156 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS A- 123docz.net

FIG. 2 - - M o r t a r joint t e m p l a t e u s e d in p r i s m c o n s t r u c t i o n . g i v e a i / 2 - i n . - t h i c k ( 1 2 . 7 - m m - t h i c k ) m o r t a r joint p r i o r to c o m p a c t i o n .

T h e t e m p l a t e f o r m was p l a c e d on the c o n c r e t e unit. M o r t a r was p l a c e d in the t e m p l a t e a n d s t r u c k off w i t h a s t r a i g h t edge. The t e m p l a t e was t h e n r e m o v e d .

I m m e d i a t e l y a f t e r the r e m o v a l of t h e t e m p l a t e , t h e n e x t c o n c r e t e u n i t was p l a c e d on t h e m o r t a r b e d in c o n t a c t w i t h t h e t h r e e a l i g n m e n t b o l t s f o r t h a t c o u r s e . A b u l l s - e y e l e v e l was u s e d on t o p of e a c h u n i t d u r i n g p l a c e m e n t t o a s s u r e t h a t t h e i n i t i a l t h i c k n e s s of t h e joint was u n i f o r m .

E a c h b e d joint was t h e n c o n s o l i d a t e d u s i n g a d r o p hammer, s h o w n in Fig.

3. T h e h a m m e r w a s p l a c e d on t o p of t h e c o n c r e t e unit, a n d its 4-1b (l.8-kg) w e i g h t was d r o p p e d o n c e f r o m a h e i g h t of 1.5 in. (38.1 mm).

T h e c o m p a c t e d m o r t a r joint w a s a p p r o x i m a t e l y 3/8 in.

(9.5 mm) thick. The six p r i s m s w e r e c o n s t r u c t e d c o n t i n u o u s l y , one c o u r s e at a time, u n t i l t h e six c o u r s e s w e r e c o m p l e t e d . M o r t a r j o i n t s w e r e t h e n cut f l u s h w i t h no t o o l i n g .

I m m e d i a t e l y a f t e r c o n s t r u c t i o n , e a c h p r i s m was

c o v e r e d w i t h a p l a s t i c bag, FIG. 3 - - D r o p h a m m e r u s e d in p r i s m c o n s t r u c t i o n .

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

MELANDER ET AL. ON CONCRETE MASONRY PRISMS T A B L E l - - S u m m a r y o f p h y s i c a l p r o p e r t i e s a n d b o n d w r e n c h d a t a .

T v D e S m a s o n r v c e m e n t m o r t a r s .

157

Mortar Added A Init. Water Cone Air unit B Cube c Mix ID Water, Flow, Rot., Penet., Cont., Wt., Strength

ib % % mm % ib/ft 3 28 Day,

psi

Bond Strength 28 Day

Mean, Std COV,

psi Dev, %

psi

N C M A

S-2 7.44 120 89 70 25.3 106.~ 1730 128 18 14

S-3 7.52 130 92 74 18.0 116.7 2490 148 37 25

S-5 7.12 124 87 66 18.7 116.7 2150 103 23 22

S-6 7.30 121 88 69 17.6 118.1 1720 130 25 19

S-7 7.70 127 88 70 15.3 119.5 1880 132 26 20

C T L

S-7 7.59 124 84 64 15.3 119.7 1800 114 20 17

8051 6.60 120 73 50 17.6 119.2 1940 99 19 20

8052 8.20 122 79 48 17.8 117.6 3290 II0 22 20

8053 7.10 127 75 48 18.1 116.7 1960 105 20 19

8054 6.70 120 83 46 20.1 114.7 2660 126 22 17

8055 6.80 128 75 45 15.0 121.3 2880 166 26 16

U T A u s t i n

IS 8.58 127 84 59 16.3 115.4 1263 54 Ii 20

2S 10.28 130 88 68 20.0 113.6 1401 96 19 20

3S 9.34 123 80 61 14.5 121.6 2052 92 18 19

4S 9.98 124 87 73 13.0 116.4 1521 103 22 21

5S 10.20 128 91 72 12.8 123.1 1482 102 17 17

6S 9.68 121 81 63 17.0 125.0 2073 87 18 21

Akg = ib X 0.4535 Bkg/m3 = ib/ft 3 X 16.02 CMPa = psi X 0.006895

t e m p o r a r i l y s e a l e d t o t h e w o r k i n g s u r f a c e , a n d l e f t i n p l a c e o n i t s p a l l e t f o r 2 0 • 4 h o u r s . T h e n e x t d a y , e a c h p r i s m w a s u n c o v e r e d a n d r e m o v e d f r o m i t s jig, p l a c e d a n d s e a l e d i n t h e s a m e p l a s t i c b a g , a n d m o v e d t o a s t o r a g e a r e a i n t h e l a b o r a t o r y f o r b o n d w r e n c h t e s t i n g a t 28 d a y s .

P r i s m t e s t i n g - - F l e x u r a l b o n d s t r e n g t h w a s d e t e r m i n e d b y b o n d w r e n c h t e s t i n g a c c o r d i n g t o U B C 2 4 - 3 0 [Z] a n d A S T M C 1 0 7 2 - 8 6 . F o r e v e r y m o r t a r , f l e x u r a l b o n d s t r e n g t h w a s d e t e r m i n e d f o r e a c h o f 30 j o i n t s ; t h e m e a n , s t a n d a r d d e v i a t i o n , a n d c o e f f i c i e n t o f v a r i a t i o n (COV) w e r e

c a l c u l a t e d .

