Preliminary study for implementations of long lasting flexible road pavements in Romania

Transcription

1 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Peliminay study fo implementations of long lasting flexible oad pavements in Romania ADREI RADU, IOA TAASELE, ELEA PUSLAU,, Faculty of Civil Engineeing, Technical Univesity Gh. Asachi Iasi, Bvd. Dimitie Mangeon, Iasi ROMAIA Abstact: - The actual flexible pavements designed accoding the existing noms ae leading usually to ovedesigned stuctues because of the lowe values fo the elastic modulus of the asphalt mateials, specified in the existing noms. Afte a shot intoduction, pesenting the geneal pinciples of flexible pavements design, the concepts of long lasting flexible pavements is consideed in detail. Then a new eseach pogam, involving Acceleating Loading Test-ALT undetaken in paallel with the expeiments development on the existing oad netwok, is poposed to the attention of the oad policy decisions factos in this county. This eseach poject, suppoted by specific design assumptions and calculations is taking into consideations the specific soil, climatic and taffic conditions of the oad netwok in Romania. Finally a discussion of the esults obtained with this new study is made. Key-Wods: - Long lasting flexible pavements, acceleating loading test - ALT, stuctual design, design methods, design taffic. Intoduction As a new membe of Euopean Community, Romania is making significant effots to integate his tanspot infastuctue in the huge Euopean oad netwok. These effots ae focusing on ehabilitation and modeniation of the existing oad netwok and its development by using new moden and efficient methods fo stuctual design in paallel with the implementation of new constuction technologies. Ou eseach is dedicated mainly to the assimilation and the development, in the specific taffic and climatic conditions of Romania chaacteied by vey sevee wintes and vey hot summes, of the new concept of long lasting pavements, especially fo the constuctions of the new oads and motoways. The actual flexible pavements designed accoding the existing noms [] ae usually leading to ovedesigned stuctues because of the lowe values fo the elastic module of the asphalt mateials specified in the existing noms. The total thickness of classical pavement stuctues, cuently used fo impotant motoway pojects in this county, is cuently eaching significant values anging fom 7 to 9 cm. In compaison with these taditional pactices the long lasting flexible pavements LLFP, conceived on new pinciples and involving the use of high quality mateials such as stone matix asphalt SMA [] ae leading to thinne and in the same time moe duable pavements. Hee follows some typical example of LLFP stuctues envisaged to be studied on the Acceleating Testing Facility ALT-LIRA [] existing in the fame of Technical Univesity Gh. Asachi Iasi (see Fig.). Fig. The ALT cicula tack facility of Technical Univesity Gh. Asachi Iasi [] In ode to evaluate the pefomance of these new long lasting flexible pavements, in compaison with the classical ones, the following expeiment (see Fig.) involving the acceleating testing of a set of six distinct pavement sectos, including thee witness classical ones (secto o., o. & o.) and othe thee LLFP sectos (o., o. & o.) constucted in accodance with the new LLFP concept which is envisaged to be ealied in the nea futue on the ALT-LIRA facility. Taffic of 0 and 0 million standad axle loads of k have been consideed in the design of the new ISS: Issue 9, Volume, Septembe 00

