The effects of temperature and traffic on stone orientation of seals with different binders

Date
2022-04
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: The purpose of this investigation was to gain an understanding of the effect that different variables have on the orientation of surfacing seal aggregates. The aggregate orientation referred to in this study is the orientation due to induced traffic, after construction orientation has occurred. The variables that formed part of this investigation were the effect of different binder types on the aggregate orientation, the effect of different pavement temperatures on the orientation of the surfacing aggregates and the effect of different aggregate matrices on the orientation of the aggregates, together with the effect of traffic on the orientation of the seal aggregates. The combination of these variables was measured and discussed in the respective chapters. This was done to determine the optimal conditions for aggregate orientation. This investigation thus tested four different binder types (70/100 penetration grade bitumen, SC-E1, SC-E2 and Cat65 bitumen emulsion), three different temperatures (10°C, 20°C, 30°C), two different aggregate matrices (shoulder-to-shoulder and “over- application) and simulated traffic going up to five thousand load repetitions per surface temperature. The model mobile load simulator Mk. 3 (MMLS3) was used to apply the traffic loads at specific intervals, namely 100, 500, 2000 and 5000, for each surface temperature. This was then followed by the laser texture meter (LTM) to measure the texture of the surfacing seals after each load interval was applied. To aid in the understanding of the texture at each interval, a volumetric sand patch (VSP) test was conducted along with the readings of the LTM. These two methods were also then compared to find a correlation between the preferred in-field method, the VSP test, and the preferred laboratory method, the LTM. The results indicated that with an increase in traffic, the mean profile depth (MPD) decreased. The bitumen emulsions experienced greater decreases in MPD, when compared to the hot applied 70/100 penetration grade bitumen. When looking at the two aggregate matrices tested, the “over-application” matrix experienced greater MPD decreases when compared to the shoulder-to-shoulder aggregate matrix. Lastly, it was seen that, in general, seals at 30°C experienced a greater rate of change than the other two temperature tested.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om 'n beter begrip van die effek wat die verskillende veranderlikes op die oriëntasie van seëlaggregate het, te kry. Die oriëntasie wat in hierdie studie na verwys word, is die oriëntasie as gevolg van verkeer, nadat konstruksie -oriëntasie plaasgevind het. Die veranderlikes wat deel is van hierdie studie is die effek van verskillende bindmiddeltipes op die oriëntasie, die effek van verskillende oppervlakte temperature op die oriëntasie van die aggregaat en die effek van verskillende aggregaatmatrikse op die oriëntasie van die aggregaat, gepaard met die effek van verkeer op die orientasie van die aggregaat. Die kombinasie van hierdie veranderlikes was gemeet en bespreek in die onderskeie hoofstukke. Dit was gedoen om die optimale toestande vir oriëntasie te bepaal. Hierdie ondersoek het dus vier verskillende bindmiddeltipes getoets (70/100 penetrasiegraad-bitumen, SC-E1, SC-E2 en Cat65-bitumenemulsie), drie verskillende temperature (10°C, 20°C, 30°C), twee verskillende aggregaat matrikse (skouer-aan-skouer en oor-toediening) en gesimuleerde verkeer wat tot vyfduisend toegepasde laste per oppervlaktetemperatuur styg. Die model mobiele lassimulator Mk. 3 was gebruik om die verkeerslaste met spesifieke intervale, naamlik 100, 500, 2000 en 5000, vir elke oppervlaktetemperatuur toe te pas. Daarna was dit met die lasertekstuurmeter (LTM) gevolg om die tekstuur van die seëls te meet. Om die tekstuur van elke interval te verstaan, was 'n volumetriese ‘sand patch’ -toets ook uitgevoer, tesame met die metings van die LTM. Hierdie twee metodes was ook daarna vergelyk om 'n korrelasie te vind tussen die voorkeur-in-veld-metode, die volumetriese ‘sand patch’-toets en die voorkeur-laboratoriummetode, die LTM. Die resultate het aangedui dat die gemiddelde profieldiepte met 'n toename in verkeer verminder het. Die bitumenemulsies het 'n groter afname in die gemiddelde profieldiepte ervaar in vergelyking met die warm toegepaste 70/100 penetrasiegraad bitumen. Wanneer daar gekyk word na die twee aggregaat matrikse wat getoets was, het die oor-toediening - matriks 'n groter afname in gemiddelde profieldiepte ervaar in vergelyking met die skouer- aan-skouer-aggregaatmatriks. Laastens was daar gesien dat seëls by 30°C oor die algemeen 'n groter veranderingstempo ondergaan het, in vergelyking met die ander twee temperature wat getoets was.
Description
Thesis (MEng)--Stellenbosch University.
Keywords
Mean profile depth, UCTD, Rheology -- Binders (Materials), Bitumen -- Emulsions, Shakedown Theory, Pavements, Concrete -- Effect of temperature on
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