Publisher’s version / Version de l'éditeur:
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.
Questions? Contact the NRC Publications Archive team at
PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.
https://publications-cnrc.canada.ca/fra/droits
L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.
Technical Paper (National Research Council of Canada. Division of Building
Research), 1965-07
READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright
NRC Publications Archive Record / Notice des Archives des publications du CNRC : https://nrc-publications.canada.ca/eng/view/object/?id=c681aced-d448-47bf-b335-0a52ad7d1dd3 https://publications-cnrc.canada.ca/fra/voir/objet/?id=c681aced-d448-47bf-b335-0a52ad7d1dd3
NRC Publications Archive
Archives des publications du CNRC
For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.
https://doi.org/10.4224/20378713
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
Current Research on Ice Control
Ser THl N21t2 n o . 2 O 2 c . 2 BIDG \ i i " j . : .
NATIONAL RESEARCH CANADA DIVISION OF BUILDING C O U N C I L RESEARCH CURRENT RESEARCH I C E C O N T R O L ON b y L " W " G o l d
( A tolk presenlcC tc tlrc Annucl Meetind of tFd 'r'cskotchernon li:.icl'y Ccuncil in April i965, ond ieproduced in this icin rv;rh their perrr:ission )
T e c h n i c a l P a p e r N o . ? O Z of the D i v i s i o n o f B u i l d i n g R e s e a r c h OTTAWA J u l y 1 9 6 5
A SJ
rXIYZED
CURRENT RESEARCH ON ICE CONTROL
b y
L . W . G o l d *
I wish to e>rpress to you rny appreciation for this opportunity t o s p e a k t o y o u o n a s u b j e c t o f real concern to all motorists. B e f o r e beginning on the subject of my talk, however, I would like to tel.I you about some of the activities of the National Research Council, so that t h e c o n t r i b u t i o n t h e s e activities can make to the solution of problems of s n o w r e m o v a l a n d i c e c o n t r o l w i l l be quite clear to you. The NRC is only one of a number of institutes and departments that is investigating o r c a n i n v e s t i g a t e t h e p r o b l e m s of control of ice on roadways. B u t i t is probably the organLzation most actively engaged in studies of this p r o b l e m a t p r e s e n t , and because of its position within the frarnework of
s c i e n c e i n C a n a d a , t h e C o u n c i l is the organization best able to provide t h e m e a n s b y w h i c h s t u d i e s o n ice control throughout the country can be c o o r d i n a t e d .
L a t e i n 1 9 1 6 , t h e G o v e r n m e n t o f C a n a d a established an Honorary A d v i s o r y C o u n c i l f o r S c i e n t i f i c and Industrial Research, now known by the s h o r t t i t l e ' t N a t i o n a l R e s e a r c h C o u n c i l r r . The Council is at present
c o m P o s e d o f t w e n t y - o n e C a n a d i a n s , including the President and three V i c e - P r e s i d e n t s a s f u l l - t i m e o f f i c i a l s , a n d r e p o r t s d i r e c t l y t o t h e P r i v y C o u n c i l o f C a n a d a .
T h e f i r s t a c t i v i t y o f t h e N a t i o n a l Research council was to u n d e r t a k e a s u r v e y o f C a n a d a r s scientific resources, T h i s i n v e n t o r y s h o w e d t h a t i n d u s t r i a l r e s e a r c h , at that time, was practica[y non-e x i s t non-e n t , a n d t h non-e n a t i o n a l s u p p l y of rnon-esnon-earch mnon-en non-entirnon-ely inadnon-equatnon-e. T o h e l p r e m e d y t h i s situation, a system of scholarships and research g r a n t s w a s e s t a b l i s h e d in 19I7. This program, which has been continued a n d e x p a n d e d o v e r t h e y e a r s , i s one of the rnajor activities of the National R e s e a r c h C o u n c i l . T o d a y , o v e r I 8 m i l l i o n d o l l a r s p e r y e a r i s d i r e c t e d t o w a r d t h e s u p p o r t o f r e s e a r c h at Canadian universities in this wzrlr or H e a d , s n o w a n d I c e s e c t i o n , Division of Building Research, National
z
-a b o u t o n e - t h i r d o f t h e C o u n c i l r s b u d g e t . T h e s y s t e m o f s c h o l -a r s h i p s -a n d r e s e a r c h g r a n t s i s o n e m e t h o d b y w h i c h m o n e y c a n b e r n a d e a v a i l a b l e f o r r e s e a r c h o n i c e c o n t r o l , b u t o n l y t o u n i v e r s i t i e s " I n 1 9 1 7 t h e N a t i o n a l R e s e a r c h C o u n c i l b e g a n t o c o o r d i n a t e r e s e a r c h p r o g r a m s o f a n a t i o n a l c h a r a c t e r b y m e a n s o f A s s o c i a t e C , o m -m i t t e e s . T h e s e C o m r n i t t e e s a r e n a t i o n a l i n s c o p e , e a c h a c t i n g a s a n autorrornous unit; their membership is drawn from federal, provincial, university, and industrial orgar.izations. When a rnajor problern arises, t h e N a t i o n a l R e s e a r c h C o u n c i l f o r m s a C o m m i t t e e c o m p o s e d o f l e a d i n g w o r k e r s i n t h e a r e a o f t h e p r o b l e r n w h o a r e p a r t i c u l a r l y q u a l i f i e d t o g i v e g u i d a n c e a