Fillers and Reinforcements for Plastics

20 Reinforced Plastics in Low Cost Housing

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ARMAND

G.

WINFIELD

and

BARBARA

L.

WINFIELD

A r m a n d G . Winfield Inc., 82 Dale St., West Babylon, Ν. Y . 11704

Our company designed and produced a low cost prototype house for Bangladesh to withstand cyclonic winds in excess of 150 mph and tidal waves. The house was constructed primarily of jute-reinforced polyester with a.010-inchex terior layer of glassfiber-reinforcedpolyester. The two-room house was 10 ft X 20 ft with an average height of 7.5 ft. Constructed of two monocoques, it has a dividing partition. The prototype successfully underwent full scale simulated cyclonic testing. A jet aircraft was used to create winds greater than 230 mph; 750 gal of water/min were released simultaneously to complete the cyclonic conditions. Surface temperatures of 200°F were recorded. Maximum deflection on prototype walls was 2.3 inches. The prototype indicates a major breakthrough in the use of plastics for low cost housing.

" C a r l y i n 1972, C A R E , I n c . i n i t i a t e d a p r o g r a m to establish goals f o r shelter u s i n g plastics m a t e r i a l s f o r the A s i a n s u b - c o n t i n e n t , specifically Bangladesh, where a major w a r for independence fought.

h a d recently been

T h e w a r left t r a g i c d e v a s t a t i o n a n d homelessness,

and on the

I s l a n d o f B h o l a , at t h e m o u t h o f t h e G a n g e s , t h e effects of t h e w a r w e r e m a g n i f i e d b y a 1971 t i d a l w a v e w h i c h l e v e l l e d this i s l a n d a n d k i l l e d 225,000 persons i n a single d a y . T h e A s i a n s u b - c o n t i n e n t — a c c o r d i n g to the U n i t e d N a t i o n s — i s one of t h e areas of t h e w o r l d c r i t i c a l l y i n n e e d of h o u s i n g . T h i s p r o g r a m is p a r t o f C A R E s c o n t i n u i n g effort to p r o v i d e safe a n d i n e x p e n s i v e h o u s i n g i n t h e d e v e l o p i n g countries of t h e w o r l d . Background T h e most i m p o r t a n t l o w cost b u i l d i n g system i n use u n d e r C A R E ' s aegis is t h e C i n v a r a m system. A c o m p o s i t i o n of d i r t , w a t e r , a n d 7 - 1 2 % 207 Deanin and Schott; Fillers and Reinforcements for Plastics Advances in Chemistry; American Chemical Society: Washington, DC, 1974.

208

FILLERS

concrete is p r e p a r e d .

A N D REINFORCEMENTS F O R PLASTICS

A $50.00 C i n v a r a m press is o p e r a t e d b y m a n u a l

lever action a n d produces a "green" block.

T w o m e n can produce ap-

p r o x i m a t e l y 300 b l o c k s p e r d a y , a n d t h e b l o c k s m u s t c u r e f o r 28 to 30 days p r i o r to use. C u r e d b l o c k s are p l a c e d o n a p e r i p h e r a l concrete slab a n d are m o r t a r e d together.

R o o f i n g m a d e of c o r r u g a t e d g a l v a n i z e d i r o n

sheets a r e a t t a c h e d to t h e C i n v a r a m b y c o m p l i c a t e d roofing struts a n d trusses. A t y p i c a l C i n v a r a m house 10 ft X 20 f t uses a p p r o x i m a t e l y 1500


blocks for walls a n d partitions. A t o t a l of 7500 units w e r e b u i l t i n B a n g l a d e s h u n d e r C A R E

super-

v i s i o n i n late 1972, a n d s e v e r a l t h o u s a n d m o r e w e r e b u i l t i n 1973. T h e C i n v a r a m s t r u c t u r e has m a n y d r a w b a c k s , i n c l u d i n g its i n a b i l i t y t o w i t h s t a n d h u r r i c a n e s , tornadoes, e a r t h q u a k e s , o r tsunamis. H i g h w i n d s c a n r i p a w a y t h e m e t a l roofing, a n d earthquakes a n d floods c a n c r u m b l e o r disintegrate its w a l l s . T o date, h o w e v e r , this seems to b e t h e most exrO-10

2-4 x3-0 [WINDOW, 2-4x6-0 J DOOR I

b. SIDE ELEVATION

Figure

1.

