One of the examples

cement

of e t t r i n g i t e

and six u n h y d r a t e s

Estimated

kind

of h a r d e n e d

water

existed

dis-

from

the a m o u n t ettr~nglte

(~)

of free Ca~C}!)2 ~>

3h.

1.*),)56 1.OO98

1:3 i:l

0.0250 0.0299

O.Oh29 0.0723

0.0026 O.OA59

1.6l 1.68

1 .0037

1:3

1.OO96

i:l

0.0296 0.0285

O.O&79 0.0700

O.03&O

1.62 1.62

91.9

id.

25.0 2~,1

1.0008 1.OOO3

1:3 I:i

O.Oi86 O.O210

0.0575 O.IOOO

0.0375

3.09 3.51

28.5

3d.

16.3 l~.h

~.OO15 ~.OO&3

1:3 1:I

0.0206 0.0230

O.1371 0.2369

0.OO98

6.65 IO.O

26.7

~.d 5.1

5.5

Id.

iO.OO~3 3d. 10.OO81 10.OO56

1:5 1:3 i:l

O.O125 O.O1~3 O.O17~

O.1575 0.2625 0.6300

O.OO~6 0.0267

12.6 i~.O 3~.3

19.6

1.2 l.& l.~

Ii.3

90.5

IS.9 17.7

(~ote) " : D - d r i e d state

EG : e t h y l e n e g l y c o l

M : methanol

A : special super high early strength cement B : o r d l n a r y p o r t l a n d cement S a m p l e was s h a k e d a n d a g i t a t e d w i t h 2OOml Of e t h y l e n e ~ l y c o l - m e t h a n o l

s o l u t i o n for two

ho~rs.

830

Vol. 4, No. 5 H. Uchikawa, S. Uchida

solves

into

V) b e c o m e s gite

the s o l u t i o n . larger

converts

tringite

in the

In the s p e c i a l concentration

recommend

to use

tractin@

solution molar showed

ened

paste

early

age

by

the

of as

the

retical

cement

at

age.

later

droxide

in

ettringite

is

The

and

destroying

makes

as

low eT-

cement,

little

the

influence

case we s h o u l d

the f i l t r a t i o n

high

early

Ca(0H)2

from

molar the

is

X-ray

on

like

to

of ex-

extracted value

in

strength alite

into the

hard-

cement was

the

at

consumed

deviates

hardened

for

paste

high

this

extracted

from

is

that

to

the

ordinary

of

early

theo-

strength calcium

cement hy-

solution

before

extracted. diffraction

patterns

by ethylene

5 indicate

calcium

ratio

super

reason

completely

the

strength

theoretical

special

extraction

in Fig.

pletely

in

sample

powder

and after

the

and

the

etTrin-

ettringite.

1.65

The

early

(Ca0-0.TS03)/AI203

super

contrary,

portland

the

(C

easier.

produced

of

bringing

error

ratio.

solvent

of

of

the p r o d u c e d

as

in this

approximately

the

value

even

becomes

formation

On

shown

dilute

special

paste

glycol

but

ratio

analytical

hydrate

super high

value

relative

hydrate

of e t h y l e n e

the a n a l y t i c a l

solution

older

to m o n o s u l f a t e

to m o n o s u l f a t e

The

The

that

before

solution

is a l m o s t

is p a r t i a l l y

other hydrates

sample

glycol-methanol

ettringite

hydroxide

com-

dissolved

without

and un/%ydrates.

Recommended

From before-mentioned

of

procedure

experiment,

following

procedure

is r e c o m m e n d e d . i).

Grind

the

dry by D-drying. in p a s t e 2). sponding 0.2g

at

this

(1:3)

ethylene

at r o o m amount

Shake

the

200 m e s h

amount

sieve

and

of e v a p o r a b l e

then water

time. quickly,

of p o w d e r e d

of e t t r i n g i t e

stopper.

to pass

Determine

Pulverize amounts

sample

and p o u r

and agitate

then weigh sample

of m o n o s u l f a t e

containing

into a c o n i c a l on the

glycol-methanol

temperature.

exactly

In the ease hydrate,

approximately

flask with

stirrer with

solution

the c o r r e -

for

one

200ml

of

to two h o u r s

of ssmlple c o n t a i n i n g

use d i l u t e

a

ethylene

much

glycol-

Vol. 4, No. 5

831 ETTRINGITE, EXTRACTION, CEMENT PASTE super I~iol~ early strenoth cement past 3d. O-dried state e~ e= ,¢~CIt =e m • • m a

speciat

1

~= ~.

•

'

I

a~ter e~tractin~ m

ordinary portland cement past O-dried state ~ ~ ~ e /Ic

aftermeXtrocting

3d.

~ ~

10

~ ~ ~ /'//~

~

20

~0

40

2 ~ (~) Cu ~e not •

) e : ettring~te ~ m : monosulfate ~ydrate ~ c : ~a(OH)~ C~I: CIlAT.Ca~ z ~ ~ : calcium s u l f a t e hemihydrate

~G. ~-~ ~d

~ ~ o ~ ~e~o~e e ~

~

p~e~s

o~ ~ e ~

p~s~e

~e~

~

m e t h a n o l solution. 3). S e p a r a t e

the soluble part b y G-4 glass f i l t e r u n d e r

r e d u c e d pressure and w a s h the r e s i d u a l part ten times b y 20 ml of methanol. 4). Evaporate

the s o l u t i o n of filtrate b y h e a t i n g the

beaker. 5). Dissolve

the r e s i d u a l part in p r o c e d u r e

20ml of (l+l) HC1 and d e t e r m i n e

4 into lO-

the amount of A1203 by means

of chemical analysis or atomic a b s o r p t i o n spectrometry. 6). The amount of e t t r i n g i t e

(E)

(%, wet paste base)

is c a l c u l a t e d from next equation. E = ( 1 2 5 4 / I 0 2 ) . X x i00 = 1 2 . 2 9 - X ( l O O - a ) / S

S'lOO/(lOO-a) where S : sample w e i g h t

(g, D - d r y i n g base)

832

Vol. 4, No. 5 H. Uchikawa, S. Uchida

X

: the a m o u n t

of A1 0 e x t r a c t e d

a

: the a m o u n t

of e v a p o r a b l e

wet

paste

(g)

water

in p a s t e

(%,

base)

1254/102=12.29

: molar

weight

ratio

of C3A.

