Browsing by Author "Gerber, Daymen"
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- ItemThe effects of temperature and traffic on stone orientation of seals with different binders(Stellenbosch : Stellenbosch University, 2022-04) Gerber, Daymen; Jenkins, Kim J.; Van Zyl, Gerrie; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.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.