Aging effects on rheological properties of high viscosity modified asphalt

This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.

Effect of different high viscosity modifiers on rheological properties of high viscosity asphalt

High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.

Influence of Viscosity in Fluid Atomization with Surface Acoustic Waves

In this work, aqueous glycerol solutions are atomized to investigate the influence of the viscosity on the droplet size and the general atomization behavior in a setup using standing surface acoustic waves (sSAW) and a fluid supply at the boundary of the acoustic path. Depending on the fluid viscosity, the produced aerosols have a monomodal or polymodal size distribution. The mean droplet size in the dominant droplet fraction, however, decreases with increasing viscosity. Our results also indicate that the local wavefield conditions are crucial for the atomization process.

Synergistic effects of multiple rotors and hydrogen-bond interactions lead to sensitive near-infrared viscosity probes for live-cell microscopy

Changes in cellular viscosity are associated with various physiological processes and pathological conditions.To study these cellular processes and functions,highly sensitive fluorescent probes that detect subtle changes in viscosity are urgently needed but remain lacking.In this study,we present a series of viscosity-responsive near-infrared(NIR)fluorescent probes based on styrene-coated boron dipyrromethene(BODIPY).The probe modified with dimethylaminostyrene and piperazine at the two terminals of the BODIPY scaffold showed extremely high viscosity sensitivity values(x,around 1.54),with excellent performance for detecting viscosity below 20 c P.This outstanding property is attributed to the synergistic effects of multiple rotatable bonds and hydrogen-bond interactions.Additionally,this probe has been successfully deployed to monitor viscosity changes in various cellular compartments(i.e.,cytoplasm)and processes(such as during autophagy).This work provides a rational molecular design strategy to construct fluorescent probes with high viscosity sensitivity for exploring cell functions.