Zveza društev gradbenih inženirjev in tehnikov slovenije
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Objavljeno v: Gradbeni vestnik - november 2010

Avtorji

mag. Bojana Lukač, univ. dipl. inž. kem. teh.
doc. dr. Andreja Zupančič Valant, univ. dipl. kem. inž.

RAZISKOVANJE OBNAŠANJA GUMIBITUMNA KOT VEZIVA ZA PROIZVODNJO GUMIRANIH ASFALTNIH ZMESI

UDK: 665.77:678

Povzetek

Uporaba gumenega prahu, pridobljenega iz odpadnih pnevmatik kot modifikator bitumenskega veziva, predstavlja ekološko rešitev in izboljša lastnosti asfaltnih zmesi. V prispevku predstavljamo raziskavo vpliva gumenega prahu odpadnih pnevmatik na lastnosti veziva – gumibitumna, in lastnosti ekstrahiranega bitumna iz gumiranih asfaltnih zmesi. Kot osnovno vezivo smo uporabili cestogradbeni bitumen tipa B 50/70 iz Madžarske. Mehanske in reološke lastnosti pripravljenega gumibitumna smo primerjali z lastnostmi veziva, ki je vsebovalo vhodni bitumen in dodatek amina, pripravljeno pa je bilo pod enakimi pogoji kot gumibitumen. Amin olajša vmešavanje gumenega prahu v vezivo in proces nabrekanja prahu v vezivu. Pripravili smo asfaltno zmes AC 8 surf in gumirane asfaltne zmesi AC 8 surf po suhem in po mokrem postopku, iz katerih smo z ekstrakcijo in destilacijo ponovno pridobili vezivo (bitumen). Raziskali smo mehanske in reološke lastnosti ekstrahiranega bitumna iz gumiranih asfaltnih zmesi in jih primerjali z ekstrahiranim bitumnom iz asfaltne zmesi, ki ni vsebovala gume, da bi lahko napovedali vpliv gumenega prahu na lastnosti v asfaltni plasti. Preizkusi so pokazali, da dodatek gumenega prahu bitumnu poveča dinamične module, viskoznost in rutting parameter, poleg tega poviša temperaturo zmehčišča po PK in zniža temperaturo pretrgališča po Fraasu. Ugotovili smo, da lahko z optimiranimi pogoji priprave dobimo z gumo modificirani bitumen (RmB), ki s svojimi dobrimi lastnostmi poveča temperaturni razpon uporabnosti veziva, kar je v času podnebnih sprememb, ki smo jim priča, zelo pomembna ugotovitev.

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THE INVESTIGATION OF RUBBER MODIFIED BITUMEN AS A BINDER FOR PRODUCTION OF ASPHALT MIXTURES

Summary

The use of waste tire rubbers as bitumen modifiers can contribute to alleviate pollution problems derived from discarding scrap tires and improves chemical and mechanical properties of asphalts. The paper examines the influence of waste tire rubber powder on mechanical and rheological properties of rubberised bitumen binder and on the extracted bitumen from rubberised asphalt mixtures. Samples were prepared by using pavement grade bitumen B50/70 from Hungary. Mechanical and rheological properties of rubberised bitumen binders were compared with the properties of native bitumen modified with amine at the same preparation condition as rubberised binders. Amine is added to improve rubber powder swelling and as a mixing agent. The rubberised asphalt mixtures AC 8 surf were prepared according to wet and dry procedures. In order to examine the effect of waste rubber powder on mechanical properties of asphalt mixtures, the mechanical and rheological properties of extracted bitumen from these asphalt mixtures were compared with the properties of extracted bitumen from asphalt mixture AC 8 surf prepared without rubber powder. It was found that the addition of ground tire rubber to bitumen increases both the linear viscoelastic moduli, rutting parameter and viscosity, at high in-service temperatures. From mechanical tests it was observed that the presence of rubber powder in bitumen increases ring and ball temperature and decreases Fraas temperature. As a consequence, a crumb tire rubber modified bitumen displays enhanced mechanical properties, which improves its resistance to both rutting and fatigue cracking. Therefore, the addition of waste rubber tire powder to bitumen extends the application temperature range of binder.

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