紫外老化对沥青流变性能的影响

This paper simulated the ultraviolet aging process of asphalt and used dynamic mechanic analysis （DMA） method to evaluate the effect of ultraviolet aging on the asphalt theological properties. After having experienced ultravio- let aging, the low temperature performance of asphalt binder decreased significantly, with its complex modulus increased and phase angle decreased along with changing rheological properties as compared to the performance of original asphalt binder. The ultraviolet aging process would make asphalt binder more sensitive to brittle and fatigue failure. On the basis of the time-temperature superposition principle （TTSP）, the viscoelastic transition frequency （coT） is proposed to evaluate the effect of ultraviolet aging. It is found that with the increase in ultraviolet aging time, the cox moves to the lower frequency range gradually. Since the viscoelastic transition frequency is sensitive to the effect of aging, it can be used as an indicator of ultraviolet aging.     

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.     

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.     

Long-term Aging Properties of Bitumen With Expanded Vermiculite and Different Inorganic Nanoparticles

The authors evaluate a novel bitumen modification by using the expanded vermiculite (EVMt) and three inorganic nanoparticles. The effect of EVMt and inorganic nanoparticles on physical and long-term aging properties of bitumen was investigated. The results show that the physical properties of bitumen are slightly influenced by with the introduction of nanomaterials. As a result of pressurized aging vessel, ultraviolet (UV) radiation aging, the viscosity aging index of bitumen is decreased obviously by adding the nanomaterials. It indicates that nanomaterials can improve the thermal and UV aging resistance of bitumen simultaneously. Furthermore, this improvement depends on the inorganic nanoparticle types. Compared with nano-silica and nano-titanium dioxide modified bitumens, bitumen with 1% EVMt and 3% nano-zinc oxide shows the lower viscosity aging index values, indicating its good long-term aging resistance.     

改性沥青的紫外老化研究

我国大部分地区尤其是西部地区日照时间长,太阳光谱中紫外线比例高,而紫外辐射同样也会导致沥青的老化。对传统基质沥青和SBS、消石灰、反应型三元共聚物(RET)及多聚磷酸(PPA)改性沥青的紫外老化特性进行了研究。试样的降解使用傅里叶变换红外光谱和热分析进行了分析,从红外光谱结果可以看出,当紫外老化200 h时,SBS、多聚磷酸(PPA)和消石灰改性沥青与传统基质沥青相比表现出更高的耐光降解能力。SBS改性沥青和消石灰改性沥青,老化后最大降解率的温度和降解终止温度增加。     

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.     

热老化行为对磁流变脂流变学性能的影响

磁流变器件在工作过程中因耗能不可避免地出现温升现象,为研究热效应对介质磁流变脂(MRG)流变学性能的影响,通过静态热处理方式模拟磁流变脂热老化情况。将磁流变脂在温度120 ℃的环境中进行4、8和24 h的热老化后,分别进行傅里叶变换红外光谱(FT-IR)、磁学性能及流变性能分析,以探究热老化行为对磁流变脂流变学性能的影响。结果表明：热老化对磁流变脂基载液润滑脂的皂纤维结构产生影响,进而影响磁流变脂性能。随着热老化时间的增加,磁流变脂出现剪切屈服现象的时间点不断提前,长时间高温条件下的热效应对磁流变脂微观结构破坏更大,更容易造成磁流变脂流变性能的显著变化。经过24 h热老化的磁流变脂在恒定剪切速率10 s^-1和温度85 ℃的测试条件下,磁场强度0 mT时磁流变脂的剪切应力为202.04 Pa,磁场强度440 mT时剪切应力可达1843.2 Pa。磁场在一定程度上降低了磁流变脂对温度的依赖性,但持续的热效应最终将会导致磁流变脂服役寿命缩短。     

紫外线作用下道路沥青老化行为研究

为了研究紫外线老化下沥青性能变化,选取同种产地、不同标号的两种基质沥青以及两种常规改性沥青,分析基质沥青在不同紫外线老化后组分变化,研究四种沥青在不同时长紫外绒老化后的三大指标、DSR和BBR试验。结果表明,选用沥青老化后C/H值来评价同种来源基质沥青紫外老化性能是可行的,并可以通过使用DSR、BBR补充评价基质沥青和改性沥青紫外线老化后的高低温流变性能。     

Storage Stability of SBS-Modified Road Asphalt: Preparation,Morphology, and Rheological Properties

Abstract

The hot storage stability of styrene-butadiene-styrene triblock copolymer (SBS)-modified road asphalt can be improved significantly by reactive blending of SBS and asphalt under high share mixing at high temperature with elemental sulfur and vulcanization accelerator. The storage stability, morphology, and rheological properties were analyzed and evaluated by means of the hot storage test, fluorescent microscopy, and conventional and dynamic mechanical analysis using a dynamic share rheometer (DSR), respectively. The test results indicate that not only storage stability but also rheological properties of SBS-modified asphalt were enhanced by reactive blending of SBS and asphalt. Moreover, the addition of cross-linking agent resulted in the change in morphology of SBS-modified asphalt from a continuous asphalt phase with dispersed SBS particles to two interlocked continuous phases. The formation of a chemically cross-linked network enhanced the elasticity and deformation resistance of SBS-modified asphalt.     

