Effects of Acid Deposition on Portland Cement Concrete - American

16 Effects of Acid Deposition on Portland Cement Concrete

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R. P. Webster and L. E. Kukacka Department of Applied Science, Process Sciences Division, Brookhaven National Laboratory, Upton, NY 11973 Presented are the results of a program, sponsored by the Environmental Protection Agency, conducted to determine the state-of-the-art knowledge pertaining to the effects of acid deposition on the properties of portland cement concrete structures (PCC). Information was collected from a computerized literature survey, interviews, and replies to mail and telephone inquiries addressed to cement and concrete researchers and to governmental agencies and private firms active in the maintenance and restoration of concrete structures. In general, the study revealed very little qualitative or quantitative information on the effects of acid deposition on PCC structures. The rate of deterioration of reinforced PCC structures in polluted areas, however, appears to be increasing, and available information makes it readily apparent that acids and acid waters significantly affect the durability of concrete, and that SO , NO , and HCl accelerate the corrosion of reinforcing steel. On the basis of this evidence, it was recommended that an experimental test program, consisting of both laboratory and field tests, be developed and implemented to quantitatively measure the effects of acid deposition on PCC structures. 2

x

Over the l a s t 25 y e a r s , an i n c r e a s i n g amount of evidence has been gathered i n d i c a t i n g t h a t a c i d d e p o s i t i o n , r e s u l t i n g from the emiss i o n o f o x i d e s of s u l f u r and n i t r o g e n i n t o the atmosphere, has a s i g n i f i c a n t l y a d v e r s e e f f e c t upon man's environment i n c l u d i n g the a c i d i f i c a t i o n of l a k e s , r i v e r s and groundwaters, a c i d i f i c a t i o n and démineraiization of s o i l s , r e d u c t i o n of f o r e s t p r o d u c t i v i t y , damage to c r o p s , and d e t e r i o r a t i o n of b u i l d i n g m a t e r i a l s ( 1 - 9 ) . Although much of t h i s e v i d e n c e p e r t a i n s to the e f f e c t s of a c i d d e p o s i t i o n

0097-6156/86/0318-0239$06.00/ 0 © 1986 American Chemical Society

In Materials Degradation Caused by Acid Rain; Baboian, R.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

