Faster & Bet­ter Road Con­struc­tion is Pos­si­ble

Dr. John Muk­abi and Nick Muller give an anal­y­sis of the in­no­va­tive char­ac­ter­is­tics of SoilTech MK. Ill, a poly­mer sta­bi­lized ge­o­ma­te­rial for con­struc­tion of pave­ments.

NBM&CW - - CONTENTS -

Road Trans­port & High­ways min­is­ter Nitin Gad­kari has time and again been urg­ing to use more of in­no­va­tive tech­niques and ma­te­ri­als for faster and bet­ter-qual­ity con­struc­tion of roads and high­ways. While launch­ing the coun­try's first High­way Ca­pac­ity Man­ual (HCM), he said that the gov­ern­ment of­fi­cials and de­part­ments should be more proac­tive in adopt­ing su­pe­rior sta­bi­liz­ing tech­nolo­gies that would speed up road con­struc­tion sig­nif­i­cantly, while en­abling bet­ter and more long-last­ing roads.

HCM is a guide to road en­gi­neers and pol­icy mak­ers on road con­struc­tion code, traf­fic man­age­ment and con­struc­tion ca­pac­ity of high­ways. It is based on a coun­try­wide study of traf­fic on dif­fer­ent cat­e­gories of roads and high­ways by CSIR-CRRI.

Chal­lenges & So­lu­tions

Sta­bi­liza­tion tech­niques have long been used for pur­poses of en­hanc­ing the geotech­ni­cal engi­neer­ing prop­er­ties of pave­ment ge­o­ma­te­ri­als. These tech­niques mainly in­clude me­chan­i­cal, tra­di­tional hy­draulic (ce­ment, lime, fly ash etc), bi­tu­mi­nous, poly­mer and other non- tra­di­tional liq­uid chem­i­cal sta­bi­liza­tion. Liq­uid chem­i­cal sta­bi­liza­tion is yet to gain pop­u­lar­ity due to lack of proper sci­en­tific and engi­neer­ing back­ground and prag­matic per­for­mance jus­ti­fi­ca­tion based on en­hanced R&D. In due con­sid­er­a­tion, the main chal­lenges as­so­ci­ated with sta­bi­liza­tion that re­quire rig­or­ous R&D in­clude: i) De­vel­op­ing sta­bi­liza­tion tech­niques that can be ef­fec­tively use­ful for in­fe­rior con­struc­tion ma­te­ri­als that are usu­ally ren­dered use­less ii) De­ter­min­ing op­ti­mum batch­ing ra­tios for vary­ing ge­o­ma­te­ri­als to en­hance me­chan­i­cal sta­bi­liza­tion prior to ap­pli­ca­tion or ad­di­tion of sta­bi­liz­ing agents iii) Se­lec­tion of ap­pro­pri­ate sta­bi­liz­ing agents that are chem­i­cally com­pat­i­ble with the ap­pli­ca­ble ge­o­ma­te­rial iv) De­ter­min­ing the op­ti­mum con­tent to be added to the ge­o­ma­te­rial in or­der to achieve op­ti­mally en­hanced phys­i­cal and me­chan­i­cal prop­er­ties whilst min­i­miz­ing as­so­ci­ated detri­men­tal ef­fects such as crack­ing v) De­vel­op­ing so­phis­ti­cated and ad­vanced an­a­lyt­i­cal mod­el­ling tech­niques that can ef­fec­tively char­ac­ter­ize the be­hav­iour of sta­bi­lized ge­o­ma­te­ri­als both quan­ti­ta­tively and qual­i­ta­tively. In this study, so­phis­ti­cated an­a­lyt­i­cal mod­els are em­ployed in char­ac­ter­iz­ing and fos­ter­ing the salient prop­er­ties of SoilTech Mk. Ill poly­mer sta­bi­liz­ing agent

"There is an ur­gent need to give up con­ser­va­tive ap­proach in gov­er­nance and adopt new tech­nolo­gies to push the pace of high­way con­struc­tion." Nitin Gad­kari, Road & High­ways Min­is­ter

with re­spect to the­o­ret­i­cal and prag­matic con­sid­er­a­tion in­clud­ing: a. In­ter­layer nano-poly­mer mi­gra­tion ef­fects b. Elas­tomeric prop­er­ties c. En­hanced re­sponse to com­paction ef­fects

d. En­hanced ten­sile char­ac­ter­is­tics vi) In­creased re­silience to de­for­ma­tion; vii) Ex­panded range of stress-strain elas­tic

lim­its; and, viii) Ap­pre­cia­ble re­sis­tance to crack­ing un­der ex­ces­sive load­ing

SoilTech Mk. III - a third gen­er­a­tion soil sta­bi­lizer, was de­vel­oped 20 years ago in by Poly­mer Pave­ments in South Africa, and is cur­rently rep­re­sented in In­dia by J.V part­ner Kaveri Ul­tra Poly­mers. SoilTech was pur­posely de­signed and man­u­fac­tured to ad­dress these chal­lenges and to leapfrog some­what ar­chaic road sta­bi­liza­tion tech­nolo­gies.