Initial house design by Anthony Marchese for Bangladesh proved by CARE, Inc.

Deanin and Schott; Fillers and Reinforcements for Plastics Advances in Chemistry; American Chemical Society: Washington, DC, 1974.

as ap-

20.

WINFIELD

AND WINFIELD

LOW

Cost

209

HoUStUg

p e d i e n t , e t h n i c a l l y a c c e p t a b l e house for c o n s t r u c t i o n i n m a n y d e v e l o p i n g areas—one w h i c h replaces the o p e n s k y ( or a tree ) for a roof. D u r i n g the U N I D O meetings i n V i e n n a , A u s t r i a , Sept. 2 0 - 2 4 , 1971, e n t i t l e d " E x p e r t G r o u p M e e t i n g o n the U s e of P l a s t i c s i n the B u i l d i n g I n d u s t r y , " one of the i m p o r t a n t conclusions w a s that plastics l e n d t h e m selves best to mass p r o d u c t i o n t e c h n i q u e s

w h i c h are r e q u i r e d i f the

w o r l d ' s h o u s i n g needs are to be met. Downloaded by HONG KONG UNIV SCIENCE TECHLGY on May 6, 2018 | https://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0134.ch020

A l t h o u g h C A R E p e r s o n n e l h a d e x p e r i m e n t e d w i t h plastics i n h o u s i n g i n B a n g l a d e s h , p r i o r to t h e i r w a r for i n d e p e n d e n c e , no successful structures h a d b e e n p r o d u c e d . T h i s w o r k , h o w e v e r , c r e a t e d m u c h l o c a l interest a n d i n d i c a t e d f u t u r e possibilities.

Figure

Research and In

2.

Typical window (wood)

Development

e a r l y 1972, C A R E , Inc. i n i t i a t e d a p r o g r a m w i t h A r m a n d G .

W i n f i e l d Inc. for the m a t e r i a l f e a s i b i l i t y , d e s i g n , p r o t o t y p e and

construction

development,

testing of a l o w cost house for B a n g l a d e s h . C r i t e r i a f o r this house

w e r e to i n c l u d e : ( 1 ) T h e use of j u t e — t h e m a i n staple of B a n g l a d e s h — i n association w i t h a m i n i m u m of plastics m a t e r i a l s . (2)

E t h n i c a n d s o c i a l a c c e p t a b i l i t y to the B a n g l a d e s h p e o p l e .

(3)

U s e of self-help i n construction.

( 4 ) C a p a b i l i t y for h i g h speed, on-site p r o d u c t i o n b y u n s k i l l e d or s e m i - s k i l l e d l o c a l l a b o r , i n excess of 100 c o m p l e t e d houses p e r day. (5)

C o s t u n d e r $300.00 for each 10 ft X 20 ft s t r u c t u r e .

( 6 ) A b i l i t y to w i t h s t a n d c y c l o n i c w i n d s greater t h a n 150 m p h a n d other n a t u r a l p h e n o m e n a , i n c l u d i n g m o n s o o n flooding a n d l a n d u p h e a v a l s . A f t e r C A R E briefings, i n i t i a l designs w e r e c r e a t e d b y the architect, A n t h o n y M a r c h e s e , a n d w e r e a p p r o v e d b y C A R E , Inc. for p r o t o t y p i n g ( F i g u r e 1 ). T h e house was to b e 10 ft X 20 ft b y a n average h e i g h t of


210

FILLERS

AND

REINFORCEMENTS FOR

PLASTICS

7.5 ft a n d was to b e b u i l t as t w o m o n o c o q u e s , w i t h a n i n t e r n a l p a r t i t i o n w h i c h w o u l d p r o v i d e t w o rooms. T h e d e s i g n i n c l u d e d three

doors—two

e x t e r n a l a n d one i n t e r n a l — a n d f o u r w i n d o w s , a l l of w h i c h o p e n e d i n w a r d ( a n e t h n i c n e c e s s i t y ) . T h e doors a n d w i n d o w s w o u l d b e w o o d — a v a i l a b l e o n site i n B a n g l a d e s h ( F i g u r e 2 ) .