M A T E R I A L S D E G R A D A T I O N C A U S E D BY A C I D R A I N


240

on the n a t u r a l environment, i . e . l a k e s , r i v e r s , f o r e s t s and c r o p s , i t i s becoming i n c r e a s i n g l y c l e a r t h a t a c i d d e p o s i t i o n has a s i g n i f i c a n t impact a l s o on the d u r a b i l i t y of b u i l d i n g m a t e r i a l s such as m e t a l s , masonry, b u i l d i n g s t o n e , and c o n c r e t e ( 1 0 - 2 4 ) . Since c o n c r e t e i s the most w i d e l y used c o n s t r u c t i o n m a t e r i a l i n the u n i t e d S t a t e s , any comprehensive assessment of the economic impact of a c i d d e p o s i t i o n on m a t e r i a l s should i n c l u d e c o n s i d e r a t i o n of PCC and s t e e l r e i n f o r c e d PCC. To t h i s end, Brookhaven N a t i o n a l Labo r a t o r y (BNL) has c a r r i e d out a program as p a r t of the N a t i o n a l A c i d P r e c i p i t a t i o n Assessment Program (NAPAP) Task F o r c e P r o j e c t G3-1.05, sponsored by the E n v i r o n m e n t a l P r o t e c t i o n Agency/Atmos p h e r i c S c i e n c e s R e s e a r c h L a b o r a t o r y (EPA/ASRL), e n t i t l e d " E f f e c t s of A c i d D e p o s i t i o n on the P r o p e r t i e s of R e i n f o r c e d P o r t l a n d Cement Concrete S t r u c t u r e s . " The s p e c i f i c o b j e c t i v e s of the BNL program were (a) t o d e t e r mine the s t a t e - o f - t h e - a r t - k n o w l e d g e p e r t a i n i n g to the e f f e c t s of a c i d d e p o s i t i o n on the p r o p e r t i e s of PCC, and (b) i f the r e s u l t s i n d i c a t e d a need f o r q u a n t i t a t i v e d a t a , to develop recommendations f o r an e x p e r i m e n t a l t e s t program to be submitted f o r Task Group G a p p r o v a l and i m p l e m e n t a t i o n . S t a t e - o f - t h e - A r t Review G e n e r a l Summary. I n f o r m a t i o n f o r the s t a t e - o f - t h e - a r t review was o b t a i n e d from a c o m p u t e r i z e d l i t e r a t u r e s u r v e y , i n t e r v i e w s , and r e p l i e s to m a i l and telephone i n q u i r i e s addressed to cement and c o n c r e t e r e s e a r c h e r s and to governmental a g e n c i e s and p r i v a t e f i r m s a c t i v e i n the maintenance and r e s t o r a t i o n of c o n c r e t e s t r u c t u r e s . I n g e n e r a l , the c o m p u t e r i z e d l i t e r a t u r e survey i n d i c a t e d t h a t an abundance of l i t e r a t u r e on a c i d p r e c i p i t a t i o n i s a v a i l a b l e , but most of i t d e a l s w i t h the c h e m i s t r y of a c i d p r e c i p i t a t i o n and i t s e f f e c t s on the n a t u r a l environment. L i t e r a t u r e d e a l i n g w i t h the e f f e c t s of a c i d d e p o s i t i o n on b u i l d i n g s and b u i l d i n g m a t e r i a l s does e x i s t , however, very l i t t l e of i t p e r t a i n s to cement or c o n c r e t e . The i n f o r m a t i o n t h a t was found r e g a r d i n g the e f f e c t s of a c i d depos i t i o n on b u i l d i n g s and b u i l d i n g m a t e r i a l s i n d i c a t e s t h a t the i n c r e a s i n g a c i d i t y of p r e c i p i t a t i o n enhances normal w e a t h e r i n g and c o r r o s i o n processes. I n a d d i t i o n , p r i v a t e communications I n d i c a t e d t h a t a r a p i d l y i n c r e a s i n g number of r e i n f o r c e d c o n c r e t e s t r u c t u r e s i n c i t i e s are showing d e t e r i o r a t i o n w h i c h the respondents a t t r i buted to S O 2 , NO , and HC1. The l i t e r a t u r e a l s o i n d i c a t e s t h a t w h i l e i t i s f e l t , by some, t h a t a c i d p r e c i p i t a t i o n does have an adverse e f f e c t on the p e r f o r mance of b u i l d i n g m a t e r i a l s , no work a p p a r e n t l y i s being done to i n v e s t i g a t e these e f f e c t s . A s h t o n and Sereda (24) r e p o r t t h a t : " M o n i t o r i n g of the c o n c e n t r a t i o n of p o l l u t a n t s i n the atmosphere and i n r a i n i s done by v a r i o u s government a g e n c i e s i n many count r i e s , but l i t t l e e f f o r t i s d i r e c t e d to the study of t h e i r e f f e c t on b u i l d i n g m a t e r i a l s , p a r t i c u l a r l y t h a t of a c i d i c components i n rainwater." None of the i n d i v i d u a l s and o r g a n i z a t i o n s r e s p o n d i n g to the m a i l and telephone i n q u i r i e s were aware of any documented i n f o r m a t i o n d e a l i n g s p e c i f i c a l l y w i t h the e f f e c t s of a c i d d e p o s i t i o n on PCC s t r u c t u r e s , or of any r e s e a r c h t h a t had been or was being done x


16.

WEBSTER A N D K U K A C K A

Acid Deposition on Portland Cement Concrete

i n t h i s a r e a . Comments on the need f o r such r e s e a r c h work were varied: some respondents thought i t was needed because the l a r g e volume of c o n c r e t e s t r u c t u r e s i n the U n i t e d S t a t e s c o u l d p r e s e n t a p o t e n t i a l l y l a r g e problem; o t h e r s thought the need f o r such r e s e a r c h was open to q u e s t i o n because they c o n s i d e r e d o t h e r mechanisms of d e t e r i o r a t i o n to be more i m p o r t a n t . The study r e v e a l e d v e r y l i t t l e q u a l i t a t i v e or q u a n t i t a t i v e i n f o r m a t i o n on the e f f e c t s of a c i d d e p o s i t i o n on PCC s t r u c t u r e s . The r a t e of d e t e r i o r a t i o n of r e i n f o r c e d PCC s t r u c t u r e s i n p o l l u t e d a r e a s , however, appears to be i n c r e a s i n g , and a v a i l a b l e i n f o r m a t i o n makes i t r e a d i l y apparent t h a t a c i d s and a c i d waters s i g n i f i c a n t l y a f f e c t the d u r a b i l i t y of c o n c r e t e , and t h a t S 0 2 , N 0 , and HC1 a c c e l e r a t e the c o r r o s i o n of r e i n f o r c i n g s t e e l . Downloaded by STANFORD UNIV GREEN LIBR on April 16, 2013 | http://pubs.acs.org Publication Date: September 25, 1986 | doi: 10.1021/bk-1986-0318.ch016

