废旧橡胶粉改性沥青研究进展

介绍了废旧橡胶粉改性沥青的国内外应用状况,分析了胶粉改性沥青的特点、机理、方法以及胶粉改性沥青的贮存稳定性和感温性等。指出将废旧橡胶粉用于改性沥青,既能提高沥青的性能,又有利于废旧橡胶的循环利用,减少环境污染,有着良好的发展前景。提出我国应尽快制定出废旧橡胶粉改性沥青的行业标准规范。     

Utilization of sulfur and crumb rubber in asphalt modification

In this study, waste crumb rubber and sulfur were utilized to enhance the performance of asphalt binder for pavement applications. About 20–50% of sulfur and 1–6% crumb rubber were used. Melt properties were investigated using thermal analysis, dynamic and steady shear rheology, and artificial aging. Rheological tests were carried out in ARES rheometer. Both steady and dynamic shear rheology showed that crumb rubber improved the viscoelastic properties of the sulfur‐extended asphalt binder. Crumb rubber modification reduced temperature susceptibility of sulfur/asphalt, and increased the upper grading (performance) temperature of sulfur asphalt. The combined effect of sulfur and crumb rubber reduced the activation energy compared with that of pure asphalt. Zero‐shear viscosity and strategic highway research program rutting parameter (G*/sinδ) improved by crumb rubber incorporation into the sulfur asphalt binder. Short‐term aging improved G*/sinδ with slight increase in activation energy. The addition of sulfur to asphalt matrix increased the viscoelastic properties (G′ and G″) of sulfur asphalt. The addition of crumb rubber to sulfur asphalt enhanced the temperature resistance of the binder. Utilization of waste crumb rubber and sulfur in asphalt modification proved to enhance asphalt pavement life. In addition, utilization of such wastes can help in meeting the extra demand for asphalt, reduce the pavement cost, and help in solving a waste disposal problem. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40046.     

Fracture behavior of crumb rubber‐filled elastomers

The fracture behavior of a crumb rubber‐filled elastomer was observed in optical micrographs. It was found that the failure started from the surface of the unfilled samples. The failure, however, started from a cavity around a crumb in the crumb‐filled samples. This paper suggests that the failure mechanism in the crumb‐filled elastomers (NR, NBR) was based on the microscopic observation of highly strained samples. This paper also considers the failure behavior of two‐component systems: NR/NBR, SBR/NR, and NR/SBR. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3137–3144, 1999     

胶粉改性沥青的流变特性及改性机理

研究了胶粉改性沥青(CRMA)母料的流变特性,考察了混合时间及混合温度对CRMA母料流变特性的影响,提出并验证了胶粉对沥青改性的"力化学"机理。结果表明,与基质沥青相比,CRMA母料的表观黏度较高,黏流活化能与非牛顿指数较低,加入胶粉显著降低了沥青流变特性对剪切速率和温度变化的敏感性;提高混合温度与延长混合时间对CRMA母料流变特性的影响较大,最佳的混合时间为2h;胶粉与沥青混合过程中,混合体系的温度和胶粉的降解度随着混合时间的延长而增大,且在混合时间为2h时,80%以上的胶粉已发生降解;改性机理符合"力化学"原理。     

高胶粉含量改性沥青的稳定化制备及路用性能

研究了剪切时间、剪切温度以及胶粉、交联剂和活化剂用量对胶粉改性沥青性能的影响。结果表明,提高胶粉用量会增大体系的黏度,交联剂在增大体系黏度的同时也改善了其耐老化性能和高温储存稳定性,活化剂的加入可以降低体系黏度并提高其高温储存稳定性。在剪切时间为45 min和剪切温度为180℃的条件下,通过添加质量分数为25%的胶粉、占胶粉质量0.5%的交联剂以及少量的活化剂制备了高温储存稳定性及其他性能良好的胶粉改性沥青。对所制备胶粉改性沥青在沥青混合料密级配AC-16中的应用性能进行了检测,各项指标均能满足相关技术标准的要求。     

Obtaining a rubber-bitumen asphaltic concrete pavement binder by the thermocatalytic processing of petroleum residues in a mixture with rubber crumb in the presence of zeolites and organo-mineral activators

