scholarly journals Numerical Prediction of Storage Stability of Polymer-Modified Bitumen: A Coupled Model of Gravity-Driven Flow and Diffusion

2017 ◽  
Vol 2632 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Jiqing Zhu ◽  
Romain Balieu ◽  
Xiaohu Lu ◽  
Niki Kringos
Keyword(s):  
Phase Separation ◽  
Dynamic Viscosity ◽  
Flow Model ◽  
Storage Stability ◽  
Coupled Model ◽  
Modified Bitumen ◽  
Coupled Diffusion ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
Polymer Modified Bitumen

A coupled diffusion–flow model by phase-field method is proposed in this paper with the goal of predicting the storage stability of polymer-modified bitumen (PMB). In this study, the incompressible Navier–Stokes equations were coupled with a previously developed phase-field model for PMB phase separation. The coupled model was implemented in a finite element software package with experimentally calibrated parameters and reported data in the literature. Effects of the parameters (bitumen density and dynamic viscosity) that affected the gravity-driven flow and phase separation in PMB were evaluated at 180°C with the simulation results. The results indicate that the coupled diffusion–flow model can predict the storage stability (and instability) of PMBs. A good correlation between the simulation results and the previously reported experimental results (storage stability tube test) was observed. The different gravity-driven phase separation behaviors of PMBs might have resulted from the different composition of the equilibrium phases in the PMBs as well as the different densities and dynamic viscosities of the individual components (polymer and bitumen). A bigger polymer–bitumen density difference, a lower bitumen dynamic viscosity, or both caused a faster flow and separation in the PMB at storage temperature. The investigated variation of bitumen dynamic viscosity had a more significant influence than the investigated variation of bitumen density in this study, but this finding might depend on the specific values of the model parameters. With this study as a foundation, further experimental and numerical studies will be conducted to increase understanding of storage-stable PMB binders and to develop a more efficient test method for determining PMB storage stability.

scholarly journals Identifying the Long-Term Thermal Storage Stability of SBS-Polymer-Modified Asphalt, including Physical Indexes, Rheological Properties, and Micro-Structures Characteristics

2021 ◽  
Vol 13 (19) ◽  
pp. 10582
Author(s):  
Peng Wang ◽  
Hong-Rui Wei ◽  
Xi-Yin Liu ◽  
Rui-Bo Ren ◽  
Li-Zhi Wang
Keyword(s):  
Phase Separation ◽  
Rheological Properties ◽  
Softening Point ◽  
Storage Stability ◽  
Thermal Storage ◽  
Least Squares Regression ◽  
Modified Bitumen ◽  
Long Term Storage ◽  
Asphalt Performance

The thermal storage stability of styrene–butadiene–styrene tri-block copolymer modified bitumen (SBSPMB) is the key to avoid performance attenuation during storage and transportation in pavement engineering. However, existing evaluation index softening point difference within 48 h (ΔSP48) cannot effectively distinguish this attenuation of SBSPMB. Thus, conventional physical indexes, rheological properties, and micro-structure characteristics of SBSPMB during a 10-day storage were investigated in this research. Results showed that during long-term thermal storage under 163 °C for 10 days, penetration, ductility, softening point, recovery rate (R%), and anti-rutting factor (G*/sinδ) were decayed with storage time increasing. This outcome was ascribed to the phase separation of SBS, which mainly occurred after a 4-day storage. However, ΔSP48 after a 6-day storage met the specification requirements (i.e., below 2.5 °C). Thus, the attenuation degree of asphalt performance in field storage was not effectively characterized by ΔSP48 alone. Results from network strength (I) and SBS swelling degree tests revealed that the primary cause was SBS degradation and base asphalt aging. Moreover, conventional indexes, including penetration, ductility, and softening point, were used to build a prediction model for rheological properties after long-term storage using partial least squares regression model, which can effectively predict I, R, Jnr, G*/sinδ, and SBS amount. Correlation coefficient is above 0.8. G*/sinδ and I at the top and bottom storage locations had high coefficient with SBS amount. Thus, phase separation of SBSPMB should be evaluated during thermal storage.

Shallow, gravity-driven flow in a poro-elastic layer

2015 ◽  
Vol 778 ◽  
pp. 335-360 ◽  
Author(s):  
Duncan R. Hewitt ◽  
Jerome A. Neufeld ◽  
Neil J. Balmforth
Keyword(s):  
Coupled Model ◽  
Solid Matrix ◽  
Rigid Base ◽  
Surface Uplift ◽  
Hydrogel Particles ◽  
Dense Fluid ◽  
The Matrix ◽  
Gravity Driven ◽  
Flow Through ◽  
Gravity Driven Flow

By combining Biot’s theory of poro-elasticity with standard shallow-layer scalings, a theoretical model is developed to describe axisymmetric gravity-driven flow through a shallow deformable porous medium. Motivated in part by observations of surface uplift around $\text{CO}_{2}$ sequestration sites, the model is used to explore the injection of a dense fluid into a horizontal, deformable porous layer that is initially saturated with another, less dense, fluid. The layer lies between a rigid base and a flexible overburden, both of which are impermeable. As the injected fluid spreads under gravity, the matrix deforms and the overburden lifts up. The coupled model predicts the location of the injected fluid as it spreads and the resulting uplift of the overburden due to deformation of the solid matrix. In general, the uplift spreads diffusively far ahead of the injected fluid. If fluid is injected with a constant flux and the medium is unbounded, both the uplift and the injected fluid spread in a self-similar fashion with the same similarity variable $\propto r/t^{1/2}$. The asymptotic form of this spreading is established. Results from a series of laboratory experiments, using polyacrylamide hydrogel particles to create a soft poro-elastic material, are compared qualitatively with the predictions of the model.