X

R e s i s t a n c e of Concrete

to Chemical

Attack

Because the l i t e r a t u r e on the e f f e c t s of a c i d d e p o s i t i o n on PCC i s l i m i t e d , the l a r g e amount of l i t e r a t u r e d e a l i n g w i t h the c o r r o s i v e e f f e c t s of a c i d s , a c i d w a t e r s , and s u l f a t e s on c o n c r e t e was r e viewed i n an attempt to e s t i m a t e the e f f e c t s of a c i d d e p o s i t i o n on PCC (25-48). E f f e c t s of A c i d s . S i n c e c o n c r e t e , c h e m i c a l l y , i s a b a s i c m a t e r i a l , h a v i n g a pH of about 13, i t i s s u b j e c t to a t t a c k by a c i d s . Woods (32) r e p o r t s t h a t c o n c r e t e i s not v e r y r e s i s t a n t to s t r o n g s o l u t i o n s of s u l f u r i c , s u l f u r o u s , h y d r o c h l o r i c , n i t r i c , hydrobromic, or h y d r o f l u o r i c a c i d s , and i s d e s t r o y e d by prolonged c o n t a c t w i t h any of these, though not n e c e s s a r i l y a t the same r a t e . Weaker s o l u t i o n s (3 the c o r r o s i o n r a t e should be h a r d l y g r e a t e r than t h a t due to l e a c h i n g by pure w a t e r , i . e . the a c i d e f f e c t becomes n e g l i g i b l e . There i s a l s o e v i d e n c e , however, t h a t c a r b o n i c a c i d a t t a c k i s enhanced by the presence of s u l f a t e s ( 3 9 ) .


243


244

Tremper (27) developed a damage f u n c t i o n to d e s c r i b e the de t e r i o r a t i o n observed i n h i s work. The damage f u n c t i o n , which i s expressed as


log

L • K*log Τ

where L = the percentage of the o r i g i n a l lime l o s t from the concrete Τ « the time i n days f o r which the c o n c r e t e has been exposed Κ - a c o n s t a n t which v a r i e s w i t h the pH of the s o l u t i o n to which the c o n c r e t e i s exposed and the s u r f a c e to volume r a t i o of the c o n c r e t e , p r e d i c t s the r a t e of d e t e r i o r a t i o n due to a c i d a t t a c k based upon the l o s s of l i m e from c o n c r e t e . Based upon the r e s u l t s of a s e r i e s of l a b o r a t o r y t e s t s , Tremper concluded t h a t f o r purposes of compu t a t i o n the m e c h a n i c a l f a i l u r e of average p o r t l a n d cement c o n c r e t e w i l l occur when 50% o f the o r i g i n a l l i m e c o n t e n t has been removed. V a l u e s f o r Κ are developed based upon the r e s u l t s of the l a b o r a t o r y t e s t s , however, Tremper had to make s e v e r a l assumptions d u r i n g the development of these v a l u e s , thereby l i m i t i n g the a c c u r a c y of the damage f u n c t i o n . F r i e d e (43) p u b l i s h e d a s e r i e s of e q u a t i o n s f o r c a l c u l a t i n g the depth of the c o r r o d e d zone f o r c o n c r e t e specimens exposed to c a r b o n i c a c i d a t t a c k as a f u n c t i o n of the p h y s i c a l and m e c h a n i c a l p r o p e r t i e s of c o r r o d e d and noncorroded specimens, i . e . d e n s i t y , volume, mass, modulus of e l a s t i c i t y and s t r e n g t h . The e q u a t i o n s , however, do not take i n t o c o n s i d e r a t i o n such f a c t o r s as the compo s i t i o n of the c o n c r e t e or the degree of a t t a c k to which i t i s sub j e c t e d . I n a d d i t i o n , the wide v a r i a t i o n i n t e s t r e s u l t s , o b t a i n e d from l a b o r a t o r y t e s t s performed to v a r i f y the t h e o r e t i c a l l y d e r i v e d equations, l i m i t their a p p l i c a b i l i t y . E f f e c t s o f S u l f u r D i o x i d e . S u l f u r d i o x i d e , when d r y , has l i t t l e or no e f f e c t on d r y PCC. I t does, however, combine w i t h water to form s u l f u r o u s a c i d ( H 2 S O 3 ) , which g r a d u a l l y r e a c t s w i t h oxygen to form s u l f u r i c a c i d ( H 2 S O 4 ) , b o t h of which w i l l a t t a c k c o n c r e t e ( 3 2 ) . Most of the damage to m a t e r i a l s from SO2 i s a t t r i b u t e d to h i g h l y r e a c t i v e s u l f u r i c a c i d formed e i t h e r i n the atmosphere o r on the s u r f a c e of m a t e r i a l s . Damage to l i m e s t o n e p r o d u c t s , c o n c r e t e , and marble has been observed i n those areas e x p e r i e n c i n g r e l a t i v e l y h i g h l e v e l s of SO2 over a p r o l o n g e d p e r i o d ( 2 3 ) . As p r e v i o u s l y d i s c u s s e d , s u l f u r i c a c i d a t t a c k s c o n c r e t e (a) by c o n v e r t i n g c a l c i u m c a r b o n a t e to gypsum, which i s s u b s e q u e n t l y l e a c h e d away, and (b) by r e a c t i n g w i t h c a l c i u m compounds to form s a l t s w h i c h c r y s t a l l i z e , p r o d u c i n g enormous s t r e s s e s w i t h i n the pores of the cement paste which e v e n t u a l l y l e a d to s p e l l i n g and c r a c k i n g . The l a t t e r form o f a t t a c k i s commonly known as s u l f a t e a t t a c k . B o t h mechanisms of d e t e r i o r a t i o n were i d e n t i f i e d by Hansen e t a l (31) i n t h e i r work r e g a r d i n g the c o r r o s i o n of c o n c r e t e due to s u l f u r i c a c i d a t t a c k , i n w h i c h they conclude t h a t exposure to s u l f u r i c a c i d can p r o g r e s s from a s t r a i g h t c o r r o s i v e a t t a c k to a com b i n a t i o n of c o r r o s i o n and s u l f a t e a t t a c k .



