Age-related performance of typical seal binders in South Africa

Engelbrecht, Francois (2018-03)

Thesis (MEng)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: The age-related performance of typical seal binders in South Africa was studied to understand the behaviour of the binders as it ages. The three main failure mechanisms for surfacing seals include surface cracking, ravelling and texture loss. These mechanisms shorten the life of the pavement exponentially. Various factors may be the cause of these failures. This study includes the analyses of the rate at which oxidation influences the performance of surfacing seals. Rheology was used to analyse the age-related performance of the selected seal binders. Low and high temperature testing was conducted in the laboratory at various ages such as RTFO and PAV (20hr, 40hr and 80hr) which includes short-term ageing and long-term ageing of a binder. Several ageing parameters were used to analyse the results of each seal binder. The South African Performance Grade Specification and the AASHTO M320 specification are established to set the required performance of asphalt binders. These specifications were used to compare the performance of surfacing seal binders to asphalt binders. Results showed that ageing influences the modification within surfacing seal binders. It appears that the performance of the elastic component in the modifier decreases as the binders age. The low temperature results show that the difference between the unmodified and modified binders are minimal. The high temperature results indicate that the highly modified binders perform well considering the influence of ageing.

AFRIKAANSE OPSOMMING: Die ouderdomsverwante gedrag van verskeie seël bindmiddels in Suid-Afrika is gebestudeer om die gedrag van die bindmiddels te evalueer soos wat die seëls verouder. Die drie hoof faling meganismes van seëls sluit in oppervlak kraking, rafeling en tekstuur verlies (Gerber, 2016). Hierdie meganismes verkort die lewe van die pad eksponensieël. Verskeie faktore mag die oorsaak wees van hierdie falings. Hierdie studie behels die ontleding van die tempo waarteen oksidasie die gedrag van die seels beinvloed. Reologie was gebruik om die ouderdomsverwante gedrag van die seël bindmiddels te analiseer. Lae en hoë temperatuur toetse was gedoen in ‘n laboratorium teen verskeie ouderdomme, soos ‘RTFO’ en ‘PAV’ (20ure, 40ure en 80ure) wat korttermynveroudering en langtermynveroudering van 'n bindmiddel insluit. Verskeie ouderdomsparamters was gebruik om die gedrag van die seël bindmiddels te analiseer. Die Suid-Afrikaanse Prestasiegraadspesifikasie asook die ‘AASHTO M320’-spesifikasie is gestig om die gedragsvereistes van asfalt bindmiddels vas te stel. Hierdie spesifikasies was gebruik om die gedrag van seël bindmiddels te vergelyk met asfalt bindmiddels. Die resultate het getoon dat veroudering wel ‘n invloed het op seël bindmiddels. Dit blyk dat die gedrag van die elastiese komponent in die modifiseerder afneem namate die bindmiddels verouder. Die lae temperatuur resultate toon dat die verskil tussen die ongemodifiseerde en gemodifiseerde bindmiddels minimaal is. Die hoë temperatuur resultate dui daarop dat die hoogs gemodifiseerde binders goed presteer met inagneming van die invloed van veroudering.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103432
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