2 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET LLFP and also of the witness secto o., with the diffeence that the design life of the LLFP stuctues was consideed of 0 yeas instead of yeas, used fo the taditional stuctue. - Classical pavement stuctue cuently used o. - The new long lasting pavements LLP o. - Classical pavement stuctue cuently used o. - The new long lasting pavements LLP o. - Classical pavement stuctue cuently used o. - The new long lasting pavements LLP o. Fig. Expeimental sectos envisaged to be tested on the ALT cicula tack facility Fo long lasting pavements to be viable, they must pefom fom the pespectives of both engineeing and economic consideation. Designing against stuctual defects, pope mateials selection, good constuction pactices, and scheduling esufacing activities to maintain the functionality of the pavement ae the pimay engineeing concens fo pefomance []. Efficient design, low maintenance ehabilitation costs, and long pavement life will ensue the economy of the pavement. In accodance with long lasting pavement concept, it is necessay to peiodically monito the pavement condition to identify suface distesses and to ensue they do not futhe pogess into the stuctue than the top few cm of the pavement. Thus, distesses such as top-down fatigue cacking, themal cacking, utting, and suface wea can be confined only to the weaing couse by timely esufacing. Thee ae a numbe of case histoies [] that suppot the idea that thick, well-constucted asphalt pavements have distesses extending no deepe than thei sufaces. The futue wok involves the constuction of the envisaged expeimental sectos on the cicula tack of the ALT facility of Technical Univesity of Iasi, paallel with the constuction of simila expeimental sectos on a eal motoway selected on the existing public oad netwok, followed by monitoing thei pefomances in time and the dafting of specific technical ecommendations fo the design and constuctions of LLFP. Stuctual design of flexible pavements In this study two types of pavement stuctue have been consideed, a classical one and a Long Lasting Flexible Pavement conceived accoding the pincipals mentioned above. This design study has been conducted accoding the Romanian nom PD 77/00 which is based on simultaneously obsevance of the following citeia: the admissible tensile stain at the bottom of the bituminous layes; the admissible compession stain at the subgade level; the admissible tensile stain at the bottom of the laye of natual aggegates stabilied with hydaulic o poolan bindes This analytical design method involves the establishing of a specific oad pavement stuctue and veification of the loading conditions of pavement, unde the design taffic and also fost veifications. The following input data ae necessay fo the design: stuctue and intensity of taffic and thei evolution; the geotechnical chaacteistics of the subgade; the hydological egime of the oad pavement (type of coss section, the way of ainfall wates dainage, possibilities of dainage, level of gound wate).. Conception and design of classical/witness ALT sectos The expeimental oad secto envisaged fo study was consideed to be located in a climatic egion type I, having coss sections in embankment with a maximum height of.00 m, the subgade soil being a P type accoding []. In this hypothesis, and consideing thee categoies of design taffic expessed in million standad axles (m.s.a.), namely: 0, 0 and espectively 0 m.s.a., the following pavement stuctues have been studied: a) Classical pavement cuently used Type (Design taffic: 0 m.s.a.) Table. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Weaing couse (MASF /SMA) 000* 0,* Binde couse (B.A.D. ) 00* 0,* Bituminous base - AB 000* 0,* Ballast stabilied with cement 0 000** 0,** Ballast Foundation *** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..; ** Item..; *** Item..; Design pogam to compute stesses and stains in pavement stuctue Caldeom 000 Secto - Input paametes: Load... Pessue tie Radius cicle 7.0 k 0. MPa 7. cm Laye : Module 9. MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness.0 cm ISS: Issue 9, Volume, Septembe 00

