Characterization of two types of modified sulphur pellets for sulphur-extended asphalt mixtures

The application of sulphur to partially replace traditional bituminous binder in asphalt mixture can offer attractive technical, economic and environmental advantages. Globally, Kazakhstan is the seventh largest producer of sulphur as this element is abundantly generated by many petroleum refining industries. This study concisely evaluates the performance of asphalt mixtures added with two types of modified sulphur pellets pivoting on laboratory and field investigations. Wheel track tests indicate a substantial reduction in rutting development for sulphur-extended asphalts (average final value ≈ 2 mm) compared to unmodified ones (average final value ≈ 7 mm). Further, uniaxial tension stress tests evaluating the durability at −20 °C, −30 °C, −40 °C document very similar results between modified and regular mixtures in terms of tensile strength and corresponding failure strain. Eventually, the construction of a pilot road surface stretch laid employing the sulphur-based pellets points at an approximate 5 % economic saving. Such promising experimental outcomes buttress the application suitability of sulphur-extended asphalt mixtures in Kazakhstan and encourage further thorough research in this direction.