A Novel Approach to Recycle the Waste Plastics by Bitumen Modification for Paving Application

2011 ◽  
Vol 356-360 ◽  
pp. 1763-1768 ◽  
Author(s):  
Moumita Naskar ◽  
Tapan Kumar Chaki ◽  
Kusum Sudhkar Reddy
Keyword(s):  
Optical Microscopy ◽  
Storage Stability ◽  
Consumer Products ◽  
Waste Plastics ◽  
New Materials ◽  
Spectroscopy Analysis ◽  
Modified Bitumen ◽  
Novel Approach ◽  
Polymer Modified Bitumen ◽  
Bitumen Modification

Recycling of waste plastics (WP) denotes an effectual method to dispose the post-consumer products for possible alternative way to obtain new materials with good properties. With this aim the influences of WP and maleic anhydride (MA) grafted WPs (MA-g-WP) were investigated as the bitumen modifiers for paving applications. Fourier transform infrared (FTIR) spectroscopy analysis established the effective grafting of MA with the waste plastic (WP). Polymer modified bitumen (PMB) binders were analyzed under scanning electron microscopy (SEM) and optical microscopy (OP) in an effort to characterize the bitumen/modifier interphase morphology. The conventional rheological tests such as penetration test, softening point, and ductility results indicate that the degree of polymer modifications are function of the nature of modifier, bitumen–modifier compatibility, and modifier concentration. It has also been confirmed that the morphology observed by SEM and optical microscopy revealed the compatibility between MA-g-WP and bitumen, and the storage stability of binder was improved significantly compared with WP modified bitumen (WPMB) binders. Consequently, the use of grafted modifier with polar site can be considered as a suitable alternation for modification of binder in pavement by expecting their chances for better performance during service.

scholarly journals Study of Rheological Properties of Bituminous Binders in Middle and High Temperatures

2016 ◽  
Vol 12 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Eva Remišová ◽  
Viera Zatkaliková ◽  
František Schlosser
Keyword(s):  
Rheological Properties ◽  
Dynamic Viscosity ◽  
Complex Modulus ◽  
Climatic Conditions ◽  
Modified Bitumen ◽  
Optimal Production ◽  
Traffic Loading ◽  
Loading Effect ◽  
Bituminous Binders ◽  
Polymer Modified Bitumen

Abstract The bitumen binders in road pavements are exposed traffic loading effect at different climatic conditions. A resistance to these stresses depends on bitumen properties as well. The paper presents rheological properties (G*, δ, ν*) determined and compared for four bituminous binders (unmodified and polymer modified bitumen) at temperature 46 – 60 (80) °C and dynamic viscosity at temperature 130 – 190 °C (Brookfield viscometer). On the basis of viscosity results it is possible to set optimal production and compaction temperatures. Elastic and viscous behavior of binder in the middle temperature is determined in rheometers. The higher value of complex modulus, the stiffer bitumen binder is able to resist deformation. The greater content of elastic components (e.g. polymer in bitumen) varies mainly elastic-viscous properties of primary bitumen.

scholarly journals Storage Stability and Morphology of Latex Modified Bitumen

2019 ◽  
Vol 9 (1) ◽  
pp. 4435-4440
Keyword(s):  
Phase Separation ◽  
Softening Point ◽  
Storage Stability ◽  
Asphalt Binder ◽  
Natural Rubber Latex ◽  
Modified Bitumen ◽  
Liquid Form ◽  
Modified Asphalt ◽  
Modified Asphalt Binder ◽  
Temperature Susceptibility

Bitumen modification is done to enhance the properties of bitumen related to elasticity, temperature susceptibility, softening point etc. This research intends to assess the effects of natural rubber latex (NRL) in liquid form as a bitumen modifier. Conventional tests, temperature susceptibility and phase separation due to hot storage were investigated using two separate mixing speeds of 1200 and 1300 revolution per minutes (rev/min). Morphology due to the addition of NRL has also been explored utilizing Atomic Force Microscopy (AFM). NRL was incorporated into the bitumen by weight of the binder for the modification at three different amounts (i.e. 3%, 5% and 6%). Based on the softening point, penetration value, temperature susceptibility and storage stability the latex-modified asphalt binder were analyzed. Results of the investigation showed that owing to enhancement in viscoelastic properties, the latex-modified asphalt binder will not undergo phase separation during hot temperature storage. Meanwhile, a uniform dispersed network was indicated by the morphological analysis with the presence of three phases of para, peri and cata. It can be deduced from the results obtained that the latex-modified asphalt binders will perform better in terms of softening point, penetration value and susceptibility due to temperature.

EFFECT OF FLOCCULATING AGENTS ON DRAG IN GRAVITY-DRIVEN FLOW SYSTEMS

2017 ◽  
Vol 44 (4) ◽  
pp. 339-347
Author(s):  
M. K. S. V. Raghav ◽  
Ravi Teja ◽  
Chirravuri Subbarao
Keyword(s):  
Flow Systems ◽  
Gravity Driven ◽  
Gravity Driven Flow
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