3 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Laye : Module 000. MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module 9. MPa, Poisson Coeff..70, Thickness.0 cm Laye : Module 80. MPa, Poisson Coeff..0 it is semifinit - Classical pavement stuctue cuently used o. REZULTS: R Z Radial effot Radial defom. Vetical defom. cm cm MPa micodef micodef E+00.90E E E-0.90E+0 -.E E+00.88E+0 -.8E E-0.88E+0 -.9E E-0.78E+0 -.E E-0.78E E+0 Weaing couse - MASF Binde couse - BAD Bituminouse base - AB Ballast stabilied with cement Foundation - Ballast Assessment of behavio of the pavement stuctue unde taffic loading The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated with the elation (): 8,97,7 0,9 ( m. s. a.),() Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 fo motoways and expess oads, accoding []: c RDO RDO( 0,8) RDOadmisibil ( 0,80),() Veifications of the hoiontal tensile stess at the bottom of laye(s) of natual aggegates stabilied with hydaulic o poolan bindes, in MPa accoding [] using elations: = R t (0,0-0,0 log c) = 0,8,() (0,07) (0,8),() Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c 77( mico stains),() ( 77) 77,(). As all design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: Fig. Poposed expeimental sectos on the ALT cicula tack facility. Secto b) Classical pavement cuently used Type (Design taffic: 0 m.s.a.) Table. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Weaing couse (MASF /SMA) 000* 0,* Binde couse (B.A.D. ) 0 00* 0,* Bituminous base - AB 000* 0,* Ballast stabilied with cement 0 000** 0,** Ballast Foundation *** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..; ** Item..; *** Item.. Design pogam to compute stesses and stains in pavement stuctue Caldeom 000 Secto - Input paametes: Load... Pessue tie Radius cicle 7.0 k 0. MPa 7. cm Laye : Module. MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module. MPa, Poisson Coeff..70, Thickness.0 cm Laye : Module 80. MPa, Poisson Coeff..0 it is semifinit RESULTS: R Z Radial effot Radial defom. Vetical defom. cm cm MPa micodef micodef e+00.e E E-0.E+0 -.0E E-0.E+0 -.E E-0.E+0 -.E E-0.E+0 -.7E E-0.E+0 -.E+0 Assessment of behavio of the pavement stuctue unde taffic loading The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated with the elation (7): ISS: Issue 9, Volume, Septembe 00

4 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET 8,97,7 0,87 ( m. s. a.),(7) Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 max 0.80 fo motoways and expess oads, accoding []: c RDO RDO( 0,8) RDOadmisibil ( 0,80),(8) This condition is satisfied. Veifications of the hoiontal tensile stess at the bottom of laye(s) of natual aggegates stabilied with hydaulic o poolan bindes, in MPa accoding [] using elations: = R t (0,0-0,0 log c)=0,07,(9) (0,08) (0,07),(0) Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c ( mico stains),() ( ),(). As all design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: - Classical pavement stuctue cuently used o. Weaing couse - MASF Binde couse - BAD Bituminouse base - AB Ballast stabilied with cement Foundation - Ballast Table. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Weaing couse (MASF /SMA) 000* 0,* Binde couse (B.A.D. ) 0 00* 0,* Bituminous base - AB 000* 0,* Ballast stabilied with cement 0 000** 0,** Ballast Foundation *** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..; ** Item..; *** Item.. Design pogam to compute stesses and stains in pavement stuctue Caldeom 000 Secto - Input paametes: Load... Pessue tie Radius cicle 7.0 k 0. MPa 7. cm Laye : Module 9.MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000.MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000.MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module 9.MPa, Poisson Coeff..70, Thickness.0 cm Laye : Module 80.MPa, Poisson Coeff..0 it is semifinit RESULTS: R Z Radial effot Radial defom. Vetical defom. cm cm MPa micodef micodef e+00.98e E E-0.98E+0 -.7E E-0.07E E E-0.07E+0 -.0E E-0.0E E E-0.0E+0 -.0E+0 Assessment of behavio of the pavement stuctue unde taffic loading