3CaSO4"32H20/AI203

Summary In o r d e r for

to e s t a b l i s h

by

the e x t r a c t i o n

existing

in h a r d e n e d

methanol

solution,

the

solubility

conclusion

the r e l i a b l e

of ettringite

the d e t e r m i n a t i o n

paste

and

technique

cement

and rate

of e t h y l e n e

of ettringite

capable

organic

to the

glycol

of b e i n g

and

cement

solvent,

ethylene

of coexisting

of d i s s o l u t i o n

concentration

method

in the h a r d e n e d

using

paste

the effect

analytical

the

glycol-

Ca(0H)2

upon

of e a c h h y d r a t e s ,

the

analysed

limit

of the

in paste

and

amount

were

investigated. Results (i). ene

obtained

The

rate

such

in h a r d e n e d (2). from

the

cement

suitable

analytical

hardened

hydrate

C3AH6,

that

of

AI(0H)3

the existing

of A I 2 0 3

of ettringite

the a m o u n t

from the Ca0 and the SO 3 in the s o l u t i o n

were

tend

estimated

paste

were

from

It was

in the

respectively

also

extracted

ettringite

effective

separation

as C a ( 0 H ) 2

in the

simultaneously

partially

brings

the rate

was

amount

dilute

and

precipitated

dissolution

part

solvent

as

was

present.

completely even

glycol-methanol

when

in the

solution

in w i d e r

was

lower.

cement

case w h e n

solvent

solution

becomes

in h a r d e n e d

extracted

large

Dilute

of extracting

of e t t r i n g i t e

coexisting

for

solution

from monosulfate

especially

filtration

of e t t r i n g i t e

ethylene

paste

hydrate

easier

almost

to use

of e t t r i n g i t e cement

(4). Ettringite

(1:3)

than

data

in h a r d e n e d

solution

the

hydrate,

to e s t i m a t e

value

of m o n o s u l f a t e

Ca(OH)2

larger

sulfate.

clear

though

was

to the e t h y l -

The

cement

(3).

amount

of e t t r i n g i t e

solution.

the SO 3 d i s s o l v e d calcium

as f o l l o w s :

paste.

over and u n d e r

to be

the

solution

as m o n o s u l f a t e

It was

calculated

summarized

of d i s s o l u t i o n

glycol-methanol

hydrates

are

paste

range

a dilute

used.

of

with

Vol. 4, No. 5

833 ETTRINGITE, EXTRACTION, CEMENTPASTE

(5). Little effect of the difference of produced ettringite Estimated

of the crystallinity

to the solubility was observed.

ettringite based on the analytical value of AI203

in the solution according with the ettringite formed in hardened

to this method showed coincidence

mixed or theoretical

value of ettringite

cement paste w i t h i n i0% in relative

value and the coefficient value was 5%. From these results,

of v a r i a t i o n recommended

of the analytical

procedure was proposed

and this method is considered

to be one of the most suitable

methods

of ettringite

for the determination

in h a r d e n e d

cement

and Conc. Res.,

vol.l,

paste.

Reference I. H. G. Midgley and K. Pettifer; No.

i, 101-104

Cam.

(1971)

2. H. Uchikawa and K. Tsukiyama; No.

3, 263-277

Cem.

of Cement,

4. S. Takashima;

Res.,

vol.

3,

(1979)

3. H. G. Midgley and D. Rosaman; Chemistry

and Conc.

Proc.

Washinton,

4th Int. Symp.

259-262

Semento Gijutsu Nenpo

on the

(1960)

(in Japanese)

1__2, 49

(19~) 5. G. Yamaguchi Chemistry

and S. Takagi;

of Cement,

181-217

6. W. Lerch and R. H. Bogue; 7. G. Yamaguchi,

Nenpo

5th Int. Symp.

8. H. Raudoja and E. Djamma;

Chem.

H. Uchikawa

1__3, 62

on the

(1968)

Ind. Eng.

K. Takemoto,

Semento G i j u t s u

Proc.

i_~8, 739

(1926)

and S. Takagi;

(1959)

Issled.

Stroit.

No. i0,

37

(1969) 9. H. A. Berman and Newman; Chemistry

of Cement,

10. K. Murakami, Japanese)

4th Int. Symp. 247-257

H. Tanaka and Sugimoto;

761 15,

on the

(1960)

Gypsum and Lime

J. Am. Chem.

(1958) 212

Chemistry and Chemical (1962)

(in

(1971)

D. L. Kantro and L. E. Copeland;

12. Niichiro Tokura; Japanese)

Washigton,

No. ll~, 202-210

ll. S.Brunauer, Soc. 80,

Proc.

Industry

(in

834

Vol. 4, No. 5 H. Uchikawa, S. Uchida

13. C. Reichardt;

Angew. Chem.,

(1965) 14. G. Charlot and B. Trimillon;

77, 30 (1965),

(IE) ~, 29

"Chemical Reaction in

Solvents and Melts" Pergamon Press Ltd.,

(1969)