Capillary Absorption of Some Canadian Building Bricks

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Capillary Absorption of Some Canadian Building Bricks

Ritchie, T.; Meincke, H. R.

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NATIONAL RESEARCH C O U N C I L CANADA

CAPILLARY ABSORPTION OF SOME

F

C A N A D I A N BUILDING BRICKS j I

i

by

I

f

I

T . R i t c h i e and H e R. Mefncke f Thfs r e p o r t i s based on

a

paper p r e s e n t e d b y M r . R i t c h i e , a t t h e Annual Mee t f n g of t h e Canadian Ceranic S o c f e t y i n Toronto, February 16,

1 7

and 18, 1953.

Research Paper No.

8

of t h e D f v i s f on o f B u i l d i n g R e s e a r c h Ottawa

B

I

NRC No. 2966

ij

P r i c e 25 c e n t s Appfl 1953 DBR No.

34

PREFACE

The r e l a t i o n s h i p between t h e p h y s i c a l p r o p e r t i e s o f q a s o n r y m a t e ~ i a l s and t h e i r d u r a b i l i t y under v a r i o u s c o n d i t i o n s of use i s an u l t i m a t e c o n s i d e r a t i o n i n b u i l d i n g r e s e a . r c h , A c c o r d i n g l y , many s t u d i e s on v a r i o u s p r o p e r t i e s of masonry m a t e r i a l s have b e e n made,

The S n v e s t i g a t i o n s d e s c r i b e d h e r e i n a r e c o n c e r n e d wftli t h e w a t e r a b s o r p t i on p r o p e r t i e s of a number o f c l a y and

s h a l e b u i l d i n g b r i c k s , and a r e a p a r t of c u r r e n t s t u d i e s by

t h e D i v i s i o n of t h e p h y s i c a l p r o p e r t f e s o f masonry m a t e r i a l s . used i n Canada, A l l work i n t h i s f i e l d by t h e D i v i s i o n i s done i n c l o s e a s s o c i a t i o n w f t h t h e s t a f f of t h e Mines Branch, Department o f Mines and T e c h n i c a l S u r v e y s , D P , J, Convey, D i r e c t o ~ ,

T h i s pepox.$ i s a p r o g r e s s s t a t e m e n t o n some a s p e c t s o f t h i s work and i s p u b l i s h e d f o r g e n e r a l i n f o r m a t i o n f n view of t h e wfde i n t e r e s t i n b ~ f c k c o n s t ~ u c t f o n i n Canada, The

a u t h o r s a r e members of t h e B u i l d i n g M a t e r i a l s S e c t i o n o f t h e D l v f s i o n ,

IWo

R f t c h f e b e i n g a r e s e a r c h o f f i c e r and h a v i n g b e e n a s s f s t e d i n h i s i n v e s t i g a t i o n s i n t h e l a b o r a t o r y b y h i s c o - a u t h o r ,

Mr,

Meincke, a member o f t h e l a b o r a t o r y s t a f f . Ottawa A p ~ ~ f l ~ 1953 R o b e r t I?, L e g g e t , D i r e c t o r ,

CAPILLARY ABSORPTION OF SOIa C A N A D I A N BUILDING BRICKS I n t r o d u e t f s n P I t i s w e a l known t h a t , b e c a u s e of t h e i r p o r o u s n a t u r e , c l a y a n d s h a l e b u i l d i n g b r i c k s w i l l a b s o r b w a t e r by c a p i l l a r i t y when t h e y a r e p l a c e d i n c o n t a c t w i t h w a t e r , I t i s a i s o w e l l lcnown t h a t t h e amount and r a t e o f c a p f l l a q a b s o ~ p t i o n o f b r i c k s

v a r i e s hrfdely, e v e n among b r i c k s f r o m t h e same k f l n ,

The r a t e a t w h i c h b r i c k s a b s o r b w a t e r by c a p i l l a ~ i t y i s a n i m p o r t a n t p r o p e r t y , I t h a s b e e n shown t h a t t h e s t r e n g t h and e x c e n t o f bond o r a d h e s f o n w h i c h d e v e l o p s b e t w e e n b r f c k a and m o r t a r d e p e n d s t o a c o n s i d e r a b l e d e g r e e on t h e r a t e o f w a t e r a b s o r p t l o n ( b y c a p i l l a r i t y ) o f t h e b r i c k s

( 1 1 ,

The w e a t h e r ~ e s f s t a n c e , and p a r t i c u l a ~ l y t h e r e s f s t a n c * t o r a i n p e n e t r a t i o n , o f b r i c k w a l l s f s i n f l u e n c e d g r e a t l y by t h e r a t e o f c a p i l l a ~ y a b s o r p t i o n of t h e b r i c k s u s e d , R e c e n t s t u d i e s ( 2 ) have i n d i c a t e d t h a t t h i s p r o p e r t y o f b r i c k s q u s t b e w i t h i n a r a t h e r n a r r o w r a n g e o f v a l u e s t o e n s u r e a d e q u a t e r a i n r e s i s t a n c e o f t h e masonry, A s t a n d a r d method of t e s t o f t h e p r o p e r t y of ErS-,i'cfd p a t e o f a b s o ~ p t f o n o f c l a y a n d s h a l e b r f e k s h a s b e e n e s t a b l i s h s d b y t h e A r n e ~ l c a n S o e f e t y f o r T e s t l n g M a t e r f a l s