The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated with the elation (): 8,97 adm.,7 0 78,0( m. s. a.),() Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 max 0.80 fo motoways and expess oads, accoding []: c RDO RDO( 0,77) RDOadmisibil ( 0,80),() Fig. Poposed expeimental sectos on the ALT Cicula tack facility. Secto c) Classical pavement cuently used Type (Design taffic: 0 m.s.a.) Veifications of the hoiontal tensile stess at the bottom of laye(s) of natual aggegates stabilied with hydaulic o poolan bindes, in MPa accoding [] using elations: = R t (0,0-0,0 log c) = 0,00,() (0,0) (0,00),() ISS: Issue 9, Volume, Septembe 00

5 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c 09( mico stains),(7) ( 0) 09,(8). As all design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: - Classical pavement stuctue cuently used o. Weaing couse - MASF Binde couse - BAD Bituminouse base - AB Ballast stabilied with cement Design pogam to compute stesses and stains in pavement stuctue Caldeom 000 Secto - Input paametes: Load k Pessue tie 0. MPa Radius cicle 7. cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 9. MPa, Poisson Coeff..70, Thickness.0 cm Laye : Module 80. MPa, Poisson Coeff..0 it is semifinit RESULTS: R Z Radial effot Radial defom. Vetical defom. cm cm MPa micodef micodef E+00.E+0 -.8E E-0.E+0 -.E E-0.E E E-0.E+0 -.E+0 Assessment of behavio of the pavement stuctue unde taffic loading Foundation - Ballast Fig.8 Poposed expeimental sectos on the ALT cicula tack facility. Secto. Conception and design of Long Lasting Flexible Pavement - LLFP ALT sectos The oad secto envisaged fo the study of classical pavements has been consideed but the design was conducted fo same thee highe categoies of taffic, namely: 0, 0 and espectively 0 m.s.a. The following LLFP pavement sectos have been conceived and veified accoding PD pocedues: a`) The new long lasting pavement Type LLFP Secto (design taffic: 0 m.s.a.) Table 7. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Uppe (Weaing) couse (MASF /SMA) 7000* 0,* Medium Compession Resistance couse (Asphaltic Macadam) 000* 0,* Lowe Tensile Resistance couse (MASF 8/SMA) 7000* 0,* Ballast Subbase 9*** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..; ** Item..; *** Item.. The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated with the elation (9): 8,97,7 0 7,9( m. s. a.),(9) Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 max 0.80 fo motoways and expess oads, accoding []: c RDO RDO( 0,) RDOadmisibil ( 0,80),(0) Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c 7( mico stains),() ( ) 7,(). As both design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: ISS: Issue 9, Volume, Septembe 00

6 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET - The new long lasting pavements LLP o. with the elation (): Weaing couse - SMA Resistence couse Resistence couse - SMA Subbase - ballast 8,97,7 0,8( m. s. a.),() Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 max 0.80 fo motoways and expess oads, accoding []: c RDO RDO( 0,7) RDOadmisibil ( 0,80),() Fig. 0 Poposed expeimental sectos on the ALT cicula tack facility. Secto b ) The new long lasting pavement Type LLFP Secto (design taffic: 0 m.s.a.) Table 9. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Uppe (Weaing) couse (MASF /SMA) 7000* 0,* Medium Compession Resistance couse (Asphaltic Macadam) 0 000* 0,* Lowe Tensile Resistance couse (MASF 8/SMA) 7000* 0,* Ballast Subbase 0 08*** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..; ** Item..; ***; Item..; Design pogam to compute stesses and stains in pavement stuctue Caldeom 000 Secto - Input paametes: Load... Pessue tie Radius cicle 7.0 k 0. MPa 7. cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 9. MPa, Poisson Coeff..70, Thickness 0.0 cm Laye : Module 80. MPa, Poisson Coeff..0 it is semifinit RESULTS: R Z Radial effot Radial defom. Vetical defom. cm cm MPa micodef micodef e+00.e+0 -.9E