Lignin into closed-loop recycled SMA: field application and performance evaluation

By implementing the principles of a circular bioeconomy, the asphalt industry can reduce greenhouse gas emissions and decrease its use of fossil-based materials. This study shows the results of using reclaimed asphalt pavement (RAP) and hydrolysis lignin (HL) in SMA in a full-scale test section. The performance of laboratory- and plant-produced mixtures was evaluated through performance testing to assess the effects of RAP and HL on rutting potential, cracking resistance, and fatigue life. The results demonstrate that SMA mixtures containing RAP, together with an appropriate amount of rejuvenator, can achieve properties comparable to those of conventional SMA. For the SMA mixture incorporating both RAP and HL, reductions in fatigue life and cracking resistance were observed. The use of RAP and HL reduces the Global Warming Potential up to 55%. The manufacturing and construction process proceeded smoothly, demonstrating that RAP and HL can be successfully integrated into industrial asphalt production and paving.