( 3 3 ,

T h i s p r a p e r t y h a s a l s o b e e n t e r m e d s u c t i o n , I n this method of t e s t f o r i n i t i a l r a t e o f a b s o r p t i c l n a d r y b r f c k i s p a r t l y immersed i n w a t e ~ r o r one m l n u t e , t h e b o t t o m s u r f a c e o f t h e b r f c k b e i n g s u p p o r t e d

l / 8

I n c h b e n e a t h 'cha s u r f a c e o f t h e - w a t e r , Thf s d e p t h of w a t e r i s k e p t c o n s t a n t ' t h r o u g h o u t t h e t e s t , The i n c r e a s e i n w e i g h t of t h e b r i c k , whfch r e s u l t s f r o m c a p i l l a r y a b s o r p t i o n of w a t e r , i s c a l l e d t h e f n i t i a f r a t e o f a b s o r p t f o n , O P s u c t f o n , of t h e b r f c k , T h i s p r o p e r t y i s e x p r e s s e d i n g r a m s o f w a t e r f o r a s t a n d a r d b r i c k a r e a o f t h i r t y s q u a p e i n c h e s ,

The main p u r p o s e o f t h i s i n v e s t i g a t i o n was t c d e t e r m i n e t h e e f f e c t s o f c h a n g i n g some o f t h e c o n d i t i o n s o f t e s t i n t h e A.S,T,M, method of t e s t f o r i n i t i a l r a t e o f a b s o r p t l o n , The

i n f l u e n c e o f some o t h e r f a c t o r s o n t h e amount o f w a t e ~ a b s o r b e d i n t h e I n i t i a l s t a g e s o f c a p i l l a r y a b s o r p t i o n was a x s o s t u d i e d , S t u d y of F a c t o r s I n f l u e n c i n g t h e Amount c f W a t e r Absorbed b y C a p i l l a r i t y o f B r i c k s A s e r i e s o f t e s t s was made t o d e t e r m f n e t h e i n f l u e n c e o f c e r t a i n c o n d i t i o n s o n t h e i n i t i a l r a t e o f c a p i l l a r y a b s o r p t i o n o f t b e e t y p e s o f c l a y and s h a l e b r i c k s ,

The f o l l o w f n g f a c t o r s , and e f f e c t s of changes i n them on t h e amount o f w a t e r a b s o r b e d by t h e b r i c k s i n t h e i n i t i a l s t a g e s of c a p i l l a r y a b s o r p t i o n , were i n v e s t i g a t e d :

( a ) Temperature of t h e b r i c k s and w a t e r ;

( b ) Depth of w a t e r i n which t h e b r i c k s were immersed; ( c ) Time of p a r t i a l immersfon o f t h e b r i c k s ; ( d ) Moisture c o n t e n t of t h e b r i c k s ; ( e ) S u r f a c e t r e a t m e n t of the b r i c k s w i t h a s i l i c o n e m a t e r i a l . I n a d d i t i o n , t h e e f f e c t of r e p e a t e d t e s t s on t h e sane b r i c k s , on t h e i r i n i t f a l r a t e s of a b s o r p t i o n , was s t u d f e d , t h e b r i c k s b e i n g a l t e r n a t e l y d r i e d and p a r t l y immersed i n w a t e r , F r o c e d u r e

The equipment used I n t h e c a p i l l a r y a b s o r p t i o n t e s t s was e s s e n t i a l l y t h e same a s t h a t r e q u i r e d by t h e A,S,T,M. method of t e s t f o r i n i t i a l r a t e of a b s o r p t i o n .

The b r i c k s were p l a c e d on s u p p o r t s a t t a c h e d t o a metal p l a t e which was l e v e l l e d by means of

3

screw l e g s . A bubble

l e v e l a t t a c h e d t o t h e p l a t e i n d i c a t e d t h e h o r i z o n t a l . The p l a t e was p l a c e d i n a t r a y of 300 s q u a r e i n c h e s a r e a t o which w a t e r was added t o t h e d e s i r e d h e i g h t above t h e s u p p o r t s . The h e i g h t of w a t e r above t h e s u p p o r t s was measured by v e r t i c a l n e e d l e s ( p o i n t s downwards); one n e e d l e was p l a c e d 1/100 i n c h above t h e d e s i r e d h e i g h t above t h e s u p p o r t s , t h e o t h e r 1/100 i n c h below t h f s h e i g h t . Water was added t o t he t r a y s o t h a t i t c o v e r e d t h e lower n e e d l e p o i n t b u t was n o t t o u c h e d by t h e upper, Water was added manually when n e c e s s a r y due t o l o s s of w a t e r i n t o a b r i c k d u r f n g t e s t .

A s t o p watch was used t o measure t h e time of i m e r s i o n , Weights of b r i c k s were measured t o t h e n e a r e s t 1/10 gram.

I n d r y i n g , the b r i c k s were p l a c e d i n an oven a t 220°Fo f o r

4

days. I t was f o u n d t h a t t h i s method o f d r y i n g , c a r r i e d o u t a number o f t i m e s on t h e same b r i c k s , r e s u l t e d i n t h e i r d r y w e i g h t s b e i n g c o n s t a n t t o w i t h i n a f r a c t i o n of a gram i n a t o t a l weight of about 2500 grams.