n d a d v i c e . T h e s e m e n c o n t r i b u t e t h e i r t i m e w i t h o u t s a l a r y , a n d by exchanging inforrnation and views, work out a coordinated approach to t h e p r o b l e m " A t p r e s e n t t h e r e a r e s o r n e 4 0 C o m m i t t e e s , o p e r a t i n g i n d i v e r s e f i e l d s , s u c h a s , A e r o d y n a m i c s , S p a c e R e s e a r c h , P a i n t R e s e a r c h , a n d P 1 a n t B r e e d i . n g . O n e C o m m i t t e e i n p a r t i c u l a r , t h e A s s o c i a t e C o r n -rnittee on Soil and Snow Mechanics, has a Subcommittee on Snow and Ice t h a t g i v e s a t t e n t i o n t o p r o b l e r n s c r e a t e d b y t h e s e r n a t e r i a l s . T h i s S u b c o r n -m i t t e e i s c u r r e n t l y s t u d y i n g t h e p r o b l e -m o f s n o w r e -m o v a l a n d i c e c o n t r o l "F o r t h e f i r s t e i g h t y e a r s o f i t s e x i s t e n c e t h e C o u n c i l e m p l o y e d a srnall administrative staff but no working scientific staff. It gradually b e c a m e c l e a r t h a t i n o r d e r t o f u l f i l i t s r e s p o n s i b i l i t i e s t o C a n a d i a n i n d u s t r y , t h e C o u n c i l w o u l d r e q u i r e i t s o w n l a b o r a t o r i e s . T h e s e f a c i l i t i e s w e r e i n i t i a t e d i n 1 9 2 5 a n d h a v e i n c r e a s e d t h r o u g h t h e y e a r s , a n d p a r t i c u l a r l y d u r i n g t h e w a r y e a r s , s o t h a t t h e y n o w i n c l u d e e l e v e n D i v i s i o n s a n d t w o R e g i o n a l L a b o r a t o r i . e s , p r o v i d i n g a c a p a b i l i t y o v e r a b r o a d r a n g e o f s c i e n c e a n d e n g i n e e r i n g . I n 1 9 4 7 , t h e D i v i s i o n o f B u i l d i n g R e s e a r c h w a s f o r m e d t o p r o v i d e a r e s e a r c h s e r v i c e f o r t h e c o n s t r u c t i o n i n d u s t r y a n d t e c h n i c a l a s s i s t a n c e t o t h e n e w l y e s t a b l i . s h e d C e n t r a l M o r t g a g e a n d H o u s i n g C o r p o r a t i o n . W i t h i n t h i s D i v i s i o n t h e r e w a s e s t a b l i s h e d a S e c t i o n t h a t w a s t o g i v e a t t e n t i o n t o p r o b l e r n s c r e a t e d b y s n o w a n d i c e . T h e a c t i v i t i e s o f t h e S n o w a n d I c e S e c t i o n a r e b r o a d i n d e e d , ranging from fundarnental research to engineering, and include providing t e c h n i c a l i n f o r r n a t i o n . T h i s S e c t i o n c o n s i d e r s p r o b l e r n s s u c h a s e s t a b -l i s h i n g t h e t h i c k n e s s o f i c e o n -l a k e s a n d r i v e r s r e q u i r e d t o e a r r y a g i v e n l o a d ; d e t e r m i n i n g t h e f o r c e s t h a t i c e c a n e x e r t a g a i n s t s t r u c t u r e s , s u c h a s d a m s , w h a r f s , b r i d g e p i e r s ; o b t a i n i n g i n f o r m a t i o n o n h o w i c e d e f o r r n s a n d f a i l s u n d e r l o a d ; a v a l a n c h e d e f e n c e , a n d s n o w r e m o v a l a n d i c e c o n t r o l " I n s h o r t , i t a t t e r n p t s t o p r o v i d e t o t h e e n g i n e e r k n o w l e d g e n e c e s s a r y f o r t h e s o l u t i o n o f p r o b l e m s , a n d t o o b t a i n n e e d e d k n o w l e d g e , w h e n i t i s n o t
3 -a l r e -a d y -a v -a i l -a b l e , t h r o u g h t h e -a p p l i c -a t i o n o f s c i e n c e . T o p l a c e t h e a c t i v i t i e s o f t h e S e c t i o n i n t h e r i g h t p e r s p e c t i v e , h o w e v e r , i t s h o u l d b e p o i n t e d o u t t h a t i t i s a s m a l l g r o u p , c o m p o s e d a t p r e s e n t o f f o u r p e o p l e t r a i n e d i n t h e s c i e n c e s a n d e n g i n e e r i n g a n d t w o t e c h n i c i a n s , w i t h t h e p a r t - t i r n e a s s i s t a n c e o f a c l i r n a t o l o g i s t s e c o n d e d f r o r n t h e M e t e o r o l o g i c a l S e r v i c e . O t h e r g r o u p s w i t h i n t h e N R C c o n s i d e r p r o b l e r n s c a u s e d b y s n o w a n d i c e , o r s t u d y t h e p r o p e r t i e s o f t h e s e m a t e r i a l s . F o r e x a r n p l e , t h e D i v i s i o n o f M e c h a n i c a l E n g i n e e r i n g h a s d e v e l o p e d a s p e c i a l g a t e a t t a c h m e n t f o r p l o u g h s t h a t c a n b e u s e d t o p r e v e n t p l o u g h e d s n o w f r o m b l o c k i n g d r i v e w a y s ; t h e D i v i s i o n o f A p p l i e d C h e r n i s t r y i s c o n d u c t i n g f u n d a m e n t a l s t u d i e s o n t h e o p t i c a l a n d t h e r r n a l p r o p e r t i e s o f i c e "
It is useful to emphasize that the three activities of the l.fational R e s e a r c h C o u n c i l , n a m e l y , a d m i n i s t e r i n g U n i v e r s i t y s c h o l a r s h i p s a n d r e s e a r c h g r a n t s , A s s o c i a t e C o r n m i t t e e s , a n d r u n n i n g t h e l a b o r a t o r i e s , are quite independent. A1I three activities contribute in their own way t o w a r d t h e s o l u t i o n o f p r o b l e r n s o f i c e c o n t r o l .
