LAUSR

Abstract Warm mix asphalt (WMA) technologies which enable production at lower temperatures in pavement engineering have been developing. In the present study, the efficiency of colemanite mineral, which the largest reserve is located in Turkey, on the WMA technology was examined. In the first stage, natural colemanite mineral, which is a kind of boron, was milled in a high-energy ball mill for 30 min. The milled powder was sieved by using 53 μm and 25 μm sieves. For the size analysis; powder over the size of 53 μm (C + 53 μm) was preferred for micron size, and powder under the size of 25 μm (C − 25 μm) was preferred for submicron size/nanosize. Particle size distribution (PSD), morphology and element content properties of the powders were measured alternately by using a particle size analyzer, microscopes, and an energy dispersive X-ray spectrometer. In the PSD analysis, d50 values were detected as 91.102 μm for C + 53 μm powder and 7.063 μm for C − 25 μm powder. Additionally, dmin values were found to be 2188 nm for C + 53 μm powder and 275 nm for C − 25 μm powder. In the morphology analysis, the presence of particles below 100 nm (nanoparticles) was observed on a scanning electron microscope. In the elemental analysis, it was determined that there was no contamination in the powders. In the second stage, bitumen and asphalt mixture experiments were conducted. Bending Beam Rheometer test was conducted as the bitumen experiment for colemanite additive. Mixtures were prepared by adding C + 53 µm and C − 25 µm powders at 5% and 10% ratios for both. Marshall Stability, Indirect Tensile Stiffness Modulus and Repeated Creep Test experiments were performed on the produced asphalt briquettes. As a result, it was observed that the colemanite minerals which were stabilized by reducing them into nanosize improved the mechanical properties of asphalt samples.