Three t y p e s of b r i c k s were u s e d ; two o f t h e s e were made by t h e s t f f f - m u d method, t h e o t h e r by d r y - p r e s s . One of t h e s t i f f - m u d t y p e s was c o r e d w i t h

3

h o l e s .

A b s o r p t i o n p r o p e r t i e s of s e v e r a l o f t h e b r i c k s used

I n t h e t e s t s a r e shown i n T a b l e I. The p r o p e r t i e s were determified by t h e A.S.T.M, methods of t e s t . B r i c k s marked "A" a r e d r y - p r e s s ; b r i c k s "5" and " C t t a r e s t i f f-mud, t h e l a t t e r b e h g c o r e d w f t h

T a b l e I

-

A b s o r p t f o n P r o p e r t i e s o f Some o f t h e B r i c k s Used A b s o r p t i o n I n f t i a l R a t e A b s o r p t f o n 5 - h o u r o f Ab s o r p t f o n

24-

h o w I m m e r s i o n C o r r e c t e d t o B r i c k I m m e r s i o n B o i l i n g W a t e r

30

s q , i n , a r e a

-

a m r y W e i g h t Grams C a p i l l a r y a b s o r p t i o n t e s t s w e r e made a t room t e m p e r a t u r e , w h i c h v a r i e d f r o m 72OF, t o

7 7 O ~ .

The r e l a t f v e h u m i d i t y was n o t c o n t r o l l e d . It h a s b e e n f o u n d

( 4 )

t h a t w f d e c h a n g e s i n +,he r e l a t i v e h u m i d i t y h a v e v e r y small e f f e c t s on t h e v o i s t u r e c o n t e n t o f c l a y a n d s h a l e b r i c k s , E f f e c t o f R e p e t i t i o n o f C a p f l l a r y A b s o r p t i o n T e s t s on t h e I n f t f a l R a t e of A b s o ~ p t i o n S i n c e i n many o f t h e t e s t s made, t h e b r i c k s w e r e a l t e r n a t e l y d r i e d and p a r t i a l l y immersed 9n w a t e r f o r s h o r t p e r i o d s of t f m e , t h i s s e r i e s o f t e s t s w a s made t o d e t e r m i n e t h e e f f e c t o f t h i s a l t e r n a t e w e t t i n g a n d d r y i n g o n t h e i n f t i a l r a t e of a b s o r p t i o n , S i x b r i c k s , two o f e a c h t y p e , w e r e u s e d , The i n 1 t f a l r a t e of a b s o r p t i o n o f e a c h b r i c k was m e a s u r e d and t h e b r i c k s w e r e d r i e d f o r

4

d a y s a t 2 2 0 ~ F , The i n i t i a l r a t e o f a b s o r p t f o n was a g a i n m e a s u r e d a n d t.he b r i c k s d r i e d a s b e f o r e , T h i s p r o c e s s w a s c a r r f e d o u t

4

t i m e s , The r e s u l t s of t h e s e t e s t s a r e shown i n T a b l e 2 , F o r e a c h b r f ck f s g i v e n t h e i n i t f a1 r a t e o f a b s o r p t i o n ( g r a m s o f w a t e r a b s o r b e d by 1 m i n u t e p a r t i a l i m m e r s f o n i n

1 / 8

i n c h o f w a t e r ) , and t h e d i f f e r e n c e b e t w e e n t h e h i g h e s t a n d l o w e s t v a l u e f o r e a c h t e s t on e a c h b r i c k f s a l s o shown, T h i s d i f f e r e n c e is shown a l s o e x p r e s s e d as a p e r c e n t a g e o f t h e l o w e s t m e a s u r e d v a l u e o f f n i t i a l r a t e o f a b s o r p t f o n f o r e a c h b r f e k , T h e s e t e s t s r,,rere c a r r i e d o u t a t room t e m p e r a t u r e , t\rhfch v a r f e d b e t w e e n

74

and 77OFO

T a b l e 2

-

E f f e c t of R e p e t f t l o n o f A b s o r p t i o n T e s t s on t h e I n i t i a l R a t e o f A b s o r p t f o n .

-

Measured I n f t f a1 R a t e o f A b s o r p t i o n D f f f e r s n c e b e t w e e n ( g r a m s o f w a t e r a b s o r b e d f n h i g h e s t and l o w e s t 1/8 i n c h of w a t e r / m i n u t e ) r a t e s o f a b s o r p t i o n F i r s t Second T h i r d F o u r t h

%

o f l o w e s t B r i c k Te s t T e s t T e s t Te s t Grms v a l u e E f f e c t o f Changes f n t h e T e m p e r a t u r e o f B r f c k s a n d W a t e r o n t h e I n i t f

-

a 1 R a t e o f A b s o r p t f on

Six b r i c k s , two o f e a c h t y p e , were u s e d , and f o r e a c h t h e i n i t i a l r a t e o f a b s o r p t i o n o f t h e d r y b r i c k s ( b y p a r t i d immersion En 1/8 i n c h o f w a t e r f o r one n i n u t e ) was m e a s u r e d a t room t e m p e r a t u r e of