16.



The e f f e c t s of s u l f a t e a t t a c k on p o r t l a n d cement c o n c r e t e have been w e l l documented (25,26,32,33,40-42,44-48). Kuenning (26) des c r i b e s the mechanism of s u l f a t e a t t a c k as f o l l o w s : "The d e s t r u c t ive a c t i o n of s u l f a t e s on c o n c r e t e i s p r i m a r i l y the r e s u l t of t h e i r r e a c t i o n w i t h e i t h e r C3A o r the C3A h y d r a t i o n p r o d u c t s to form the h i g h - s u l f a t e form of c a l c i u m s u l f o a l u m i n a t e ( e t t r i n g i t e ) . The c r y s t a l l i n e r e a c t i o n p r o d u c t i s of l a r g e r volume than the o r i g i n a l a l u m i n a t e c o n s t i t u e n t , and e x p a n s i o n r e s u l t s . The c o n c r e t e o r mortar i n c r e a s e s i n s t r e n g t h a t f i r s t , because of the i n c r e a s e i n s o l i d m a t t e r , even though i t i s changing c h e m i c a l l y . As the process c o n t i n u e s the c o n c r e t e or mortar expands, c r a c k s , becomes prog r e s s i v e l y weaker, and f i n a l l y d i s i n t e g r a t e s . " Jambor (42) has p u b l i s h e d a damage f u n c t i o n d e s c r i b i n g s u l f a t e a t t a c k i n terms of the p e r c e n t of SO3 bound i n hardened cement p a s t e , which he r e p o r t s as b e i n g the prime cause of s u l f a t e c o r r o s i o n . The damage f u n c t i o n (DC) which i s expressed as DC -

(0.11s0.45)(

0

0 a 4 3 t

0.33)( 204e 0 e

1 4 5 C

3A)