T E S T R E S U L T S

T a b l e s 1 a n d 2 p r e s e n t a s u m m a r y o f t h e p h y s i c a l p r o p e r t i e s a n d b o n d w r e n c h d a t a ( m e a n f l e x u r a l b o n d s t r e n g t h , s t a n d a r d d e v i a t i o n a n d c o e f f i c i e n t o f v a r i a t i o n ) f o r a l l m o r t a r s t e s t e d b y t h e t h r e e

p a r t i c i p a t i n g l a b s . F l e x u r a l b o n d s t r e n g t h r e s u l t s f o r a l l m o r t a r j o i n t s ( n o m i n a l l y 30 j o i n t s p e r m o r t a r c o n z b i n a t i o n ) t e s t e d b y t h e t h r e e l a b s a r e p r e s e n t e d i n A p p e n d i x A. T h e f i v e j o i n t s o f e a c h p r i s m a r e

C o p y r i g h t b y A S T M I n t ' l ( a l l r i g h t s r e s e r v e d ) ; S u n D e c 2 7 1 4 : 4 1 : 4 0 E S T 2 0 1 5 D o w n l o a d e d / p r i n t e d b y

U n i v e r s i t y o f W a s h i n g t o n ( U n i v e r s i t y o f W a s h i n g t o n ) p u r s u a n t t o L i c e n s e A g r e e m e n t . N o f u r t h e r r e p r o d u c t i o n s a u t h o r i z e d .

158 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

g r o u p e d t o g e t h e r , a n d a r e g i v e n f r o m t o p t o b o t t o m . T h e c a l c u l a t e d v a l u e s f o r m e a n , s t a n d a r d d e v i a t i o n , a n d c o e f f i c i e n t o f v a r i a t i o n i n T a b l e s 1 a n d 2 w e r e d e t e r m i n e d f r o m t h e t e s t d a t a c a r r i e d t o t w o d e c i m a l p l a c e s r a t h e r t h a n f r o m t h e r o u n d e d v a l u e s s h o w n i n A p p e n d i x A.

S I G N I F I C A N C E O F T E S T R E S U L T S

T h e i r m n e d i a t e o b j e c t i v e o f t h e s e t e s t s w a s t o e s t a b l i s h

c h a r a c t e r i s t i c f l e x u r a l b o n d s t r e n g t h v a l u e s f o r m a s o n r y c e m e n t m o r t a r s , a n d t o c o m p a r e t h o s e v a l u e s w i t h c o r r e s p o n d i n g c h a r a c t e r i s t i c f l e x u r a l b o n d s t r e n g t h v a l u e s f o r p o r t l a n d c e m e n t / l i m e m o r t a r s , o b t a i n e d i n t h e p r e v i o u s M I C C s t u d y [i]. B y a g r e e m e n t w i t h i n M I C C , t h e m o r t a r s t r e n g t h s w e r e t o b e c o m p a r e d i n t e r m s o f l o w e r c h a r a c t e r i s t i c v a l u e s ( v a l u e s s e t a t t h e l i m i t b e l o w 90% o f t h e t e s t d a t a ) , R a t i o s o f t h o s e l o w e r

c h a r a c t e r i s t i c s t r e n g t h s w e r e t o b e u s e d t o s e t c o r r e s p o n d i n g r a t i o s o f a l l o w a b l e t e n s i l e b o n d s t r e s s . F o r a n o r m a l d i s t r i b u t i o n , s u c h a 1 0 % f r a c t i l e is c o m p u t e d a s t h e m e a n m i n u s 1 . 2 8 s t a n d a r d d e v i a t i o n s .

U s i n g a l l r e s u l t s f r o m A p p e n d i x A, t h e f o l l o w i n g l o w e r

c h a r a c t e r i s t i c b o n d s t r e n g t h v a l u e s w e r e o b t a i n e d f o r t h e T y p e S a n d T y p e N m a s o n r y c e m e n t m o r t a r s t e s t e d i n t h i s s t u d y :

T y p e S m a s o n r y c e m e n t m o r t a r : 69 p s i ( 0 . 4 8 M P a ) T y p e N m a s o n r y c e m e n t m o r t a r : 44 p s i ( 0 . 3 0 M P a )

T A B L E 2 - - S u m m a r y o f P h y s i c a l D r o n e r t i e s a n d b o n d w r e n c h d a t a , T v o e N m a s o n r v c e m e n t m o r t a r s