Storage Stability of SBS-Modified Road Asphalt: Preparation, Morphology, and Rheological Properties

The hot storage stability of styrene-butadiene-styrene triblock copolymer (SBS)-modified road asphalt can be improved significantly by reactive blending of SBS and asphalt under high share mixing at high temperature with elemental sulfur and vulcanization accelerator. The storage stability, morphology, and rheological properties were analyzed and evaluated by means of the hot storage test, fluorescent microscopy, and conventional and dynamic mechanical analysis using a dynamic share rheometer (DSR), respectively. The test results indicate that not only storage stability but also rheological properties of SBS-modified asphalt were enhanced by reactive blending of SBS and asphalt. Moreover, the addition of cross-linking agent resulted in the change in morphology of SBS-modified asphalt from a continuous asphalt phase with dispersed SBS particles to two interlocked continuous phases. The formation of a chemically cross-linked network enhanced the elasticity and deformation resistance of SBS-modified asphalt.     

Influence of multi-dimensional nanomaterials on the aging behavior of bitumen and SBS modified bitumen

The influence of multi-dimensional nanomaterials on the aging behavior of bitumen and styrene-butadiene-styrene copolymer (SBS) modified bitumen was compared. The laboratory aging methods included thin film oven test, pressure aging vessel and accelerated ultraviolet aging. The results showed that the deterioration of physical and rheological performances of two types of bitumens during thermal oxidation and photo oxidation aging could be slowed down by adding multi-dimensional nanomaterials effectively. In contrast with base bitumen, multi-dimensional nanomaterials had a better improvement on anti-aging ability of SBS modified bitumen. Fourier transform infrared spectroscopy test result manifested that multi-dimensional nanomaterials could retard the degradation of SBS modifiers during the aging process.     

湿度对PAV老化后沥青胶结料流变性能的影响

For the most coastal areas where the air is very humid, study on the effect of humidity on the performance of asphalt has its practical signiifcance. However, limited research has been done to investig...     

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.     

Study on the Technological Conditions of Crumb Tire Rubber-Modified Bitumens

Abstract

The use of waste tire rubbers as bitumen modifiers can contribute to alleviating pollution problems caused by discarding scrap tires. This article deals with the preparation and influencing factors of bitumens modified by crumb tire rubber. The performance of crumb tire rubber—modified bitumens (CTRMBs), such as penetration grade, softening point, and ductility, have been studied as a function of rubber selection, shearing temperature, shearing rotational speed, shearing time, rubber addition, and blended oil addition. From the experimental results obtained, optimal technology conditions were determined as: a shearing time of 40 min, a shearing temperature of 180°C, a shearing rotational speed of 7000 rpm, a rubber addition less than 25 wt%, and a blended oil addition less than 4 wt% during manufacturing operations. By using blended oil, the modified asphalt that measured up to standard of the crumb rubber—modified asphalt (FHWA-SA-92-002) was prepared, following the process flow diagram.     

生物柴油残渣对老化沥青物理性能的影响

利用生产生物柴油的残渣,经过物理分馏、冷凝过程获取可恢复老化沥青性能的生物再生剂。选择50号基质沥青进行短期老化试验,以沥青的针入度、软化点、延度为检验标准,发现添加生物再生剂的老化沥青性能可恢复到老化前标准;设定使再生沥青针入度恢复到50 1/10 mm的生物沥青掺量为最佳掺量,通过动态剪切试验(DSR)和沥青小梁弯曲试验(BBR)发现在最佳掺量条件下,再生沥青的高温抗变形能力和低温抗裂性均优于原50号基质沥青;与老化沥青相比,再生沥青高温抗变形能力略有下降,低温抗裂性大幅提高,证实了生物柴油残渣作为老化沥青再生剂的可行性。     

程序ⅥB试验老化对油品理化性能影响考察

通过对程序ⅥB发动机台架试验新油和老化油的运动黏度、摩擦系数、钙元素浓度、总酸值和总碱值等理化性能分析,考察了程序ⅥB发动机台架试验老化对油品理化性能的影响。结果表明,在程序ⅥB发动机台架试验中油品运动黏度随老化时间的增加先下降后上升;油品的摩擦系数随老化时间的增加而增大,老化初期摩擦系数增大速度较快,老化后期摩擦系数增大速度减缓;老化造成油品钙元素浓度增大,老化初期油品钙元素浓度增大较快,后期油品钙元素浓度增大速度减缓;老化造成油品总酸值增大、总碱值下降。     

Effect of different rejuvenators on the properties of aged SBS modified asphalt

The styrene-butadiene-styrene copolymer (SBS)–modified asphalt was aged by pressure aging vessel test. The effect of different content of rejuvenators on the physical and rheological properties of aged SBS-modified asphalt was investigated. The results showed that with the increase of the content, the physical and rheological properties of the aged SBS-modified asphalt are restored more significantly. Three kinds of rejuvenators were used to rejuvenate the properties of aged SBS-modified asphalt. It can be concluded that the improvement of rejuvenator-III on the properties of aged SBS-modified asphalt is the most obvious. The results also indicate that the rheological behavior of the aged SBS-modified asphalt is improved obviously by the rejuvenator.     

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.     

煤基均聚聚丙烯1100N性能研究

研究了煤基均聚聚丙烯1100N与对比试样的结晶性能、热氧稳定性能、相对分子质量及其分布、流变性能以及其他物理性能。研究结果表明,煤基均聚聚丙烯1100N的综合性能与同类产品相当,在加工应用领域可以替代石油基聚丙烯。     

紫外线对有机涂层的破坏机理及应对措施

在常温环境使用的有机涂层主要的老化方式为光老化,文章从地面太阳光的组成、紫外线对涂层的破坏两方面分析了涂层老化的机理,并对比分析了醇酸、丙烯酸树脂、聚氨酯、丙烯酸聚氨酯、氟碳树脂、聚硅氧烷等面漆的耐候性能,提出提高涂层耐老化性能的几点建议:(1)选择高键能的高分子材料作基料;(2)添加光屏蔽剂、光吸收剂、光稳定剂,实现对有机物的保护;(3)选择合理的涂层结构;(4)加快利用无机物作外防腐层的技术研究。