Yttria stabilized zirconia (YSZ) nanocrystals were prepared by hydrothermal synthesis and were calcinated at different temperatures and with different isothermal hold time. X-ray diffraction via whole powder pattern modeling approach was used to study the grain growth as well as the evolution of grain size distribution of YSZ nanocrystals. Results show that YSZ nanocrystals start to grow along with the grain size distribution broadening at about 300 °C. The grain growth rate and the grain size distribution of YSZ nanocrystals are dependent on the calcination temperature and the isothermal hold time. The grain growth exponent and the active energy of grain growth were calculated. Grain rotation induced grain coalescence is suggested as the predominant way of grain growth of YSZ nanocrystals.
In recent years, recycling steel slag is receiving growing interest in the road base layer construction field due to its role in alleviating land occupation and resource shortages. However, the mixture compaction and its environmental impact on practical construction sites remain unclear, which may hinder the application of steel slags in road layers. This study investigates the pavement construction of the ‘Baotou-Maoming’ motorway, located in Inner Mongolia, China, analyzing the compaction procedures and assessing the environmental impacts caused by the road base layer containing steel slag. Firstly, mechanical properties and texture appearances of the steel slag aggregates are characterized. Afterwards, the comparative assessments for steel slag and andesite layers compaction are quantified from equivalent CO2 emission and energy consumption aspects, respectively. The results show that the steel slag has a better surface texture than the natural aggregates; physical properties including compactness, flatness and compressive strength comply with the requirements for applying steel slag to a hydraulically bound mixture. Compared to the base layer using andesite aggregates, the compaction vibration period of the course containing steel slags should be reduced to achieve a proper density due to the “hard-to-hard” effect that occurs between the adjacent steel slag particles. Consequently, the additional energy and the equivalent CO2 are generated at 2.67 MJ/m3 and 0.20 kg/m3, respectively.
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