F l o o r s w e r e n o t a c o n s i d e r a t i o n since

c u s t o m d i c t a t e d a t a m p e d d u n g - e a r t h floor. B a m b o o v e r a n d a h s , screens, a n d a d d i t i o n a l p a r t i t i o n s w o u l d be c o n s t r u c t e d b y the f a m i l y once the Downloaded by HONG KONG UNIV SCIENCE TECHLGY on May 6, 2018 | https://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0134.ch020

b a s i c house was erected. Table I.

W i n d T u n n e l Tests Terrain

W i n d speed , m p h a

Design load , lbs/ft 6

2

0

Exposure Flat, open country

Center of large city

Suburban area

(1) 100 (2) 150

(1) 100 (2) 150

(1) 100 (2) 150

(1) 15 (2) 34

(1) 29 (2) 65

(1) 48 (2) 106 ( 3 / 4 l b / i n ) 2

Basic wind speeds based on air flow in open, level country at 30 ft above ground and for terrain exposure as noted. Design load = effective velocity pressure multiplied by appropriate pressure coefficient: 1.86. a

6

A w i n d t u n n e l m o d e l was c o n s t r u c t e d f r o m the a p p r o v e d d e s i g n , a n d tests w e r e c o n d u c t e d to p r o v e its d e s i g n a n d c a p a b i l i t i e s to w i t h s t a n d h i g h w i n d loads ( T a b l e I ) .

E n g i n e e r i n g specifications w e r e s u b -

s e q u e n t l y d e v e l o p e d f r o m these d a t a a n d w e r e u s e d to select m a t e r i a l s f r o m w h i c h the p r o t o t y p e w o u l d u l t i m a t e l y b e c o n s t r u c t e d .

A founda-

t i o n a n d a n c h o r i n g system was d e v e l o p e d b y e x t e n d i n g the w a l l s of the house

18 inches b e l o w g r a d e a n d s i m u l t a n e o u s l y e x t e n d i n g a 1 2 - i n c h

peripheral

flange

o u t w a r d a n d p e r p e n d i c u l a r to the w a l l s .

This was

f u r t h e r s t r e n g t h e n e d b y i n c l u d i n g a net m a d e of 2 y 4 - i n c h w i d t h w o v e n p o l y p r o p y l e n e tapes

(450 l b test)

w h i c h were interwoven on 12-inch

centers i n b o t h directions of the house ( F i g u r e 3 ) . T h e c o m p l e t e d house was to be erected i n a n o p e n p i t 12 ft X 22 ft X

18 inches d e e p , a n d

e a r t h w o u l d be filled to g r o u n d l e v e l i n s i d e a n d outside the house.

The

w e i g h t of the e a r t h o n b o t h the e x t e r n a l flange a n d o n t h e i n t e r n a l n e t t i n g w o u l d h o l d the house firm d u r i n g severe w e a t h e r . V a r i o u s jute samples a n d p r o d u c t s w e r e c o l l e c t e d i n m a n y f o r m s — e.g.,

jute " h e a d s , " y a r n , w o v e n c l o t h , fibers, net, a n d rope.

The initial

goals for the h o u s e w e r e b a s e d o n the p h y s i c a l p r o p e r t i e s of g l a s s - r e i n f o r c e d polyester.

U s i n g the c r i t e r i a of 6 5 - 7 5 %

polyester r e s i n i n asso-

c i a t i o n w i t h jute r e i n f o r c e m e n t s , the m i n i m u m values w o u l d h a v e approach


to

20.

WINFIELD

AND

Low

WINFIELD

Cost

211

Housing

18,000 p s i flexural s t r e n g t h 850,000 p s i flexural m o d u l u s 9,000 p s i tensile strength. F i r s t considerations dealt w i t h c o m b i n a t i o n s a n d ratios of jute

fibers

to polyester resins. Polyesters w e r e chosen b e c a u s e t h e y c o u l d b e p u r c h a s e d e c o n o m i c a l l y for export, c o u l d b e m a d e s e l f - e x t i n g u i s h i n g , a n d w e r e c o m p a t i b l e w i t h the jute

fibers.

