46862561 mechanistic approach for fiber reinforced flexible pavements

8/12/2019 46862561 Mechanistic Approach for Fiber Reinforced Flexible Pavements

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Mechanistic Approach for Fiber Reinforced Flexible Pavements

ASEMINAR REPORT

ON

MECHANISTIC APPROACH FOR FIBER REINFORCEDFLEXIBLE PAVEMENTS

Transportation Division 1


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i

ABSTRACT

The present study investigates the benefits of reinforcing the subgrade soilsin flexible pavements. Three types of Soils A, B, and C, and one type ofpolypropylene fiber having aspect ratios of 50, !, and "00 #ere selected. TheCalifornia bearing ratio CB$ and unconfined compressive strength tests #ere

conducted on unreinforced and reinforced soils. The optimum %uantity of fibers #asdecided based on CB$, modulus of elasticity E i and failure stress. The static

triaxial tests #ere conducted on unreinforced and reinforced soils as #ell as onother pavement layers at a confining pressure of !0 &'a. These stress(strain data#ere used as input parameters for evaluating the vertical compressive strain at thetop of subgrade soils using elastoplastic finite(element analysis. This verticalcompressive strain at the top of unreinforced and reinforced subgrade soils #as used

for estimating the improvement in service life of the pavement or reduction inthic&nesses of differen t layers for the same service life due to reinforcing thesubgrade soils.



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C)*T+*TS 'age. *o

ACKNOWLEDGEMENTS iABSTRACT ii

1.0 INTRODUCTION 1

2.0 EXPERIMENTAL PROGRAM 2

2.1 MATERIAL SELECTION 2

2.2 TESTING PROGRAM 3

2.2.1 CBR TESTS 32.2.2 UNCONFINED COMPRESSION STRENGTH TESTS 4

3.0 OPTIMUM QUANTIT OF FIBERS !

4.0 FINITE"ELEMENT MODELING #

4.1 STEPS IN THE FINITE"ELEMENT METHOD $

%.0 MECHANISTIC RESPONSE MODEL 12

&.0 DIMENSIONS OF MODEL AND LOADING 13

&.1 BOUNDAR CONDITIONS 14

!.0 INPUT DATA FINITE"ELEMENT MODELING 14

#.0 BENEFITS OF REINFORCEMENT 1&

$.0 CONCLUSIONS 22

REFERENCES 23



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List of Tables 2.1.1 P'()i*+, - /- ti ) / )/i,) A B C ) 5 i6 - ) 6t )t 5( 3

2.2.1.1 CBR 7+, ) / UR R )/i,) 4

2.2.2.1 M/5 , ) / E,+)ti*it( F+i, St )) ) +65 St +i6) / 5i 6t )/i,) &

3.1 P /- ti ) / )/i,) +t O-ti8 8 i9 */6t 6t #

%.1 T'i*:6 )) / E+*' L+( / T + i* I6t 6)it( / 1%0 8)+ 12

!.1 ;+, ) / I6iti+, T+6< 6t M/5 ,ii / -+7 8 6t M+t i+,) 1.1 R i6 / * 8 6t B 6 it) i6 S 99+) B+) +65 DBM T'i*:6 )) 21

List of Figures

2.1.1 P+ ti*, )i= Di)t i9 ti/6 / )/i,) 2

2.2.2.1 T(-i*+, )t ))")t +i6 * 7 ) / )/i, A +t +)- *t +ti/ / 100 &

&.1 Fi6it " , 8 6t 5i)* ti=+ti/6 / -+7 8 6t ) *ti/6 / )/i, A 13

!.1 D 7i+t/ )t )) 7 ) ) )t +i6 * 7 ) / UR R ) 9< +5 )/i,) 1%

#.1 ;+ i+ti/6 / 7 ti*+, */8- ))i7 )t +i6 +t t/- / ) 9< +5 >it' ) 99+)

t'i*:6 )) 1!