takes i n t o c o n s i d e r a t i o n the c o n c e n t r a t i o n of the a c t i n g s u l f a t e s o l u t i o n ( S ) , the p e r i o d of time of i t s a c t i o n ( t ) , and the t r i c a l cium a l u m i n a t e (C3A) c o n t e n t of the p o r t l a n d cement used. The damage f u n c t i o n was developed on the b a s i s of e x p e r i m e n t a l t e s t r e s u l t s which demonstrated the e f f e c t s , w i t h time, of sodium s u l f a t e s o l u t i o n s , w i t h v a r y i n g SO4 c o n c e n t r a t i o n s , on the dynamic modulus of e l a s t i c i t y , compressive and f l e x u r a l s t r e n g t h , v o l m e t r i c and mass changes, and changes i n the bound SO3 c o n t e n t of p o r t l a n d cement mortar specimens. Jambor has, a p p a r e n t l y , been a b l e to r e l a t e the changes observed i n the p h y s i c a l and mechanical p r o p e r t i e s of the specimens to changes i n the bound SO3 c o n t e n t . These d a t a , however, were not g i v e n i n the paper. The data presented r e l a t e bound SO3 c o n t e n t to s u l f a t e c o n c e n t r a t i o n , C3A c o n t e n t , and time of t e s t i n g . I t i s these data upon which the damage f u n c t i o n was based. As Jambor p o i n t s out, the damage f u n c t i o n i s l i m i t e d i n t h a t i t does not take i n t o account temperature e f f e c t s , i n f l u e n c e of the cement c o n t e n t i n the mortars and c o n c r e t e , t o t a l p o r o s i t y of the composite mater i a l , as w e l l as the i n f l u e n c e of the c r o s s - s e c t i o n s i z e of the s t r u c t u r e . I t does, however, serve to g i v e a f i r s t a p p r o x i m a t i o n . Even though the mechanisms are not f u l l y u n d e r s t o o d , i t has been f a i r l y w e l l e s t a b l i s h e d t h a t SO2 a c c e l e r a t e s the c o r r o s i o n of carbon s t e e l (14-16,49-51). T h i s r e s u l t s i n the c r e a t i o n of a l a y e r of r u s t , i . e . i r o n o x i d e s , on the s u r f a c e of the s t e e l , w h i c h o c c u p i e s more than twice the volume of the i r o n from which i t was produced. I n a d d i t i o n , Haynie and Upham (15) r e p o r t t h a t I r o n o x i d e s c a t a l y z e the o x i d a t i o n of SO2 to SO3 as w e l l as r e a c t w i t h SO2 to form s u l f a t e s . B o t h c o n d i t i o n s , i . e . the e x p a n s i o n of r e i n f o r c i n g s t e e l due to c o r r o s i o n and s u l f a t e a t t a c k , have been shown to cause the d e t e r i o r a t i o n of PCC. E f f e c t s of Nitrogen Oxides. Very l i t t l e information i s p r e s e n t l y a v a i l a b l e i n the l i t e r a t u r e r e g a r d i n g the e f f e c t s of n i t r o g e n o x i d e s (N0 ) on PCC. G a u r i (19) r e p o r t s t h a t n i t r o g e n d i o x i d e produced p r i m a r i l y d u r i n g combustion p r o c e s s e s by the o x i d a t i o n of X


245



246

a t m o s p h e r i c n i t r o g e n i s the main cause of the a c i d i t y of p r e c i p i t a t i o n i n the Los A n g e l e s B a s i n where NO3" i s more than twice as c o n c e n t r a t e d as S04~2. NO3" i s a l s o p r e s e n t a t a l e s s e r e x t e n t i n the n o r t h e a s t e r n U n i t e d S t a t e s . But due to h i g h e r s o l u b i l i t y , i t s lodgement time i n the atmosphere i s much s h o r t e r . I t i s perhaps due to t h i s t h a t n i t r a t e s have not y e t been i d e n t i f i e d i n stone and concrete s t r u c t u r e s . N i t r o g e n o x i d e s w i l l r e a c t w i t h water o r , as ammonia ( N H 3 ) , w i t h oxygen to form n i t r o u s (HNO2) and n i t r i c (HNO3) a c i d . B i c z o k (25) r e p o r t s t h a t a l t h o u g h n i t r i c a c i d i s not as s t r o n g as s u l f u r i c a c i d , i t i s more h a r m f u l to c o n c r e t e on b r i e f exposure as i t t r a n s f o r m s the C a ( 0 H ) 2 of c o n c r e t e i n t o h i g h l y s o l u b l e c a l c i u m n i t r a t e . N i t r i c a c i d i s d e s t r u c t i v e enough to b r i n g about extens i v e d e t e r i o r a t i o n even i n h i g h l y d i l u t e d s o l u t i o n s . Conclusions