Mortar Added A Init. Water Cone Air Unit B Cube C

Mix ID Water, Flow, Ret., Penet., Cont., Wt,, Strength

ib % % mm % ib/ft 3 28 Day,

psi

Bond Strength 28 Day

Mean, Std COV,

psi Dev, %

psi

N C M A

N-I 7.18 126 91 75 21.4 112.0 690

N-2 7.10 122 89 70 24.5 108.0 640

N-3 7.24 130 94 74 18.9 i15.6 740

N-4 7.46 127 91 72 16.1 I19,2 1490

N-5 7.30 124 92 71 18.7 115.6 770

N-6 7.84 126 94 75 15,2 119.7 870

N-7 7.04 121 92 70 21.2 112.8 1030

C T L

N-I 7.10 130 96 69 19.8 112.7 600

N-2 7 .32 123 93 70 25.2 I06.5 600

N-3 7.15 125 90 67 22.2 111.3 780

N-4 7.65 124 91 72 16.3 118.5 1440

U T A u s t i n

7N 8.60 129 83 65 13.8 121.2 1535

8N 8.86 125 92 69 21.0 109.0 598

66 13 20

50 6 12

56 i0 17

65 13 20

60 9 15

71 13 18

69 13 19

77 15 20

49 18 36

65 15 23

75 19 25

92 13 14

68 14 20

Akg = ib X 0.4535 Bkg/m3 = ib/ft 3 X 16,02 CMPa = psi X 0.006895

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

MELANDER ET AL ON CONCRETE MASONRY PRISMS 159

U s i n g all r e s u l t s f r o m the p r e v i o u s M I C C s t u d y of p o r t l a n d c e m e n t / l i m e m o r t a r s [l], e x c e p t t h o s e for one p o r t l a n d c e m e n t w i t h e n t r a i n e d air, t h e f o l l o w i n g l o w e r c h a r a c t e r i s t i c b o n d s t r e n g t h v a l u e s h a d b e e n o b t a i n e d :

T y p e S p o r t l a n d c e m e n t / l i m e m o r t a r : 126 p s i ( 0 . 8 7 MPa) T y p e N p o r t l a n d c e m e n t / l i m e m o r t a r : 90 p s i ( 0 . 6 2 MPa) T h o s e t w o s e t s of l o w e r c h a r a c t e r i s t i c v a l u e s w e r e u s e d t o c a l c u l a t e t h e f o l l o w i n g r a t i o s b e t w e e n t h e f l e x u r a l b o n d s t r e n g t h s of m a s o n r y c e m e n t m o r t a r a n d n o n - a i r - e n t r a i n e d p o r t l a n d c e m e n t / l i m e m o r t a r :

T y p e S m o r t a r : 0.55 T y p e N m o r t a r : 0.50

A f t e r c o n s i d e r a t i o n of t h o s e ratios, M I C C a g r e e d t o s u b m i t t h e f o l l o w i n g a l l o w a b l e b o n d s t r e s s r a t i o s (for m a s o n r y c e m e n t m o r t a r , c o m p a r e d to p o r t l a n d c e m e n t / l i m e mortar) to I C B O for u s e in t h e U n i f o r m

T y p e S m o r t a r : 0.60 T y p e N m o r t a r : 0.50

C O N C L U S I O N S

The i m m e d i a t e o b j e c t i v e of t h e s e t e s t s was to e s t a b l i s h

c o n d u c t e d in t h r e e d i f f e r e n t l a b o r a t o r i e s to e s t a b l i s h t h e s t a t i s t i c a l v a r i a t i o n of f l e x u r a l b o n d s t r e n g t h s u s i n g the b o n d w r e n c h test.

D e s p i t e t h e c a r e f u l l y d e s i g n e d test p r o g r a m , w h i c h e l i m i n a t e d m a n y p o s s i b l e s o u r c e s of d i f f e r e n c e s b e t w e e n labs, n o t all f a c t o r s c o u l d b e c o m p l e t e l y c o n t r o l l e d . F o r e x a m p l e , t h e a m o u n t of w a t e r to be u s e d for e a c h m o r t a r was s p e c i f i e d as t h a t w h i c h w o u l d p r o v i d e t h e d e s i r e d f l o w of 125 • 5%. T a b l e s 1 a n d 2 s h o w that w a t e r w e i g h t s v a r i e d s o m e w h a t b e t w e e n labs, r e s u l t i n g in d i f f e r e n t w a t e r / c e m e n t r a t i o s . Also, d i f f e r e n t m i x e r s at e a c h l a b o r a t o r y m a y h a v e p r o d u c e d d i f f e r e n t a i r c o n t e n t s . F a c t o r s such as t h e s e w o u l d be e x p e c t e d to c r e a t e s o m e d i f f e r e n c e s in f l e x u r a l b o n d s t r e n g t h v a l u e s b e t w e e n l a b o r a t o r i e s .

H o w e v e r , as s h o w n in Fig. 4, t h e a v e r a g e b o n d s t r e n g t h s for t h o s e m a s o n r y c e m e n t m o r t a r s t e s t e d in d u p l i c a t e d i d not v a r y c o n s i s t e n t l y b e t w e e n t h e t w o r e s e a r c h l a b o r a t o r i e s (NCMA a n d CTL) t h a t c o n d u c t e d d u p l i c a t e tests. Also, t h e r e s u l t s w i t h i n all t h r e e l a b o r a t o r i e s s h o w e d c o e f f i c i e n t s of v a r i a t i o n w h i c h w e r e u s u a l l y 25% or less.