In February of 1964, the Subcornmittee on Snow and Ice s p o n s o r e d a C o n f e r e n c e o n S n o w R e r n o v a l a n d I c e C o n t r o l ( 1 ) . T h i s C o n f e r e n c e h a d t h r e e p r i n c i p a l o b j e c t i v e s : t o b e g i n t o d e f i n e t h o s e f a c t o r s p r i m a r i l y r e s p o n s i b l e f o r t h e c o s t o f s n o w r e m o v a l a n d i c e c o n t r o l ; t o b e g i " n t o r e c o r d i n o n e p l a c e e a s i J . y a c c e s s i b l e t o a l l t h e c o n s i . d e r a b l e e x p e r i e n c e a v a i l a b l e o n t h e p r o b l e m ; a n d t o b e g i n t o d e f i n e a r e a s w h e r e r e s e a r c h a n d d e v e l o p r n e n t s h o u l d b e e n c o u r a g e d " One of the results of that Conference was the establishrnent of a Working Group under the chaj"rrnanshi.p of Mr" W" D" Hurst, City Engineer for Winnipeg, which will consider the problern of Snow Removal and Ice C o n t r o l i n U r b a n A r e a s "
T h e p a p e r s p r e s e n t e d a t t h i s C o n f e r e n c e p o i n t e d o u t q u i t e c l e a r l y t h a t o n e o f t h e m o r e s e r i o u s p r o b l e m s o f w i n t e r r n a i n t e n a n c e i s that of the control of ice on roadways" Abor:.t 50 per cent of the winter rnaintenance budget for the Highway Departrnents of the Provinces of O n t a r i o a n d Q u e b e c i s s p e n t o n t h e p u r c h a s e a n d a p p l i c a t i o n o f c h e r n i c a l s and abrasives for ice control. For exarnple, the annual highway winter maintenance cost {or the province of Ontario is now about $15. 5 rnillion, with about $5 rnillion spent on ploughing snow, $5 mill"ion for sanding h i g h w a y s , $3 rnillion for salting, and the remainder for road patrols, e r e c t i o n o f s n o w f e n c e s , a n d o t h e r s p e c i a l t a s k s ( 2 ) . D i s c u s s i o n s w i t h
4
-t h e s -t a f f o f -t h e R o a d R e s e a r c h I n s -t i -t u -t e s in Norway, Sweden, and England, and with others in Switzerland, showed that the forrnation of ice on
r o a d s i s a l s o a m a j o r p r o b l e r n i n these countries.
F o r t h e p u r p o s e o f r h e p r e s e n t d i s c u s s i o n , the ice control p r o b l e m c a n b e d i v i d e d i n t h e f o l l o w i n g way: 1 ) I c e f o r m a t i o n a n d d e t e c t i o n , t h e f o r m a t i o n o f i c e , Z l P r e v e n t i o n o f 3 ) R e r n o v a l o f i c e , 4 l T h e i n t e r a c t i o n b e t w e e n i c e a n d t r a f f i c , 5 ) I c e c o n t r o l m e a s u r e s f o r v e h i c l e s .
I n t h e f o l l o w i n g , i n f o r m a t i o n i s p r e s e n t e d on the research being c o n d u c t e d o n t h e s e a s p e c t s o f t h e ice control problem, and an indication o f s o m e o f t h e p r o b l e m s t h a t still require study" It is very probable that s o m e c u r r e n t r e s e a r c h p r o j e c t s h a v e b e e n o m i t t e d , a n d i f s o , w e w o u l d b e g r a t e f u l i f t h e s e o m i s s i o n s c o u l d be brought to our attention.
ICE FORMATION AND DET'ECTION
With the traffic conditions that exist on many of our modern h i g h w a y s , i t w o u l d b e u s e f u l " i f t h . o s e responsible for winter maintenance h a d s o m e m e t h o d o f p r e d i c t i n g w h e n t h e f o r m a t i o n of ice on a road surface c o u l d b e e x p e c t e d . T h i s a b i i i t y would have two practical applications: p r o v i d i n g a d e q u a t e w a r n i n g s o t h a t p r e v e n t i v e action could be taken, and p r o v i d i n g r n o t o r i s t s w i t h a w a r n i n g o f dangerous highway conditions.