and

Recommendations

The r e s u l t s of the l i t e r a t u r e s u r v e y , p r i v a t e d i s c u s s i o n s , and the responses to m a i l and telephone i n q u i r i e s have i n d i c a t e d t h a t v e r y l i t t l e q u a l i t a t i v e or q u a n t i t a t i v e i n f o r m a t i o n i s a v a i l a b l e d e a l i n g s p e c i f i c a l l y w i t h the e f f e c t s of a c i d d e p o s i t i o n on PCC s t r u c t u r e s , but there i s a c o n s i d e r a b l e amount of i n f o r m a t i o n a v a i l a b l e i n d i c a t i n g t h a t a c i d s and a c i d w a t e r s have a s i g n i f i c a n t e f f e c t on the d u r a b i l i t y of c o n c r e t e . T h i s e f f e c t may not be sudden or d r a m a t i c , but i t i s a cause f o r c o n c e r n . I t has been w e l l documented t h a t h i g h l e v e l s of p o l l u t a n t s ( S O 2 , N 0 , e t c . ) have g r e a t l y a c c e l e r a t e d the d e t e r i o r a t i o n of many of the a n c i e n t s t a t u e s , monuments, and b u i l d i n g s made u s i n g c a l c a r eous b u i l d i n g stone i n and near the i n d u s t r i a l i z e d areas of Europe. E v i d e n c e i s now b e g i n n i n g to i n d i c a t e t h a t r a p i d l y i n c r e a s i n g numb e r s of r e i n f o r c e d c o n c r e t e s t r u c t u r e s are a l s o showing i n c r e a s e d r a t e s of d e t e r i o r a t i o n which are a t t r i b u t e d by some to be due to exposure to h i g h l e v e l s of S O 2 , N 0 , and H C 1 . On the b a s i s of t h i s e v i d e n c e , i t i s recommended t h a t an exp e r i m e n t a l t e s t program, c o n s i s t i n g of both l a b o r a t o r y and f i e l d t e s t s , be developed and implemented to q u a n t i t a t i v e l y measure the e f f e c t s of a c i d d e p o s i t i o n on both the a s t h e t i c and s t r u c t u r a l prop e r t i e s of PCC s t r u c t u r e s . I t i s , however, recommended t h a t a prel i m i n a r y s e r i e s of c o n t r o l l e d , a c c e l e r a t e d l a b o r a t o r y t e s t s be c a r r i e d out b e f o r e a f u l l - s c a l e f i e l d e v a l u a t i o n program i s i n s t i t u t e d . The o b j e c t i v e s of the a c c e l e r a t e d l a b o r a t o r y t e s t program should be to i d e n t i f y the magnitude of the problem and to attempt to d i f f e r e n t i a t e between the e f f e c t s of wet d e p o s i t i o n , dry d e p o s i t i o n , and normal w e a t h e r i n g . The p r e l i m i n a r y t e s t program should c o n c e n t r a t e on s u r f a c e c h e m i s t r y e f f e c t s and p e n e t r a t i o n r a t e s of S O 4 , N 0 , and C l ~ as d e p o s i t e d from wet and dry d e p o s i t i o n . The t e s t s can be run u s i n g s m a l l p o r t l a n d cement mortar specimens, f o r mulated to s i m u l a t e the q u a l i t y of cement p a s t e s n o r m a l l y encount e r e d i n c o n c r e t e c o n s t r u c t i o n . Parameters to be s t u d i e d i n the t e s t program should i n c l u d e : X

X

X

wet

deposition

- various simulated acid r a i n mixtures to d i f f e r e n t i a t e between the e f f e c t s of S O 2 , N 0 , and the normal background components of r a i n . X


16.



247

-

dry d e p o s i t i o n


normal w e a t h e r i n g

s i m u l a t e d a c i d r a i n m i x t u r e s of v a r y i n g pH v a l u e s . - v a r i o u s l e v e l s of S0£ and N 0 . - various relative humidities, - freeze-thaw c y c l e s . X