T h e t e s t r e s u l t s g i v e n h e r e w e r e o b t a i n e d u s i n g s t r i c t l y c o n t r o l l e d m a t e r i a l s , c o n s t r u c t i o n t e c h n i q u e s , a n d c u r i n g c o n d i t i o n s . T h e f l e x u r a l b o n d s t r e n g t h s o b t a i n e d in this t e s t p r o g r a m a r e i n t e n d e d o n l y t o p r o v i d e a m e a n s of e v a l u a t i n g a n d c o m p a r i n g m a t e r i a l s , a n d s h o u l d not b e u s e d as d e s i g n v a l u e s or c o m p a r e d d i r e c t l y w i t h a l l o w a b l e f l e x u r a l b o n d s t r e s s e s p r e s c r i b e d b y m a s o n r y b u i l d i n g c o d e s .

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

160 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

FIG. 4 - - C o m p a r i s o n of Bond W r e n c h Results, Type S a n d Type N M a s o n r y Cement Mortars

A C K N O W L E D G M E N T S

The authors w o u l d like to thank the P o r t l a n d Cement A s s o c i a t i o n and the N a t i o n a l Lime A s s o c i a t i o n for s p o n s o r i n g the t e s t i n g program. The opinions a n d findings e x p r e s s e d in this paper are those of the authors, a n d not n e c e s s a r i l y those of the sponsors. The authors appreciate the e x c e l l e n t work a n d e n t h u s i a s m of all who w o r k e d h a r d to complete this project. The authors are also very a p p r e c i a t i v e of the input of the M a s o n r y Industry Code Committee (MICC), c h a i r e d by Stu Beavers. Testing at UT A u s t i n was c o n d u c t e d by the last author with the assistance of G r a d u a t e R e s e a r c h Assistants Deepak Ahuja and Chris Higgins.

R E F E R E N C E S

[1] Hedstrom, E. G., Tarhini, K. M., Thomas, R. D., Dubovoy, V. S., Klingner, R. E., a n d Cook, R. A., "Flexural B o n d S t r e n g t h of C o n c r e t e M a s o n r y Prisms using P o r t l a n d Cement a n d H y d r a t e d Lime M o r t a r s , " The M a s o n r y Societv Journal, Vol. 9, No. 2, F e b r u a r y 1991, pp. 8-23.

[2] " U n i f o r m B u i l d i n g Code Standard No. 24-30 (Standard Test M e t h o d for F l e x u r a l B o n d Strength of M o r t a r Cement)," I n t e r n a t i o n a l C o n f e r e n c e of B u i l d i n g Officials, Whittier, CA, 1991.

[3] " U n i f o r m Building Code Standard No. 24-20 (Mortar for Unit M a s o n r y a n d R e i n f o r c e d M a s o n r y Other Than Gypsum)," I n t e r n a t i o n a l

C o n f e r e n c e of B u i l d i n g Officials, Whittier, CA, 1988.

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

MELANDER ET AL. ON CONCRETE MASONRY PRISMS

A P P E N D Z X A - C O M P L E T E B O N D W R E N C H R E S U L T S

T A B L E A l - - B o n d w r e n c h r e s u l t s ~ D s l } A f r o m N C M A a n d C T L . T y p e S m a s o D r y c e m e n t m o r t a r s .

161

J o i n t No.

N C M A - M o r t a r M i x ID C T L - M o r t a r M i x ID

S-2 S - 3 S - 5 S - 6 8-7 8-7 8 0 5 1 8 0 5 2 8 0 5 3 8054 8 0 5 5

1 1 5 9 233 117 1 3 9 133 1 2 9 77 1 2 B 69

2 77 ... III 135 135 109 120 ... 74

3 1 3 6 177 86 155 120 I00 99 82 99

4 1 0 3 2 2 3 81 174 92 104 133 ... S7

5 122 217 120 163 102 142 i00 116 117

6 1 5 2 180 119 192 143 133 79 108 108

7 120 117 127 ... 137 92 128 99 87

8 140 118 146 133 173 1 0 9 72 118 86

9 1 4 5 132 121 187 159 112 94 113 130

10 117 115 95 122 150 140 107 150 1 1 9

ii 143 2 0 6 70 139 182 135 106 99 99

12 ... 115 109 140 179 80 126 63 96

13 121 126 82 124 120 97 118 104 119

14 122 121 91 123 118 95 114 128 80

25 i17 227 241 107 161 ... 95 143 2 2 9

16 117 181 121 113 161 113 63 70 1 2 9

17 113 186 80 108 129 123 108 123 88

18 1 4 6 151 118 214 160 82 125 96 103

29 132 133 106 115 126 90 89 122 137

20 1 3 6 124 130 222 155 1 4 6 69 134 113

21 140 149 66 218 121 117 108 126 224

22 121 121 116 117 207 113 96 80 i00

23 1 2 3 iii 68 1 0 9 Ii0 93 121 99 104

24 1 1 6 123 118 i0 100 109 83 94 1 2 6

25 1 5 9 144 105 115 122 156 99 94 98

26 112 175 iii 1 0 6 133 117 86 123 92

27 252 225 65 117 96 120 107 iii 88

28 114 132 i00 2 0 9 104 114 98 97 87

29 117 112 66 108 117 95 63 143 Iii

30 142 109 117 157 I01 128 91 118 152

90 1 3 3 1 2 6 143 132 189 II~ 134 117 232 126 137 89 192 139 182 125 151 144 221 150 167 1 4 6 175 137 168 137 158 1 3 9 187 1 1 6 147 I13 141 101 132 123 157 173 169 120 168 106 158 114 150 115 165 145 204 157 150 144 144 73 204 120 142 142 165

M e a n 128 148 103 130 132 114 99 ii0

S t d

D e v 18 38 23 25 26 19 19 22

COV, % 14 25 22 19 20 17 20 20

A M P a = p s i X 0 . 0 0 6 8 9 5

105 1 2 6 166

20 22 26

19 17 16

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

162 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

T A B L E A 2 - - B o n d w r e n c h t e s t r e s u l t s ( D s i ~ A f r o m U T A u s t i n . T Y P e S m a s o n r v c e m e n t m o r t a r s .