E-0.E+0 -.E E-0.E+0 -.E E-0.E+0 -.0E+0 Assessment of behavio of the pavement stuctue unde taffic loading The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c 09( mico stains),() ( 0) 09,(). As both design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: - The new long lasting pavements LLP o. Weaing couse - SMA Resistence couse Resistence couse - SMA Subbase - ballast Fig. Poposed expeimental sectos on the ALT cicula tack facility. Secto c ) The new long lasting pavement Type LLFP - Secto (design taffic: 0 m.s.a.) Table. The pavement stuctue selected fo the design Laye ame h, cm E, MPa Uppe (Weaing) couse (MASF /SMA) 7000* 0,* Medium Compession Resistance couse (Asphaltic Macadam) 0 000* 0,* Lowe Tensile Resistance couse (MASF 8/SMA) 7000* 0,* Ballast Subbase 0*** 0,7*** /Soil Type - P 80 0, ote, accoding []: * Item..;** Item..; *** Item.. ISS: Issue 9, Volume, Septembe 00

7 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Design pogam to compute stesses and stains in pavement stuctue Caldeom The new long lasting pavements LLP o. Secto - Input paametes: Load... Pessue tie Radius cicle 7.0 k 0. MPa 7. cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 000. MPa, Poisson Coeff..0, Thickness 0.0 cm Laye : Module MPa, Poisson Coeff..0, Thickness.0 cm Laye : Module 9. MPa, Poisson Coeff..70, Thickness.0 cm Laye : Module 80. MPa, Poisson Coeff..0 it is semifinit RESULTS: R Z Radial effot Radial defom Vetical defom cm cm MPa micodef micodef e+00.7e+0 -.7E E-0.7E+0 -.E E-0.E+0 -.0E E-0.E E+0 Assessment of behavio of the pavement stuctue unde taffic loading The admissible numbe loading of standad axle of k în m.s.a., which may be taken of the bituminouse layes, coesponding to stain condition at thei bottom accoding [] point 7...a is calculated with the elation (7): 8,97 adm.,7 0 7,9( m. s. a.),(7) Checking the RDO condition fo the poposed stuctual design consideing RDO admisibil max. 0.8 max 0.80 fo motoways and expess oads, accoding []: c RDO RDO( 0,7) RDOadmisibil ( 0,80),(8) Veifications of the vetical stain at the level of subgade accoding [] using elations: 0,7. 9 c 90( mico stains),(9) ( 87,9) 90,(0). As both design citeia ae satisfied the following pavement stuctue is poposed at this stage of design: Weaing couse - SMA Resistence couse Resistence couse - SMA Subbase - ballast Fig. Poposed expeimental sectos on the ALT cicula tack facility. Secto Checking the fost esistance of the Classical/LLFP pavements a ) Fost esistance veifications fo Classical Secto The pavement stuctue was design as wey to esist at feee and thaw accoding [],[],[7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm Depth at fost in the new pavement: foundation ballast laye: cm Ballast stabilied with cement: 0 cm Bituminous base - AB: cm binde couse type B.A.D. : cm weaing couse type MASF : cm Zc Z Z 9 cm,() Z = 70 depth feee of subgade (accoding [] fig. pag.) Z HSR Hech. cm,() H SR = thickness of pavements stuctue H SR = 70 cm H ech = equivalent thickness calculation to feee (accoding [] Chapte..) H ech =cmx0,70+0cmx0,+cmx0,0+cmx0, 0+cmx0,0 =, cm ISS: Issue 9, Volume, Septembe 00

8 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Index of feee is I /0 med = 70 (accoding [] fig., pag.7) H SR < Z c < af 70 < 9 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee (accoding [] pag., tab.) K ef = Hech/Zc =/9 = 0, > 0,0 (accoding [] table, pag. ) the poposed pavement stuctue satisfied the feee-thaw conditions. b ) Fost esistance veifications fo LLFP - Secto The pavement stuctue was design as way to esist at feee and thaw accoding [], [], and [7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm Depth at fost in the new pavement: Uppe (Weaing) couse (MASF /SMA): cm Medium Compession Resistance couse (Asphaltic Macadam): cm Lowe Tensile Resistance couse (MASF 8/SMA): cm Ballast Subbase: cm Z Z Z 9 cm,() c Z = 70 depth feee of subgade (accoding [] fig. pag.) Z HSR