Rationing of Technological Properties of Asphalt Mixtures based on Analysis of their Structurally- Mechanical Properties

Transcription

1 MOJ Cvl Engneerng Ratonng of Technologcal Propertes of Asphalt Mxtures based on Analyss of ther Structurally- Mechancal Propertes Abstract The artcle s devoted to the forecast and evaluaton of the quanttatve requrements for mechancal and structural-mechancal propertes of asphalt mxtures n the producton stage. Constant change of operatng condtons of asphalt concrete pavement n Russa, whch assocated wth ncreasng traffc, ncreasng axal loads, speed, weather and clmate effects and other factors every years requres the use of the structural layers of the pavement of the new asphalt mxtures wth elevated freght performance characterstcs. Ths s evdenced by the contnuous mprovement of normatve base of techncal requrements for asphalt concreten our country and abroad. Volume 3 Issue Professor of Techno scences, MADI, Russa Revew Artcle *Correspondng author: Kotlyarevsky EV, Professor Dr Techno scences, MADI, Russa, Emal: Receved: Aprl 21, 2017 Publshed: July 17, 2017 Introducton The analyss of ths experence shows that both domestc and foregn regulatons do not address the requrements to technologcal propertes of asphalt mxtures. It s known that asphalt mxtures and asphalt concrete on that n Russa and abroad have dfferent classfcatons and classfcaton attrbutes are appled to the producton machnes and mechansms have sgnfcant dfferences n technologcal possbltes when layng and compactng of asphalt mxtures n meanngful layers of flexble pavement. When desgnng Work Project at specfc facltes professonals contractors, buldng on the model advanced technology solutons take nto account clmatc factors, weather condtons, logstcs n the delvery of asphalt concrete mxtures from the asphalt plant to the place of nstallaton, the desgn of the pavement, real qualfcatons operators of road-buldng machnes and mechansms and a ton of other less weghty crcumstances, n consequence of the adopton of optmal technologcal schemes entrely depends drectly on vendor-specfc works. In other words, the entre fnal producton cycle, from whch manly and formaton depends on the structure and propertes of asphalt mxtures depends entrely on the qualfcatons and experence of the contractor. The experence of the asphalt coatng and bases suggests that technology s not always optmal, whch ultmately affects the lfetme of the asphalt constructon layers and the whole road constructon. The formaton of an optmum structure and propertes of complex composte of polydsperson compound materal based on organc bnders wth complex non-lnear rheologcal propertes cannot occur n the case of sub-optmal process parameters durng the mxng process n asphalt-mxng plants, the delvery of the mxture, ts stowage and ts sealng. It must be borne n mnd that technologcal equpment has dfferent desgn features and energy capabltes, there may be sgnfcant varatons n the condtons for road works and desgn structures of asphalted constructon layers and underlyng structural layers on roads of dfferent categores. On the bass of theoretcal and expermental studes [1] t s establshed that asphalt mxtures and asphalt n dfferent technologcal and operatonal stuatons can be regarded as a hghly concentrated dspersed system, the propertes of whch are largely dependent on the physco-chemcal processes takng place n the structure of the materal. The assessment of these processes needs to take nto account the basc laws of physco-chemcal mechancs and the specfcs of the contact nteractons [1,2]. The man patterns were establshed by researchers at the School of Academcan P. Rebndera on varous model trans (2). To study the structural-mechancal propertes of dspersed materals P.A. Rebnder and V.VMkhalov [1,3] revewed the processes of structure formaton n vew of addtvty strength elementary contacts when the lmtng shear stress (or strength of dsperse system) s from the expresson (1) φ φ δ 1 c 2 3 P = k F n = k F S k F móä c = (1) Where: P m -lmt shear stress, Pa; F C -average bondng strength n contact between partcles, n; N s the average number of contacts per unt volume (cm 3 ); φ -relatve densty; S -specfc surface mneral part, у cm2 ekv /g,δ j - I equvalent (weghted average) sze of dsperse phase partcles. 5,44 φ 2 n = 6, 7373 e δ (2) The average number of ndvdual contacts n unt volume [1] s determned by the formula (2) The average force of adheson n contact by the formula (3), and the average strength of a sngle contact from equaton (4) Submt Manuscrpt MOJ Cvl Eng 2017, 3(1): 00060

