COMBINED USE OF RAP AND LIGNIN FOR REDUCING VIRGIN BITUMEN CONTENT IN AC 14 ASPHALT MIXTURES

In pavement engineering, virgin bitumen is one of the most expensive components of asphalt mixtures, motivating the development of technologies to reduce virgin binder consumption while maintaining adequate mechanical performance. Also, reducing the consumption of high-quality virgin materials contributes to environmental sustainability. In this context, reclaimed asphalt pavement (RAP) has become an important alternative due to its potential to reuse aged asphalt binder and aggregates from milled pavements. Lignin, a by-product of the wood, paper, and biofuel industries, has potential as a binder. This study investigates the development of recycled asphalt mixtures using a combination of RAP and lignin, aiming to reduce the consumption of virgin bitumen and aggregates, as well as the production and compaction temperatures of the mixtures. AC 14 asphalt mixtures containing 20% RAP were produced with lignin contents corresponding to 20% by binder mass. The mixtures were manufactured at lower temperatures than in conventional hot-mix asphalt production processes. Tests were carried out on the virgin asphalt binder, the binder recovered from RAP, and lignin to compare their properties and to understand the influence of the binder blend on the performance of the asphalt mixtures produced. Experimental results demonstrated that the investigated formulations exhibited satisfactory mechanical behaviour and adequate performance potential for wearing-course applications. Furthermore, these sustainable asphalt paving solutions contribute to lower energy consumption and reduced atmospheric emissions during asphalt mixture manufacturing.