Due to repeated loads, the pavement structures will experience repeated stresses and strains resulting in permanent deformation even though the working loads are still smaller than the design load. The permanent deformation will lead to cracking and fatigue failure with the life of the pavement. This phenomenon can be reduced by increasing the stiffness, flexibility, durability, stability and water absorption of the pavement. Material modification including the utilization of waste tire rubber (WTR) and natural zeolite is one of the efforts to increase those parameters in semi flexible pavement (SFP). The aim of this study therefore, to assess the deformation and fatigue failure of SFP incorporating WTR and natural zeolite under cyclic loading. The WTR was used as an additive at the level of 3% of asphalt content while natural zeolite was used as cement replacement at the 0, 5, 15 and 25% replacement levels. Permanent deformation tests were conducted by applying wheel tracking loads with the pressure of 6.4 ± 0.15 kg/cm2 on the surface of the specimens with 1260 cycles per hour while fatigue tests were conducted on the simple supported beams with the span length of 30 cm by applying forth point loading at the frequency of 10 Hz. The test results showed that the best performance in sustaining cyclic loading was achieved at the zeolite content of 5%.
Hydrogen is a low or zero-carbon energy source that is considered the most promising and potential energy carrier of the future. In this study, the energy sources, feedstocks, and various methods of hydrogen production from power generation are comparatively investigated in detail. In addition, this study presents an economic assessment to evaluate cost-effectiveness based on different economic indicators, including sensitivity analysis and uncertainty analysis. Proton exchange membrane fuel cell (PEMFCs) technology has the most potential to be developed compared to several other technologies. PEMFCs have been widely used in various fields and have advantages (i.e., start-up, zero-emissions, high power density). Among the various sources of uncertainty in the sensitivity analysis, the cost estimation method shows inflationary deviations from the proposed cost of capital. This is due to the selection process and untested technology. In addition, the cost of electricity and raw materials, as the main factors that are unpredictable.
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