U T A u s t i n - M o r t a r M i x ID J o i n t

No.

IS 2S 3S 4S 5S 6S

1 63 124 98 91 83 103

2 34 78 81 88 74 86

3 71 94 71 90 102 77

4 77 84 96 88 103 i01

5 59 87 134 I~2 99 124

6 49 113 79 77 85 94

7 38 95 78 82 86 89

8 77 95 76 79 93 98

9 54 79 ii0 96 104 118

i0 47 102 83 127 119 92

ii 39 63 67 84 88 65

12 55 102 65 79 73

13 49 134 90 71 87 114

14 49 102 103 103 110 69

15 52 132 97 i00 131 97

16 48 116 56 133 91 102

17 61 95 I 0 0 1 1 9 84 51

18 68 88 90 99 86 73

19 53 89 77 84 129 i00

20 72 96 94 96 II0 68

21 57 86 88 i00 124 61

22 38 i 0 0 9q 113 87 105

23 65 81 93 135 99 85

24 41 112 99 126 112 90

25 48 134 144 150 124 i00

26 48 74 88 117 104 82

27 54 60 89 87 126 52

28 50 88 91 124 120 84

29 58 76 i01 126 86 80

30 5B 96 92 13] 132 85

M e a n 54 96 92 104 102 87

S t d

D e v ii 19 18 22 18 18

COV, % 20 20 19 21 17 21

A M P a = p s i X 0 . 0 0 6 8 9 5

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

MELANDER ET AL. ON CONCRETE MASONRY PRISMS

T A B L E A 3 - - B o n d w r e n c h t e s t r e s u l t s ( p s i ) A f r o m N C M A . T y p e N m a s o n r v c e m e n t m o r t a r s .

163

N C M A - M o r t a r M i x ID J o i n t

No.

N - I N - 2 N - 3 N - 4 N - 5 N - 6 N-7

1 72 50 69 54 50 81 63

2 61 43 48 58 56 56 60

3 53 52 45 63 58 61 74

4 76 48 42 80 56 54 71

5 105 48 38 62 62 60 54

6 82 46 55 79 64 63 92

7 51 56 46 67 82 80

8 86 41 43 45 59 49 59

9 67 52 51 51 40 49 60

i0 62 44 60 85 56 65 65

Ii 53 40 65 57 71 80 81

12 50 48 60 51 62 69 75

13 63 57 61 51 58 74 69

14 65 48 53 85 67 73 92

15 64 43 61 74 77 80 87

16 60 49 59 53 58 50 62

17 51 41 58 80 50 71 57

18 75 58 62 57 59 78 48

19 69 54 68 62 74 73 53

20 46 53 54 52 57 85 76

21 80 43 79 88 69 75

22 61 54 68 76 g6 55 90

23 56 62 72 55 57 74 55

24 61 51 47 74 52 77 51

25 67 63 55 58 60 88 78

26 84 57 52 41 47 92 g0

27 72 54 49 67 55 83 86

28 60 51 51 65 75 86 64

29 62 45 49 79 60 83 84

30 53 51 59 78 70 52

M e a n 66 50 56 65 60 71 70

$ t d 13 6 10 13 9 13 13

D e v

COY, % 20 12 17 20 15 18 19

A M P a = p s i X 0 . 0 0 6 8 9 5

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

164 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

T A B L E A 4 - - B o n d w r e n c h t e s t r e s u l t s ~ D s i ) A f r o m C T L a n d U T A u s t i n . T y P e N m a s o n r v c e m e n t m o r t a r s .

J o i n t No.

