The Properties of Asphalt Binder Modified with WMA Additives

Abstract

Asphalt binder is very important in ensuring the durability of asphalt surfaces. Unfortunately, as an organic material, it is subject to the ageing process. During its transport from petrochemical plants and the production of asphalt mixture, it is exposed to high temperatures. The process of asphalt oxidation takes place, as a result of which its viscoelastic properties are reduced. This stage of ageing is called technological ageing (short-term ageing). However, during the operation of the asphalt surface, it is subject to the action of atmospheric factors such as wind, water and solar radiation. Operational ageing takes place (long-term ageing), the asphalt binder becomes more rigid. As a result of asphalt binder ageing, the operational durability of the road surface is reduced. In order to limit this negative process, various types of ageing inhibitors are used for asphalt binders, which can be chemical and mineral materials or natural and synthetic oils. In the tests, two WMA (Warm Mix Asphalt) additives were used in order to limit the ageing of asphalt binder-synthetic wax and tall oil amidopolamine, which were added to the asphalt binder at the same time. Synthetic wax was used in the amount of 1.0% w/w, 1.5% w/w, 2.0% w/w and 2.5% w/w and tall oil amidopolamine in the amount of 0.2% w/w, 0.4% w/w and 0.6% w/w in relation to the amount of asphalt binder. The influence of technological and operational ageing on the change of physic-mechanical and rheological properties of the bitumen composition with both WMA additives. Based on the analysis of the obtained research results, the optimum content of WMA additives in bitumen was determined and the effect of their synergy was demonstrated, which ensures the limitation of the influence of short-term and long-term ageing on the bitumen properties. Therefore, the required durability of the asphalt surface will be ensured in the long term of operation.