( F o a m e d p o l y u r e t h a n e as a core


m a t e r i a l h a d f a i l e d i n earlier b e a m tests. ) J u t e i n association w i t h plastics m a t e r i a l s was l a r g e l y u n e x p l o r e d , except o n a d e c o r a t i v e basis, a n d little h a d b e e n c o m p i l e d o n the p h y s i c a l characteristics of these c o m b i n a t i o n s . T h e soft o r g a n i c jute fibers, u n l i k e i n o r g a n i c glass fibers, absorb resin. E a r l y experiments i n d i c a t e d that the jutes u s e d p r o v i d e d little s t r e n g t h or stiffness i n tensile a n d flexural tests. T h e a d d i t i o n of a glass fiber l a y e r also a d d e d l i t t l e s t r e n g t h to the l a m i n a t e a n d i n some c o m b i n a t i o n s p r o v e d ineffectual or even d e t r i m e n t a l as m o r e r e s i n s o a k e d i n t o the jute layers ( T a b l e I I ) .

A l t h o u g h the i n i t i a l tests

u s e d jute, polyester r e s i n ( P o l y l i t e 94-158, R e i c h h o l d C h e m i c a l s , I n c . ) a n d glass fibers h a d e s t a b l i s h e d the d i r e c t i o n for m a t e r i a l composites; the r a t i o b e t w e e n t h e jute a n d polyester r e m a i n e d to b e d e v e l o p e d f u r t h e r — a s w o u l d t h e stiffness a n d strength.

I?

ITER. M U - U

/ /

FLOOR

/ /

UNE

Τ.g. ror-*|

ZZZZZL

ι-ο O.C. BOTH WAVS T o i m p r o v e the

flexural

Figure

3.

Anchonng flange and

system netting

showing

strength a n d m o d u l i , it w a s necessary

to

i n t r o d u c e finely d i v i d e d i n o r g a n i c fillers w h i c h w o u l d pass t h r o u g h the apertures

of

the

Florida, Inc.).

airless s p r a y - u p

C a l c i u m carbonate

equipment filler

(Glas-Mate, Ransburg

( A t o m i t e 319, W h i t a k e r , C l a r k ,

a n d D a n i e l s , I n c . ) , 20 w t % to t h e polyester resin, p r o v i d e d the accept a b l e properties.

A s s h o w n i n T a b l e I I I , p a n e l 1 A w a s m a d e of f o u r

layers of jute s a t u r a t e d w i t h u n f i l l e d polyester resin. T h e flexural m o d u l i r e c o r d e d w e r e 444,000, 634,000 a n d 447,000 p s i , r e s p e c t i v e l y . P a n e l 1 B ,


212

FILLERS

Table II.

AND

REINFORCEMENTS

Flexural


Panel 1°, resin-soaked #1 11,700 #2 6,800 #3 6,400

PLASTICS

F R P Test Laminates" Tensile

h

Strength, psi

FOR

Modulus, psi

Thickness, inch

jute 232,000 120,000 63,000

Strength, psi

Thickness, inch

0.037 0.034 0.034

2,600 1,900

0.032 0.035

0.054 0.052 0.052

6,600 5,900

0.050 0.052

Panel 16 , 1 jute/1 resin and glass #1 21,500 576,000 #2 22,200 563,000 #3 9,000 510,000

0.066 0.068 0.067

4,000 4,300

0.072 0.072

Panel 13, S jute/2 resin and glass #1 15,200 643,000 #2 15,000 577,000 #3 12,000 588,000

0.153 0.157 0.156

7,600 10,000

0.164 0.161

Panel 11, 4 jute/S resin and glass #1 11,700 548,000 #2 17,200 736,400 #3 13,900 642,300

0.238 0.235 0.235

8,200 8,300

0.260 0.259

Panel 15 , 1 resin and glass only #1 23,000 674,000 #2 21,200 613,000 #3 18,800 555,000 d

6

d

f

0

9

Standard conditions after 48-hr post cure at 150°F. Samples # 1 and 2 were tested with resin rich side in compression; sample # 3 was tested with glass side in compression. Jute only; note low physicals. Panels 15 and 16 were made simultaneously. Note higher physicals for glass alone. Note that addition of jute weakened the laminate. Note the more jute layers added, the weaker the composite became because the jute was absorbing resin and the glass became ineffectual. a

b

c

d

e

s

0

w h i c h w a s m a d e of f o u r layers of jute staturated w i t h 20 w t % A t o m i t e to the p o l y e s t e r r e s i n , shows

flexural

m o d u l i of 549,000, 527,000, a n d

480,000 p s i . T e n s i l e strengths of p a n e l 1 A are 5400 a n d 5100 p s i vs. p a n e l 1 Β w i t h readings of 7900 a n d 8200 p s i . C r i t e r i a for the p o l y e s t e r - j u t e c o m p o s i t e w e r e d e t e r m i n e d b y t w o factors : ( 1 ) It w a s necessary to use a filler to a c h i e v e stiffness w i t h o u t affect i n g other p r o p e r t i e s . (2)

