SBS modifiye bitüm hazırlama parametrelerinin bitüm karakterizasyonu üzerine etkilerinin değerlendirilmesi

Increment in the volume of traffic and vehicle loads caused by developing technology with environmental effects cause deterioration in asphalt pavements. Bitumen modification with various polymer additives is a prerequisite for enhancing the long term behavior of the pavement and improving its mechanical properties. In Turkey, Styrene-Butadiene-Styrene (SBS) is the most commonly used elastomeric polymer additive in polymer modified bitumen (PMB). Modification of bitumen by different modifiers, causes the morphological, rheological and chemical characterisation differences related to the following three main factors: the type of the polymer, bitumen components and blending conditions such as the temperature, shearing rates and duration of mixing. Blending conditions, can be evaluated in relation with the polymer dispersion, phase separation and most importantly the aging of the bitumen. Among the blending conditions the duration of mixing and shearing rates among the blending conditions were chosen as key parameters. A mixing speed of 1000 rpm was selected to represent a low shear rate and 3000 rpm for a high shear rate, whereas two mixing durations were chosen, 15 and 45 minutes to represent nominal minimum and maximum mixing times. Different PMB samples were produced with the combination of selected key under the constant mixing temperature, aiming to evaluate the characterisation alters. Structural and microstructural characterisation, thermal characterisation as well as the rheological characterisation were investigated on the prepared samples. Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM) were employed for structural and microstructural characteristics; Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA) for thermal characteristics; Optical Microscopy (OM) and Confocal Laser Scanning Microscopy (CLSM) for morphological characteristics and two different rheometer for rheological characteristics. Consequently, mixing polymer with bitumen under longer duration or higher shear rates caused the bitumen to be oxidised, since it directly affects the interaction of the oxygen with the bitumen.