#.2 ;+ i+ti/6 / 7 ti*+, */8- ))i7 )t +i6 +t t/- / ) 9< +5 >it' 9+) t'i*:6 )) 1$



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1.0 INTRODUCTION

T' )*+,+ti6< */)t / 8+t i+,) +65 6 it' )'/ t i9 ) i) /6

) *' +,t " 6+ti7 . R * 6t,( )(6t' ti* 8+t i+,) ,i: < /t ?ti, ) < /< i5 +65 i9 ) '+7

7/: 5 */6)i5 +9, i6t )t +8/6< 9/t' 'i 7 +9) 6* / +

> ,," 5/* 8 6t 5 5 )iit' )'/ t i9 )+-- + ) t/ '+7 t' < +t )t -/t 6ti+, / ) ** )) ,

+--,i*+ti/6 i6 t' 5 )i


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2.0 E !ERI"ENTAL !RO#RA"

2.1 "aterial Sele$tio%

T' t(- ) / )/i,) 5 t/ +) S/i,) A B +65 C i6 t'i) -+- +65 /6 t(- / i9 > ) , *t 5 /

t' P ) 6t )t 5(. T' < +i6 )i= 5i)t i9 ti/6 * 7 ) /9t+i6 5 / t' ) )/i,) + )'/>6 i6 Fi

*/8- ))i9i,it( A"& S/i, B i) )i,t / ,/> */8- ))i9i,it( A"2"4 +65 S/i, C i) )i,t( )+65 A"3.

T' -/,(- /-(, 6 i9 >it' + 5i+8 t / 0.3 88 >+) ) , *t 5 / i6 / *i6< t'

)/i,). T' i9 ) > * t i6t/ -i * ) / 1% 2% +65 30 88 , 6


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igure -."." 'article si e distribution of soils

Table2.1.1. P'()i*+, P /- ti ) / S/i,) A B +65 C U) 5 i6 P ) 6t St 5(

2.2 Testi%g !rogra&

Transportation Division !


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-.-." CB$ Tests

A )t+65+ 5 P /*t/ ) t )t >+) *+ i 5 / t /6 6 i6 / * 5 +65 i6 / * 5 )/i,) +t

5i 6t i9 */6t 6t) +65 +)- *t +ti/) t/ /9t+i6 t' 8+?i8 8 5 ( 5 6)it( MDD

+65 t' /-ti8 8 8/i)t */6t 6t OMC . T' 5 ( > i *+,* ,+t 5 )i6< t' P /*t/ ) 5 6)it( +65 t' 7/, 8 / CBR

8/ ,5. A t/t+, / 3$ )+8-, ) > t )t 5 / t' t(- ) / )/i,) +t 5i 6t i9

*/6t 6t) +65 +)- *t +ti/) + t )/+:i6< t' )+8-, ) i6 >+t / 4 5+(). It >+)

/9) 7 5 t'+t t' CBR +t % 88 - 6 t +ti/6 >+) */6)i)t 6t,( 'iit' )- *t t/ 6 i6 / * 5 )/i,) +

- ) 6t 5 i6 T+9, 2. A) 8+( 9 ) 6 t' CBR i6* +) ) ) 9)t+6ti+,,( 5 t/

i6 / * 8 6t. T' i6* +) i) ) 6)iti7 t/ 9/t' i9 */6t 6t +65 +)- *t +ti/. A,t'/ it' t' i6* +) i6 i9 */6t 6t +65 +)- *t +ti/

8i?i6< / i9 ) i6 )/i, 9 (/65 + i9 */6t 6t / 1.% >+) ?t 8 ,( 5i i* ,t +65 i6iti+,

*/6*+7it( >+) /9) 7 5 i6 t' ,/+5"- 6 t +ti/6 * 7 / +,, )- *i8 6).

Table 2.2.1.1 CBR ;+, ) / U6 i6 / * 5 +65 R i6 / * 5 S/i,)

Transportation Division #


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-.-.- /nconfined Compression Strength Tests

U6*/6 i6 5 */8- ))i/6 +65 t i+?i+, */8- ))i/6 t )t )- *i8 6) > - -+ 5

i6 + )-,it 8/ ,5 / 100 88 5i+8 t +65 200 88 ' i */65 *t 5 /6

6 i6 / * 5 +65 i6 / * 5 )/i,) +t 5i 6t i9 */6t 6t) +65 +)- *t +ti/) +65 t'