C T L - M o r t a r M i x ID UT A u s t i n - M o r t a r M i x ID

N - I N - 2 N - 3 N-4 7N 8N

1 74 84 61 74 103 65

2 72 87 52 60 75 56

3 79 36 70 51 99 47

4 67 ..o 80 34 92 57

5 62 ... 63 50 102 49

6 II0 52 76 100 112 82

7 76 41 63 57 80 82

8 73 39 44 81 105 74

9 65 34 45 74 95 78

i0 68 72 72 94 70 80

ii 83 48 83 1 0 6 110 64

12 71 64 59 54 93 84

13 71 42 51 75 97 69

14 71 17 30 73 113 57

15 74 56 75 113 102 102

16 83 55 64 81 108 54

17 73 46 48 60 79 69

18 55 30 68 52 102 61

19 89 51 54 71 91 45

20 112 66 95 91 84 69

21 117 65 60 70 68 64

22 64 40 44 79 86 84

23 85 64 70 86 88 73

24 81 40 75 81 77 55

25 87 18 76 104 69 80

26 73 43 65 93 86 63

27 65 49 73 60 89 83

28 73 35 76 80 86 70

29 82 24 74 80 91 51

30 47 63 93 58 95 52

M e a n 77 49 65 75 92 67

S t d 15 18 15 19 13 14

D e v

COV, % 20 36 23 25 14 20

A M P a = p s i X 0 . 0 0 6 8 9 5

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

Brian E. T r i m b l e I and Bohdan T. Kulakowski 2

F R I C T I O N A L C H A R A C T E R I S T I C S O F C L A Y B R I C K P A V E R S

REFERENCE: Trimble, B.E., Kulakowski, B.T., "Frictional C h a r a c t e r i s t i c s of Clay B r i c k Pavers", Masonry: D e s i q n and C o n s t r u c t i o n t P r o b l e m s and R e p a i r t A S T M STP 1180, J. M. M e l a n d e r and L.R. Lauersdorf, Eds., A m e r i c a n s o c i e t y for T e s t i n g a n d Materials, Philadelphia, 1993.

A B S T R A C T : The use of b r i c k as a paving m a t e r i a l h a s a long history. Over the p a s t few years b r i c k has again been specified in v e h i c u l a r areas.

Engineers are n o w requesting i n f o r m a t i o n on the skid r e s i s t a n c e p r o p e r t i e s of brick. A r e s e a r c h p r o j e c t was u n d e r t a k e n to d e t e r m i n e b r i c k ' s skid resistance, as w e l l as to compare brick's frictional c h a r a c t e r i s t i c s w i t h those of other paving materials. It was also d e s i r e d to determine if skid resistance c o r r e l a t e d with other p h y s i c a l properties of brick.

Tests using the British P e n d u l u m Tester c o n f i r m e d that these b r i c k have e x c e l l e n t frictional characteristics. It was also d e t e r m i n e d that skid resistance does not correlate w i t h brick's c o m p r e s s i v e strength, a b r a s i o n index n o r cold w a t e r absorption.

KEYWORDS: brick, friction, paving, skid resistance.

~NTRODUCTION

Brick has b e e n used s u c c e s s f u l l y in v e h i c u l a r a p p l i c a t i o n s in the past. In the early p a r t of the 20th century b r i c k roads w e r e the norm.

At the time b r i c k p r o v i d e d a stable, durable p a v i n g surface w h i c h was fairly safe. As concrete and bituminous roadways became m o r e popular, the use of brick as a m a j o r surfacing m a t e r i a l d r o p p e d off. It w a s n ' t until r e c e n t l y that b r i c k streets became desirable a g a i n b e c a u s e of their performance, unique look a n d their c o n n e c t i o n w i t h the p a s t in m a n y places. The d e s i g n of m o d e r n roadways is v e r y complex, and designers require t e s t i n g on all facets of a roadway. This includes t e s t i n g the skid resistance of paving materials. There has b e e n little data in this c o u n t r y to support the use of b r i c k in v e h i c u l a r applications. A r e s e a r c h p r o g r a m was u n d e r t a k e n to determine the frictional c h a r a c t e r i s t i c s of clay b r i c k pavers [~]. The objective of the r e s e a r c h was to d e t e r m i n e the skid r e s i s t a n c e of n e w clay b r i c k pavers as well as to i n v e s t i g a t e a c o r r e l a t i o n b e t w e e n skid resistance and other p h y s i c a l p r o p e r t i e s of brick.

S k i d resistance is m e a s u r e d by the dynamic c o e f f i c i e n t of friction.

It is r e l a t e d to the t i r e / r o a d w a y friction and is t h e r e f o r e a p p l i c a b l e to v e h i c u l a r traffic. Slip resistance is r e l a t e d to p e d e s t r i a n t r a f f i c a n d is m e a s u r e d by the static c o e f f i c i e n t of friction. The test m e t h o d s used

i S e n i o r Engineer, T e c h n i c a l Services, B r i c k Institute of America, Reston, V A 22091.

2 P r o f e s s o r of Mechanical Engineering, P e n n s y l v a n i a State University, U n i v e r s i t y Park, PA 16802.

165

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

166 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

i n t h i s r e s e a r c h m e a s u r e t h e d y n a m i c c o e f f i c i e n t of f r i c t i o n . A l t h o u g h d y n a m i c c o e f f i c i e n t of f r i c t i o n is p r i m a r i l y t h o u g h t to r e l a t e t o s k i d r e s i s t a n c e , o n e a u t h o r b e l i e v e s t h a t t h e s e f r i c t i o n a l t e s t s a r e a l s o a p p r o p r i a t e for s l i p r e s i s t a n c e [~]. M o r e r e s e a r c h n e e d s t o b e c o n d u c t e d to v e r i f y t h i s t h e o r y .

