Evaluation of Waste Express Bag as a Novel Bitumen Modifier

With the rapid development of China’s e-commerce and logistics industry, a large number of waste express bags (WEBs) have been produced, which are difficult to recycle. The existing methods of waste express bag disposal often cause severe environmental pollution. It was discovered in this paper that the use of WEBs to modify bitumen could be an environmentally friendly way to recycle WEBs. This study aimed to investigate the feasibility of using WEBs to modify bitumen and promote the performance of WEB-modified bitumen. In order to verify this assumption, a series of basic or rheological experiments were conducted on different dosages of WEB-modified bitumen. The test results and phenomenon showed that the WEBs could be used to modify the binder homogeneously by using a high-speed shearing machine. The basic experiments showed that the WEBs could decrease the penetration and ductility while increasing the softening point and the rotational viscosity. Additionally, the rheological experimental data indicated that the high temperature performance was improved while the low temperature performance stayed the same. The Fourier-transform infrared spectroscopy (FTIR) results demonstrated that modification of the WEB was a physical modification without chemical reaction and the main component of the modifier was polyethylene. The fluorescence microscope (FM) data revealed the micro-structures of different dosages of WEB-modified bitumen. In conclusion, WEB can be a feasible binder modifier.

Investigation of UV Absorber Residue Improving Aging Properties of Bitumen

Ultraviolet (UV) absorber residue was used to modify bitumen. Effects of UV absorber residue on thermo-oxidative and UV aging properties of bitumen were evaluated by conventional physical properties and SARA (saturates, aromatics, resins and bitumenenes) analysis. The results showed that the viscosity aging index (VAI) and softening point increment (SPI) of bitumen decreased significantly due to introduction of the UV absorber residue, and the ductility retention rate (DRR) was evidently higher compared to the pristine bitumen. SARA show that UV absorber residue can effectively restrain the gelatinization of bitumen resulted from aging. As a consequence, the UV absorber residue modified bitumen displays enhanced aging resistance properties, which can be attributed to the physical sorption of activated carbon to lighter components in the thermo-oxidative aging process and the absorption of UV absorption residue to the ultraviolet light in the process of UV aging.

Optimization of content of a new modifier type in bitumen intended for waterproofing products

Styrene-butadiene-styrene (SBS) is currently the most popular bitumen modifier. Its weaknesses have become a strong incentive to search for new materials that could modify bitumen in a similar scope as SBS, but would be cheaper and easier to use. The article presents the results of studies of oleic imidazoline — a new generation bitumen modifier. The analysis of the results of laboratory tests allowed for the optimization of its content in bitumen. It has been demonstrated that the new type modifier developed by the authors of the article has a significant impact on physical characteristics of bitumen. Its use results in a significant increase of bitumen plasticity range, both before and after laboratory ageing, and a considerable improvement of bitumen resistance to ageing.

Investigation of Anti-UV Aging of Bitumen Modified with Layered Double Hydroxides

Layered double hydroxides (LDHs) were used to modify bitumen. Effect of LDHs on physical properties and chemical compositions of bitumen was investigated. Fourier transform infrared (FTIR) spectroscopy was carried out to analyze the structural change of LDHs modified bitumen after UV aging. The results show that LDHs is effective in improving the UV aging resistance of bitumen since the viscosity aging index (VAI) and softening point increment (SPI) of bitumen decrease while the retained penetration ratio (RPR) increases with increasing LDHs contents. The carbonyl and sulfoxide of LDHs modified bitumen presented a smaller increase after UV aging in comparison with unmodified bitumen according to FTIR analysis, and the changing rate of carbonyl and sulfoxide index of aromatics and asphaltenes reduced obviously compared with the slight changes of saturates and resins after the introduction of LDHs during UV aging, which demonstrated that LDHs mainly inhibit the oxidation of aromatics and asphaltenes during the UV aging.

Influence of Nanoparticles Modification on the Properties of Bitumen

In this study, the influence of some inorganic nanoparticles on the properties of bitumen binder was investigated. Three types of particles at nanometer level, calcium carbonate powder, graphite and carbon black, were introduced to modify bitumen respectively. The modified binders were prepared using a laboratory high-shear mixer. A dynamic shear rheometer (DSR) was adopted to characterize the properties of modified binders, including their rheological parameters and dynamic viscosity, over a certain range sweeps of temperatures, frequencies and shear rates. It was found that the addition of the nanoparticles increased the binder’s elasticity at low temperature which might negatively influence its resistance to crack. However the decrease of phase angle at high temperature might improve its deformation resistance. The shear rate dependence of dynamic viscosity for the binders depended on the type of nanoparticle. The research results indicated that the addition of nanoparticles to bitumen binder can change its physical properties to some extent and its potential should be researched further.