72"F0

The b r f c k s were d r f e d f o r f o u r d a y s a t 220°F, a n d t h e d r i e d b r i c k s and t h e c a p i l l a r y a b s o r p t f o n a p p a r a t u s w e r e p l a c e d f n a c o l d chamber a t a b o u t

39'~.

f o r

24

h o u r s , The b r i c k s were t e s t e d f o r f n f t i a l r a t e of a b s o r p t i o n f n t h e c o l d chamber,

The b r f c k s w e r e s u b s e q u e n t l y d r f e d a t 220°F, f o p

4

d a y s and t h e b r f c k s and a b s o r p t i o n e q u i p m e n t were p l a c e d i n a w a r m chamber a t a t e m p e r a t u r e o f a b o u t 13O0F0 f o r

24

h o u r s . The f n f t i a l r a t e o f a b s o r p t f o n o f t h e b r f c k s was m e a s u r e d i n t h e warm chamber, B e f o r e e a c h ' t e s t , t h e w a t e r t e m p e r a t u r e was m e a s u r e d , and a l t h o u g h t h e t e m p e r a t u r e of t h e b r i c k s was n o t m e a s u r e d , f t w a s assumed t h a t t h e y would b e a t a t e m p e r a t u r e v e r y c l o s e t o t h a t of t h e w a t e r , The r e s u l t s of t h e s e t e s t s a r e shown i n T a b l e

3

a n d t h e r e s u l t s f o r t h r e e of t h e b r i c k s a r e shown i n Fig. 1.

T a b l e

3

-

_{E f f e c t - " Changes i n t h e T e m p e r a t u r e o f B r i c k s and}

W a t e r

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o n t h e I n i t i a l R a t e o f A b s o r p t i o n ,

W a t e r I n i t i a l Wa%er I n f t i a 1 W a t e r I n i t f al

Temper- R a t e o f Ternpep- R a t e o f Temper- Rate of

B r i c k a t u r e Absciaution -;? B r i c k t e m p e r a t u r e 1 s assumed t o be v e r y c l o s e t o w a t e ~ t e m p e r a t u r e . E f f e c t o n I n i t i a l R a t e o f A b s o ~ p t i o n of Changes I n t h e D e p t h o f P a r t i a l I m m e r s i o n S i x b ~ i c k s , two of e a c h t y p e , w e r e p a r t i a l l y f m e r s e d i n w a t e r t o v a r f o u s d e p t h s f o r o n e m i n u t e t o d e t e r m i n e t h e e f f e c t of d e p t h o f p a r t f d i m m e r s i o n o n t h e amount of w a t e r a-bsorbed b y c a p i i l a r f t y . The b r i c k s w e r e p a r t i a l l y immersed t o d e p t h s o f 1 / 1 6 i n c h ,

118

i n c h , 3/16 i n c h and

164

i n c h , t h e b r i c k s b e f n g d r i e d f o r

4

d a y s a t 220°F. b e t w e e n t e s t s . The h e f g h t o f w a t e r above t h e s u p p o r t s f o r t h e b r i c k s w a s c o n t r o l l e d by r e f e r e n c e t o L n e e d l e s , p o f n t f n g downwards, f o r e a c h d e s i r e d d e p t h of w a t e r . One n e e d l e was p l a c e d 1 / 1 0 0 i n c h above t h e d e s i r e d d e p t h and t h e o t h e r was p l a c e d 1 / 1 0 0 f n c h b e l o w t h e d e s i r e d d e p t h o f waten., The n e e d l e s w e r e c a r e f u l l y s e t t o t h e p r o p e r h e i g h t s b y means o f f f n e c a l i p e r s . The w a t e r s u r f a c e was a d j u s t e d s o t h a t t h e l o w e r n e e d l e p i e r c e d t h e s u r f a c e 'out t h e u p p e r n e e d l e was n o t t o u c h e d by t h e w a t e ~ ,

The t e s t s w e r e made a t room t e m p e r a t u r e a n d t h e r e s u l t s a r e shown f n T a b l e

4.

The r e s u l t s f o r t h r e e o f t h e b r f c k s a r e a l s o shown, g r a p h i c a l l y , i n F f g . 2,

T a b l e

4

-

E f f e c t of Changes i n Depth o f P a r t f a l Immersfon o n I n f t f a l R a t e o f A b s o r p t i o n .

I n f t i a l R a t e of A b s o ~ p t i o n

-

rams

a b s o r b e d i n tfme of p a r t i a l immersion o f one m i n u t e )

B r f c k Depth 1/16" Depth

1/sn

Depth 3/16" Depth 1/&

E f f e c t of Changes i n t h e Time o f P a r t i a l I m m e ~ s i o n on t h e Amount of Water Absorbed by C a p i l l a ~ f t y

S i x b r i c k s , t w o of e a c h t y p e , were used t o d e t e r m f n e t h e e f f e c t on t h e amount of w a t e r a b s o r b e d f o r 1/8 i n c h p a ~ t f a l immersion in w a t e r f o r v a r i o u s l e q t h s of tfme. The b r i c k s were a l t e r n a t e l y d r i e d and p a r t i a l l y immersed

1/8

i n c h . i n w a t e r , The t i m e s of immersion were 1 / 2 m i n u t e , 1 m i n u t e , 1-1/2 m i n u t e s , and 2 mfnutes. Between t e s t s t h e b r i c k s were d r i e d a t 220°F, f o r

4

days.