I n i t i a l l y , w o v e n jute cloths, nets, a n d tapes w e r e a b s o r b i n g r e s i n

i n excessive a m o u n t s . Studies of the jute itself s h o w e d that its fibers are e x t r e m e l y porous a n d a b s o r b resin. It w a s also d e t e r m i n e d that a d o u b l e sheared a n d c a l e n d e r e d w e a v e of jute w o u l d m i n i m i z e r e s i n a b s o r p t i o n . T h u s , a 22 X 22 ( t h r e a d c o u n t ) B e n g a l o n f a b r i c w a s chosen as the f a b r i c


20.

WINFIELD

AND

for t h e p r o t o t y p e .

LOW Cost

WINFIELD

213

Housing

( B e n g a l o n is i m p o r t e d i n t o the U n i t e d States f r o m

I n d i a b y W h i t e , L a m b , F i n l a y of M o n t c l a i r , N . J . ) U l t i m a t e l y , P a n e l 1 Β ( T a b l e I I I ) b e c a m e t h e i n n e r s k i n of t h e house c o m p o s i t e . S i n c e the f o a m e d p o l y u r e t h a n e c o r e p o t e n t i a l w a s a b a n d o n e d because o f core failures, a substitute c o r e w a s necessary. A c o r r u g a t i o n


Table III.

F R P Test Laminates" Tensile

Flexural

b

Strength, psi

Modulus, psi

Panel 1A , 4 layers jute/unfilled 10,700 444,000 #1 12,100 #2 634,000 #3 8,700 447,000 C

Strength, psi

Thickness, inch resin 0.0895 0.079 0.077

5,400 5,100

0.084 0.088

7,900 8,200 —

0.080 0.086

Panel lB , 4 layers jute/with 20% #4 15,100 549,000 #5 12,500 527,000 #6 11,700 480,000

Atomite in 0.077 0.0775 0.079

Panel lC , 2 layers jute/with 20% #7 11,800 54,200 #8 12,900 65,200 #9 10,600 53,600

Atomite in resin 0.0445 5,000 0.044 5,600 0.0455 —

d

e

Thickness, inch

resin

Panel 1D , 1 layer jute/resin with 20% Atomite #10 6,400 59,200 0.0375 #11 4,300 65,000 0.0465 #12 7,000 60,500 0.033

0.047 0.046

{

Panel 2A ', 2 jute/unfilled resin/2 strands glass #13 17,300 575,000 0.111 #14 18,800 573,000 0.118 #15 13,200 416,000 0.097

4,100 3,700 —

0.028 0.040

13,100 10,500 —

0.111 0.104

Panel 2B°, 1 jute/resin with 20% #16 16,200 510,000 #17 13,200 378,000 #18 13,700 422,000

Atomite/2 strands glass 0.0855 7,800 0.083 9,800 0.077 —

Panel 2C", 2 jute/resin with 20% #19 13,200 553,000 #20 14,300 528,000 #21 11,500 616,000

Atomite/2 0.092 0.091 0.084

strands glass 12,900 13,600 —

0.094 0.077

0.087 0.086 —

" Tests done under standard conditions. Specimens # 1 and 2 were tested with resin-rich surface in compression; specimen # 3 was tested with glass rich surface in compression. Unfilled resin shows low flexural strength and modulus. Atomite increases flexural strength and modulus. ' Reduction of jute reduces flexural strength and modulus. Too weak. ' Used to determine criterion for outer skin. 6

e

d

f


214

FILLERS

A N D REINFORCEMENTS F O R PLASTICS

of jute r e i n f o r c e d polyester p r o v e d satisfactory.

