الفهرس | Only 14 pages are availabe for public view |
Abstract Despite the importance of using sulfuric asphalt in road construction, it causes some negative effects on the physical and mechanical properties of asphalt binders and mixtures. Therefore, there is a need to address this impact and extend the service life of the pavement and preserve non-renewable bitumen sources for future generations. It is extremely important that sulfur asphalt suits the different environmental conditions and the increasing traffic volumes. Under this hypothesis, this study examines the effect of two different recycled plastic waste (RPW) which are high and low-density polyethylene (RHDPE and RLDPE) on the rheological/viscoelastic characteristics and aging performance of virgin asphalt and sulfur extended asphalt (SEA) and their mixtures. Four dosages of the RPW additives representing 2%, 4%, 6%, and 8% by weight of the asphalt binder were investigated. Then determining the melting point of the RPW through Differential Scanning Calorimetry (DSC). The optimum blending time was determined based on the results of the Brookfield Rotational Viscosity (RV) test. Physical properties (penetration and softening point) and Chemical properties (X-ray Diffraction and Fourier transform infrared spectroscopy) of RPW-asphalt and RPW-SEA composites were investigated. The morphology of the investigated blends was quantified using Scanning Electron Microscopy (SEM). The rheological characteristics of the RPW modified binders (virgin asphalt and SEA) are characterized at original and short-term aging conditions through the RV and dynamic shear rheometer (DSR) tests. Fatigue performance is also characterized at the long-term aging condition. Also, high-temperature performance, dynamic storage stability (DSS), and multiple stress creep and recovery (MSCR) are studied. The DSR test was conducted at different frequencies reflecting different highway traffic speeds. Different historical predictive equations that model the rheological properties of asphalt binders in terms of dynamic shear modulus (G*) and phase angle (δ) are studied. The investigated models are employed to describe the rheological viscoelastic characteristics of the different investigated III binders at different aging conditions under the influence of different frequencies and temperatures based on Dynamic Mechanical Analysis (DMA). The analysis of variance (ANOVA) is applied to measure the influence of the different factors such as RPW concentration, temperature, frequency, and aging conditions on the RPW binders’ performance. Marshall mix design was used for the preparation of asphalt mixtures. All the mixes were prepared at 4% target air void content. The moisture susceptibility of the mixtures was also evaluated using the retained Marshall stability test and tensile strength ratio. The evaluation of rutting and fatigue performance of the asphalt mixtures were evaluated using a double punching test at 60 °C and 20 °C, respectively. Finally, pavement performance of typical pavement sections under different environmental conditions and traffic levels was predcited using the the state of the art AASHTWOWare Pavement ME Design. Also, a comparative economic analysis is performed in terms of initial material cost. The effect of incorporating sulfur into asphalt binder formulation on the environment is also determined based on the results of the H2S/SO2 gases analyzer and leaching of metals into water tests. The estimation of the environmental benefits of RPW modified asphalt is performed by comparing the carbon emissions and nonmethyl volatile organic compound (NMVOCs) of the various RPWs with the manufacturing process of the same quantities of virgin LDPE and HDPE when used to modify asphalt. |