scholarly journals Chemo-Rheological Study of Hardening of Epoxy Modified Bituminous Binders with the Finite Element Method

2018 ◽  
Vol 2672 (28) ◽  
pp. 190-199 ◽  
Author(s):  
P. Apostolidis ◽  
X. Liu ◽  
C. Kasbergen ◽  
M.F.C. van de Ven ◽  
G. Pipintakos ◽  
...  
Keyword(s):  
Activation Energy ◽  
Mechanical Response ◽  
Chemical Interaction ◽  
Influential Factors ◽  
Polymerization Rate ◽  
Gel Point ◽  
Physical Factors ◽  
Modified Bitumen ◽  
Reaction Extent ◽  
Bituminous Binders

The chemical irreversible hardening of epoxy modified bitumen is affected by various physical factors and the successful application of this technology is directly linked with full understanding of chemo-rheological material characteristics. This study proposes a model to describe the material viscosity evolution during hardening of epoxy modified bitumen. The findings from numerical analyses performed to assess the mechanical response of epoxy modified bituminous binders are presented. Information of the chemical interaction of epoxy within a bituminous matrix was collected and all the influential factors have been determined. The proposed chemo-rheological model accounting for the polymerization of the epoxy in the bitumen was formulated and the sensitivity of material parameters, such as activation energy, reaction order and extent of hardening reaction until the gel point of epoxy modified binders, was demonstrated. Results of the analyses suggest that lower levels of activation energy increase the degree of hardening and the rate of viscosity development. By decreasing the hardening reaction until the gel point the achieved viscosity of epoxy modified bitumen was increased showing the importance of gel reaction extent on material viscosity evolution. The numerical studies have shown also that the polymerization rate in the epoxy modified bitumen is highly dependent on the temperature under various (non-) isothermal conditions. Also, the polymerization rate should be considered through all the material curing processes to avoid unwanted variations in the mechanical properties.

scholarly journals Analysis of Fatigue and Healing Properties of Conventional Bitumen and Bio-Binder for Road Pavements

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 420 ◽  
Author(s):  
Elena Gaudenzi ◽  
Fabrizio Cardone ◽  
Xiaohu Lu ◽  
Francesco Canestrari
Keyword(s):  
Experimental Approach ◽  
Fatigue Behavior ◽  
Self Healing ◽  
Aged Condition ◽  
Temperature Dependent ◽  
Modified Bitumen ◽  
Complex Issue ◽  
Rheological Measurements ◽  
Bio Oil ◽  
Bituminous Binders

The analysis of fatigue behavior of bituminous binders is a complex issue due to several time-temperature dependent phenomena which interact simultaneously, such as damage accumulation, viscoelasticity, thixotropy, and healing. The present research involves rheological measurements aimed at evaluating the fatigue behavior and compares the self-healing capability of two plain bitumen and a bio-binder obtained by partially replacing one of the plain bitumen with a renewable bio-oil. Healing potential was assessed by means of an experimental approach previously implemented for modified bitumen and bituminous mastic and based on the use of a dynamic shear rheometer (DSR). The effects of some variables such as bitumen type, bio-oil addition, and aging on the healing potential of binders were taken into account. Results showed that the above-mentioned method for healing analysis is also suitable for conventional and bio-add binders. Outcomes of the experimental investigation highlight that fatigue and self-healing are mainly dependent on binder consistency and also affected by aging. Finally, the addition of bio-oil may induce even better performances in terms of healing potential compared to conventional bitumen, especially in aged condition.

Application of New Emulsifier on Acrylic Emulsion Polymerization

2012 ◽  
Vol 554-556 ◽  
pp. 236-239
Author(s):  
Shi Gao Song ◽  
Shao Guo Wen ◽  
Ji Hu Wang ◽  
Yan Shen
Keyword(s):  
Activation Energy ◽  
Emulsion Polymerization ◽  
Correlation Coefficient ◽  
Polymerization Rate ◽  
Initiator Concentration ◽  
Acrylic Emulsion ◽  
Alkyl Glycosides ◽  
New Type ◽  
The Relationship ◽  
Emulsifier Concentration

In this paper, we studied the influence of the amount of alkyl glycosides emulsifier, reaction temperature and the amount of initiator on emulsion polymerization kinetics. The results show that when we apply the new alkyl glycosides emulsifier in acrylic emulsion polymerization, the relationship between polymerization rate Rp and emulsifier concentration [S] is Rp∝[S]0.70 and the correlation coefficient is 0.93; the relationship between polymerization rate Rp and the initiator concentration [I] is Rp∝[I]1.00 and the correlation coefficient is 0.86; the apparent activation energy of polymerization is 32.34KJ/mol and the correlation coefficient is 0.93. We got good results after applying the new type emulsifier in acrylic emulsion polymerization.

Characterizing mechanical response of bio-modified bitumen at sub zero temperatures

2020 ◽  
Vol 240 ◽  
pp. 117940
Author(s):  
Pouria Hajikarimi ◽  
Albert Onochie ◽  
Ellie H. Fini
Keyword(s):  
Mechanical Response ◽  
Modified Bitumen

Thermomechanics of Elastomers Undergoing Scission and Crosslinking at High Temperatures

2003 ◽  
Vol 31 (2) ◽  
pp. 68-86 ◽  
Author(s):  
A. Wineman ◽  
A. Jones ◽  
J. Shaw
Keyword(s):  
Service Life ◽  
High Temperatures ◽  
Material Properties ◽  
Mechanical Response ◽  
Mechanical Energy ◽  
Physical Factors ◽  
Material System ◽  
Dissipative Effects ◽  
Elastomeric Materials ◽  
Materials Used

Abstract The elastomeric materials used in tires are frequently subjected to severe thermal, chemical, and mechanical stress conditions. These conditions produce significant changes in material properties that affect their service life. The prediction of service life has become an increasingly important part of the engineering design process, and there is a need for a robust life-prediction model. There are many physical factors that affect the durability of an elastomeric material, such as deformation, conversion of mechanical energy to heat arising from dissipative effects, heat transfer within the component, and changes in material properties because of changes in microstructure. The goal of this work is the development of a thermomechanics model that incorporates these factors. This study focuses on the effect of high temperatures on an elastomeric component. There are two sources of temperature increase, a hot environment and internal heating attributed to mechanical loading such as occurs during cyclic loading. Internal mechanical heating can lead to substantial temperatures occurring within the component. When the temperature of the material becomes sufficiently high, macromolecules undergo time-dependent scission, recoil, and may crosslink to form new networks with new reference configurations. This process can affect the stiffness of the material system, induce anisotropy, and lead to permanent set. A constitutive theory is presented that accounts for this temperature-dependent microstructural change on the mechanical response. It is based on experimental results and is motivated by the two-network theory of Tobolsky. The theory is applicable for large deformation and varying temperature histories. An example is presented that illustrates the implications of scission and re-crosslinking.

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