T e s t methods used i n the e v a l u a t i o n s h o u l d i n c l u d e ; (a) tests to e v a l u a t e changes i n the p h y s i c a l and m e c h a n i c a l p r o p e r t i e s of the specimens, (b) c h e m i c a l a n a l y s e s to determine the depth and r a t e of p e n e t r a t i o n of the a g g r e s s i v e s o l u t i o n s , and (c) t e s t s to m o n i t o r and c o n t r o l the treatment s o l u t i o n s and to a n a l y z e them f o r m a t e r i a l s b e i n g l e a c h e d from the t e s t s p e c i m e n s . I f the r e s u l t s of the p r e l i m i n a r y t e s t program i n d i c a t e t h a t a problem does e x i s t , f u l l - s c a l e f i e l d t e s t s s h o u l d be i n i t i a t e d , a l o n g w i t h c o n t i n u e d i n t e r - r e l a t e d l a b o r a t o r y - s c a l e bench t e s t s and e n v i r o n m e n t a l chamber s t u d i e s . As w i t h the p r e l i m i n a r y t e s t p r o gram, the f i e l d t e s t s s h o u l d be d e s i g n e d to d i f f e r e n t i a t e between the e f f e c t s of wet d e p o s i t i o n , dry d e p o s i t i o n , and normal w e a t h e r ing on both the as t h e t i c and s t r u c t u r a l p r o p e r t i e s of p o r t l a n d cement c o n c r e t e . Exposure parameters s t u d i e d i n the p r e l i m i n a r y program s h o u l d a l s o be s t u d i e d i n the f i e l d t e s t program. In a d d i t i o n , s e v e r a l d i f f e r e n t q u a l i t i e s of p o r t l a n d cement c o n c r e t e , i . e . , s t r u c t u r a l q u a l i t y and d e c o r a t i v e , s h o u l d be i n c o r p o r a t e d i n t o the program. I f p o s s i b l e , more than one f i e l d t e s t s i t e s h o u l d be used to o b t a i n e n v i r o n m e n t a l exposure c o n d i t i o n s r e p r e s e n t a t i v e of v a r i o u s a r e a s of the U n i t e d S t a t e s . The f i e l d t e s t program s h o u l d a l s o i n c l u d e s u r v e y s o f e x i s t i n g PCC s t r u c t u r e s i n a r e a s where a i r q u a l i t y , r a i n c h e m i s t r y and m e t e o r o l o g i c a l data a r e r e a d i l y a v a i l a b l e for a n a l y s e s i n o r d e r to o b t a i n a comparison b e tween the e f f e c t s observed i n e x i s t i n g s t r u c t u r e s w i t h those o b s e r v e d i n the t e s t specimens. Literature 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Cited

G a l l o w a y , J. N. A c i d R a i n , P r o c e e d i n g s o f a Symposium Sponsored by ASCE. A p r i l 2 - 6 , 1979, 1-20. L i k e n s , G . Ε . , and F . H . Bormann. Science. 184(4142), 1974, 1 1 7 6 - 9 . G l a s s , N. R . , e t al. Environmental I n t e r n a t i o n a l . 4, 1980, 443-52. Fisher, T. Prog. Arch. 7 , 1983, 9 9 - 1 0 5 . Stanwood, L . The C o n s t r u c t i o n Specifier. Nov. 1983, 7 4 - 9 . G a u r i , K. L . P r o c . o f a S e s s i o n H e l d a t the N a t i o n a l C o n v e n t i o n , ASCE. B o s t o n , MA, April 2, 1979, 7 0 - 9 1 . C o w l i n g , Ε. B. E n v i r o n . Sci. T e c h n o l . 1 6 ( 2 ) , 1982, 110A-123A. M a r t i n , H . C. M a t e r i a l s Performance. 2 1 ( 1 ) , J a n . 1982, 3 6 - 9 . L i k e n s , G. E . Chem. and E n g r . News. 5 4 ( 4 8 ) , Nov. 2 2 , 1976, 29-44. D o r n b e r g , J . Pan Am Clipper. J u l y 1982, 18-22 and 7 7 - 9 . Fassina, V. Atmospheric Environment. 12, 1978, 2 2 0 5 - 1 1 . G a u r i , K. L . and G . C . H o l d e n , Jr. E n v i r o n . Sci. and Technol. 1 5 ( 4 ) , April 1981, 3 8 6 - 9 0 .



