In order to take a precise and objective evaluation on asphalt-aggregate adhesion, this paper analyzed the function at asphalt- aggregate interface using surface free energy theory. Two asphalts and two aggregates wer...In order to take a precise and objective evaluation on asphalt-aggregate adhesion, this paper analyzed the function at asphalt- aggregate interface using surface free energy theory. Two asphalts and two aggregates were selected and their surface free energy parameters, FLW, F and F-, were measured by the Wilhelmy plate method and the column wicking technique, respectively. Then, the resistance to moisture damage of asphalt mixture were predicted using calculated asphalt-aggregate adhesive bond energy and asphalt cohesive bond energy. The results show that moisture damage is a thermodynamically favorable phenomenon. Asphalt with a great acid-base polar component and a low Lifshitz-van der Waals apolar component always exhibits perfect cohesion.展开更多
In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag ...In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag powder and mineral powder(limestone powder)were compared by scanning electron microscope(SEM),and the high-temperature rheological properties of asphalt mortar with difierent ratio of filler quality to asphalt quality(F/A)and difierent substitution rates of mineral powder(S/F)were studied by dynamic shear rheological test.The results show that the surface microstructure of steel slag powder is more abundant than that of mineral powder,and the adhesion of steel slag to asphalt is better than that of limestone.At the same temperature,the lower the ratio of S/F is,the greater the rutting factor and complex modulus will be.In addition,the complex modulus and rutting factor of the asphalt mortar increase with the increase of F/A,and the filler type and F/A have a negligible efiect on the phase angle.展开更多
In order to solve the problems caused by the storage of iron ore tailings (IOTs), many researchers conducted a series of experimental studies on the reuse of IOTs. The results of many studies showed that it was feasib...In order to solve the problems caused by the storage of iron ore tailings (IOTs), many researchers conducted a series of experimental studies on the reuse of IOTs. The results of many studies showed that it was feasible to use IOTs for road engineering. This paper summarized the composition, gradation and particle characteristics of IOTs from chemical and physical aspects, and proved the feasibility of IOTs replacing traditional aggregate for asphalt concrete. Then, the research on the road performance of asphalt concrete incorporating IOTs were summarized and reviewed, including the evaluation of high-temperature stability, low-temperature crack resistance, fatigue resistance and water stability. The water stability and the improvement of adhesion between asphalt and IOTs aggregate were discussed in detail. Finally, the performance of IOTs as asphalt concrete aggregate and the existing defects were evaluated, and future research directions were proposed.展开更多
Breaking waste tires into crumb and adding it to asphalt as modifier to prepare asphalt rubber (AR) is an effective method to solve the waste tire problem and improve the performance of matrix asphalt. The modified as...Breaking waste tires into crumb and adding it to asphalt as modifier to prepare asphalt rubber (AR) is an effective method to solve the waste tire problem and improve the performance of matrix asphalt. The modified asphalt has better high and low temperature performance. However, the segregation of the crumb rubber modifier (CRM) causes storage instability of the AR. At present, studies have been conducted that improving the solubility of the CRM or adding some macromolecular polymer can improve the storage stability of the AR. However, the structure and polarity of the CRM surface are rarely explored for its correlation with the storage stability of AR. In this paper, the surface structure and polarity of the CRMs was changed by four different reagents, and the properties of the ARs prepared by the CRM were measured to analyze the adhesion between the CRM and the asphalt. It is concluded that the CRM with rough porous and non-polar surface has higher storage stability due to the better interfacial adhesion, which provides a research direction for improving the storage stability of rubber asphalt.展开更多
原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥...原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥青结合料与集料之间的水分相互作用是一种出现在微观尺度,甚至纳米尺度的现象,因此从微纳观角度探究在水分存在条件下沥青与集料的结构变化,对于改善沥青混合料水稳定性能,探究其水损害机制具有深远的意义。本文在总结AFM工作原理及沥青微观“bees”结构特性的基础上,重点分析了AFM在纳米尺度上对沥青混合料水稳性能的研究成果,并探讨了AFM在沥青路面材料研究中的发展方向,为今后对于沥青路面病害研究与防治方面提供一定的借鉴。展开更多
Chip seal is widely used for preventive maintenance to mitigate pavement deterioration,but it is prone to aggregate loss during pavement service.To further promote the development and application of chip seals in road...Chip seal is widely used for preventive maintenance to mitigate pavement deterioration,but it is prone to aggregate loss during pavement service.To further promote the development and application of chip seals in road engineering in China,the research progress of the adhesion behavior of aggregate and binder in chip seals was reviewed in this paper,focusing on the adhesion mechanism of emulsified asphalt and alkaline aggregate.The Influencing factors and evaluation methodology of chip seals'aggregate adhesion behavior were also discussed.The results demonstrate that the adhesion process between emulsified asphalt and alkaline aggregate is divided into three processes including infiltration,demulsification,and cluster,which is more complicated when compared to hot asphalt.When designing a chip seal,not only the characteristics of single material should be paid attention to,but also the combination of binder and aggregate matters a lot.To form good adhesion between aggregate and asphalt binder,various influencing factors such as material selection,design method,and construction technical index should be considered comprehensively in the whole design,construction,and operation process.Three methods for evaluating adhesion behavior are summarized,including macroscopic adhesion performance tests,image analysis technology,and model prediction.It is not objective to evaluate the aggregate adhesion behavior of chip seal only by a single evaluation method.A comprehensive evaluation based on the micro-macro multi-scale method should be considered in the future.展开更多
文摘In order to take a precise and objective evaluation on asphalt-aggregate adhesion, this paper analyzed the function at asphalt- aggregate interface using surface free energy theory. Two asphalts and two aggregates were selected and their surface free energy parameters, FLW, F and F-, were measured by the Wilhelmy plate method and the column wicking technique, respectively. Then, the resistance to moisture damage of asphalt mixture were predicted using calculated asphalt-aggregate adhesive bond energy and asphalt cohesive bond energy. The results show that moisture damage is a thermodynamically favorable phenomenon. Asphalt with a great acid-base polar component and a low Lifshitz-van der Waals apolar component always exhibits perfect cohesion.