Hech. cm,() H SR = thickness of pavements stuctue H SR = 0 cm H ech = equivalent thickness calculation to feee (accoding [] Chapte..) H ech =cm x 0,70 + cm x 0,0 + cm x 0,0 + cm x 0,0 =7, 8cm Index of feee is I med /0 = 70 [] H SR < Z c < af 0 < 9 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee [] K ef = Hech/Zc =8/9 = 0, > 0, 0 [] the poposed pavement stuctue satisfied the feee-thaw conditions. c ) Fost esistance veifications fo Classical - Secto The pavement stuctue was design as wey to esist at feee and thaw accoding [],[],[7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm Depth at fost in the new pavement: foundation ballast laye: cm Ballast stabilied with cement: 0 cm Bituminous base - AB: cm binde couse type B.A.D. : 0 cm weaing couse type MASF : cm Zc Z Z 0 cm,() Z = 70 depth feee of subgade (accoding [] fig. pag.) Z HSR Hech. cm,() H SR = thickness of pavements stuctue H SR = 70 cm H ech = equivalent thickness calculation to feee (accoding [] Chapte..) H ech =cmx0,7+0cmx0,+cmx0,0+0cmx0, 0+cmx0,0 cm Index of feee is I /0 med = 70 (accoding [] fig., pag.7) H SR < Z c < af 8 < 0 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee (accoding [] pag., tab.) K ef = Hech/Zc =/9 = 0, > 0,0 (accoding [] table, pag. ) the poposed pavement stuctue satisfied the feee-thaw conditions. d ) Fost esistance veifications fo LLFP - Secto The pavement stuctue was design as way to esist at feee and thaw accoding [], [], and [7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm ISS: Issue 9, Volume, Septembe 00

9 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET Depth at fost in the new pavement: Uppe (Weaing) couse (MASF /SMA): cm Medium Compession Resistance couse (Asphaltic Macadam): cm Lowe Tensile Resistance couse (MASF 8/SMA): cm Ballast Subbase: cm Z Z Z 9 cm,(7) c Z = 70 depth feee of subgade [] Z HSR Hech. cm,(8) H SR = thickness of pavements stuctue H SR = 70 cm H ech = equivalent thickness calculation to feee [] H ech =0cm x 0,70 + cm x 0,0 + 0cm x 0,0 + cm x 0,0 =cm Index of feee is I med /0 = 70 [] H SR < Z c < af 70 < 9 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee [] K ef = Hech/Zc =/9 = 0, > 0, 0 [] the poposed pavement stuctue satisfied the feee-thaw conditions. e ) Fost esistance veifications fo Classical - Secto The pavement stuctue was design as wey to esist at feee and thaw accoding [],[],[7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm Depth at fost in the new pavement: foundation ballast laye: cm Ballast stabilied with cement: 0 cm Bituminous base - AB: cm binde couse type B.A.D. : 0 cm weaing couse type MASF : cm Zc Z Z 0 cm,(9) Z = 70 depth feee of subgade (accoding [] fig. pag.) Z HSR Hech. cm,(0) H SR = thickness of pavements stuctue H SR = 70 cm H ech = equivalent thickness calculation to feee (accoding [] Chapte..) H ech =cmx0,7+0cmx0,+cmx0,0+0cm x0,0+cmx0,0 =0cm Index of feee is I /0 med = 70 (accoding [] fig., pag.7) H SR < Z c < af 9 < 0 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee (accoding [] pag., tab.) K ef = Hech/Zc =0/0 = 0,7 > 0,0 (accoding [] table, pag. ) the poposed pavement stuctue satisfied the feee-thaw conditions. f ) Fost esistance veifications fo LLFP - Secto The pavement stuctue was design as way to esist at feee and thaw accoding [], [], and [7] soil type: P Hydological egime: Level of undegound wate af : 00 cm Depth of feeing: 70 cm Depth at fost in the new pavement: Uppe (Weaing) couse (MASF /SMA): cm Medium Compession Resistance couse (Asphaltic Macadam): cm Lowe Tensile Resistance couse (MASF 8/SMA): cm Ballast Subbase: cm Zc Z Z 00 cm,() Z = 70 depth feee of subgade (accoding [] fig. pag.) Z HSR Hech. 0 cm,() H SR = thickness of pavements stuctue H SR = 8 cm H ech = equivalent thickness calculation to feee (accoding [] Chapte..) H ech =cm x 0,7+cm x 0,0 + 0cm x 0,0 + cm x 0,0 =, cm Index of feee is I /0 med = 70 (accoding [] fig., pag.7) H SR < Z c < af 8 < 00 < 00 cm (hydological conditions unfavoable, land vey sensitive) equies veification fo feee (accoding [] pag., tab.) ISS: Issue 9, Volume, Septembe 00