Cements w h i c h could

m e e t t h e p h y s i c a l r e q u i r e m e n t s n e e d e d to fasten t h e core to t h e skins w e r e d e v e l o p e d a n d tested. T h e final f o r m u l a t i o n w a s m a d e f r o m r i g i d a n d flexible polyester resins stiffened w i t h a t h i x o t r o p i c filler ( C a b - o - s i l , Cabot Corp.). T h e final c o m p o s i t e f o r t h e s t r u c t u r e consisted of f o u r layers of jute r e i n f o r c e d polyester f o r the i n n e r s k i n ; three layers of jute r e i n f o r c e d p o l y Downloaded by HONG KONG UNIV SCIENCE TECHLGY on May 6, 2018 | https://pubs.acs.org Publication Date: June 1, 1974 | doi: 10.1021/ba-1974-0134.ch020

ester f o r t h e c o r r u g a t i o n s ; a n d one l a y e r of jute r e i n f o r c e d polyester a n d one

l a y e r o f .010-inch glass r e i n f o r c e d polyester

(Figure

4).

T h e exterior glass r e i n f o r c e d

f o r t h e outer

layer provided

skin

a barrier

against w e a t h e r i n g . T h e c o m p o s i t e w a s a n a e r o d y n a m i c structure—i.e., t h e s k i n c o u l d b e p i e r c e d w i t h a s h a r p b l o w , b u t t h e flexural m o d u l i w o u l d p r e c l u d e f a i l u r e i n h i g h w i n d a c t i v i t y . F i n a l b e a m tests o n t h e c o m p l e t e d c o m p o s i t e structures p r o v e d that loads greater t h a n 1800 l b s c o u l d b e a p p l i e d , w i t h deflections u p to .68 i n c h ( T a b l e I V ) . WALL PANEL ~ OlATElR I. " .

SECTION

SKIN

Figure 4. Field

CROSS

Final composite sandwich for prototype

structure

Testing

A l t h o u g h laboratory testing h a d been conducted

throughout the

entire r e s e a r c h a n d d e v e l o p m e n t phase, i t was felt that f u l l scale p r o t o t y p e t e s t i n g w o u l d b e m o r e significant a n d c o n c l u s i v e t h a n a n y single o r sect i o n a l test.

F u r t h e r , t h e f o u n d a t i o n / a n c h o r i n g system c o u l d o n l y b e

tested u n d e r c y c l o n i c c o n d i t i o n s . G r u m m a n A e r o s p a c e E n g i n e e r i n g C o r p . p r o v i d e d its C a l v e r t o n , L . I . test f a c i l i t i e s f o r this p u r p o s e . T h e f u l l y a s s e m b l e d p r o t o t y p e house w a s t r a n s p o r t e d f r o m A r m a n d G . W i n f i e l d I n c . to C a l v e r t o n w h e r e i t w a s a n c h o r e d i n t h e g r o u n d . T h e a n c h o r i n g c o n d i t i o n s w e r e s i m i l a r to those i n B a n g l a d e s h ( F i g u r e 5 ). It w a s p l a c e d 50 ft f r o m a n d p a r a l l e l to a cross section of a i r p o r t r u n w a y ( F i g u r e 6 ) . U s i n g a N a v y A - 6 A I n t r u d e r jet fighter, t h e engine p r o f i l e i n d i c a t e d that w i n d speeds a p p r o a c h i n g c y c l o n i c forces c o u l d b e g e n -


20.

WINFIELD

AND

Table IV.

LOW Cost

WINFIELD

215

Housing

Flexure Test of Flat Sandwich Construction

0

Panel 1-1


1- 2

2- 1

2-2

3- 1

4-layer core, new c e m e n t , tested w i t h w o v e n r o v i n g side i n c o m pression u l t i m a t e l o a d — 1 8 1 0 lbs u l t i m a t e deflection—0.65 i n c h m o d e of f a i l u r e — c o r e failure S a m e as 1-1, tested w i t h w o v e n r o v i n g i n t e n s i o n u l t i m a t e l o a d — 1 6 5 0 lbs u l t i m a t e deflection—0.52 i n c h m o d e of f a i l u r e — c o m p r e s s i o n i n s k i n a n d core 6

