Effect of Nano-zinc Oxide on the Morphology and Ultraviolet Aging Properties of Various Bitumens

Effect of nano-zinc oxide (nano-ZnO) on the morphology and ultraviolet (UV) aging properties of two bitumens was investigated by atomic force microscopy, physical properties and Fourier transform infrared spectroscopy before and after UV aging. The results show that the mechanism of nano-ZnO depends on the base bitumen. In one case, nano-ZnO contributes to the homogeneous dispersion of bee-like structures. In the other case, it leads to the separation of asphaltenes from the matrix. Compared with B2, nano-ZnO exhibits a better improvement in UV aging resistance of B1 by showing the lower increased viscosity values, rheological aging index, and carbonyl indexes.     

The Effect of Surface-modified Nano-titania on the Ultraviolet Aging Properties of Bitumen

The effect of surface modification of nano-titania on ultraviolet (UV) aging properties of bitumen was investigated. The results show that γ-(2,3-epoxypropoxy) propytrimethoxysilane is bound on the surface of nano-titania according to Fourier transform infrared spectroscopy analysis. The dispersion stability of nano-titania in bitumen is improved by surface modification of nano-titania. Viscosity aging index values and carbonyl indexes of the bitumen are decreased by adding nano-titania. After surface modification, the UV aging resistance of nano-titania modified bitumen can be further improved. The result suggests that nano-titania can be effectively used as a modifier to improve the UV aging resistance of bitumen.     

The Effect of Sodium and Organic Montmorillonites on the Thermal Aging Properties of Bitumen

Effect of sodium and organic montmorillonites on the thermal aging properties of bitumen was investigated by thin-film oven test and pressure-aging vessel test. The microstructures of montmorillonite and the binders were characterized by X-ray diffraction. The results show that the sodium montmorillonite (Na⁺-Mt) modified bitumen forms a phase-separated structure, while the organic montmorillonite (OMt) modified bitumen forms an intercalated structure. The thermal aging properties of bitumen are improved obviously with the introduction of montmorillonite. Compared with Na⁺-Mt, the changes of physical properties of bitumen are further decreased by OMt, indicating the good aging resistance of intercalated OMt modified bitumen.     

Improving the Aging Resistance of Bitumen by Reduction

The aging properties of bitumen evaluated by means of Fourier transform Infrared spectroscopy. The effect of sodium borohydride as a reducing agent on the chemical structure of bitumen in aging process was studied. The bitumen was aged by means of the rolling thin film oven test then pressure aging vessel. Reduced modified bitumen were resistant to the formation of carbonyl and sulfoxide groups nearly unchanged, indicating the improvement of aging resistance of bitumen by the reduction process. As well as physical properties tests (penetration and softening point) of bitumen showed the more resistance of reduced modified bitumen against aging.     

Microstructures and Thermal Aging Properties of Layered Silicate Modified Bitumens

The influence of the layered silicate (LS) nature and its organic modification on microstructures and thermal aging properties of bitumen was evaluated. The results show that montmorillonite and expended vermiculite modified bitumens form the phase-separated structure, while the rectorite modified bitumen forms the intercalated nanostructure. After organic modification, montmorillonite and rectorite modified bitumens show the intercalated nanostructure, while the expended vermiculite modified bitumen shows the exfoliated nanostructure. The thermal aging properties of the binders mainly depend on the nature of LS (mainly its specific surface area), with no significant influence of the nanostructure formed in the modified bitumens.     

Isolation of Naphthenic Acids and Influence on the Properties of Bitumen

Naphthenic acids, separated from a bitumen and a furfural extract by extraction with solution of ammonia in ethylene glycol, have been added to the bitumen for the investigation of the influence on its properties. The results indicate that the ductility of the bitumen decreased and its penetration increased after mixed with these naphthenic acids. The data obtained also show that the naphthenic acids of furfural extract with lower molecular weight have greater impact on the ductility of bitumen than the naphthenic acids of bitumen with higher molecular weight.     