10 WSEAS TRASACTIOS on EVIROMET and DEVELOPMET K ef = Hech/Zc =/00 = 0, > 0, 0 (accoding [] table, peg. ) the poposed pavement stuctue satisfied the feee-thaw conditions. PDG [8] o the actual UK Highway Agency method. Conclusions The final synthetic esults of the compaative study of both classical and LLFP pavements ae pesented in Table : Table. The final synthetic esults of the compaative study of both classical and LLFP pavements Classical pavement stuctue Laye Weaing couse (MASF /SMA) Binde couse (B.A.D. ) Bituminous base - AB 0 Design Taffic Ballast stabilied with cement Foundation P Total thickness (cm) Long lasting pavement stuctue Laye Uppe (Weaing) couse (MASF /SMA) Medium Compession Resistance couse (Asphaltic Macadam) Lowe Tensile Resistance couse (MASF 8/SMA) Design Taffic Ballast Subbase 0 /Soil Type P Total thickness (cm) In elation with the esults pesented in Table 7 the following conclusions could be discussed:. By using asphalt mateials with highe elasticity modulus value (e.g. E= MPa), and disposing them accoding the LLFP concept, it is possible to constuct flexible pavement stuctues with total thicknesses lowe than those of classical/witness ones, but capable to suppot consideable highe design taffics.. These new stuctues poved also to be fost esistant when checked accoding the Romanian standads [], [], [7].. This eseach execise will be extended in the nea futue, by consideing a paallel design appoach using the actual Romanian nom and the new methods, specially developed in the fame of the Asphalt Pavement Alliance [] and also some othe moden stuctual design methods, like Mechanistic-Empiic Pavement Design Guide ME- Futue wok Based on existing knowledge[9],[0] and latest developments in this field [],[],[], the futue wok intends the constuction of the envisaged expeimental sectos on the cicula tack of the ALT facility of Technical Univesity of Iasi, paallel with the constuction of simila expeimental sectos, selected on the existing public oad netwok, followed by monitoing thei pefomances in time and the dafting of specific technical ecommendations fo the design and constuctions of LLFP. Refeences: [] Romanian Doc. PD Recommendation fo the design of flexible and composite pavements, 00 [] Andei R.& othes, Technical ecommendation fo the asphalt mixes stabilied with cellulose fibes, AD [] Andei R., Options on LLRP expeimental sectos intended to be constucted and tested on the ALT cicula tack facility of Technical Univesity Gh. Asachi Iasi, STREP FP poject, 009. []Asphalt Pavement Alliance, [] Vlad., STAS 709/-90, Fost depth in pavement oad [] Vlad., STAS 709/-90, Pevention and epaation of fost-thaw damages 990. [7] Vlad., STAS 709/-90, Detemination of sensitivity to fost of the soil Method of test, 990. [8] ational Highway Institute, Intoduction to Mechanistic- Empiical Design of ew and Rehabilitated Pavements, 00. [9] R. Andei & othes: Climatic and ecological aspects of stuctual design of Long Lasting Rigid Pavements LLRP fo demonstation pojects located in diffeent Euopean egions, ISS: , ISB: , 00. [0] Montalvo, J., & othes : A ew Ecological Pavement Fo Enhancement Of Uban Envionments, WSEAS intenational confeence on enegy, envionment, ecosystems and sustainable development, July -, 00 [] Rajab M & othes, Application Of Image Pocessing To measue oad distesses WSEAS tansactions on infomation science & applications volume, 008 [] Kau D., Soft Computing Technique In Pediction Of Pavement Condition, th WSEAS int. confeence on computational intelligence, man-machine systems and cybenetics, Teneife, Spain, Decembe -, 007 [] Shandi H. T., & othes, Using Multi Laye Pecepton etwok to Classify Road Cacks, Poceedings of the th WSEAS int. conf. on neual netwoks ISS: Issue 9, Volume, Septembe 00