3-layer core, tested w i t h w o v e n r o v i n g side i n compression u l t i m a t e l o a d — 1 3 5 0 lbs ultimate deflection—0.68 inch m o d e of f a i l u r e — c o r e failure S a m e as 2 - 1 , tested w i t h w o v e n r o v i n g i n t e n s i o n u l t i m a t e l o a d — 1 0 5 0 lbs u l t i m a t e deflection—0.51 i n c h m o d e of f a i l u r e — c o m p r e s s i o n i n s k i n a n d core 3-layer core, o l d c e m e n t , tested w i t h w o v e n r o v i n g i n tension u l t i m a t e l o a d — 7 3 0 lbs ultimate deflection—0.63 inch m o d e of f a i l u r e — c o r e failure 0

° Round steel bars, 2 inches in diameter, were used in loading. Specimens were loaded at two quarter-span points with the span length equal to 18 inches. The panel width was 6 inches. Load was applied at the rate of 0.10 inch/min, and defletion measured was crosshead movement. Ultimate formulation of rigid and flexible polyesters stiffened with a thixotropic filler (see text). Earlier, unsatisfactory cement formulation. b

c

e r a t e d against the p r o t o t y p e at a d i s t a n c e of 50 ft. H o w e v e r , the surface t e m p e r a t u r e o n the p r o t o t y p e s k i n at this distance w o u l d r e a c h over 200°F.

A n o n o m e t e r s w o u l d be u s e d to c l o c k the a i r speed of a s i n g l e

jet engine. T o c o o l the p r o t o t y p e s k i n a n d to s i m u l a t e c y c l o n i c c o n d i tions f u r t h e r , 750 g a l / m i n of w a t e r f r o m a h i g h s p e e d p u m p e r fighting

(fire

e q u i p m e n t ) w o u l d b e d i r e c t e d i n t o the p a t h of the jet.

F o u r tests w e r e p l a n n e d — e a c h to last at least 5 m i n u t e s ( T a b l e V ). Tests 5 a n d 6 w e r e to be f u l l jet blasts a n d w o u l d b e r u n "to d e s t r u c t . " Tests 1, 2, a n d 5 w o u l d be a i m e d at w a l l N o . 1—i.e., t h e 10 X 10 ft e n d — w h i l e tests 3, 4, a n d 6 w o u l d be a i m e d at the 10 X 20 ft side. Results N o p r e v i o u s jet tests w e r e m a d e to c h e c k o u t the l o c a t i o n of the anonometer i n r e l a t i o n to the jet blasts. I n the first test, b o t h jet engines w e r e o p e r a t i n g a l t h o u g h o n l y the use of one engine h a d b e e n p l a n n e d .



216

FILLERS

Figure 5.

Completed

AND

REINFORCEMENTS FOR

PLASTICS

prototype prior to testing at Grumman Aerospace neenng Corp., June 1972

Engi-

I n a c c u r a t e anonometer readings s h o w e d that this a p p a r a t u s w a s b e t w e e n t h e jets r a t h e r t h a n i n l i n e w i t h the blasts. W h e n the p i l o t a c c e l e r a t e d b o t h engines to get a r e a d i n g , this blast r i p p e d a w a y the v e r a n d a , the t a p e g r i d , a n d e x t e r n a l t e m p e r a t u r e gages.

T h e p u m p e r h a d not

yet

been turned on ( F i g u r e 7 ) . E x t r a p o l a t i o n of the d a t a f r o m the s p a s m o d i c r e a d i n g s o n the a n o n o m e t e r , c o u p l e d w i t h the e n g i n e profiles as t h e y r e a c h e d p e a k a c c e l e r a t i o n , p r o v i d e d a conservative estimate ( G e o r g e L u b i n a n d Peter D o n a h u e , G r u m m a n A e r o s p a c e E n g i n e e r i n g C o r p . ) t h a t b y the t i m e the w a t e r w a s

Figure

6.

Ground pZan of prototype to airport taxiways

adjacent


20.

WINFIELD

AND

Low

WINFIELD

Table V .

Cost

Planned Test Sequence and Conditions Wind


217

Housing

Test No.

Wall No.

1 2 3 4 5 6

1 1 2 2 1 2

Velocity, mph 50 100 50 100 136 136

Water Spray, gpm 750

750

—Courtesy CARE, Inc.

Figure 7.