I c e f o r m s o n r o a d w a y s a s a consequence of weather conditions alone, or through the ri.ght cornbination of weather and traffic. In any p r o g r a r n t o c o m b a t i c e , i n p a r t i c u l a r to predict when and where it will
f o r m , i t i s n e c e s s a r y t o h a v e a g o o d u n d e r s t a n d i n g o f h o w t h e o c c u r r e n c e o f ice depends on weather and on traffi"c. This inforrnation can be obtained o n l y t h r o u g h a s t u d y o f t h e r n i c r o r n e t e o r o l o g i c a l c o n d i t i o n s a t r o a d
s u r f a c e s p r i o r t o a n d d u r i n g p e r i o d s o f i c e f o r m a t i o n , and the characteristics o f t h e t r a f f i c " S u c h s t u d i e s a r e n o t b e i n g c o n d u c t e d i n C a n a d a , as far as w e a r e a w a r e , b u t t h e y a r e b e i n g actively pursued in Sweden, Switzerland, a n d E n g l a n d . A d i f f e r e n c e b e t w e e n t h e a v e r a g e i c i n g c o n d i t i o n s that occur
5
-i n t h e s e t h r e e c o u n t r -i e s , a n d t h e c o n d -i t -i o n s g e n e r a l l y e n c o u n t e r e d -i n C a n a d a , s h o u l d b e n o t e d . I n S w e d e n , S w i t z e r l a n d , a n d E n g l a n d , i c e formation usually results from the freezing of water on the roadway, or by the deposition and subsequent fr eezir.g of moisture on the road
s u r f a c e . I n C a n a d a , t h e s e r i o u s i c e p r o b l e r n s u s u a j . l y r e s u l t f r o m either freezing rain or by packing of the snow by traffic"
In Sweden, an instrumenl is being tested that gives a signal i n d i c a t i n g a r i s k o f s l i p p e r i n e s s w h e n t h e t e m p e r a t u r e o f t h e a i r o r g r o u n d s u r f a c e i s l o w e r t h a n 3 0 " F ( - l ' C ) a n d a t t h e s a r r e t i m e t h e relative humidity is higher than 95 per cent. An apparatus has been developed to rneasure at intervals of five rninutes the coefficient of
f f i c t i o n b e t w e e n a s l i d e w i t h r u b b e r r u n n e r s a n d a d u r n r n y r o a d s u r f a c e ( 3 ) " This apparatus has not given satisfactory correlation between the signal i n d i c a t i n g a r i s k o f s l i p p e r i n e s s a n d t h e r o a d c o n d i t i o n s t h a t . d i d o c c u r . Development work is continuing.
I n S w i t z e r l a n d , e q u i p m e n t h a s b e e n d e v e l o p e d t o m e a s u r e
ternperature at various depths in the ground and at various heights above t h e g r o u n d s u r f a c e " T h e h u m i d i t y o f t h e a i r i s m e a s u r e d a t v a r i o u s Ievels as well" The ternperature and hurnidity, and their change with t i m e , a r e u s e d t o p r e d i c t w h e n i c e c a n b e e x p e c t e d t o f o r r n o n t h e r o a d surface. In England, a device has been developed that gives a signal w h e n t h e t e m p e r a t u r e o f t h e r o a d s u r f a c e i s 3 7 " F ( 3 ' C ) a n d m o i s t u r e conditions are suitable for ice forrnation" For only about 50 per cent o f t h e c a s e s w h e n t h i s d e v i c e g a v e a w a r n i n g , h o w e v e r , d i d i c i n g
o c c u r " T h e r e s u l t s o f t h e s e s t u d i e s h a v e b e e n e n c o u r a g i n g . I n b o t h England and Switzerlard it is hoped that ability to predict the forrnation of ice can be irnproved by further research and developrnent,
T h e p r e s e n t c o s t o f i n s t a l l a t i o n s f o r p r e d i c t i n g w h e n i c e rnay form is about 3 to 5 thousand dollars per site, and so they cannot be used in great quantity. The general thinking at present is that such i n s t r u m e n t s c o u l d b e u s e f u l l y l o c a t e d a t s i t e s w h e r e i c e u s u a l l y f o r r n s first, and that the warning they provide must then be interpreted by the individual responsible for the maintenance of the roadway.
T h e s e d e v i c e s a r e p r i r n a r i l y f o r p r e d i c t i n g i c e f o r r n a t i o n o n roadways due to freezLng rain or deposition and subsequent freezing of water vapour as ice or frost. They would not be suitable for predicting the forrnation of ice due to the packing of snow by traffic" It is possible that adequate warning of all types of ice conditions can be o b t a i n e d f r o m s p e c i a l w e a t h e r o b s e r v a t i o n s o n c e t h e i n t e r - r e l a t i o n s h i p b e t w e e n i c e f o r r n a t i o n , w e a t h e r a n d t r a f f i c i s w e l l u n d e r s t o o d . T h i . s
6
-knowledge would be very useful background inforrnation for the problem of i c e c o n t r o l i n C a n a d a , a n d s o t h e n e c e s s a r y o b s e r v a t i o n s s h o u l d b e e n c o u r a g e d at universities and in those departments and institutes that have a direct
i n t e r e s t i n w i n t e r m a i n t e n a n c e o f r o a d s .
