1. basics of pavement, mmh

8/16/2019 1. Basics of Pavement, MMH

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PAVEMENT

Defnition: The pa'ement is a structure hich separates the tires of'ehices from the underyin% foundation materia. Foundationmateria is %eneray the soi or structura concrete or stee "rid%edec-. &a'ements o'er soi are mutiayer construction ithreati'ey ea- materia "eo and pro%ressi'ey stron%er onea"o'e.

&a'ement shoud "e STRONG enou%h to resist the stresses inducedupon them and THICK enou%h to distri"ute the e!terna oads onearthen su"%rade, so that the su"%rade can safey "ear the stress.



T&PES OF PAVEMENT

There are four types of pa'ement. They are

/. Fe!i"e pa'ement0. $i%id &a'ement2. Semi:ri%id &a'ement3. Composite &a'ement

'( F!e)i!e "a$e%ent:. This is a ayered system hich has o ;e!ura stren%th.. E!terna oads are ar%ey transmitted to the su"%rade "y atera

distri"ution ith increasin% depth.. &a'ement de;ects momentariy on the appication of oads, "ut

re"ounds to its ori%ina e'e upon remo'a of oad.. Stron% su"%rade is 'ery important for the dura"iity of ;e!i"e

pa'ement.. &erformance of ;e!i"e pa'ement is %o'erned "y the deformation

su<ered "y the su"%rade.



T&PES OF PAVEMENT

*( Ri+i, Pa$e%ent:

+t ithstands the oad from ;e!ura stren%th or "eam stren%th. &ermits the sa" to "rid%e o'er minor irre%uarities of the

su"%rade. &erformance of ri%id pa'ement depends ar%ey on the stren%th of

the sa".

-( Se%i.ri+i, Pa$e%ent: Has much oer ;e!ura stren%th compared to ri%id pa'ement. Aso deri'es support "y atera distri"ution of oads as in ;e!i"e

pa'ement. E!ampe Lean:concrete "ase, soi:cement and ime:pu==aona

concrete construction.

( Co%"osite Pa$e%ent: Consists of mutipe structuray si%nicant ayers, sometimes of

hetero%eneous composition. E!ampe >ric- sandich concrete pa'ement.

(Our concern will be fexible and rigid pavement)



0A&ERS OF PAVEMENT

F!e)i!e Pa$e%ent Ri+i, Pa$e%ent

Sur#acin+ 12earin+ course3

4 ase course5

Concrete Sa" (upper sa" ?

oer sa"*

6ase Su":"ase (upper su":"ase ?oer su":"ase*

Su.ase Su"%rade

Su+ra,e



F0E9I60E RIGID PAVEMENT 1GENERA05

F!e)i!e Pa$e%ent:

/. &ermanent deformation occurs as the tra1c oad is appied. +n e:

desi%ned pa'ement this deformation is e'eny distri"uted amon% the

di<erent ayers of pa'ement

0. Bertica compressi'e stress is induced in a the ayers. earin% course,

"indin% course and any "ituminous "ase materia i aso "e su"ected

to tensie stress.

2. Biscosity of the "ituminous materia increases ith time. This increases

the sti<ness of "ituminous materia and reduces the stresses de'eoped.

3. Structura faiure i %eneray "e initiated "y fati%ue crac-in% of the

surface course.

Ri+i, Pa$e%ent:

/. ot suscepti"e to surface deformation under tra1c oad.

0. Load is distri"uted "y "eam action of sa".

2. Structura deterioration is indicated "y crac-in%.

3. hee oad %i'es rise to tensie stress in the underside of the sa" hich

in under:desi%ned pa'ement %i'es rise to fati%ue crac-in%.



COMPARISON 6ET;EEN F0E9I60E RIGID PAVEMENT

'( Desi+n Precision: $i%id pa'ement can "e desi%ned more precisey than;e!i"e pa'ement. >ecause anaysis of stresses in ri%id pa'ement is "ased

on "eam action;e!ura stren%th hich is "etter understood. >ut anaysis of;e!i"e pa'ement is compicated and desi%n is mosty "ased on empiricareations.

*( 0i#e.c8c!e: $i%id pa'ement has hi%her ife than ;e!i"e pa'ement. e:desi%ned ri%id pa'ement ith proper maintenance can ast upto 3 to 4years. Hi%hest ife e!pectancy of a ;e!i"e pa'ement is / to 0 years.

-( Maintenance: The ony maintenance needed for cement:concretepa'ement is the maintenance of oints. Continuousy $einforced Concrete&a'ement has no oints, therefore needs no maintenance. Gn the otherhand ;e!i"e pa'ements need maintenance for

Seain% crac-s

Treatin% pothoes

resurfacin%

$eseain%

( Initia! Cost: +nitia cost is hi%her for ri%id pa'ementthan ;e!i"e pa'ement.



COMPARISON 6ET;EEN F0E9I60E RIGID PAVEMENT1CONT(5<( Sta+e Construction: Sta%e construction can "e done for ;e!i"e

pa'ement. +t is not appica"e for ri%id pa'ement.

=( A$ai!ai!it8 o# Materia!s: Depends on the country.

>( Sur#ace C?aracteristics: Concrete pa'ement has %ood surfacecharacteristics as it is free from ruttin%, pothoes and corru%ation. +n ;e!i"epa'ement ony asphatic concrete %i'es %ood ridin% 5uaity. Durin%construction ri%id pa'ement needs specia consideration for ensurin% s-idresistance.