• 1998: the first com­mer­cial ap­pli­ca­tion of SoilTech Mk. I was in 1998. Ini­tially, the prod­uct was de­vel­oped as a bin­der for ru­ral roads. Over the next cou­ple of years, Poly­roads mod­i­fied SoilTech with new cross-link­ing poly­mers to im­prove com­pres­sive strengths – SoilTech Mk. I.

• 2006: ma­jor tech­nol­ogy ad­vances saw the in­tro­duc­tion of long-chain poly­mers into SoilTech and thereby adding a sec­ond per­for­mance di­men­sion to SoilTech. The high CBRs achieved in ma­te­ri­als with SoilTech were com­ple­mented by new and highly im­proved elas­tic mod­u­lus in the sta­bi­lized pave­ments, al­low­ing greater flex­u­ral strengths and load­ing ca­pa­bil­i­ties, not to men­tion im­proved longevity in the pave­ments – first of a kind - SoilTech MK. II.

• 2010: Poly­roads chem­i­cal en­gi­neers in­tro­duced nano-poly­mer­iza­tion into SoilTech. The spe­cific nano-poly­mers be­ing sub­stan­tially smaller than the nor­mal SoilTech poly­mer par­ti­cle, al­lows for eas­ier slid­ing ve­loc­ity on cap­il­lary ad­he­sion in the ma­te­ri­als. Specif­i­cally en­gi­neered sur­fac­tants, mixed with the nano-poly­mers, fur­ther re­duces ten­sions as SoilTech nano-par­ti­cles mi­grate from the sta­bi­lized base-layer into the sub­base, re­sult­ing in two-layer sta­bi­liza­tion. First of a kind – SoilTech Mk. III.

Poly­roads’ en­gi­neers have de­vel­oped ap­pro­pri­ate meth­ods of de­sign in­volv­ing ad­vanced geotech­ni­cal engi­neer­ing con­cepts re­lated to the Elas­tic Limit De­sign Cri­te­rion (ELDC) and Mod­u­lus-Thick­ness De­sign Cri­te­rion (MTDC). The prow­ess of these meth­ods, de­vel­oped for both un­re­in­forced and sta­bi­lized pave­ments, with fun­da­men­tal ob­jec­tives of achiev­ing pro­longed pave­ment de­sign life through pro­tracted main­te­nance of the elas­tic prop­er­ties, is demon­strated by en­sur­ing that the im­pact of im­posed loads and en­vi­ron­men­tal changes is con­tained within the lin­ear elas­tic re­gion.

The most dis­tin­guished ad­van­tage of the ELDC and MTDC, is that all de­sign pa­ram­e­ters de­rived are based on only three pri­mary pa­ram­e­ters; namely, the pave­ment thick­ness, elas­tic mod­u­lus and the cu­mu­la­tive ESALs (Equiv­a­lent Sin­gle Axle Loads), to which all other pa­ram­e­ters are cor­re­lated. Non-lin­ear­ity is an­a­lysed based on the soil me­chan­ics con­cepts of the KHSSS (Kine­matic Hardening Small Strain Stiff­ness). Due to the suc­cess­ful ap­pli­ca­tion and cost-con­struc­tion time ef­fec­tive­ness of these meth­ods of de­sign, Poly­roads’ en­gi­neers will ad­vise on the ap­pli­ca­tion of the elas­tic limit stress-strain and mod­u­lus-thick­ness ra­tio con­cepts as the ap­pro­pri­ate quasi-mech­a­nis­tic meth­ods of de­sign for poly­mer sta­bi­lized pave­ment ge­o­ma­te­ri­als.

More than 20 roads have al­ready been con­structed in In­dia us­ing SoilTech Mk. III sta­bi­liz­ers. SoilTech.

I. Re­duce ag­gre­gate re­quired for lay­ered

works

II. Re­duce con­struc­tion time

III. Re­duce costs

IV. Im­prove road longevity.

iTRARR 2018 - In­ter­na­tional Con­fer­ence – Mom­basa, Kenya

The Kenya Roads Board in col­lab­o­ra­tion with Ma­te­rial Test­ing and Re­search Divi­sion will host the 2nd In­ter­na­tional Con­fer­ence on Trans­port and Road Re­search (iTRARR 2018) from 11 – 14 June in Mom­basa, Kenya. Dr. John Muk­abi will be pre­sent­ing a Paper on ‘In­no­va­tive An­a­lyt­i­cal Char­ac­ter­i­za­tion of SoilTech MK. III Poly­mer Sta­bi­lized Ge­o­ma­te­ri­als for Unique De­sign and Con­struc­tion of Pave­ments’, at the con­fer­ence. http://www.trans­port­con­fer­encekenya.org/#about

Ta­ble 1: Chronol­ogy of 3rd Gen­er­a­tion Sta­bi­lizer

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