It has been ascertained that qualitative rubber-bitumen asphaltic concrete pavement binders can be obtained at one stage by the method of the catalytic thermolysis of residual oil in the mixture with rubber crumb of worn-out tires in the presence of synthetic or natural zeolites or pyroshale that adsorb coke besides catalyzing the process. The mineral part of pyroshale and zeolite powder with adsorbed coke and soot forming during the decomposition of rubber are a thin-disperse modifier of paving bitumens. The catalytic thermolysis of residual oil with adding 30–40% of rubber crumb proceeds under comparatively soft conditions (a temperature of 350–375° C, isothermal exposure with a duration of 10–30 min) in the presence of 1–3% of zeolite or pyroshale. The yield of a high-qualitative rubber-bitumen binder with the content of 18–20% of mineral and organic modifiers can reach 50–60 wt % of the used raw material. Rubber crumb is utilized completely. There are no foreign analogs of the suggested technology. An experimental-industrial installation with a capacity of 9000–10000 t of bitumen component/year was created in the city of Kudepsta in the Krasnodar Territory.     

Influence of processing conditions on the rheological behavior of crumb tire rubber‐modified bitumen

Traditional or technological studies about crumb tire rubber‐modified bitumens (CTRMBs) do not provide detailed rheological information. In that way, this article describes the influence of processing conditions on the linear viscoelastic and viscous behaviors of CTRMBs. The results of the study reveal an exponential increase in dissolved/dispersed rubber with processing temperature and, therefore, lower solid content that affect the rheological behavior in different ways. No influence of the processing device was observed, probably due to the fact that processing temperature (180°C) was not high enough to break up the crosslinked network of the rubber. The presence of rubber particles avoids the negative hardening effects observed for unmodified bitumens, resulting in a more flexible binder at low temperature. At high in‐service temperature, better rutting resistance would also be expected for CTRMBs. Flow results at 135°C indicates that modified bitumens can satisfy the AASHTO MP1 requirements if high‐enough shear rates are reached. All the CTRMBs studied present segregation, due to rubber settling during storage at high temperature, although an increase in processing temperature seems to enhance its stability. The results obtained seem to indicate that the optimum CTRMB processing temperature is 210°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1683–1691, 2007     

Graft copolymerization of acrylonitrile and methyl methacrylate monomer mixtures on crumb natural rubber

Graft copolymerization of mixtures of acrylonitrile and methyl methacylate on crumb natural rubber was carried out in toluene at 60°C. The nitrogen content of the grafted copolymer was determined by elemental analysis and used to estimate the composition of the copolymer samples. It was found that the amount of acrylonitrile monomeric units incorporated into the polymer was disproportionately lower than the acylonitrile content of the feed and explanations in terms of the e‐value of the monomers and the inherent heterogenous nature of the polymerization mixture were offered. The miscibility of the natural rubber‐g‐polyacrylonitrile‐co‐poly(methyl methacrylate) with poly(vinyl chloride) was studied by viscometry, differential scanning calorimetry, and phase contrast microscopy. It was found that the natural rubber‐g‐polyacrylonitrile‐co‐poly(methyl methacrylate) formed semimiscible blends with poly(vinyl chloride). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1872–1877, 2002; DOI 10.1002/app.10474     

废轮胎橡胶粉改性沥青混合料的性能研究进展

介绍了国内外废轮胎橡胶粉的分类、物理和化学指标及其改性沥青的性能指标,对北京地区路用废轮胎橡胶粉改性沥青混合料的性能指标提出了建议,并对废轮胎橡胶粉改性沥青混合料的路用性能进行了分析,指出将废轮胎橡胶粉改性沥青用于道路建设是资源再利用的一条有效途径。     

The biological and chemical desulfurization of crumb rubber for the rubber compounding

The disposal of used car tires has become a major environmental problem, especially in densely populated countries that use motor vehicles as the principle means of transportation. Widespread recycling of waste tires has not taken place because it has not proven to be cost effective. Although there are obvious environmental reasons for recycling waste tires, to date it has not proven to be economically valuable. The aim of this study is to find a more economical way of recycling used car tires. This was done by the “unvulcanization” of vulcanized crumb rubber by two different treatments; chemical treatment with di‐(cobenzanidophenyl)disulfide, and microbial treatment with T. peromatabolis. The experimental results indicate that the processing of crumb rubber, as well as the end‐product properties, were enhanced by both these treatments, with the microbial treatment being the most effective. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1543–1549, 1999     