THE PREVENTION OF ICE FORMATION
Once it is known that ice may form on a road surface, what s t e p s c a n b e t a k e n t o p r e v e n t i t s f o r m a t i o n ? A t p r e s e n ! , t h e r e i s o n l y o n e e c o n o m i c a l m e t h o d - b y t h e a p p l i c a t i o n o f c h e m i c a l s s u c h a s
s o d i u r n o r c a l c i u m c h l o r i d e . T h e a p p l i c a t i o n o f a c h e m i c a l t o t h e r o a d s u r f a c e p r i o r t o t h e f o r r n a t i o n o f i c e e n s u r e s t h a t t h e w a t e r w i l l r e m a i n l i q u i d e v e n w h i l e t h e a i r a n d r o a d s u r f a c e t e r n p e r a t u r e s a r e b e l o w
freezing. Considerable knowledge is now available on the action of c h e r n i c a l s i n p r e v e n t i n g t h e f o r m a t i o n o f i c e , b u t g o o d p r a c t i c a l g u i d e lines have yet to appear on how chemicals should be applied, and at w h a t r a t e , f o r g i v e n w e a t h e r , r o a d a n d t r a f f i c c o n d i t i o n s , S o m e w o r k has been done on this problem in Canada, notably by the Ontario Depart-m e n t o f H i g h w a y s , a n d i n v e s t i g a t i o n s a r e c u r r e n t l y b e i n g c o n d u c t e d i n S w i t z e r l a n d a t t h e S w i s s F e d e r a l I n s t i t u t e f o r S n o w a n d A v a l a n c h e R e s e a r c h . T h e r e i s c o n s i d e r a b l e p r a c t i c a l e x p e r i e n c e o n t h e u s e o f c h e r n i c a l s , b u t t h i s e x p e r i e n c e i s l a r g e l y u n r e c o r d e d a n d n o t t h o r o u g h l y c h e c k e d b y c o n t r o l l e d f i e l d s t u d i e s . S p t e a d i n g e q u i p r n e n t h a s y e t t o b e d e v e l o p e d t h a t w i l l p r o v i d e t o t h e o p e r a t o r a d e q u a t e c o r t r o l o f t h e a p p l i c a t i o n o f c h e r n i c a l s . I t i s u s e f u l t o e r n p h a s i z e t h e s e f a c t s s i n c e t h e c u r r e n t c o n s u r n p t i o n o f s a l t f o r i c e c o n t r o l p u r p o s e s i n C a n a d a i s n o w about I million tons annually with the cost between $15 to $40 per ton, d e p e n d i n g o n t h e d i s t a n c e a n d m e t h o d o f t r a n s p o r t a t i o n . B e c a u s e o f t h e amount of money now being spent on chemicals for ice control, and the p r e s e n t c o n c e r n o v e r t h e i r s i d e e f f e c t s , i n v e s t i g a t i o n s s h o u l d b e
encouraged that will provide the needed information about the application of chernicals under given conditions.
T h e c o n t r i b u t i o n o f s o d i u r n o r c a l c i u m c h l o r i d e t o c o r r o s i o n c a n n o t b e t o l e r a t e d b y a i r c r a f t , a n d i s o f c o n s i d e r a b l e c o n c e r n w i t h r e s p e c t t o s t r u c t u r e s s u c h a s b r i d g e s , p a r t i c u l a r l y i f t h e y h a v e s t e e l d e c k s . T h e C e n t r a l E x p e r i r n e n t a l E s t a b l i s h m e n t o f t h e R C A F h a s c o n -d u c t e -d f i e l -d t r i a l s o f s o r n e n o n - c o r r o s i v e c h e m i c a l s f o r u s e o n a i r c r a f t r u n w a y s . T h e s e c h e r n i c a l s a r e , h o w e v e r , c o n s i d e r a b l y m o r e e x p e n s i v e t h a n s o d i u m c h l o r i d e . T h e R C A F , C i t y o f W i n n i p e g , a n d t h e M i n i s t r y o f T r a n s p o r t i n E n g l a n d h a v e c o n d u c t e d t r i a l s w i t h u r e a , b u t , i n
addition to being quite expensive, 'it was found to be slower acting and had to be used in Target quantities than sodium chloride in order to
7
-o b t a i n t h e s a m e e f f e c t i v e n e s s . S t u d i e s h a v e b e e n m a d e i n C a n a d a ( b y t h e R C A F ) a n d i n E n g l a n d o n t h e u s e o f g l y c o l s o l u t i o n s b u t t h e s e w e r e
f o u n d t o m a k e t h e s u r f a c e q u i t e s l i p p e r y a n d t o l e a v e a r e s i d u e t h a t was difficult to rernove.
T h e R C A F h a s e v o l v e d a u s e f u l t e c h n i q u e f o r p r e v e n t i n g i c e fot'rnation by the packing of snow by aircraft. A rotary broorn was developed which, when used either alone or in conjunction with ploughs, d e p e n d i n g o n t h e s n o w c o n d i t i o n s , w i l l p r o d u c e a s n o w - f r e e r u n w a y . H e a t i n g s y s t e m s b u r i e d i n t h e r o a d s u r f a c e h a v e b e e n c o n -s i d e r e d f o r p r e v e n t i n g i c e f o r m a t i o n a n d f o r m e l t i n g -s n o w ( 4 ) . T h e i n s t a l l a t i o n c o s t f o r s u c h s y s t e m s i s q u i t e h i g h , h o w e v e r , a n d t h e i r o p e r a t i n g c o s t i s b e t w e e n ? 5 a n d 5 0 y ' p e r s q u a r e f o o t p e r y e a r " B e c a u s e o f t h e i r h i g h c o s t , t h e y c a n b e c o n s i d e r e d o n l y f o r p a r t i c u l a r l y c r i t i c a l s i t e s , s u c h a s a p p r o a c h e s t o b r i d g e s a n d t h r o u g h w a y s . T h e r e i s n o t available at this time in Canada all the information that is required
f o r f e a s i b i l i t y s t u d i e s a n d d e s i g n o f h e a t i n g s y s t e m s . C o n s i d e r a b l e w o r k h a s b e e n d o n e o n t h e s e s y s t e m s b y t h e R o a d R e s e a r c h L a b o r a t o r y i n England (5), but the conditions in England are sufficiently different f r o m t h o s e i n C a n a d a t t , a t i t i s n o t p o s s i b l e t o a p p l y t h i s e x p e r i e n c e d i r e c t l y t o t h e p r o b l e m s h e r e . T h e i n v e s t i g a t i o n s r e q u i r e d t o o b t a i n t h e n e c e s s a r y b a c k g r o u n d k n o w l e d g e f o r t h e d e s i g n o f h e a t i n g s y s t e r n s f o r i c e c o n t r o l i n C a n a d a s h o u l d b e e n c o u r a g e d . REMOVAL OF ICE F o r c o n s i d e r a t i o n o f p o s s i b l e , e c o n o r n i c a l r n e t h o d s o f p r e -v e n t i n g t h e f o r m a t i o n o f i c e o n r o a d s , i t w o u l d b e u s e f u l t o h a -v e a t h o r o u g h u n d e r s t a n d i n g o f t h e w a y i c e a d h e r e s t o r o a d s u r f a c e s . Infbtrnation is available on this subject but our knowledge is still incomplete. Sorne quite fundamental studies on adhesion of ice to s o l i d s h a v e b e e n c a r r i e d o u t b y P r o f . H . J e l l i n e k a t A s s u r n p t i o n U n i v e r s i t y i n W i n d s o r , O n t a r i o .