7+, ) / 8/5 , ) / ,+)ti*it( +65 +i, )t )) ) > 7+, +t 5. A t/t+, / 3$

)+8-, ) > t )t 5 +65 t' t )t 5+t+ +6+,(= 5. T' )t ))" )t +i6 * 7 ) / )/i, +

6/6,i6 + )i6* t' /6) t / ,/+5i6


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Fig. 2.2.2.1 T(-i*+, )t ))")t +i6 * 7 ) / S/i, A +t +)- *t +ti/ / 100

T' / i6iti+, */ *ti/6 >+) +--,i 5 >'i, *+,* ,+ti6< t' ,+)ti*



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8/5 , ) / )/i,) i6 / * 5 >it' i9 */6t 6t ?* 5i6< 1.% . T' +i, )t )) +65

*/ )-/65i6< )t +i6 > / 65 t/ i8- /7 >it' i6* +) i6 i9 */6t 6t. T' 7+, )

/ 8/5 , ) / ,+)ti*it( E i) +i, )t )) 1 +65 */ )-/65i6< )t +i6) f )/9) 7 5

i6 t' *+) / 6 i6 / * 5 +65 i6 / * 5 )/i,) + - ) 6t 5 i6 T+9, 2.2.2.1 /

5i 6t i9 */6t 6t) +65 +)- *t +ti/). A */8-+ i)/6 / T+9, ) 2.2.1.1 +65 2.2.2.1

i65i*+t ) t'+t E i 7+, ) + 6/t +) ) 6)iti7 t/ i9 i6 / * 8 6t +) t' CBR 7+, ).

T'i) i) +tt i9 t 5 t/ t' 6+t / t' t>/ t )t). T' CBR i) + - 6 t +ti/6 t )t +65 +6

i65i *t 8 +) / )' + )t 6


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'.0 O!TI"U" (UANTIT) OF FIBERS

O-ti8 8 +6tit( / i9 ) >+) 5 t 8i6 5 9+) 5 /6 CBR 7+, 8/5 , ) /

,+)ti*it( Ei) +65 t' +i, )t )) 1 / i9 " i6 / * 5 )/i,) +) ?-,+i6 5

+ ,i . A,t'/ it' +6 +)- *t +ti/ / #4 >+) / 65 t/ 9 /-ti8 8 / S/i, C. T' CBR /

S/i,) A B +65 C > / 65 t/ 9 1.1& 1.$% +65 &.20 )- *ti7 ,(. T' ) 7+, )

i6* +) 5 t/ 4.33 &.42 +65 1#.03 )- *ti7 ,( 5 t/ i6 / *i6< t' )/i, +t /-ti8 8i9 */6t 6t.

T' -+ +8 t ) ,i: 8/5 , ) / ,+)ti*it( +65 +i, )t )) > ) 5 +) + ) */65

@ 5


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Table 3.1. Properties of Soils at Optimum Fiber Content

*.0 FINITE+ELE"ENT "ODELIN#

A t>/"5i8 6)i/6+, 2D +?i)(8 t i* ,+)t/-,+)ti* i6it " , 8 6t+6+,()i) / t'

8 *'+6i)ti* -+7 8 6t 8/5 , )ti6< /6 6 i6 / * 5 +65 i6 / * 5 ) 9< +5 )/i,)

>+) *+ i 5 / t 9( )i6< ANS S )/ t>+ i6 / 5 t/ +6ti ( t' 9 6 it) /

i6 / * 8 6t. T' 7+, ) / 5 / 8+ti/6) )t +i6) +65 t' )t )) +t t' t/- / ) 9< +5

> *+-t 5 /8 +*' */8- t 6. A,)/ + -+ +8 t i* )t 5( >+) *+ i 5 / t t/

i67 )ti


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!." Steps 0n The ,inite +lement 1ethod

1. 2iscreti ation 3 The structure is divided into no. of elements 4and the no. of

nodes I5 +,i=+ti/6 / t' )t *t / +6+,()i) C'//) t(- / , 8 6t 6 89 / 6/5 ) / , 8 6t) 5 < / 5/8

- 6/5

F/ t' 5i8 6)i/6+, +6+,()i) )'+- ) / t' , 8 6t) + 9 i*: /t t +' 5 /6

F/ t' 5i8 6)i/6+, +6+,()i) )'+- ) / t' , 8 6t) +

F/ -,+t 9 65i6< - /9, 8)P,+t , 8 6t) )'/ ,5 9 ) 5

Transportation Division

#"6/5 5 9 i*:

, 8 6t

-(d elements

14


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F/ )' ,, +6+,()i) )' ,, , 8 6t )'/ ,5 9 ) 5

2. 2etermine the element characteristics 3 Sti 6 )) 8+t i? / t' , 8 6t E i7+, 6t 6/5+, / * 7 *t/ )

a .A)) 8 7+ i+ti/6 / 5i)-,+* 8 6t >it' i6 t' , 8 6t i6 t 8) / 6/5+,5i)-,+* 8 6t)It 8 +6) t' 5i)-,+* 8 6t) +6( >' i6 t' , 8 6t i) 5i *t,( 5 - 65) /6 6/5+,5i)-,+* 8 6t) /6,(

I6 8+t i? / 86f78 9*: 6;7 4"

6f78; *t/ / t' 5i)-,+* 8 6t) >it' i6 t' , 8 6t6;78; *t/ / t' 6/5+, 5i)-,+* 8 6t) >it' i6 t' , 8 6t9*:8S'+- 6*ti/6 8+t i?

b. > it t' )t ))")t +i6 ,+ti/6)'i-6


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9B: T8t +6)-/) / 9J 8+t i?

9?:6;78 6,7 45

4 . A--,( 9/ 65+ ( */65iti/6) t/ t'


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,.0 "EC-ANISTIC RES!ONSE "ODEL

T' -+7 8 6t ) *ti/6 >+) 8/5 , 5 +) +6 +?i)(88 t i* )/,i5 t/ /9t+i6

8 *'+6i)ti*+,,( t' ,+( 5 -+7 8 6t )-/6) 5 t/ t + i* ,/+5i6< +65 t/

i67 )ti


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.0 DI"ENSIONS OF "ODEL AND LOADIN#

Di8 6)i/6) / i6it , 8 6t )'/ ,5 9 ) i*i 6t,( ,+ < )/ t'+t */6)t +i6t)

i8-/) 5 +t t' 9/ 65+ i ) '+7 7 ( ,itt, i6 , 6* /6 t' )t )) 5i)t i9 ti/6 i6 t'

)()t 8.

I6 t' - ) 6t )t 5( t' i'i*' i) 8/ t'+6 ) 7 6 ti8 ) t' +5i ) /

t' +--,i 5 ,/+5 / 1%0 88. Eii,, 9 *+ ) 5 9( + )i6' , ,/+5 / 40.# :N

4 0#0 :< .

Transportation Division 1#


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Fig.6.1. Fi6it " , 8 6t 5i)* ti=+ti/6 / -+7 8 6t ) *ti/6 / S/i, A

K

.1 Bou%/ar Co%/itio%s

F/ +--,i*+ti/6 / + i6it " , 8 6t 8/5 , i6 t' -+7 8 6t +6+,()i) + i7 ",+( 5

)()t 8 / i6 i6it ?t 6t '+) 9 6 5 * 5 t/ + )()t 8 '+7i6< i6it 5i8 6)i/6).

Fi< &.1 )'/>) + t(-i*+, 2D +?i)(88 t i* i6it " , 8 6t 8/5 , / t' -+7 8 6t

)ti6< /6 ) 9< +5 S/i, A. R/,, ) --/ t) > - /7i5 5 +,/6< t' +?i) / )(88 t (

t/ +*'i 7 t' */65iti/6 t'+t 9/t' t' )' + )t )) ) +65 +5i+, 5i)-,+* 8 6t) + +,t/ = /. Si8i,+ ,( t' /,, ) -" -/ t) > - /7i5 5 +,/6< t' i


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.0 IN!UT DATA FOR FINITE+ELE"ENT "ODELIN#

T' i6it " , 8 6t FE +6+,()i) / t' -+7 8 6t )()t 8 >+) *+ i 5 / t 9(

)i6< t' )t+65+ 5 -+*:+< ANS S 8-,/(i6< t' 8 ,ti,i6 + "i)/t /-i* ,+)t/"-,+)ti*

'+ 5 6i6< 8/5 , >'i*' 5 i6 )t' */6)tit ti7 ,+ti/6)'i- / t' 8+t i+,) i67/,7 5.

