Study on mixing processes of buton rock asphalt mixture

Buton rock asphalt (BRA) is a natural asphalt modifier that can improve different properties of mixture. The traditional mixing process for BAR mixture is to mix aggregates with BRA firstly, and then mix them with heated base asphalt and mineral powder in that order. However, it results in an unevenness of asphalt film thickness, which can influence the performance of mixtures. Therefore, the primary objective of this research is to develop an advanced mixing process for BRA mixture. Six mixing processes were attempted. Air void, dynamic stability (DS), indirect tensile strength, and tensile strength ratio (TSR) were selected as the evaluation parameters. By comparison, the optimum mixing process is changed by adding the BRA and base asphalt in different orders. Lastly, contact angle measurements and inverse gas chromatography (IGC) were conducted to analyze the adhesion work in different mixing processes, which can explain the improvements of the advanced mixing process.