The r e s u l t s o f t h i s t r e a t m e n t a r e shown f n T a b l e

5,

and a l s o , f o r t h r e e of t h e b r i c k s ir! F i g o

3.

T a b l e

5

-

Amount of Water Absorbed by B r f c k s i n V a r f o u s L e n g t h s of Tfme of P a r t i a l Immersion i n

1/8

I n c h of W a t e r

-

--

Amount of Water (Grams) Absorbed by B r i c k Placed f n

1/8 I n c h of Water f o r L e n g t h of Time

B r i c k 1 / 2 Minute 1 Mfnute 1 - 1 / 2 M i n u t e s 2 M i n u t e s

E f f e c t of Changes i n the Moisture Content of B r i c k s on t h e I n i t i a l Rate of Absorption

-

S i x b r i c k s , two of e a c h t y p e , were used i n a s e r i e s of t e s t s t o determine t h e e f f e c t of changes i n t h e m o i s t u r e c o n t e n t of t h e b r i c k s on t h e amount of water absorbed f n t h e i n i t i a l s t a g e s of c a p i l l a r y a b s o r p t f on.

The i n i t f a1 r a t e of a b s o r p t i o n of e a c h b r i ck was measured ( t h i s being, a s b e f o r e , t h e anount of w a t e r i n grams

absorbed by t h e b r i c k when p l a c e d f n

1/8

i n c h of water f o r one mfnute].

A f t e r t h i s measurement, e a c h b r i c k was indf v i d u a l l y wrapped f n a paper-backed aluminum f o i l , i n o r d e r t o r e t a f n

the moisture f n t h e b r i c k s .

A f t e r 24 hours, o r l o n g e r , t h e covering was q u i c k l y removed from each b r i c k i n t u r n and a measurement made of t h e amount of water absorbed by t h e b r i c k when p l a c e d i n 1/8 i n c h of w a t e r f o r one minute. The b r i c k s were i n d i v i d u a l l y wrapped a g a i n , and i n 24 hours, o r l o n g e r , the procedure r e p e a t e d ,

The maximum time r e q u i r e d t o unwrap, measure f o r f n i t i a l r a t e of a b s o r p t i o n , and re-wrap a b r i c k was found t o

be

3

mfnutes.

By t h i s means a measurement was made of t h e amount of w a t e r absorbed f n t h e i n i t i a l s t a g e s of c a p i l l a r y a b s o r p t f o n f o r a s e r i e s o f moisture c o n t e n t s of t h e b r i c k s ,

The r e s u l t s of t h e s e t e s t s a r e shown f n Table

60

_The

m o i s t u r e c o n t e n t of t h e b r i c k s , a t t h e s t a r t of t h e c a p i l l a r y a b s o r p t i o n t e s t s , i s e x p r e s s e d a s a p e r c e n t a g e o f t h e dry weight of t h e b r i c k s .

The r e s u l t s f o r t h r e e crC _{the b r f c k s a r e shown a l s o}

T a b l e 6

-

E f f e c t o f Changes f n M o i s t u r e C o n t e n t o f B r i c k s on T h e i r I n f t f a l

-

' R a t e s of A b s o r p t i o n ,

--

Mais- I n i t f d Mois- I n i t i a l Mcfs- I n f t f a l Mots- I n i t i a l

t u r e R a t e o f t u r e R a t e o f t u r e R a t e o f t u r e R a t e of Con- Absorp- Con- A b s o r p - Con- Absorp- Con- Absorp- B r i c k tent'.: t f o n t e n t % t i o n tent%- t i o n tent-:: t i o n

-

gFarns g r a m s g r a m s gpams

--

-:$ M o i s t u r e c o n t e n t e x p r e s s e d a s p e r c e n t a g e o f t h e d r y w e i g h t o f t h e b ~ f e k , E f f e c t on t h e I n i t i a l R a t e o f A b s o r p t f o n o f t h e A p p l i i e a t f o n o f

-

a Sf l i c o n e - t ~ e W a t e r R e p e l l a n t M a t e r i a l t o B r B c k s The f n i t f al r a t e o f a b s o r p t i o n o f s i x b r f c k s , t w o o f e a c h t y p e , was m e a s u r e d by p a r t i a l f m m e r s i o n i n

148

i n c h o f w a t e r f o r o n e m f n u t e . A f t e r t h i s t e s t , t h e b r B e k s w e r e d r i e d f o r

4

d a y s a t 2 2 o 0 F O and t h e n c o o l e d t o room t e m p e r a t u r e , A p r o p r i e t a r y l f quf d w a t e r r e p e l l a n t mate ~i a 1 o f t h e s i l i c o n e t y p e w a s a p p l i e d t o t h e b r f c k s b y b r u s h i i n g , T h r e e b r i c k s ( A l l , B11, and C 1 1 ) w e r e t r e a t e d w f t h t h e m a t e r i a l o n l y on t h e b o t t o m s u r f a c e and on t h e s i d e s f o r a d i s t a n c e o f a b o u t one i n c h f r o m t h e b o t t o m s u r f a c e ( t h a t 18, t h e s u r f a c e p l a c e d I n c o n t a c t w i t h w a t e r i n t h e i n i t i a l r a t e o f a b s o r p t i o n t e s t ) , The a a t e r f a . 1 was a p p l i e d t o a l l s u r f a c e s o f b r f e k s A12, B12, and C l 2 , I n a l l c a s e s , a. r e l a t i v e l y l i g h t a p p l f c a t f o n o f t h e m a t e ~ f a l was made, t h e m a t e r i a l b e f n g p u t on w i t h a s o f t b r u s h .