I t i s k n o w n t h a t i c e w i l l a d h e r e t o r n a t e r i a l s , s u c h a s c o n c r e t e and asphalt, with a strength that can exceed the strength of ice" Labo-r a t o Labo-r y s t u d i e s o f t h e s h e a Labo-r s t Labo-r e n g t h o f t h e b o n d b e t w e e n i c e a n d s u c h rnaterials have shown that the failure usually occurs in the ice rather than at the interface. Those resporxsible for winter maintenance know h o w d i f f i c u l t i t i s t o r e m o v e i c e m e c h a n i c a l l y , e v e n w i t h a g r a d e r - - a rnachine with quite a good planing action. It is not unusual for rnachines t o c a u s e c o n s i d e r a b l e d a r n a g e t o r o a d s a n d c u r b s w h e n a t t e m p t i n g t o r e m o v e i c e .
8
-I f t h e a i r t e m p e r a t u r e i s a b o v e a b o u t l 0 " F ( - -I 2 ' C ) , s o m e s u c c e s s i n r e m o v i n g i c e c a n b e a c h i e v e d t h r o u g h t h e a p p l i c a t i o n o f c h e m i -c a l s . T h i s t e c h n i q u e m a y b e s 1 o w , h o w e v e r , b e c a u s e t h e c h e r n i c a l
must melt through the ice before it can af.f.ect the bond between the ice a n d t h e r o a d . I n a d d i t i o n , t h e a c t i o n o f t r a f f i c d o e s n o t p r o v i d e t h e a s s i s -t a n c e i -t d o e s w h e n -t h e c h e m i c a l i s a p p l i e d d i r e c -t l y -t o -t h e r o a d s u r f a c e . S t u d i e s a r e b e i n g c o n d u c t e d c u r r e n t l y o n t h e a c t i o n o f c h e m i c a l s o n i c e b y t h e S t a t e R o a d R e s e a r c h I n s t i t u t e i n O s l o , N o r w a y . I f t h e a i r t e r n p e r a t u r e i s b e l o w a b o u t l 0 ' F ( - 1 2 ' C ) , t h e o n l y p r a c t i c a l w a y a t p r e s e n t t o c o n t r o l i c e i s t h r o u g h t h e a p p l i c a t i o n o f a b r a -s i v e -s . S t u d i e s c o n d u c t e d i n S w e d e n s h o w t h a t i f s a n d o n l y i s a p p l i e d , t h e c o e f f i c i e n t o f f r i c t i o n b e t w e e n t h e t i r e a n d t h e i c e s u r f a c e r n a y b e r e a s o n a -bly high initially, but the coefficient decreases with time due to the sand
being rernoved by the action of the traffic. A technique of water sanding
h a s b e e n d e v e l o p e d i n N o r t h e r n S w e d e n , w h e r e t e r n p e r a t u r e s a r e l o w a n d snowfall quite light, in which sand is bonded to the road surface by
applying a thin layer of water" This provides a surface with a coefficient of friction nearly as high as that for bare pavement, and the coefficient
remains at a satisfactory value fot a reasonable length of tirne depending
o n w e a t h e r c o n d i t i o n s . T h e w a t e r - s a n d i n g t e c h n i q u e i s a l s o u s e d u n d e r e m e r g e n c y c o n d i t i o n s b y t h e R o y a l C a n a d i a n A i r F o r c e ( l ) . A s t a n d a r d s t r e e t f l u s h e r v e h i c l e h a s b e e n r n o d i f i e d s u c c e s s f u l l y f o r t h i s p u r p o s e , a n d i s n o w a l s o u s e d f o r a v a r i e t y o f j o b s a b o u t R C A F s t a t i o n s , s u c h a s weed control and as an auxiliaxy fir e fighting unit.
INTERACTION BETWEEN ICE AND TRAFFIC
C a n a d a n o w h a s a t l e a s t 4 6 7 , O O 0 r n i l e s o f r o a d , o f w h i c h a b o u t 6 5 p e r c e n t a r e s u r f a c e d , T h e r e a r e a b o u t 5 , 0 0 0 , 0 0 0 v e h i c l e s r e g i s -t e r e d i n -t h e c o u n -t r y ; e v e r y y e a r e a c h v e h i c l e t r a v e l s a n a v e r a g e o f 8 , ? . 5 0 m i l e s a n d c o n s u r n e s 6 0 0 g a l l o n s o f f u e I . I n t e r r n s o f p a s s e n g e r miles;, automobiles accounted for about 86 per cent of the total performed b y a l l m o d e s o f t r a n s p o r t a t i o n i n 1 9 6 2 . T h e a v e r a g e f a r n i . l y s p e n d s a b o u t 9 per cent of its incorne on this forrn of transportation" The idea that it s h o u l d b e p o s s i b l e t o d r i v e a n a u t o m o b i l e u n d e r a I I w e a t h e r c o n d i t i o n s i s c o m i n g t o b e w i d e l y a c c e p t e d .