The Relationship Between Colloidal Chemistry and Ageing Properties of Bitumen

Abstract

The colloidal indices based on generic fractions, namely saturates (Sa), aromatics (Ar), resins (Re), and asphaltenes (As), were applied to evaluate the correlations between colloidal chemistry and ageing properties of bitumen. The results show that colloidal index Ip (value of Re/As) is positively correlated with penetration retention rate and ductility retention rate. The softening point increment is significantly influenced by colloidal index Is [value of As/(Sa + Ar + Re)]. The colloidal index Ic [value of (Ar + Re)/(Sa + As)] is obviously correlated with viscosity ageing index. Higher value of Ip and Ic, as well as lower value of Is, implies a better ageing resistance of bitumen.     

不同方法制备的硫转移剂物化性质及脱硫性能

常规方法制备的RFS-1硫转移剂MgO含量较低且磨损指数较差,采用铈化合物全部加入成胶过程的方法制备的RFS 2及采用铈化合物全部加入浸渍过程的方法制备的RFS-3硫转移剂在提高MgO含量的前提下保证了催化剂的抗磨损性能,并采用XRF、XRD、DTA、BET、XPS、SEM、TEM等分析手段及FCC再生烟气脱硫性能评价实验对3种不同制备方法得到的硫转移剂进行表征和性能考察。结果表明：RFS-3为MgAl2O4表面负载金属CeO2且富集MgO的结构、镁铝尖晶石晶体结晶保留度高,具有较为优良的热稳定性、孔道结构及表面、体相元素分布状态;具有较好催化剂外观形貌,且催化剂球形度好、破损黏联少;烟气脱硫效果最好,吸附时间500 s之内烟气SO2体积分数最低,且烟气脱硫效果及性能保留时间最长。     

HR3C钢焊接接头高温时效后的显微组织和力学性能试验研究

通过力学性能试验、光学金相显微镜、透射电子显微镜,研究了HR3C钢焊接接头高温时效后的显微组织和力学性能。试验结果表明,经650 ℃时效,HR3C钢焊接接头的强度和硬度升高,焊缝硬度上升幅度大于母材;焊缝的时效脆化倾向明显,时效7 000 h后冲击功都保持在15 J以下。对试验结果的分析表明,焊缝区晶界处M₂₃C₆相的连续网状分布及σ相、G相的存在导致了其较低的缺口冲击功,而晶内均匀细小Z相的沉淀强化作用则提高了接头的强度和硬度。     

不同形貌MCM-22分子筛的合成及其催化性能

在MCM-22分子筛的合成中,通过调节水热晶化参数、改变硅源及搅拌条件,得到了具有片状、饼状、球形且晶粒尺寸不同的MCM-22分子筛,采用XRD、SEM和氮气物理吸附对样品进行表征,并考察了其在连续固定床苯与乙烯液相烷基化反应及在1,3,5-三异丙苯裂解反应中的催化性能。结果表明,MCM-22分子筛的形貌对其催化性能影响显著,晶粒尺寸越大、聚集程度越高,其在苯烷基化反应和1,3,5-三异丙苯裂解反应中的催化性能越差。     

制管工艺及应变时效对X70抗大变形钢管性能的影响

结合中缅天然气管线工程用X70级准1016mm×17.5mm抗大变形直缝埋弧焊管的试制,研究了直缝埋弧焊管制管前后、应变时效前后力学性能变化的一般规律。成型、扩径工艺导致母材发生加工硬化,产生较强的形变强化,使其屈服强度、抗拉强度、屈强比同时增大,使均匀延伸率、应力比降低,且屈服强度、屈强比的增加幅度要大于抗拉强度的增加幅度。应变时效使材料均匀延伸率进一步降低。但是制管和时效后钢管管体各项性能均在X70抗大变形钢管标准要求的范围内,管体纵向应力-应变曲线仍呈圆屋顶形,试制的X70抗大变形钢管具有优异的变形能力。     

Ultraviolet and PAV aging procedures influence on rheological characteristics of Sasobit/SBS modified binder containing titanium dioxide nanoparticles

Abstract

The objective of this study is to evaluate the rheological properties of styrene-butadiene-styrene and Sasobit modified asphalt binder blended with various contents (0%, 1%, 3% and 5%) of nano-titanium dioxide (TiO₂) after Ultraviolet (UV) aging and PAV aging procedures. Rheological test results showed that nanoparticles generally had no effect on the complex modulus and phase angle of binders. UV aged binders showed better fatigue and cracking resistance than the PAV aged binders. Finally, compared to the control binder, the binder with nanoparticles had a higher fatigue resistance after UV aged, but worse fatigue resistance after PAV aged.