The b r f c k s were d r i e d a t room t e m p e r a t u r e r o r n f n e d a y s f o l P o w f n g t h e a p p l f c a t f o n of t h e w a t e r r e p e l l a n t , and were t h e n p l a c e d i n

118

i n c h o f w a t e r f o r one m i n u t e t o n e a s u r e t h e i n i t i a l r a t e o f a b s o r p t f o n , The r e s u l t s o f t h e t e s t a r e shown I n T a b l e

7,

T h e f n f t f a l p a t e o f a b s o r p t f o n o f e a c h b r i c k , b e f o r e , and a f t s ~ a t r e a t m e n t w f t i i t h e s i l i c o n e t y p e w a t e r r e p e l l a n t , i s shown, T a b l e

7

-

E f f e c t o f t h e A p p l f c a t f o n o f a S f l i e o n e - t y p e W a t e ~ R e p e l l a n t M a t e r i a l on t h e I n i t i a l H a t e o f A b s o r p t f o n o f B r f e k s , I n f t f a l R a t e of A b s o r p t f o n ( g r a m s o f w a t e r a b s o r b e d when b r f c k p l a c e d f n

1/8

i n c h o f w a t e r f o r 1 m f n u t e ) A f t e r S u r f a c e Trde a t m e n t B r f c k --" B e f o r e T r e a t m e n t

t

n

a

-

1

Summary and C o n c S u s f o n s T h e s e t e s t s showed t h e e f f e c t s o f some c h a n g e s f n t h e c c n d i t f o n s of c o n t a c t b e t w e e n b r f c k s a n d w a t e r o n t h e amount of w a t e r a b s o r b e d i n t h e i n f t i a l s t a g e s o f c a p f l l a r y a b s o r p t f o n , The work w a s r e s t r i c t e d t o t h e u s e of o n l y t h r e e t y p e s o f b r f c k s , ( a ) E f f e c t o f Temperatugde Changes o n t h e I n i t i a l R a t e o f A b s o r p t i o n o f B r f c k s

.

The ~ e s u l t s , as i l l u s t r a t e d f n F i g , P , i n d f c a t e f o r t h e b r f c k s u s e d f n t h e t e s t s , an f n c r e a s e i n t h e f n f t f a l i a a t e o f a b s o r p t f o n w f t h f n c r e a s e i n t e m p e r a t u r e of' t h e b r f c k s and waten?, Anderegg

(51,

f n d i s c u s s i n g d e s i r a b l e a b s o r p t f o n p g d o p e r t f e s o f b r f c k s , w i t h r e s p e c t t o t h e f o r m a t f o n o r a d e q u a t e bond b e t w e e n b r f c k s and m o r t a r , h a s w ~ i t t e n , " I n w f n t e r t h e v f s c c s f t y o f w a t e ? i s so much h i g h e r t h a n f n summer t h a t t h e r a t e o f a b s o r p t i o n f s g r e a t l y Powered, r e q u f ~ f n g bnaiek o f h f g h e ~ s u c k i n g p o w e r P H e recommended, t h e r e f o r e , i n coZd w e a t h e r c o n s t r u c t f o n , t h e u s e o f b r f c k s o f d o u b l e t h e a b s o y p t 8 e n r a t e o f t h o s e u s e d i n summer c o n s t r u e t f o n t o s e c u r e w e a t h e y - r e s i s t a n t a a s o n p y ,

The r e s u l t s o f t h i s i n v e s t i g a t i o n , however, i n d f c a t e a r e l a t i v e l y s m a l l d e c r e a s e i n r a t e o f a b s o r p t i o n w i t h d e c r e a s s i n t e n p e r a t u r e . Assuming a t e ~ p e r a t u r e r a n g e of betweera S O O F ,

and 100°F, f o p w i n t e r and surnqer, F i g . 1 shows t h e B r i c k A9 h a s an i n E t i a l r a t e o f a b s o r p t f o n a t 1 0 0 ~ F , o f 8 6 gpams p e p n i n u t e , and a t S O O F , of 72 grams p e r r c i n u t e , For B r i c k B9 t h e

r a t e c h a n g e s from

44

grams p e r m i n u t e a t 1 0 0 ° F , t o

38

gpams a t

S O O F , 3'9% b r i c k C9 t h e change i s f r o m

35

t o 29 grams i n a

change c f t e v p e r a t u r e fro^ iOO°F, t o SOOF,

I t is c o n s i d e r e d , t h e r e f o r e , t h a t t h e change f n i n i t i a l r a t e o f absoraption w i t h change i n t e m p e r a t u r e , u n d e r t h e c o n d f t f o n s o f t h e s e t e s t s , i s r e l a t i v e l y s m a l l .