@( Penetration o# ;ater: ater may penetrate throu%h the oer ayers inri%id pa'ement throu%h the oints. Mud:pumpin% or pumpin% can occur inri%id pa'ement if ater %et to the "ase ayer. +f propery maintained this can"e a'oided. +n ;e!i"e pa'ement some ater i aays penetrate to theoer ayers as it is not imper'ious. Crac-s and pors are o"'ious in ;e!i"epa'ement. &othoes are created in ;e!i"e pa'ement.

( TraBc ,is!ocation ,urin+ construction: $i%id pa'ement cannot "e madeopen for tra1c "efore at east 08 days after construction. >ituminouspa'ement can "e opened for tra1c shorty the na roin% is done.

'(En$iron%enta! Consi,eration: >ituminous pa'ement construction isha=ardous to en'ironment than ri%id pa'ements.

**Discuss the suitabilit o fexible and ri id avement or road construction in



FACTORS AFFECTING THE PERFORMANCE OF PAVEMENT

TraBc oadin% ma%nitude, con%uration and the num"er of oad repetitions

"y hea'y 'ehices.

Moisture: Moisture can enter the pa'ement structure throu%h crac-s and

hoes in the surface, ateray throu%h the su"%rade, and from the underyin%

ater ta"e throu%h capiary action. Conse5uences are u"rication of

partices, oss of partice interoc- and su"se5uent partice dispacement

resutin% in pa'ement faiure.

Su+ra,e: For too ea- Su"%rade, the pa'ement i ;e! e!cessi'ey hich

utimatey causes the pa'ement to fai. +f natura 'ariations in the

composition of the su"%rade are not ade5uatey addressed "y the pa'ement

desi%n, si%nicant di<erences in pa'ement performance i "e e!perienced.

Construction ua!it8: +mproper compaction, improper moisture conditions

durin% construction, 5uaity of materias, and accurate ayer thic-ness (after

compaction* a directy a<ect the performance of a pa'ement.

Maintenance: o matter ho e the pa'ement is "uit, it i deteriorate

o'er time "ased upon the mentioned factors. The timin% of maintenance is

'ery important,.



FACTORS AFFECTING THE PAVEMENT DESIGN

( C!i%atic Factors:$ainfa

Frost Temperature

<( Roa, Geo%etr8:

Hori=onta Cur'es

Bertica &roe

=( Su+ra,e Stren+t? an, Draina+e

Su"%rade type and compacted density

Surface and Su"surface Draina%e property

>( Materia! Pro"erties #or Structura! Desi+n:

C>$ (Caifornia >earin% $atio* 'aue for ;e!i"e pa'ement

Moduus of Su"%rade $eaction(-* for $i%id pa'ement



IMPORTANT TERMS AND DEFINITIONS

TraBc 0oa, 1ESA05

E5ui'aent Standard A!e Load that is /8 -ip8 I.Barious tra1c oads are con'erted to ESAL.

This is to ha'e a common %round on the Desi%n method.

oncept o !"# (!oad "$uivalency #actor)%Di<erent for Di<erent A!e (&able ' + ',- right + Dixon)

)enerai=ed forth poer a

Sin%e Tandem Tridem



IMPORTANT TERMS AND DEFINITIONS 1CONT(5

TraBc Ana!8sis:

&redictin% Future Demand

T J E!pected Tra1c Durin% Desi%n &eriodr J tra1c %roth rate. J Desi%n &eriod T/ J Tra1c 'oume durin% /st year.

**"xample ''. '- (right + Dixon)

1

(1 ) 1][

n

r T T

r

+ −=




Re!iai!it8 1R5

+ncorporates a de%ree of certainty into desi%n process.

Ensures 'arious desi%n aternati'es i ast the anaysis period.

KFor e!ampe, a desi%ner may specify that there shoud ony "e a 4 chance that the desi%n does not ast a specied num"er of years (e.%.,

0 years*. This is the same as statin% that there shoud "e a 94 chance that the desi%n does ast the specied num"er of years (e.%., 0years*. Then, the reia"iity is 94 (/ 4 *N

For a %i'en reia"iity e'e, $ is function of Standard De'iation S.

S J .34 for Fe!i"e pa'ement # .24 for $i%id pa'ement

9(AASHTG*.




Ser$iceai!it8 Conce"t:

+s estimated "y &resent Ser'icea"iity +nde! 1PSI5(

>ased on data on the roads on%itudina rou%hness, patch or-, ruttin% andcrac-in%.

SV = mean of the slope variance in the two

wheel paths (measured with the CHLO profilo!

meter or "#$ $ou%hometer)

C = total linear feet of Class & and Class ' cracs

per 1 ft* of pavement area+

# = #atchin%, e-pressed in terms of ft* per 1

ft* of pavement surfacin%+

(don/t hurt yoursel)

0rticle ''' or detail- right + Dixon

( ).+'1 1+/) lo% 1 )+0 PSI SV C P = − + − +




Mo,u!us o# Su+ra,e Reaction 15:• Determined from oadin% test on a circuar pate of 2O dia.• - J Load, & deformation,

•

Fied test, e!pensi'e # time consumin%.• Estimation "ased on C>$ etc. tests (Fi%ure 7.26, Huan%, 03*

E!astic Mo,u!us 1E or K '3 K * etc(5:• Measure of soi sti<ness.• Dened as the ratio of the stress aon% an a!is o'er the

strain aon% that a!is in the ran%e of eastic soi "eha'ior.• often used for estimation of soi settement and eastic

deformation anaysis.• Used for desi%n of "ase, su":"ase ayers.



Re#erences:

$i%ht, &. H. and Di!on, I. Hi%hay En%ineerin%. 7th Edition.02

Huan%, P. &a'ement Anaysis and Desi%n. 0nd Edition. /992.

1. basics of pavement, mmh

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