SCOPE

T h e r e s e a r c h p r o g r a m c o n s i s t e d of t e s t i n g a set of i0 b r i c k p a v e r s f r o m 14 d i f f e r e n t m a n u f a c t u r e r s for s k i d r e s i s t a n c e , c o m p r e s s i v e s t r e n g t h , 24 h o u r c o l d w a t e r a b s o r p t i o n a n d 5 h o u r b o i l i n g w a t e r a b s o r p t i o n . T h e b r i c k w e r e t e s t e d as r e c e i v e d . T h r e e b a s i c c a t e g o r i e s w e r e i d e n t i f i e d b y m e t h o d of m a n u f a c t u r i n g : e x t r u d e d , m o l d e d a n d d r y p r e s s e d . T h e p a v e r s w e r e s e l e c t e d to r e p r e s e n t t h e e n t i r e r a n g e of t h e t y p e s of c l a y b r i c k p a v e r s c o m m o n l y a v a i l a b l e . T h e r e f o r e , t h e r e s u l t s o b t a i n e d w o u l d b e a p p l i c a b l e t o t h e m a j o r i t y of c l a y b r i c k p a v e r s w i t h i n t h e i r c a t e g o r i e s .

T h e p a v e r s , i d e n t i f i e d b y code, a r e s h o w n i n T a b l e 1 w i t h t h e i r m a n u f a c t u r i n g type. T h e size of t h e u n i t s w a s t h e s a m e f o r a l l brick, t y p i c a l l y 3 5/8 in. b y 2 1/4 in. b y 7 5/8 in. (92.1 m m b y 57.2 m m b y 193.7 m/n). T w o e x c e p t i o n s are P a v e r s 742 a n d 610B. P a v e r s 742 a n d 6 1 0 B w e r e 3 in. (76.2 mm) w i d e w h i c h is n a r r o w e r t h a n t h e w i d t h r e q u i r e d b y t h e f r i c t i o n t e s t m e t h o d . In a d d i t i o n , p a v e r 6 1 0 B w a s 3/8 in. (i0 mm) t h i c k .

T A B L E I

T y p e s a n d C o d e s o f B r i c k P a v e r s

E x t r u d e d - W i r e c u t 7 1 2 A

E x t r u d e d - W i r e c u t 3 0 0 A

E x t r u d e d - W i r e c u t 735

E x t r u d e d - W i r e c u t 1208

E x t r u d e d - W i r e c u t 6 1 0 A

E x t r u d e d - W i r e c u t 640

E x t r u d e d - S m o o t h 742

E x t r u d e d - S m o o t h 6 1 0 B

M o l d e d (Water Struck) 106

M o l d e d (Sand S t r u c k ) 450

M o l d e d (Sand S t r u c k ) 406

M o l d e d (Sand s t r u c k ) 7 1 2 B

R e p r e s s e d 3 0 0 B

D r y p r e s s e d 1165

T E S T P R O C E D U R E S

F r i c t i o n a l p r o p e r t i e s w e r e t e s t e d a c c o r d i n g t o A S T M E 3 0 3 - 8 3 S t a n d a r d M e t h o d for M e a s u r i n g S u r f a c e F r i c t i o n a l P r o p e r t i e s U s i n g t h e B r i t i s h P e n d u l u m T e s t e r . T h e B r i t i s h P e n d u l u m T e s t e r is a d e v i c e w i d e l y u s e d a r o u n d t h e w o r l d t o m e a s u r e s k i d r e s i s t a n c e of m a t e r i a l s . T h e v a l u e m e a s u r e d b y t h e tester, o r B r i t i s h P e n d u l u m N u m b e r (BPN), r e p r e s e n t s t h e a m o u n t of k i n e t i c e n e r g y l o s t w h e n a r u b b e r s l i d e r a t t a c h e d t o t h e e n d of t h e p e n d u l u m a r m i s p r o p e l l e d o v e r t h e t e s t s u r f a c e . T h e r e s u l t s p r o d u c e d b y t h e B r i t i s h P e n d u l u m t e s t s d e p e n d p r i m a r i l y o n t h e s u r f a c e m i c r o t e x t u r e , i.e., o n t h e s u r f a c e d e v i a t i o n s f r o m t h e p l a n a r s u r f a c e w i t h c h a r a c t e r i s t i c d i m e n s i o n s of w a v e l e n g t h a n d a m p l i t u d e less t h a n 0.02 in.

(0.5 mm). In g e n e r a l , m i c r o t e x t u r e d e t e r m i n e s t h e f r i c t i o n a l r e s i s t a n c e of a d r y s u r f a c e . T h e e f f e c t i v e n e s s of t h e m i c r o t e x t u r e i n g e n e r a t i n g f r i c t i o n b e t w e e n v e h i c l e t i r e s a n d p a v e m e n t s u r f a c e w h e n t h e s u r f a c e is w e t d e p e n d s o n t h e s u r f a c e d r a i n a g e a b i l i t y . T h e d r a i n a g e a b i l i t y is d e t e r m i n e d i n p a r t b y t h e s u r f a c e m a c r o t e x t u r e , w h i c h is d e f i n e d as t h e d e v i a t i o n s of t h e p a v e m e n t s u r f a c e f r o m t r u e p l a n a r s u r f a c e w i t h c h a r a c t e r i s t i c d i m e n s i o n s of w a v e l e n g t h a n d a m p l i t u d e f r o m 0.02 in.

(0.5 mm) u p to t h o s e t h a t no l o n g e r a f f e c t t i r e - p a v e m e n t i n t e r a c t i o n .