Thermomechanical properties of bitumen modified with crumb tire rubber and polymeric additives

In this paper, the influence of some additives on the rheological and technological properties of crumb rubber modified binders has been studied. The research has been mainly focused on the degree of bitumen modification, measured as the improvement of the mechanical properties, produced by the additives used, and the storage stability of these binders at high temperature. The experimental results obtained reveal that all the polymeric additives used yield an improvement in both rheological and technological properties of the binder. The storage instability of these binders has been associated to sedimentation processes of insoluble CR particles that strongly influence the mechanical properties of the binder. The additives and processing conditions selected in this study do not completely prevent problems associated with the poor stability of CRMBs during storage at high temperature. Nevertheless, the use of polyoctenamer, FT-wax or SBS-containing additives improves CRMB stability. In this sense, similar loss tangent values were found before and after hot storage of these binders.     

废旧胶粉改性沥青的高温贮存稳定性

介绍了废旧胶粉改性沥青的机理,分析了影响废旧胶粉改性沥青高温贮存稳定性的因素,从配方、工艺等方面综述了目前国内外提高废旧胶粉改性沥青高温贮存稳定性的方法,展望了废旧胶粉改性沥青贮存稳定性的发展前景,认为提高高温贮存稳定性是废旧胶粉改性沥青工厂化集中生产和稳定化应用的前提.     

常温法精细硫化胶粉在轮胎胶料中的应用研究

以常温法80目精细胶粉用于载重轮胎的胎面和胎侧胶料为例,系统考察了这两种胶料掺用胶粉后的加工性能及其硫化胶的物理性能,其中着重对胶粉在胶料中的分散状态,硫化胶各项常规物理性能以及动态力学性能等进行了试验研究和对比。结果表明,轮胎胶料中掺用80目精细硫化胶粉对其加工性能影响不大,有利于胶料的混炼操作及胎面的流动性,但用量以小于15份为宜;经精炼的胶粉还可以改善胎面胶的撕裂强度、 拉伸强度及耐磨性。     

Physical and rheological properties of crumb rubber/styrene–butadiene–styrene compound modified asphalts

In order to improve the storage stability and tenacity of crumb rubber modified (CRM) asphalt, CRM compound modified asphalt was prepared by the addition of styrene–butadiene–styrene (SBS) and sulfur. The addition of SBS improved the tenacity of CRM asphalt, due to the formation of a dense polymer network. The storage stability of crumb rubber (CR)/SBS‐modified (CRSM) asphalt was improved by the addition of sulfur. The rheological tests confirmed the effect of SBS and sulfur on the physical properties of CRM asphalt to some extent and showed the susceptibility of CR/SBS/sulfur‐modified (CRSSM) asphalt to dynamic shearing. The morphology observation showed the compatibility of CRSM asphalt was improved greatly by vulcanization. POLYM. COMPOS., 38:1918–1927, 2017. © 2015 Society of Plastics Engineers     

RD－F体系活化胶粉对胶料加工性能的影响

研究ＲＤ－Ｆ活化胶粉及其用量对混炼胶硫化性能、流变性能及硫化胶物理机械性能和动态压缩疲劳性能的影响。并与非活化胶粉进行对比。同时从理论上对影响机理作了初步探讨。试验结果表明，ＲＤ－Ｆ活化胶粉用量在１５份以下时对胶料硫化性能基本无影响；与非活化胶粉相比，可进一步减小胶料挤出膨胀率；随着ＲＤ－Ｆ活化胶粉用量增大。硫化胶拉伸强度、扯断伸长率呈下降趋势，３００％定伸应力、压缩疲劳温升、压缩永久变形呈上升趋势．撕裂强度出现极大值，而且这些性能的变化比未活化胶粉胶料的要小得多。     