( b ) E f f e c t o f Change i n Depth o f Immersion on Amount of; W a t e r Absorbed, I t was f o u n d i n t h e s e i n v e s t i g a t i o n s t h a t a s l i g h t i n c r e a s e i n t h e amount o f w a t e r a b s o r b e d b y t h e b r Z c k s r e s u l t e d f r o v i n c r e a s i n g t h e d e p t h of p a r t i a l i m - e r s i o n f r o m 1/:6 i n c h to

111;

i n c h , w i t h t h e t i m e o f i r n ~ e r s f o n c o n s t a n t a t o n e m i n u t e , I n t h e c a s e of B r i c k

A S ,

a b o u t 1 0 4 g r a m s of w a t e r tjelne a b s o r b e d when i t w a s p l a c e d i n

1/4

i n c h o f w a t e r f o r one m i n u t e ; when p l a c e d i n 1/16 i n c h o f w a t e r f o r one m i n u t e i t a b s o ~ b e d 97 grams o f w a t e r ,

( c ) E f f e c t o f Changing Time o f P a ~ t i a l Immersion o n t h e Amount o f W a t e r A b s o ~ b e d , I n c h a n g i n g t h e t i m e o f p a r t i a l i m - e r s i o n of t h e b r i c k s b e t w e e n

I

J 2 rnfnute a n d 2 m i n u t e s w h i l e t h e d e p t h o f i m e r s i o ~ r e m a i n e d c o n s t a ~ l t a t

118

I n c h , i t was f o u n d t h a t a r e l a t f v e l y l a r g e amount o f w a t e r was t a k e n up by t h e b r i c k s i n t h e f i r s t i , / ~ m i n u t e o f c o n t a c t w i t h t h e w a t e r , a s c o m p a ~ e d to t h e a m o u n t t a k e n up i n t h e s u b s e q u e n t 9-112 m i n u t e s . Thus B r f c k

A 4

absonabed

49.1

grams o f w a t e r i n t h e f i r s t h a l f - m i n u t e or" p a r t f d f m e r s i o n , m.d 30.4 grams i n t h e n e x t 9-1/2 m i n u t e s . ( d ) E f f e c t o f Changes i n t h e M o i s t u r e C o n t e n t o f B r i c k s o n I n i t f a 1 R a t e of A b s o r p t i o n , I t h a s b e e n a common p r a c t i c e i n b r i c k masonry c o n s t r u c t i o n f o r tJ he b r i c k l a y e r t o wet b r i c k s b e f o r e iay8n.g 4n o r d e r t o a d j u s t t h e f r r a t e s of a b s o r p t i o n , o r s u c t i o n . A l t h o u g h t h e s t a n d a r d s p e c f f i c a t i o n f o r c l a y b r i c k o f t h e Amerfcan S o c i e t y f o r T e s t i n g M a t e r i a l s ( 6 ) d o e s n o t p l a c e l i m i t s o n t h e v a l u e o f i n i t i a l r a t e o f a b s o r p t f o n o f b r i c k s , i t d o e s c o n t a i n t h e n o t e t h a t , ' ' ~ a t a i n d i c a t e t h a t a l o w r a t e o f s u c t i o n ( 2 0 grarns p e r m i n u t e o r l e s s ) i s d e s i r a b l e b o t h f ~ o m t h e s t a n d p o i n t or" bond and w a t e r t i g h t n e s s

. . .

and ,, , t h e s u c t i o n r a t e of b r f c k t h a t n o r r n a l l y have h i g h r a t e s o f s u c t i o n c a n b e r e d u c e d t o any p r e d e t e r m f n e d v a l u e by w e t t f n g b e f o r e l a y i n g

...

Sl

I n t h e s e i n v e s t i g a t i o n s t h e t h r e e t y p e s o f b r i c k s used were of i n i t i a l r a t e o f a b s o r p t i o n , o r s u c t i o n , g r e a t e r t h a n 2 0 grams p e r m i n u t e . The e f f e c t o f i n c r e a s e i n r n o i s t u r e c o n t e n t of t h e b r i c k s o n t h e i n i t i a l r a t e of a b s o r p t i o n i s i l l u s t r a t e d f n F i g ,

4,

Thus, i n o r d e r t o r e d u c e t h e , r a t e o f a b s o r p t i o n o f B r i c k A7 t o t h e v a l u e c o n s i d e r e d d e s i r a b l e by t h e A,S,T,M, f o r w a t e r t i g h t masonry, a n amount o f w a t e r e q u a l t o 9 - l / 4 p e r c e n t o f t h e d r y w e i g h t of t h e b r i c k was r e q u i r e d t o b e added, T h i s f s a b o u t 1/2 pound o f w a t e r . I n t h e c a s e o f B r i c k B7, t o r e d u c e t h e i n i t i a l r a t e c f a b s o r p t i o n t o 20 grams p e r m i n u t e ,

7 , s

p e r c e n t o f t h e d r y w e i g h t o f t h e b r i c k , o f w a t e r , had t o be added, o r a b o u t 4/10 pound,

I n t h e c a s e of B r i c k ~ 8 , t h e a d d i t i o n r e q u i r e d w a s a b o u t

1/4

pound o f w a t e r , t o r e d u c e t h e s u c t f o n t o 20 g r a m s p e r n i n u t e

.

