Investigation of the rheological properties of elastomeric polymer-modified bitumen using warm-mix asphalt additives

In recent years, warm-mix asphalt (WMA) is extensively used in the hot-mix asphalt industry for reducing energy requirements and emissions by lowering mixing and compaction temperatures of bitumen. In addition, the use of polymer-modified bitumen (PMB) has become a very important part of pavement construction due to its superior performance, including less ageing, enhanced rutting resistance and lower fatigue cracking properties. This paper presents an experimental evaluation of elastomeric PMB involving WMA additives. In scope of the study, base bitumen has been modified with three different concentrations of styrene–butadiene–styrene (SBS) copolymer. The prepared PMB samples have been mixed with organic and chemical types WMA additives. Following the determination of the conventional properties as well as the rheological properties of the samples using dynamic shear rheometer, rutting behaviour of bitumen samples has been evaluated by zero shear viscosity test. The results of conventional bitumen tests showed a decrease in temperature susceptibility in PMB involving WMA additives. Based on the rheological test results, it was observed that the utilisation of organic WMA additive into PMB improves rutting performance of the modified bitumen especially in the 4% concentration of SBS copolymer.