2.5 Details of Asphalt Institute Method of Design of Flexible Pavements.pptx

2.5 Details of Asphalt Institute Method of Design of Flexible Pavements •

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Historical Development of AI Method 1956 – 1969  1st to 8th Editions – Empirical Approach 1970  Revised 8th Edition - Empirical Approach 

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Thickness Design – Full Depth Asphalt Pavement Structures for Highways and Streets, The Asphalt nstitute, !anual Series "# $!S"#% ther !ersions

1981

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1991

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1999

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2001

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2008

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 9th Edition, M-E Approach

 Revised 9th Edition  9th Edition, Reprint

 Revised 9th Edition  Revised 9th Edition

Thickness Design – Asphalt Pavement for Highways and Streets, The Asphalt nstitute, !anual Series "# $!S"#%

"#$% and &arlier &ditions

"#'" and (ater &ditions

"#$% and &arlier &ditions

"#'" and (ater &ditions

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A Method is .sed to desi%n asphalt pavements composed o/ vario.s com"inations o/&

a asphalt asphalt concr concrete ete s.r/ace s.r/ace and and "ase "ase " Em.lsie Em.lsied d asphalt asphalt s.r/ace s.r/ace and and "ase "ase c 3ntreate 3ntreated d a%%r a%%re%at e%ate e "ase "ase and and s."-"a s."-"ase4 se4 &mulsi)ed asphalt is simply a suspension of small asphalt cement glo&ules in water, water, which is assisted &y an emulsifying agent $such as soap%' The emulsifying agent assists &y imparting an electrical charge to the surface of the asphalt cement glo&ules so that they do not com&ine $(o&erts et al', #))*%'

Design Principles •

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#avement is re%arded as M*(+I,(A-&&D &(A/+I0 /-/+&M 4 $esi%n #roced.re is "ased on Esta"lished heor', E!perience, est $ata and a omp.ter #ro%ram $AMA ere .sed to develop a comprehensive pavement desi%n proced.re4 Materials in each la'er are characteried "' Mod.l.s o/ Elasticit', E and #oisson:s Ratio, ;4  raa'ers

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.ll ontin.it' =.ll riction is Ass.med at the "o.ndaries "eteen each o/ the

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 nnite in oriontal $irections4

Design 0riteria •

oriontal ensile ?train, C t  on the 3nderside o/ the >oest Asphalt Do.nd >a'er sho.ld "e ithin the #ermissi"le @al.e4 / the ?train is E!cessive  rac*in% o/ the reated >a'er  ati%.e ail.re Bcc.rs 

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@ertical ompressive ?train, C c  at the ?.r/ace o/ the ?."%rade >a'er sho.ld "e s.ch that E!cessive #ermanent $e/ormation =R.ttin% sho.ld not a*e a*e #lace d.e to Bverloadin%4 Bverload in%4

Fatigue 0riterion4 Fatigue 0rac6ing  he eF.ation /or /ati%.e criterion is&

f  7 %.%$#89:t;,.2#"9&;,%.'5< Ghere, H/  I alloa"le no4 o/ repetitions o/ standard a!le load to control /ati%.e crac*in% •

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Jt I horiontal tensile strain at the "ottom o/ the asphalt la'er4

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E I d'namic mod.l.s o/ the asphalt mi!t.re

 he eF.ation /or limitin% the pavement de/ormation is&

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d 7 ".85 x "%,# 9:c;,ase +ra=c &/A(

+ra=c 0ondition

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>i%ht tra9?; =in M#a I 104 ! 5 I 5".5 MPa  or  7 ".5< x &A( and Mr 7 5".5 MPaB /rom the %iven desi%n chart, Full Depth of Asphalt 0oncrete Ho, adopt

7 25% mm

 Ho, EF.ivalent thic*ness o/ em.lsied sta"ilied "ase co.rse,  t & •

I ! I ! 200 I 2554  mm 3se "