2 2/5 (1 ) (1 ) 2 ρ ' φ φ ð F = P δ c m ρ ( φ φ ) ï ð (3) F P c m P = = (4) 1/3 S n Where: P m, F c, n, δ jekv -same as (1) ρ-relatve densty of the dspersed phase (resultng from technologcal mpacts and absolutely devastated-loose State, ρ s the densty of the partcles of the dspersed phase andρ n-densty of asphalt concrete. Wthout an analyss of the processes of asphalt mxtures materal generaton, the effects of technologcal factors cannot be explaned by the processes of structure and destructon of the structure n the desgn of road garments. In the works [3,4] authors developed the technque of desgnng asphalt mxes wth the requste structural-mechancal propertes, whch s mplemented on computer [5]. The formaton and destructon of the structure of the asphaltc mxture and asphalt at varous technologcal stages s shown n Fgure 1. Fgure 1: Formaton and destructon of structure of asphalt mxtures and the blacktop to varous technologcal stages.

3 3/5 For the analyze ofchanges for the lmt values of the structurally-mechancal propertes of asphaltc concrete techncal requrements for normalzed GOST 9128 ndcators of physcal and mechancal propertes for the varous types and types of asphalt I, II and III of the mark for all the Russan clmate zones were used. They are the tensle strength at о С fxed temperatures and speeds of 3 and mm/mn (R 3, R ), the tangent of the nternal frcton angle (tgϕ)) and the clutch (c). Usng the Coulomb s formula (5), the shear stress values were found, by expressons (2) and (4) the average clutch lmt values n the contact between the partcles and the average strength of the sngle contact P = R tg φ + c (5) m Where:- R - the lmt of tensle strength at о С temperature and mm/mn deformaton speed tgφ -tangent of the nternal frcton angle, c -channg. The change n shear stress, dependng on the tensle strength of о C and the mm/mn test speed for all asphalt tags n all road and clmate zones, has been processed on the computer. A correlatve regresson analyss was used for lnear, progressve, logarthmc, and exponental mathematcal constrants. Preference was gven to the most smple regresson of a lnear vew wth the requred accuracy and adequacy (6). m P = b R + b (6) 1 0 where b 0 and b 1 -regresson coeffcents. Table 1: Regresson coeffcents and coeffcents of multple correlaton for asphalt I, II and III mark showng. Obtaned by calculatons and ratos of multple regresson coeffcents of correlaton for asphalt I, II and III of the stamps are shown n the Table 1. Analytcal expressons derved dependences for dfferent brands n dfferent road-clmatc zones have equal regresson coeffcents and hgh rates of multple correlatons. In Fgure 1 shows a generalzed correlaton changes lmtng shear stress by compressve strength at temperature о С. Realzaton of the obtaned relatonshps has made t possble to defne requrements to lmt the voltage shft of standard GOST 9128 temperature tests, whch are shown n the Table 2. Fgure 2 shows a predcton of the change n the tensle strength of the compresson and shear stress n the wde range of operatng and technologcal temperatures. Markof Asphalt Regresson Coeffcents The Coeffcent of Multple Correlaton b0 b1 I 0,1365 0,9940 0,9772 II 0,1357 0,9857 0,9818 III 0,1258 0,9960 0,9466 Table 2: Lmted Shear Stress Requrements (P m ). Test Temperature, о С Lmted shear Stress, MPa Asphalt Mark <8 <9 <10 20 >3,0 >3,5 >4,0 >1,0 >1,0 >1,0 The operatng temperature can be assgned wthn the nterval from-20 to о С. To technology from +80 to о С. In Fgure 3 presents the exponental regresson model compressve strength changes dependng on the temperature of the test. Dependency analyss enables you to draw conclusons that the regresson coeffcents wth ncreasng brand asphalt concrete (from III to I) decreasng, ndcatng a lower temperature senstvty of asphalt concrete of Mark I. Fgure 3 shows a predcton of the change n the tensle strength of the compresson and shear stress n the wde range of operatng and technologcal temperatures. The operatng temperature can be assgned wthn the nterval from-20 to о С. To technology from +80 to о С. In Fgure 3 presents the exponental regresson model compressve strength changes dependng on the temperature of the test. Dependency analyss enables you to draw conclusons that the regresson coeffcents wth ncreasng brand asphalt concrete (from III to I) decreasng, ndcatng a lower temperature senstvty of asphalt concrete of Mark I. The obtaned values make t possble to develop technologcal schemes for the preparaton of asphalt mxtures at asphalt plants, takng nto account the capabltes and techncal parameters of asphalt nstallatons, takng nto account ther desgn and energy capabltes. You can manage process processes by changng the preparaton temperature of the mxture and varyng the duraton of the mxng n the mxng of the perodc actvty or the rate of supply of the orgnal materals (contnuous). In the development of the compresson technology, the work projects need to mplement a more mult-factor, unstatonary task, takng nto account weather and clmate condtons, the range of transportng the mxture, composton, mass parameters and type