P /- ti ) / 5i 6t ,+( ) i 5 / *+ (i6< / t t' FE +6+,()i) + t'

8/5 , ) / ,+)ti*it( P/i))/6 +ti/ +65 t' )t ))")t +i6 5+t+. It )'/ ,5 9 6/t 5 t'+t t'

i6iti+, t+6< 6t 8/5 , ) i) 6 5 5 /6,( t/ i6iti+,i= t' it +ti7 - /* 5 +65 +*t +,

* 8 ,+ti7 )t ))" )t +i6 5+t+ < 6 +t 5 - t/ t' 65 / + -+ ti* ,+ ,/+5 i6* 8 6t +

) 5 i6 t' +6+,()i) / t' ) 9) 6t ,/+5 i6* 8 6t. C'+65 + +65 M '65i +tt+ 2002-/ t 5 t'+t */6 i6 8 6t i6 t' -+7 8 6t 5 t/ )'/ ,5 ) +65 ) / 65i6< )/i,) i) i6

t' +6< / 2& 40 :P+. H 6* t i+?i+, t )t) > */65 *t 5 /6 6 i6 / * 5 +65

i6 / * 5 ) 9< +5 )/i,) +) > ,, +) /t' -+7 8 6t ,+( ) +t + */6 i6i6< - )) / 40

:P+. Fi */65 *t 5 /6 +,, t' ) -+7 8 6t ,+( 8+t i+,) +t

+ */6 i6i6< - )) / 40 :P+. T' 7+, ) / i6iti+, t+6< 6t 8/5 , ) / +,, t'

-+7 8 6t ,+( ) > )ti8+t 5 i6 t' )+8 8+66 +) ?-,+i6 5 / ) 9< +5 )/i,) +65

+ - ) 6t 5 i6 T+9, !.1 +,/6< >it' t' 7+, ) / P/i))/6 ) +ti/ +)) 8 5 /

5i 6t ,+( 8+t i+,).



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Figure. 7.1. D 7i+t/ )t )) 7 ) ) +?i+, )t +i6 * 7 ) / 6 i6 / * 5 +65 i6 / * 5 ) 9< +5 )/i,) +t*/6 i6i6< - )) / 40 :P+

Table 7.1. Values of Initial Tangent Modulii for Pa ement Materials



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.0 BENEFITS OF REINFORCE"ENT

A 8 *'+6i)ti*" 8-i i*+, 5 )i)

1. T' )+8 ) 7i* ,i / t' i6 / * 5 +65 6 i6 / * 5 -+7 8 6t ) *ti/6). It

>/ ,5 , +5 t/ 5 *ti/6 i6 ) 99+) 9+) / DBM t'i*:6 )) +65 '+) 9 6 ?- )) 5

i6 t 8) / LTR +65

2. T' )+8 -+7 8 6t ) *ti/6) / 6 i6 / * 5 +65 i6 / * 5 ) 9< +5 . It >/ ,5

) ,t i6 8/ ) 7i* ,i / t' -+7 8 6t 5 t/ i9 i6 / * 8 6t +65 '+) 9 6

?- )) 5 i6 t 8) / TBR.

St *t +, +i, ) i6 + , ?i9, -+7 8 6t + / t>/ t(- ) 6+8 ,( ) +*

* +*:i6< +65 tti6


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* it i/6. T' IRC 3!"2001 */6)i5 ) + t 5 -t' / 20 88 t/ 9 + +i, * it i/6

/ , ?i9, -+7 8 6t +65 t' tti6< i6 E . & i) ) 5

Fig . 8.1. Variation of ertical compressi e strain at top of subgrade !it" subbaset"ic#ness

&

>' N 20 6 89 / * 8 ,+ti7 )t+65+ 5 +?, ) t/ - /5 * + tti6< / 20 88

+65 v 7 ti*+, */8- ))i7 )t +i6 +t t/- / ) 9< +5 .

