43 research outputs found
Effects of GBFS content and curing methods on the working performance and microstructure of ternary geopolymers based on high-content steel slag
No full textAimed to address the low utilization rate of steel slag (SS) and its challenge in resource utilization in China, this study developed ternary geopolymers made by high-content (50%) SS together with fly ash (FA) and granulated blast furnace slag (GBFS). The effects of GBFS content (0–40%) and curing methods (water curing, standard curing, sealed curing, and heat curing) on the working performance and microstructure of geopolymers were investigated. Microscopic analysis such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM) were utilized to investigate the hydration process and products of geopolymers under different curing conditions and GBFS content. The results indicated that when the GBFS content increased from 0% to 40%, the fluidity of the mixture decreased by 11.7%, the initial setting time of the geopolymer slurry decreased by 76%, and the geopolymer mortar's 28d compressive strength increased from 31.9 MPa to 60.6 MPa. At room temperature, the geopolymer mortar's 28d compressive strength was higher under standard curing (70.8 MPa) compared to water curing (57.5 MPa) and sealed curing (68 MPa). The geopolymer mortar cured at 60 °C for 24 h exhibited the highest 28d compressive strength (76.3 MPa). However, excessively high curing temperatures or prolonged durations led to more shrinkage cracks and reduced the compressive strength. The microscopic analysis revealed that the main gel products of ternary geopolymer were C-(A)-S-H gel. The amount of gel products is directly related to the strength of geopolymers. The developed ternary geopolymer has the potential to promote the large-scale utilization of SS in the concrete industry, making a significant contribution to sustainable development.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen
Road performance evaluation of prestressed high-strength concrete pile waste powder as alternative filler in asphalt concrete
No full textAs a kind of solid waste, using Prestressed High-Strength Concrete Pile Waste Concrete (PPWC) as the replacement for limestone filler in asphalt concrete can not only reduce the accumulation of PPWC and increase its utilization but also avoid the increased road construction costs and environmental degradation associated with limestone mining. This study aims to investigate the effect of using PPWC filler to replace limestone filler on the road performance of asphalt concrete. Firstly, PPWC was ground into filler particles with a diameter less than 0.075 mm. The particle characteristics such as surface morphology, particle size distribution and chemical composition of PPWC filler and limestone filler were compared. Then, PPWC filler was used to replace limestone filler with different volume fractions to prepare asphalt concrete, and the water damage resistance, high-temperature rutting resistance, low-temperature crack resistance, fatigue resistance and adhesion performance of asphalt concrete were tested. The results showed that PPWC filler has a smaller particle size and rougher surface than limestone filler, and it contains Ca(OH)2 produced by hydration. The addition of PPWC filler can effectively improve the mechanical properties of asphalt concrete without reducing its water damage resistance. PPWC filler can improve the high-temperature rutting resistance and low-temperature crack resistance of asphalt concrete, but reduce its low-temperature fatigue resistance. The low content of PPWC filler will enhance the adhesion between asphalt mortar and aggregate. However, when the content of PPWC filler exceeds 50%, Ca (OH)2 in PPWC will reduce the adhesion between acid asphalt mortar and alkaline basalt aggregate. Therefore, the use of PPWC as filler in asphalt mixtures provides a reliable solution for the sustainable development of road materials.Materials and Environmen
Alkylation of Naphthalene with Propylene Catalyzed by Aluminum Chloride Immobilized on Al-MCM-41
No full text
Digital in-line holography with a single high-order harmonic pulse
No full textIn this paper, we review the optimization and characterization of a high-order harmonic generation (HHG) source for application in coherence imaging, and the use of this light source in a digital in-line holography setup. The high-order harmonic beam is generated by focusing a powerful infrared beam into an Ar gas cell. The length of the cell and the focusing parameters are optimized to maximize the HHG output. By spectrally filtering and focusing the generated harmonic beam and positioning a 2D detector, we obtain a table-top light source suitable for in-line holography, capable of recording a hologram with a single 40 fs XUV pulse. The reconstructed images have a spatial resolution in the micrometer range
Exploring the Utilization of PHC Pile Waste Concrete as Filler in Asphalt Mastics
No full textUsing solid waste to replace limestone filler in asphalt concrete can not only reduce the cost of road construction, but also improve the utilization rate of solid waste. In this study, PHC pile waste concrete (PPWC) was innovatively used to replace limestone filler in asphalt mixture and its effect on the physical and rheological properties of asphalt mastics was studied. Firstly, PPWC was ground into filler particles with a diameter less than 0.075 mm. The physical properties, particle characteristics and chemical composition of PPWC filler and limestone filler were compared. Asphalt mastics were prepared with different filler-asphalt volume ratios (20%, 30% and 40%) and the physical properties, high-temperature rheological properties and low-temperature cracking resistance of asphalt mastics were tested. The experimental results showed that the surface of PPWC filler is rougher and has lower density and smaller particle size than limestone filler. When the filler content is the same, PPWC filler asphalt mastics have lower penetration and ductility, higher softening point than limestone filler asphalt mastics, and the viscosity of PPWC filler asphalt mastics is more sensitive than limestone filler asphalt mastics. PPWC filler asphalt mastics demonstrated superior high-temperature stability, but poorer low-temperature cracking resistance compared to limestone filler asphalt mastics. In conclusion, PPWC fillers can be used to replace limestone fillers in asphalt mixtures. The finding of this study will provide a new solution for the construction of eco-friendly roads.Materials and Environmen