基金Funded by National Natural Science Foundation of China(No.52278446)。
文摘In order to evaluate the feasibility of steel slag powder as filler,the coating properties of steel slag and limestone aggregate were compared by water boiling test,the micro morphology difierences between steel slag powder and mineral powder(limestone powder)were compared by scanning electron microscope(SEM),and the high-temperature rheological properties of asphalt mortar with difierent ratio of filler quality to asphalt quality(F/A)and difierent substitution rates of mineral powder(S/F)were studied by dynamic shear rheological test.The results show that the surface microstructure of steel slag powder is more abundant than that of mineral powder,and the adhesion of steel slag to asphalt is better than that of limestone.At the same temperature,the lower the ratio of S/F is,the greater the rutting factor and complex modulus will be.In addition,the complex modulus and rutting factor of the asphalt mortar increase with the increase of F/A,and the filler type and F/A have a negligible efiect on the phase angle.
文摘In order to solve the problems caused by the storage of iron ore tailings (IOTs), many researchers conducted a series of experimental studies on the reuse of IOTs. The results of many studies showed that it was feasible to use IOTs for road engineering. This paper summarized the composition, gradation and particle characteristics of IOTs from chemical and physical aspects, and proved the feasibility of IOTs replacing traditional aggregate for asphalt concrete. Then, the research on the road performance of asphalt concrete incorporating IOTs were summarized and reviewed, including the evaluation of high-temperature stability, low-temperature crack resistance, fatigue resistance and water stability. The water stability and the improvement of adhesion between asphalt and IOTs aggregate were discussed in detail. Finally, the performance of IOTs as asphalt concrete aggregate and the existing defects were evaluated, and future research directions were proposed.
基金the funding support from the National Natural Science Foundation of China(No.51678251)the Fundamental Research Funds for the Central Universities(NO.SCUT.2018KZ001).
文摘Breaking waste tires into crumb and adding it to asphalt as modifier to prepare asphalt rubber (AR) is an effective method to solve the waste tire problem and improve the performance of matrix asphalt. The modified asphalt has better high and low temperature performance. However, the segregation of the crumb rubber modifier (CRM) causes storage instability of the AR. At present, studies have been conducted that improving the solubility of the CRM or adding some macromolecular polymer can improve the storage stability of the AR. However, the structure and polarity of the CRM surface are rarely explored for its correlation with the storage stability of AR. In this paper, the surface structure and polarity of the CRMs was changed by four different reagents, and the properties of the ARs prepared by the CRM were measured to analyze the adhesion between the CRM and the asphalt. It is concluded that the CRM with rough porous and non-polar surface has higher storage stability due to the better interfacial adhesion, which provides a research direction for improving the storage stability of rubber asphalt.
文摘原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥青结合料与集料之间的水分相互作用是一种出现在微观尺度,甚至纳米尺度的现象,因此从微纳观角度探究在水分存在条件下沥青与集料的结构变化,对于改善沥青混合料水稳定性能,探究其水损害机制具有深远的意义。本文在总结AFM工作原理及沥青微观“bees”结构特性的基础上,重点分析了AFM在纳米尺度上对沥青混合料水稳性能的研究成果,并探讨了AFM在沥青路面材料研究中的发展方向,为今后对于沥青路面病害研究与防治方面提供一定的借鉴。
基金supported by National Natural Science Foundation of China(No.52108396)Open Fund of Key Laboratory of Road Structure and Material of Ministry of Transport(Changsha University of Science and Technology)(No.kfj210301)。
文摘Chip seal is widely used for preventive maintenance to mitigate pavement deterioration,but it is prone to aggregate loss during pavement service.To further promote the development and application of chip seals in road engineering in China,the research progress of the adhesion behavior of aggregate and binder in chip seals was reviewed in this paper,focusing on the adhesion mechanism of emulsified asphalt and alkaline aggregate.The Influencing factors and evaluation methodology of chip seals'aggregate adhesion behavior were also discussed.The results demonstrate that the adhesion process between emulsified asphalt and alkaline aggregate is divided into three processes including infiltration,demulsification,and cluster,which is more complicated when compared to hot asphalt.When designing a chip seal,not only the characteristics of single material should be paid attention to,but also the combination of binder and aggregate matters a lot.To form good adhesion between aggregate and asphalt binder,various influencing factors such as material selection,design method,and construction technical index should be considered comprehensively in the whole design,construction,and operation process.Three methods for evaluating adhesion behavior are summarized,including macroscopic adhesion performance tests,image analysis technology,and model prediction.It is not objective to evaluate the aggregate adhesion behavior of chip seal only by a single evaluation method.A comprehensive evaluation based on the micro-macro multi-scale method should be considered in the future.