?rototype

dunng testing at Grumman

Aerospace Corp., June

1972

released a n d the test c o m p l e t e d , the force o n the p r o t o t y p e was a p p r o x i m a t e l y 200 knots—i.e., ca. 230 m p h . T h e e x t e r n a l s k i n o n the e n d h a d b u c k l e d s l i g h t l y f r o m the heat ( 2 0 0 ° F ) b u t r e l a x e d after c o o l i n g .

Tapes

a n d gages w e r e b l o w n off a n d c o u l d n o t b e u s e d as c o n c l u s i v e e v i d e n c e . T h e i n t e r i o r a n d exterior cameras w e r e s o a k e d b y w a t e r w h i c h p e n e t r a t e d the w o o d e n w i n d o w shutters. I n t e r n a l t e m p e r a t u r e rises w e r e u n d e t e c t e d . A l t h o u g h the p r o t o t y p e v i b r a t e d f r o m this force, i t d i d not m o v e .

The

f o u n d a t i o n h e l d , a n d the house was left i n t a c t w i t h o n l y m i n o r d a m a g e to its glass fiber r e i n f o r c e d p o l y e s t e r s k i n surface.

T h e 10-ft w a l l s p a n

h a d deflected o n l y 2.3 inches o v e r a l l . T e s t N o . 1 h a d , i n effect, b e c o m e tests 5 a n d 6 ( T a b l e V I ) .

T h e other tests w e r e a n t i c l i m a c t i c a n d are

covered i n Table V I .


218

FILLERS A N D R E I N F O R C E M E N T S FOR PLASTICS

A n a d d i t i o n a l series of tests o n c o m p l e t e d panels u s i n g a n e w j o i n i n g system r e q u i r e d f o r t h e second p r o t o t y p e w a s c o n d u c t e d at the D e B e l l and Richardson Testing Institute ( H a z a r d v i l l e , C o n n . ) based o n A S T M E-72. inches

T h e s e tests s h o w e d deflection r e a d i n g s f a r i n excess of the 2.3 of deflection

noted

i n t h e s p e c t a c u l a r l y effective

but limited

G r u m m a n tests.


Table V I .

Revised Test Sequence and Conditions Wind

Test No.

Wall No.

1 2 3 4

1 2 2 2

Velocity, mph

220-230 40 115 170

Water Spray, gpm 750

750

Conclusions O n l y b y u s i n g i n e x p e n s i v e fillers as stiffeners (i.e., c a l c i u m c a r b o n a t e a n d j u t e ) w a s this project successful.

J u t e as a r e p l a c e m e n t

filler

for

glass fibers p r o v e d its effectiveness once t h e e x t e r n a l fibers w e r e r e m o v e d by double shearing a n d calendering.

J u t e - r e i n f o r c e d polyester i n s u c h

c r i t i c a l a p p l i c a t i o n s suggests m a n y potentials i n this d i r e c t i o n b u t i n d i cates t h e n e e d f o r m o r e research a n d d e v e l o p m e n t . rials d e s c r i b e d a v e r a g e d $ . 4 1 2 5 / f t

2

T h e use of t h e m a t e -

of c o m p o s i t e a n d b r o u g h t t h e c o m -

p l e t e d s t r u c t u r e to p a p e r costs w i t h i n 1 5 % of t h e $300 g o a l . T h e project f r o m i n i t i a t i o n t h r o u g h m a t e r i a l f e a s i b i l i t y studies, p r o t o t y p e d e s i g n a n d c o n s t r u c t i o n , a n d f u l l scale testing w a s a c c o m p l i s h e d i n 16 weeks. This development

u s i n g plastics m a t e r i a l s a n d i n o r g a n i c fillers i n

association w i t h i n d i g e n o u s n a t i v e r a w m a t e r i a l s m a y result i n t h e c r e a t i o n of safe, d u r a b l e , a n d e t h n i c a l l y a c c e p t a b l e

l o w cost h o u s i n g f o r

d e v e l o p i n g a n d d e v e l o p e d countries. Acknowledgments T h e authors t h a n k C A R E , I n c . , a n d p a r t i c u l a r l y L o u i s S a m i a , R a l p h Devone, H e n r y Sjaardema, Robert C o w a n , a n d W i l l i a m W o u d e n b e r g for their cooperation.

T h e y also t h a n k G e o r g e L u b i n f o r s p e c i a l t e c h n i c a l

assistance. RECEIVED October 11, 1973.


Fillers and Reinforcements for Plastics

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