9
-I n o r d e r t o c a r r y t h e l a r g e t r a f f i c f l o w r a t e s t h a t o c c u r o n m o d e r n h i g h w a y s , t h o s e r e s p o n s i b l e f o r t h e c o n s t r u c t i o n a n d m a i n t e n a n c e o f r o a d s rnust provide a surface with an adequate coefficient of friction between the r o a d s u r f a c e a n d t h e t i r e . F o r b a r e p a v e r n e n t o r a s p h a l t , t h e c o e f f i c i e n t o f f r i c t i o n i s a b o u t 0 . 6 0 t o 0 . 6 5 . F o r a n i c e s u r f a c e , i t i s a b o u t 0 " 2 o r lower. Extensive investigations on the coefficient of friction between a t i r e a n d r o a d s u r f a c e s i n v a r i o u s c o n d i t i o n s h a v e b e e n m a d e b y t h e r S t a t e R o a d I n s t i t u t e i n S w e d e n ( 3 ) " I n o n e o f t h e i r r e p o r t s i t i s s t a t e d t h a t t h e
only way to reduce the risk of skid accidents i.n the winter is to adapt the s p e e d a n d t h e r r a n n e r o f d r i v i n g t o r o a d c o n d i t i o n s ( 6 ) .
One subject that should be given attention is the deterrnination o f t h e r o a d s u r f a c e c o n d i t i o n r e q u i r e d t o a l l o w t r a f f i c t o f l o w s a f e l y . ' a t a g i v e n r a t e . I n r e s i d e n t i a l a r e a s a w e I I c o r n p a c t e d s n o w s u r f a c e m a y b e q u i t e a d e q u a t e f o r t h e s p e e d s a n d f l o w r a t e s e n c o u n t e r e d t h e r e " S u c h conditions cannot be tolerated on throughways and similar high traffic d e n s i t y r o a d s . I n f o r r n a t i o n o n t h e c o n d i t i o n o f r o a d s u r f a c e r e q u i r e d f o r g i v e n t r a f f i c f l o w r a t e s w o u l d b e u s e f u l f o r d e c i s i o n s c o n c e r n i n g t h e location and design of roadways and for deterrnining the extent of winter rnaintenance and the technioues that should be used"
ICE CONTROL MEASURES FOR VEHICLES
Current research on the action t}.at can be taken with respect to a vehicle in order to irnprove its abitity to travel . urder icy conditions w i I I b e b r i e f l y c o n s i d e r e d . T h e r e i s c o n s i d e r a b l e i n t e r e s t c u r r e n t l y i n
studded tires and the Highway Departrnent of Ontario is conducting studies o n t h e i r u s e . E x t e n s i v e i n v e s t i . g a t i o n s a r e b e i n g c o n d u c t e d o n s t u d d e d t i r e s b y t h e S t a t e R o a d R e s e a r c h I n s t i t u t e o f S w e d e n ( 3 , 6 ) . I t i s o b s e r v e d that studs increase the coefficient of friction between the tire and the s u r f a c e b y a b o u t 0 " 2 t o 0 . 2 5 o v e r t h a t f o r a t i r e a n d i c e a l o n e . T h e v a l u e obtained is stilt far below that for a tire and road surface in summer. The f r i c t i o n a p p e a r s t o i n c r e a s e w i t h t h e n u r n b e r o f s t u d s , a n d e a c h t i r e w o u l d probably have to have about 200 studs in order to obtain an optimum effect. S t u d s d e c r e a s e t h e c o e f f i c i e n t o f f r i c t i o n b e t w e e n a t i r e a n d b a r e p a v e r n e n t . A l t h o u g h s t u d s d o n o t c a u s e a l a r g e i n c r e a s e i n t h e s k i d r e s i s t a n c e , t h e y d o irnprove steering ability, For rnaxirnum effectiveness, therefore, aII
four tires of an autornobile should be equipped with studs. Observations i n d i c a t e t h a t s t u d s a r e b e s t f o r i c e . c h a i n s a r e b e s t f o r s n o w .
S t u d s d o c o m e o u t o f t i r e s , p a r t i c u l a r l y a t h i g h s p e e d s , T h i s d o e s n o t a p p e a r t o b e d u e t o c e n t r i f u g a l f o r c e , b u t r a t h e r t o f o r c e s a s s o c i -a t e d w i t h s l i p b e t w e e n t h e t i r e -a n d t h e r o -a d . I n S w e d e n t h e r e h a s b e e n n o
1 0
-evidence of studs causing damage after corning out of the tire" About 15 p e r c e n t o f t h e a u t o m o b i l e s i n S w e d e n a r e e q u i p p e d w i t h s t u d d e d t i r e s . T h e r e i s e v i d e n c e t h a t t h e s t u d s d o i n c r e a s e r o a d w e a r . T h e m a i n q u e s t i o n c o n c e r n i n g t h e i r u s e i n C a n a d a a p p e a r s t o b e a I e g a l o n e r e l a t e d t o t h e p o s s i b l e d a m a g e t h a t t h e y m i g h t d o t o r o a d s u r f a c e s . T h i s a s p e c t o f t h e i r u s e r e q u i r e s f u r t h e r s t u d y . T h e c h e m i c a l s c o m m o n l y u s e d f o r i c e c o n t r o l c o n t r i b u t e t o t h e d e t e r i o r a t i o n o f s o m e c o m p o n e n t s o f a u t o m o b i l e s . C o n s i d e r a t i o n s h o u l d be givento ways in which components that are directly involved with the
s a f e o p e r a t i o n o f a v e h i c l e , s u c h a s b r a k e l i n e s , b r a k e c y l i n d e r s , t i e r o d s , a n d b a l l j o i n t s , c a n b e a d e q u a t e l y p r o t e c t e d f r o m t h e a c t i o n o f t h e s e c h e r n i c a l s . T h i s p r o b l e m d o e s n o t a p p e a r t o b e r e c e i v i n g m u c h a t t e n t i o n
in Canada. D. Craik, formerly at the University of Manitoba and now
with the Manitoba Research Council, is conducting i,nvestigations on the
effect of ice rnelting chemicals on metals.
