Herline van der Spuy, SMEC
PAPER
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Open in new tab SPEAKER PRESENTATION - PRESENTED BY ELAINE GOOSEN AT CONFERENCE
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Abstract
The intermediate temperature (construction and operating temperature) response of a binder influences the initial and longer-term performance of a seal. The creep and recovery characteristics of a binder during construction, initial trafficking and with ageing, at these temperatures, influence the resistance to stone orientation (loss of macro texture) and ability to retard crack reflection.
The goal of this study was to evaluate different types of binders used in South Africa and their performance at various temperatures, with the focus on intermediate temperatures. The properties of original and short-term aged binders were determined to evaluate changes from the refinery to the initial stage after construction. The creep and recovery characteristics were analysed to determine the behaviour of the binder, and how it could link to stone orientation.
The materials used in this study were an unmodified binder and four modified binders. The modified binders consisted of two elastomers and two rubber binders. The Bending Beam Rheometer was used to obtain data at cold temperatures, and the Dynamic Shear Rheometer for intermediate and high temperatures. The Multiple Stress Creep and Recovery (MSCR) test was used to obtain the non-recoverable creep compliance (Jnr) and the recovery (%R).
Results showed that the type and degree of modification significantly influences the performance of binders at intermediate temperatures. The modified binders demonstrated characteristics which affect stone orientation in the surface layer and could be utilised in adjustment of conversion factors used in the seal design process.
About the Author
Herline van der Spuy completed her Bachelor’s in Engineering (Civil) in 2019 and has recently received her Master’s in Engineering (Road) degree from the University of Stellenbosch. In her final year as an undergraduate student, Herline created a successful predictive model as to which type of person would be more likely to recycle and why. She has gained student experience analysing transport data with SMEC and assisting in site investigations for the Kommetjie Road Upgrade Project and the Strand Seawall Project with the City of Cape Town.
