Use of zinc borate modified ulexite as a performance enhancer in asphalt mixture

This study was carried out in two stages. In the first stage, oxide component, SEM, EDS and XRD analyzes of zinc borate and ground ulexite additive minerals were performed. In the second stage, water damage, cracking, Marshall stability and creep tests of modified hot mix asphalt were fulfilled. Tests were carried out with 3 groups in total, using control samples formed with 1150g aggregate, samples containing 6% ulexite according to the weight of the aggregate, and samples containing 4.5% ulexite and 1.5% zinc borate according to the weight of the aggregate. In the SEM micrograph, it was detected that the ZnB mineral had a small particle size and a homogeneous distribution compared to the GU mineral. In the oxide component, EDS and XRD measurements, it was understood that while the ZnB mineral was pure, the GU mineral was not pure. In the water damage test, it was determined that the mixture with ZnB+GU additive improved 23% in the unconditional condition and 2.6% in the conditional condition in comparison with the control sample. As a result of Marshall stability, its value was found to be 1291 kg for the control mixture and 1355 kg for the mixture with ZnB+GU. In the repeated creep test, the mixture with ZnB+GU showed an increase of 19% compared to the control mixture. In short, the zinc borate modified ulexite additive enhanced the asphalt mixture performance.