4 4/5 of sealng machnes at the lnk of road roller skatng, the sequence of ther movement on the Mkrozahvatke, the number of passes on one track and much other. In our opnon, the results can be Table 3: Forecast ndcators of mechancal propertes. useful to developers of asphalt mxng and compacton equpment for road and constructon. Temperature, o C Asphalt Mark Road-Clmatczone I II, III IV, V I II, III IV, V Compress vestrength lmt, MPa Lmtedshea rstress, MPa Compressve strength lmt, MPa Lmted shearstress, MPa ,1 21,5 25,2 18,1 21,4 25,2 6,06 7,26 9,15 10, 2 12, 5 16, ,8 13,8 15,8 11,9 13,7 15,8 4,31 5,08 6,24 6, 86 8,30 10, 5 0 7,68 8,82 9,88 7,77 8,82 9,96 3,07 3,55 4,25 4,64 5, 6, ,26 3,61 3,88 3,38 3,70 3,98 2,00 2,20 2, 2,00 2,23 2,55 0,90 0,95 0,95 1,03 1,07 1,07 0,60 0,65 0,70 0,71 0,78 0, ,02 0,02 0,01 0,16 0,15 0,14 0,03 0,02 0,02 0,00 0,02 0, ,01 0,01 0,01 0,14 0,14 0,13 0,01 0,01 0,01 0,00 0,01 0, ,01 0,01 0,01 0,01 0,01 0,01 0,02 0,02 0,01 0,02 0,02 0, ,00 0,00 0,00 0,00 0,00 0,00 0,01 0,01 0,01 0,005 0,004 0,003 Fgure 3: Forecast changes n compressve strength and shear stress lmt n a wde range of operatonal and technologcal temperature. Table 4: Requrements for the technologcal propertes of asphalt mxtures at compacton. Fgure 2: Change of shear stress lmt dependng on the compressve strength at oc. Compacton Strength, KPa Lmted shear stress, KPa The end of the compacton The begnnng of the compacton The end of the compacton The begnnng of the compacton

5 5/5 References 1. Kotlyavsky EV (1987) Structurng of hghly dspersed materals wth lght contact seal process nteractons (for example, asphalt concrete). Chernomaz Kollodnyzz Zhurnal Item 1: Mkhalov NV, Mkhalov NV, Rebnder PA (1955) 17(2): Kotlyarsky EV (2000) Desgn technque of composton of asphalt concrete mxtures wth the requste structural-mechancal propertes. Report to the plenary of the Interstate Assocaton of researchers asphalt Moscow. 4. Kotlyarsky EV (2007) Calculaton-expermental desgn technque btumnous concrete composton, takng nto account the structuralmechancal characterstcs of asphalt mxtures. Reports of the annual scentfc sesson of the Assocaton of researchers of asphalt concrete Moscow, MADI (STU) pp Kochnev VI (2013) Selecton of mxes. Automatng the desgn composton and qualty management n the producton of asphalt mxtures wth the requste structural-mechancal propertes. 1(974):