Thesis (MEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The use of polymer modified binders have increased drastically over the past twenty
years. It is generally accepted that current empirical specification tests do not adequately
characterise the improvement in binder properties when bitumen is modified with
polymers.
At the University of Stellenbosch, a programme was initiated to relate binder properties
to asphalt mix performance. This study forms part of that programme.
This study focuses on three binders and is an attempt to characterise binder properties
fundamentally. The binders that were tested are:
• 60/70 penetration grade bitumen
• SBS modified 60/70 bitumen
• Bitumen-Rubber
Two rheometers were used to characterise the binder properties:
• Sliding Plate Rheometer (SPR)
• Dynamic Shear Rheometer (DSR)
The Sliding Plate Rheometer was modified to allow testing at elevated temperatures. The
modification is described in this thesis.
Three types of testing were used to test the binders:
• Creep tests (SPR and DSR)
• Dynamic tests (Strain and Frequency Sweeps - DSR)
• Flow tests (high temperature viscosity tests - DSR) The results of the tests were used to characterise differences between the binders. Shear
susceptibility lines were plotted and viscosities calculated from the creep test results;
Master Curves and Black Diagrams were plotted from frequency sweep results; flow test
results were used to characterise high temperature behaviour.
A further development in the asphalt industry is the move towards the development of
performance based specifications. A programme has been initiated in this regard and this
study forms part of the programme.
As a step towards the development of performance based specifications filler was
included in this study. BinderlFiller systems were subjected to the same test programme
the binders were, to characterise the influence on binder properties of filler addition.
Some of the conclusions that were drawn at the end of the study are:
• Polymer modification improves binder properties related to rutting.
• Filler addition does not affect binder properties negatively.
• Shear rate is very important during production of asphalt mixes and construction
of asphalt layers containing polymer modified binders. / AFRIKAANSE OPSOMMING: Die gebruik van polimeer gemodifiseerde bitumen het drasties toegeneem oor die
afgelope twintig jaar. Dit word algemeen aanvaar dat die huidige empiriese spesifikasie
toetse nie die verbetering in bindmiddeleienskappe van polimeer modifisering
aanvaarbaar karakteriseer nie.
'n Program is geïnisieer by die Universiteit van Stellenbosch om 'n verband te vind
tussen bindmiddeleienskappe en asfaltmengseleienskappe. Hierdie studie vorm deel van
die program.
Hierdie werk fokus op drie bindmiddels en is 'n poging om die bindmiddeleienskappe
fundamenteel te karakteriseer. Die bindmiddels wat gebruik is in hierdie werk, is:
• 60/70 penetrasiegraad bitumen
• SBS gemodifiseerde 60/70 bittimen
• Bitumen-Rubber
Twee reometers is gebruik om bindmiddeleienskappe te karakteriseer:
• Glyplaat Reometer (SPR)
• Dinamiese SkuifReometer (DSR)
Die glyplaat reometer is aangepas om toetse by hoër temperature te doen en die
aanpassing wat gemaak is word in die tesis beskryf.
Drie tipes toetse is uitgevoer om die bindmiddels mee te toets:
• Kruiptoetse (SPR en DSR)
• Dinamiese toetse (DSR)
• Vloei toetse (DSR) Die resultate van die toetse is gebruik om die verksille tussen die bindmiddels te
kwalifiseer. Verskillende grafieke en figure is getrek van die resultate om die onderskeie
bindmiddels te karakteriseer.
Die beweging weg van empmese spesifikasies na werkverrigting gebaseerde
spesifikasies in die asfalt industrie is 'n verder nuwe ontwikkeling. 'n Program is
geïnisïeer ten opsigte hiervan en hierdie werk vorm deel van die program.
As 'n stap in die ontwikkeling van die werkverrigting gebaseerde spesifikasies is 'n
vuIler ingesluit in die toetsprogram. Bindmiddel/vuIler stelsels is onderwerp aan dieselfde
toetse waaraan die bindmiddels onderwerp is om die invloed van die vuIler op die
bindmiddels te karakteriseer.
Sommige van die gevolgtrekkings waartoe gekom is aan die einde van die tesis, is:
• Polimeer modifisering verbeter bindmiddeleienskappe met betrekking tot
wielsporing.
• Die toevoeging van vuIler affekteer nie die bindmiddeleienskappe negatiefnie.
• Die vervormingstempo is van groot belang wanneer asfaltmengsels gemeng en lae
gebou word van mengsels wat polimeer gemodifiseerde bitumen bevat.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52438 |
| Date | January 2001 |
| Creators | Burger, A. F. |
| Contributors | Jenkins, K. J., Van De Ven, M. F. C., Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 181 p. : ill. |
| Rights | Stellenbosch University |
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