Characterization of permanent deformation resistance of precipitated calcium carbonate modified asphalt mixture

Rutting in asphalt pavements that appears as an indentation in the longitudinal direction continues to create problems for pavement agencies. This paper presents the results of the laboratory study on rutting susceptibility of asphalt mixtures containing Precipitated Calcium Carbonate (PCC) coated by a thin layer of a polymeric compound. To assess the impact of PCC on rutting properties of HMA, control mixtures (without PCC) and mixtures containing PCC were tested using dynamic creep and indirect tensile stiffness modulus tests. The HMA mixtures containing 0%, 5%, 10%, and 15% of PCC were prepared. In this paper, it is shown that the use of PCC can decrease the rutting potential of asphalt mixes. According to the results obtained in this study; using a 5% PCC in HMA is acceptable for heavy traffic volume roads especially in tropical regions

Simulation and Optimization of Coal Gasification in a Moving-bed Reactor to Produce Synthesis Gas Suitable for Methanol Production Unit

This paper presents process simulation and optimization of coal gasification process&lt;br /&gt; in a moving-bed reactor using Pittsburgh No. 8 coal as feed. The system of differential&lt;br /&gt; equations for the mass and energy balances was solved using 4th-order Runge-Kutta method and optimized by non-dominated sorting genetic algorithm-II (NSGA-II) method.&lt;br /&gt; The simulation was used to predict solid and gas temperature profile and gas composition&lt;br /&gt; along the reactor. The simulation results were compared successfully with experimental&lt;br /&gt; data relevant to Westfield plant in Scotland. In addition, the effect of operating parameters such as coal-to-oxygen molar ratio, steam-to-oxygen molar ratio, inlet gas temperature, reactor pressure, and oxygen mole fraction in inlet air on amount of synthesis gas (syngas) production, hydrogen to carbon monoxide molar ratio (HCMR) in produced syngas, and coal conversion was investigated. Finally, the reactor performance was optimized to produce the highest syngas production with a HCMR of two using NSGA-II method.</jats:p