scholarly journals Performance-Based Characterization of Bituminous Mortars Prepared With Ladle Furnace Steel Slag

2020 ◽  
Vol 12 (5) ◽  
pp. 1777 ◽  
Author(s):  
Marco Pasetto ◽  
Andrea Baliello ◽  
Emiliano Pasquini ◽  
Marta Skaf ◽  
Vanesa Ortega-López
Keyword(s):  
Viscoelastic Properties ◽  
Permanent Deformation ◽  
Steel Slag ◽  
Deformation Resistance ◽  
Slight Reduction ◽  
Physical Interaction ◽  
Fine Aggregate ◽  
Ladle Furnace ◽  
Thermal Dependence ◽  
Linear Viscoelastic

A circular approach to managing resources that will promote their reuse and recycling is nowadays of crucial importance for a sustainable society. In this regard, the substitution of natural aggregates by steel slag in construction materials represents a promising option. In this paper, the use of Ladle Furnace Slag (LFS) as sustainable filler and fine aggregate for asphalt mixtures is studied. In particular, the evaluation of the LFS contribution in mastic and mortar mixes at mid-range and high-service temperatures is investigated, employing a dynamic shear rheometer to assess the main viscoelastic properties as well as the fatigue and the permanent deformation resistance of the blends. The experimental findings showed that the addition of LFS led to a clear stiffening effect, altering the chemo-physical interaction with the bitumen and producing an appreciable difference in complex stiffness moduli and phase angles. Regardless of the aging condition, the use of LFS lowered the linear viscoelastic limits and increased the elasticity of blends in the case of both mastics and mortars. It caused also a slightly higher thermal dependence of the linear viscoelastic properties even if the enhanced stiffness and elasticity produced appreciable improvements in the permanent deformation resistance. In contrast, a slight reduction of fatigue resistance was observed under the test conditions and was reasonably ascribed to the higher stiffness of LFS blends. Further research is needed to strengthen these promising results and to address the issues at a multiscale level, in particular to evaluate possible lower workability and reduced ductility due to the encountered higher stiffness of slag-based materials.

Preparation, Characterization and Processing of PCL/PHO Blends by 3D Bioplotting

2020 ◽  
Vol 35 (5) ◽  
pp. 458-470
Author(s):  
S. Gopi ◽  
B. A. Ramsay ◽  
J. A. Ramsay ◽  
M. Kontopoulou
Keyword(s):  
Viscoelastic Properties ◽  
Biomedical Applications ◽  
Synergistic Effects ◽  
Thermal And Mechanical Properties ◽  
Flow Properties ◽  
Immiscible Blends ◽  
Melt Compounding ◽  
Linear Viscoelastic ◽  
Matrix Morphology ◽  
Good Flow

Abstract Blends of polycaprolactone (PCL) and poly(3-hydroxyoctanoate) P(3HO) were prepared by melt compounding. These immiscible blends exhibited droplet-matrix morphology at compositions up to 30 wt% P(3HO). Even though the addition of amorphous P(3HO) decreased the crystallinity of PCL, the crystallization temperature of the blends increased by 6 to 7 8C. Blends containing up to 30 wt% P(3HO) had higher crystallization rates, and lower crystallization half-times compared to neat PCL. The viscosity of PCL decreased upon addition of P(3HO), making the blends suitable for processing using a 3D bioplotter. Compositions with 10 to 30 wt% P(3HO) were ideal for processing, because of their improved crystallization kinetics, reduced stickiness and good flow properties. Estimation of the interfacial tension by fitting the Palierne model to the linear viscoelastic properties of the blends revealed good compatibility, which gave rise to synergistic effects in the thermal and mechanical properties. The fibres prepared by 3D bioplotting maintained droplet matrix morphology, with finer particle size than the original compounded material. In addition to favourable viscosity and thermal properties, the extruded fibres containing 30 wt% P(3HO) had comparable modulus to the neat PCL, while exhibiting good ductility. These blends may be suitable alternatives to PCL for biomedical applications, because they provide a range of crystallinities, crystallization rates and viscosities.

scholarly journals Mass-Transfer Model for Steel, Slag, and Inclusions during Ladle-Furnace Refining

2018 ◽  
Vol 37 (7) ◽  
pp. 665-674
Author(s):  
Liguang Zhu ◽  
Yanan Jia ◽  
Zengxun Liu ◽  
Caijun Zhang ◽  
Xingjuan Wang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Molten Steel ◽  
Film Theory ◽  
Steel Slag ◽  
Reaction Model ◽  
Transfer Model ◽  
Ladle Furnace ◽  
Precise Control ◽  
Transfer Behavior ◽  
Coupled Reaction

AbstractPrecise control of inclusion and molten steel compositions during ladle-furnace refining is important to obtain high-quality steel. Mass-transfer behavior affects these compositions. A model was developed to investigate the mass transfer occurring between molten steel, slag, inclusions, and the refractory during ladle-furnace refining, using two-film theory to describe the reactions. A coupled-reaction model based on the CaO–Al2O3–MgO–SiO2–FeO–P2O5 slag and Mn–Si–Al–Ca–Mg–P–S–O steel systems was applied to describe the reactions between molten steel and slag; the reactions between the refractory lining and slag or steel were described using average industrial erosion rate data. The model was used to calculate changes in the compositions of molten steel and slag, oxygen activity at the slag–molten steel interface, and composition of the inclusions. The calculated results agreed with operational results for a 100 t ladle furnace at the Tangsteel plant in China.

Effect of fine aggregate form, angularity and texture on the viscoelastic properties of asphalt mortar

2014 ◽  
pp. 637-648 ◽  
Author(s):  
Yiqiu Tan ◽  
Hong Zhang ◽  
Huining Xu ◽  
Yizhuang Wang ◽  
Xing’ao Yao
Keyword(s):  
Viscoelastic Properties ◽  
Fine Aggregate ◽  
Aggregate Form ◽  
Asphalt Mortar
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