CONCLUSION
From this brief review it is apparent that our ability to control icy conditions on roadways is very irnperfect, It is true that rnaintenance otganizations have made noteworthy advances over the past ten years in their ability to maintain roadwals in a satisfactory condition, but it is j u s t n o t p o s s i b l e a t p r e s e n t t o c o p e w i t h a l l w e a t h e r a n d t r a f f i c c o n d i t i o n s t h a t m i g h t o c c u r . I t m a y n e v e r b e p o s s i b l e t o g u a r a n t e e a n i c e - f r e e
pavement at all tirnes, but; until such tirne, drivers rnust xealize that they are an irnportant factor in maintaining safe conditions on icy r o a d s . T o k e e p t h i s f a c t a l w a y s b e f o r e t h e r n w i l l r e q r l i r e a c t i v e a n d c o n t i n u i n g p r o g r a r n s o f e d u c a t i o n , s u c h a s t h o s e s p o n s o r e d b y t h e S a s k a t
-chewan Safety Council"
C o n s i d e r i n g t h e s c a l e o f t h e p r o b l e m o f i c e c o n t r o l a n d i t s irnportance to the economic life of Canada, the amor,lr*of research being c o n d u c t e d o n i t i n t h i s c o u n t r y i s c e r t a i n l y i n a d e q u a t e , P r a c t i c a l l y n o attention is being given to collecting and organizing knowledge on the f a c t o r s r e s p o n s i b l e f o r t h e f o r m a t i o n o f i c e , o n m e t h o d s t h a t c o u l d b e u s e d t o p r e v e n t i t f r o m f o r m i n g , o n r n e t h o d s t h a t c o u l d b e u s e d t o r e r n o v e it once it has forrned, on the interaction between ice and traffic, and on t h e s i d e e f f e c t s c a u s e d b y c u r r e n t i c e c o n t r o l t e c h n i q u e s . T h i s i s
unfortunate not only because this knowledge would be very useful in the developrnent of the techniques that are required for coping with present
and future conditions, but also because other countries naturally turn
I l
-T h e r e i s a v a i l a b l e c o n s i d e r a b l e p r a c t i c a l e x p e r i e n c e i n s n o w r e m o v a l a n d i c e c o n t r o l . P e r h a p s t h e m o s t e n c o u r a g i n g p r o g r e s s d u r i n g t h e p a s t f o u r y e a r s h a s b e e n i n g e t t i n g s o r n e o f t h i s e x p e r i e n c e p r o p e r l y r e c o r d e d . M a i n t e n a n c e g r o u p s t h a t h a v e t h i s e x p e r i e n c e h o w e v e r , a r e usually so involved with the task of removing snow and ice that theyhave n e i t h e r t h e t i m e n o r t h e r n e n t o p r o p e r l y r e c o r d e x l g e r i e n c e o r t o c a r r y o u t n e c e s s a r y r e s e a r c h a n d d e v e l o p m e n t . T h e s e a c t i v i t i e s s h o u l d b e encouraged at universities and in appropriate institutes and Government d e p a r t r n e n t s . B e c a u s e o f t h e n a t u r e o f t h e i c e c o n t r o l p r o b l e m , s u c h studies should be conducted in close association with winter rnaintenance g r o u p s w h e n e v e r p o s s i b l e . T h e A s s o c i a t e C o m r n i t t e e o n S o i l a n d S n o w Mechanics, through its Subcommittee on Snow and lce, together with the C o u n c i l r s D i v i s i o n o f B u i l d i n g R e s e a r c h , t h r o u g h i t s S n o w a n d I c e
Section, will continue to do what they can to assist inthie advance.
REFERENCES
( t ) S n o w R e m o v a l a n d I c e C o n t r o l . P r o c e e d i n g s , T e c h . M e m . 8 3 , Associate Committee on Soil and Snow Mechanics, Subcomrnittee on Snow and Ice, National Research Council, Ottawa, October 1 9 6 4 .
( Z l F i n a n c i a l P o s t , T o r o n t o , 27 March 1955.
(3) Annual Report of the National Swedish Road Research Institute, L 9 6 Z - 6 3 , S t o c k h o l r n , L 9 6 4 .
G e o r g e , J " D , , and C. S. Wiffen" Snow and Ice Removal From Road Surfaces by Electrical Heating. Presented to 44t1n Annual
M e e t i n g , H i g h w a y R e s e a r c h B o a r d , N a t i o n a l A c a d e r n y o f S c i e n c e s , Washington, January 1965.
Whiffin, A. C. , and P. J. lVilliarnson. Electrical Heating of Roads t o P r e v e n t t h e F o r r n a t i o n o f I c e a n d F r o s t . H e a t i n g ( L o n d . ) ,
V o l . 2 5 , N o , 2 0 6 , p , 4 L - 4 7 , F e b . L 9 6 3 .
(6) Kullbey, G. , and B. Kihlgren. Investigation of Friction Properties of Winter Tyres and Anti-Skid Devices. Statens Vaginstitutl . Rept. 36, Stockholrn, f950 (in Swedish with English surnmary).