It was f o u n d t h a t b y t o t a l l y immersing t h e s e b r i c k s f n w a t e r , T o r e t h a n

5

m i n u t e s immersion o f B r i c k

A 7

was r e q u f ~ e d t o r e d u c e t h e s u c t i o n t o 20 g r a m s p e r m i n u t e ; f o r B r i c k B7

immersfon f o r

3

_{m i n u t e s was r e q u i r e d ; f o r B r i c k}

_~8

_{t o t a l immersion}

i n w a t e r f o r s l i g h t l y more t h a n one m i n u t e was n e c e s s a r y t o r e d u c e t h e s u c t i o n t c 2 0 g r a m s p e r m i n u t e , I t f s c o n s i d e r e d f r o m t h e s e t e s t s t h a t a c c u r a t e c o n t r o l o f t h e i n i t i a l r a t e o f a b s o r p t i o n o f b r f c k s on t h e c o n s t r u c t i o n s i t e , b y w e t t i n g , may b e d i f f i c u l t . The r e l a t i v e l y h i g h m o f s t u r e c o n t e n t r e q u i r e d i n some b r i c k s f n o r d e r t o r e d u c e t h e s u c t i o n t o a d e s i r a b l e v a l u e may have a d v e r s e e f f e c t s i n c o l d w e a t h e r c o n s t r u c t i o n , ( e ) E f f e c t o f S i l i c o n e - t y p e W a t e r R e p e l l a n t o n I n i t i a l R a t e of A b s o r p t f o n o f B r i c k s . The a p p l i c a t i on o f a p r o p r i e t a r y s i l l c o n e - t y p e w a t e r r e p e l l a n t m a t e r l a l t o t h e b r i c k s t e s t e d , b r o u g h t a b o u t a marked, b u t n o t c o n s i s t e n t , r e d u c t i o n i n t h e i n f t f a l r a t e o f a b s o r p t i o n o f t h e b r i c k s , p r o b a b l y b e c a u s e o f uneven a p p l i c a t i o n by b r u s h i n g , A l t h o u g h riot used i n t h e s e t e s t s , o t h e r s u r f a c e t r e a t m e n t s s u c h

a s cement g r o u t , lfme wash, e t c , , would u n d o u b t e d l y r e d u c e t h e r a t e o f a b s o r p t i o n o f t h e b r f c k s ,

-

1 2

-

R e f e r e n c e s

(1) L . A o Palmer and D o A o P a r s o n s "A S t u d y of' the P r o p e r t f e s of M o r t a r s and B r i c k s and T h e i r R e l a t i o n t o Bond" R e s e a ~ c h P a p e r 683, J o u r n a l of Research, N a t i o n a l Bureau of

S t a n d a r d s , Vol. 12, 1934.

( 2 ) C , C , Cormor

co actors

i n t h e ResSstance of B r i c k Masonry Walls t o M o i s t u r e p e n e t r a t i o n " A.S.T,M. P r o c , Vol,

48,

1948,

( 3 )

American S o c i e t y f o r T e s t i n g P i a t e r i a l s . S t a n d a r d Methods of SampPfng and T e s t i n g B r i c k . A,SoT.Mo D e s i g n a t f o n C67-50; 1950. Supplement t o Book of A.SoT,No S t a n d a r d s

-

P a r t

3,

( 4 )

J a w o PlcBafn and J. F e r g u s o n "On t h e Nature of t h e I n f l u e n c e of Humidity Changes Upon t h e Composition of B u i l d i n g M a t e r i a l s " , J o u r , Phys. Chem. Vol.

319

1927.

(5

>

F O G . Anderegg " ~ o n s t r u c t i o n of Water-Tight B r i ck Fiassnrytso American Ceramfc S o c i e t y J o u r n a l Vol.

P 3 9

1930.

( 6 )

American S o c i e t y f o r T e s t f n g M a t e r i a l s . S t a n d a r d S p e c f f f - c a t f o n s f o r B u i l d i n g B r f c k ( S o l f d Masonry U n i t s made from Clay o r S h a l e ) A,S.ToMo D e s i g n a t f o n ~ 6 2 - 5 0 ; 1 9 5 0 Supplement t o Book of A,S,T,M. S t a n d a r d s

-

P a r t

3.

4 0 50 6 0 4 0 8 0 9 0 100 110 120 130 T E M P E R A T U R E ( O F ) O F W A T E R A N D B R I C K S D U R I N G T E S T F I G . I E F F E C T OF C H A N G E S I N T H E T E M P E R A T U R E O F B R I C K S A N D WATER O N T H E I N I T I A L R A T E O F A B S O R P T I O N .

D E P T H O F P A R T I A L I M M E R S I O N

-

I N C H E S

P I G . 2

E F F E C T O N I N I T I A L R A T E O F A B S O R P T I O N O F C H A N G E

T E S T 3 M A D E A T R O O M T E M P .

T I M E OF P A R T I A L I M M E R S I O N

-

3 E C O N D 3

F I G . 3

E F F E C T O N I N I T I A L R A T E O F A B 3 0 R P T I O N

M O I S T U R E C O N T E N T O F B R I C K A T S T A R T O F T E 3 T P E R C E N T O F D R Y W E I G H T F I G .

4

E F F E C T O F I N C R E A S E I N M O I S T U R E C O N T E N T O F B R I C K S O N I N I T I A L R A T E O F A B S O R P T I O N B R I C K A ?