废橡胶颗粒沥青混合料级配组成的优化

应用星点设计-效应面优化法进行废橡胶颗粒沥青混合料级配组成的优化设计,运用SPSS软件分析实验结果,描绘了橡胶颗粒掺量、粗集料用量和粗橡胶颗粒用量等影响因素的效应面,建立了相应的数学模型,得到了橡胶颗粒沥青混合料的最优级配组成。结果表明,当橡胶颗粒掺量为2.0%~6.0%、粗集料用量为60.0%~75.0%、粗橡胶颗粒用量为30.0%~60.0%时,橡胶颗粒沥青混合料综合性能最优;将星点设计-效应面优化法应用于橡胶颗粒沥青混合料的级配组成优化是可行的。     

Manufacturing an asphalt-rubber binder for asphalt concrete road pavement via joint thermolysis of crumb rubber with heavy petroleum residues

Thermolysis of heavy petroleum residues (atmospheric and vacuum residua) mixed with crumb rubber obtained via shredding of spent automobile tires was studied, and it was shown that a high-quality asphalt-rubber binder for asphalt concrete road paving can be prepared with the use of this process. Under optimal conditions (temperature 350–415 °C, isothermal holding time 10–20 min, amount of the activator oil shale 2–3 wt %), a 58–60% yield of the asphalt-rubber binder fraction on the basis of the feed mass can be obtained via the thermolysis of heavy petroleum residues in a mixture with 25–40% crumb rubber. The quality of the obtained binder meets the GOST (STate Standard) 9128-97 specifications for road pavements in Russian roadway climatic zone I–II.     

Influence of PP fiber and SBR latex on the mechanical properties of crumb rubber mortar

This article presents a new kind of rubber mortar modified by polypropylene fiber (PP fiber) and styrene‐butadiene rubber latex (SBR latex). The mechanical properties of this crumb rubber mortar were investigated in the research, including the compressive strength, flexural strength, flexural toughness, and flexural elasticity modulus. The test results showed that the flexural toughness index of the rubber mortar was seen to enhance by about 50–100% with the addition of PP fiber and SBR polymer latex. Due to the addition of PP fiber and SBR latex, the flexural elastic modulus of rubber mortar could further reduce by 4–27%. The three‐phase composite dispersion model of this rubber mortar was put forward. Furthermore, it was observed from scanning electron micrograph that the interfacial transition zone between the rubber particles and cement paste was enhanced by the SBR latex, and the interleaving of polymer films and rubber particles strengthen the flexibility and toughness of the mortar. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40591.     

Use of isocyanate production waste in the preparation of improved waterproofing bitumen

Waste residue generated during the production of toluene diisocyanate was used as a modifier in making improved waterproofing bitumen. The waste particles were surface‐modified with stearic acid. Various bitumen blends based on untreated particles, surface‐treated particles, and a combination of an SBS elastomer and waste particles were prepared. The optimized blends were subjected to evaluate their response against temperature and frequency sweeps. It was observed that improvement of the softening point and reduction in penetration could be correlated with the blend morphology in terms of the compatibility between the waste particles and the bitumen. The increased glass transition temperature and satisfactory phase miscibility in the modified bitumen observed in MDSC and DMA traces supported these findings. The coefficient of linear thermal expansion of the modified bitumen was found to be 1.21 × 10^?4/°C. The rheological studies revealed that time‐dependent properties of the modified bitumen were better in terms of its stiffness and elasticity than that of neat bitumen. The applicability of the Williams–Landel–Ferry (WLF) equation confirms the superior temperature‐dependent response of the modified systems over the control. It was noticed that stearate‐treated waste‐modified bitumen gives the best results in terms of a high complex modulus and a low phase angle. The newly formulated bituminous blend based on stearate‐treated waste meets the requirement of existing standard specifications for waterproofing felt. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1365–1377, 2003     

废旧轮胎橡胶颗粒在沥青混合料中的应用

为了探索废旧橡胶轮胎回收再利用的新途径,研究了橡胶颗粒沥青混合料的级配及拌和、成型方法,并通过车辙实验、低温小粱弯曲实验和冻融劈裂实验等分析了橡胶颗粒沥青混合料的高低温性能和抗水损害性能等基本路用性能。论证了将废旧轮胎橡胶颗粒作为骨料应用于筑路用的沥青混合料的可行性。