; ti*+, */8- ))i7 )t +i6 5 7 ,/- 5 +t t' t/- / 6 i6 / * 5 +65 i6 / * 5

) 9< +5 ) >+) *+-t 5 / 5i 6t t'i*:" 6 )) ) / ) 99+) 9+) +65 DBM. F/



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S/i,) A +65 B t'i*:6 )) / t' 9+) */ ) / 2%0 88 +65 DBM t'i*:6 )) / 200

88 > 8+i6t+i6 5 */6)t+6t +65 t' ) 99+) t'i*:6 )) >+) 7+ i 5. A+) 7+ i 5 / + */6)t+6t ) 99+) / &10 88 +65

9+) t'i*:6 )) / 2%0 88. T' 7 ti*+, */8- ))i7 )t +i6) 5 7 ,/- 5 +t t' t/- /

t' ) 9< +5 i6 6 i6 / * 5 +65 i6 / * 5 -+7 8 6t ) *ti/6) > 7+, +t 5 /

+,, t' ) +,t 6+ti7 ) /8 ,+)t/"-,+)ti* i6it " , 8 6t +6+,()i). A )i8i,+ ? *i) >+)

+,)/ 5/6 / S/i, C. Fiit' ) 99+) 9+) +65 / ) 9< +5 S/i,) A +65 B

)- *ti7 ,(. T' ) -,/t) > ) 5 t/ )t 5( t' 9 6 it) / i6 / *i6< t'

) 9< +5 )/i,) i6 t 8) / LTR +65 TBR. T' TBR itt 6 i6 t'+ti/6 / 8 +)

!

>' N 6 89 / t + i* -+)) ) i 5 / - /5 *i6< + -+7 8 6t ) +*

5 / 8+ti/6 tti6< - t/ t' +,,/>+9, t 5 -t' +65 ?- )) 5 i6 88 +65 R +65

U 5 6/t i6 / * 5 +65 6 i6 / * 5 -+7 8 6t ) *ti/6).



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Fig. 8.2. Variation of ertical compressi e strain at top of subgrade!it" base t"ic#ness

Per#ins and Edens $%&&%$ e aluated t"e benefits of

reinforcement in terms of 'T( for t"e e)ui alent ser ice life of t"e

pa ement *

It can be defined as

+ -

DU +65 D R 9+) */ ) t'i*:6 )) ) / 6 i6 / * 5 +65 i6 / * 5 -+7 8 6t

) *ti/6). A) 6/ ) -+ +t +ti/6 i) +7+i,+9, i6 t' ,it +t t/ ,+t t' 7 ti*+,

*/8- ))i7 )t +i6 +t t' t/- / t' i6 / * 5 ) 9< +5 t/ t' 6 89 / ,/+5

- titi/6) 6 * ))+ ( t/ - /5 * t' +,,/>+9, tti6< E .# > ) 5 / 9/t'

6 i6 / * 5 +65 i6 / * 5 ) 9< +5 .

Transportation Division 2%


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U)i6< E ). # +65 $ t' 9 6 it) / i9 i6 / * 5 ) 9" < +5 )/i,) i6 t 8) /

?t 6)i/6 i6 ) 7i* ,i / + , ?i9, -+7 8 6t *+6 9 ?- )) 5 +)

$

T' 7 ti*+, */8- ))i7 )t +i6 v +t t' t/- / t' ) 9< +5 *+6 9 /9t+i6 5

t' / / /t' t(- ) / )/i,). R ) ,t)

/9t+i6 5 /8 ) *' + )t 5( + ) 88+ i= 5 i6 T+9, #.1.

Transportation Division 2&


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T' ) ) ,t) )'/> t'+t / + */6)t+6t t'i*:" 6 )) / 9+) +65 DBM t'

t'i*:6 )) / t' ) 99+) 5 * ) 9( 3#.%2 2&.23 +65 1&.&! )- *ti7 ,( / S/i,) A

B +65 C / +,8/)t t' )+8 ) 7i* ,i / i6 / * 5 +65 6 i6 / * 5 -+7 8 6t).

Si8i,+ /-ti/6) *+6 +,)/ 9 ? *i) 5 / 9+) +65 DBM. T' / t' , ?i9,

-+7 8 6t *+6 9 5 )i


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3.0 CONCLUSIONS

T>/ i8-/ t+6t +)- *t) '+7 9 6 i67 )ti'i*'


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REFERENCES

S+ti)' C'+65 + M.N. ;i,+5:+ +65 P +)'+6t P.N+< +, Mechanistic Approach

for Fiber Reinforced Flexible Pavements ! Q/ 6+, O T +6)-/ t+ti/6

E6


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46862561 mechanistic approach for fiber reinforced flexible pavements

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