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

TRIMBLE AND KULAKOWSKI ON CLAY BRICK PAVERS 167

M e a s u r e m e n t of m a c r o t e x t u r e , as d e s c r i b e d b y t h e A S T M E 9 6 5 - 8 7 S t a n d a r d T e s t M e t h o d f o r M e a s u r i n g S u r f a c e M a c r o t e x t u r e D e p t h U s i n g a V o l u m e t r i c T e c h n i q u e , r e q u i r e s a t e s t a r e a l a r g e r t h a n t h e a r e a of a n i n d i v i d u a l p a v e r . T h e s e m e a s u r e m e n t s s h o u l d be c o n d u c t e d i n t h e f u t u r e o n a c t u a l b r i c k p a v e m e n t s .

P h y s i c a l p r o p e r t i e s of b r i c k w e r e t e s t e d a c c o r d i n g t o A S T M C 6 7 - 8 9 a S t a n d a r d T e s t M e t h o d of S a m p l i n g a n d T e s t i n g B r i c k a n d S t r u c t u r a l C l a y T i l e . C o m p r e s s i v e s t r e n g t h , 24 h o u r c o l d w a t e r a b s o r p t i o n a n d 5 h o u r b o i l i n g w a t e r a b s o r p t i o n t e s t s w e r e c o n d u c t e d o n a t l e a s t f i v e of e a c h t y p e of b r i c k .

R E S U L T S O F S K I D R E S I S T A N C E T E S T S

T h e r e s u l t s of t h e s k i d r e s i s t a n c e t e s t s a r e s h o w n i n T a b l e 2. T h e p a v e r s a r e l i s t e d i n o r d e r of d e c r e a s i n g B r i t i s h P e n d u l u m N u m b e r (BPN).

In a n a l y z i n g t h e d a t a i t a p p e a r s t h a t s a n d - s t r u c k m o l d e d b r i c k t e n d t o h a v e h i g h e r s k i d r e s i s t a n c e v a l u e s . T h i s m a y b e d u e t o t h e u n e v e n s u r f a c e s a n d s a n d c o a t i n g o n t h e m o l d e d b r i c k . A l s o , i n t h e B P N t e s t i n g p r o c e d u r e , t h e s u r f a c e of t h e p a v e r is f l u s h e d w i t h w a t e r . M o l d e d b r i c k , w h i c h t e n d t o b e m o r e a b s o r p t i v e , m a y b e s u r f a c e d r y w h e n t e s t e d , s i m i l a r t o b e i n g t e s t e d i n a d r y c o n d i t i o n . T h e r e s u l t is a h i g h e r s k i d r e s i s t a n c e v a l u e .

In g e n e r a l , t h e m i c r o t e x t u r e of b r i c k p r o v i d e s for a s k i d r e s i s t a n t s u r f a c e . A s m o o t h s u r f a c e d b r i c k s u c h as a d i e - s k i n b r i c k w i l l h a v e a l o w B P N v a l u e . R e p r e s s i n g o r d r y p r e s s i n g t h e u n i t w i l l f l a t t e n o u t a n y a p p l i e d t e x t u r e r e s u l t i n g i n l o w e r B P N v a l u e s . T e x t u r e s s u c h as w i r e c u t , v e l o u r , o r b l a d e c u t w i l l i n c r e a s e t h e B P N v a l u e . T h e a d d i t i o n of a grit, s u c h as sand, o n t h e p a y e r ' s s u r f a c e c a n a l s o i n c r e a s e t h e B P N v a l u e .

T h e r e s u l t s s h o w t h a t m o s t n e w b r i c k h a v e a d e q u a t e s k i d r e s i s t a n c e . T y p i c a l l y , t h e m i n i m u m a c c e p t a b l e v a l u e of B P N is 55. B P N v a l u e s of

T A B L E 2

B r i t i s h P e n d u l u m T e s t s R e s u l t s ( A v e r a g e o f 6 T e s t s )

P A V E R C O D E P A V E R T Y P E M E A N B P N STD. D E V .

7 1 2 B M o l d e d (SS a) 87.3 4.58

3 0 0 A E x t r u d e d - w i r e c u t 82.7 8.25

1165 D r y p r e s s e d 82.5 5.26

450 M o l d e d (SS) 81.4 2 . 0 3

406 M o l d e d (SS) 77.9 3.30

1208 E x t r u d e d - w i r e c u t 75.8 5 . 5 0

640 E x t r u d e d - w i r e c u t 68.9 6.95

7 1 2 A E x t r u d e d - w i r e c u t 68.8 7.22

735 E x t r u d e d - w i r e c u t 68.3 2 . 7 1

3 0 0 B R e p r e s s e d 63.8 3.96

106 M o l d e d (WS b) 61.0 4.73

6 1 0 A E x t r u d e d - w i r e c u t 51.4 4.58

742 c E x t r u d e d - s m o o t h 50.9 2.17

6 1 0 B a E x t r u d e d - s m o o t h 42.3 3.83

a S a n d - S t r u c k b W a t e r - S t r u c k c N a r r o w P a v e r

University of Washington (University of Washington) pursuant to License Agreement. No further reproductions authorized.

156 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

90 MASONRY: DESLGN AND CONSTRUCTION, PROBLEMS AND REPA{R

FLANAGAN ET AL. ON HOLLOW CLAY TILE INFILLED FRAMES 97