248

MATERIALS DEGRADATION

CAUSED BY ACID RAIN

13. Longinelli, A. and M. Bartelloni. Water, Air, and Soil Pollution. (10) 1978, 335-41. 14. Kucera, V. Ambio. 5(5,6) 1976, 243-8. 15. Haynie, F. H. and J. B. Upham. Materials Protection and Performance. 10(11) 1971, 18-21. 16. Ericsson, R. and T. Sydberger. Werkstoffe und Korrosion. 31, 1980, 455-63. 17. Schreiber, H. Air Pollution Effects on Materials. Report for Panel 3 ("Environmental Impact") of the NATO/CCMS Pilot Study on Air Pollution Control Strategies and Impact Modelling, 1982. 18. Von Ward, P., ed. Impact of Air Pollutants on Materials. A Report for Panel 3 ("Environmental Impact") of the NATO/ CCMS Pilot Study on Air Pollution Control Strategies and Impact Modelling, 1982. 19. Gauri, K. L., Polluted Rain (Environmental Science Research). 17, 1980, 125-45. 20. Dijkstra, G. Effects of Air Pollution on the Materials in the Netherlands. Report for Panel 3 ("Environmental Impact") of the NATO/CCMS Pilot Study on Air Pollution Control Strategies and Impact Modelling, 1982. 21. Skoulikidis, T. N. Atmospheric Corrosion of Concrete Reinforcements and Their Protection. Date unknown, 807-25. 22. Skoulikidis, T. N. Proc. Acid Deposition, A Challenge for Europe. Preliminary Edition, Sept. 1983, 193-226. 23. Gillette, D. G. J. Air Pollution Control Assoc. 25(12), Dec. 1975, 1238-43. 24. Ashton, Η. Ε., and P. J. Sereda. Durability of Building Materials. 1, 1982, 49-66. 25. Biczok, I. Concrete Corrosion, Concrete Protection. Akademia Kiado, Budapest, 1972. 26. Kuenning, W. H. Highway Research Record. (113), 1966, 43-87. 27. Tremper, Β. ACI Journal. 28(1), Sept. 1931, 1-32. 28. Bertacchi, P. RILEM Symposium, Durability of Concrete-1969, Final Report, Part II. Academia Prague, 1970, C159-C168. 29. Mlodecki, J. RILEM Symposium, Durability of Concrete-1969, Preliminary Report, Part II. Academia Prague, 1970, C221-C240. 30. Prudil, S. RILEM Symposium, Durability of Concrete-1969, Preliminary Report, Part I. Academia Prague, 1970, A59-A68. 31. Hansen, W. C., et al. ASTM Bulletin. 231, July 1958, 85-8. 32. Woods, H. Durability of Concrete Construction. ACI Monograph No. 4, 1968. 33. Czernin, W. Cement Chemistry and Physics For Engineers. Chemical Publishing Co., New York, NY, 1962. 34. Sentler, L. Proc. Third International Conference on the Durability of Building Materials and Components. Espoo, Finland, Vol. 3. Aug. 12-15, 1984, 569-80. 35. Verbeck, G. IN: ASTM STP-205. 1958, 17-36. 36. Leber, I. and F. A. Blakey. Journ. Amer. Conc. Institute. 53-16, Sept. 1956, 295-308. 37. Smolczyk, H. G. RILEM Symposium on Durability of Concrete1969, Preliminary Report, Part II. Academia Prague, 1970, D59-D75.



16. WEBSTER AND KUKACKA


249

38. Greschuchna, R. RILEM Symposium, Durability of Concrete-1969, Final Report, Part II. Academia Prague, 1970, C189-C191. 39. Idorn, G. M. Ph.D. Thesis, Technical University of Denmark, 1967. 40. Brown, P. W. Cement and Concrete Research. 11, 1981, 719-27. 41. Heller, L., and M. Ben-Yair. J. App. Chem. 14, Jan. 1964, 20-30. 42. Jambor, J. IN: "Durability of Building Materials and Components"; ASTM STP-691, 1980, 301-12. 43. Friede, H. IN: "Durability of Building Materials and Components"; ASTM STP-691, 1980, 355-63. 44. Reading, T. J. IN: "Durability of Concrete"; ACI SP-47, 1975, 343-66. 45. Mehta, P. K. and M. Polivka. IN: "Durability of Concrete"; ACI SP-47, 1975, 367-79. 46. Ludwig, V. IN: "Durability of Building Materials and Components"; ASTM STP-691, 1980, 269-81. 47. Klieger, P. IN: "Durability of Building Materials and Components"; ASTM STP-691, 1980, 282-300. 48 Mehta, P. K. IN: "Durability of Building Materials and Components"; ASTM STP-691, 336-45. 49. Haynie, F. H. and J. B. Upham. IN: "Corrosion in Natural Environments"; ASTM STP-558, 1974, 33-51. 50. Mikhailovskii, Y. N. and A. P. San'ko. Protection of Metals. 15(4), 1979, 342-5. 51. Matsushima, I. and T. Ueno. Corrosion Science. 11(3), 1979, 129-40. RECEIVED

January 2, 1986


Effects of Acid Deposition on Portland Cement Concrete - American

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