Evaluating the Effect of Hydrophobic Nanosilica on the Viscoelasticity Property of Asphalt and Asphalt Mixture

Li³

et al. 2020

Coatings

Self Cite

Applications of water-foamed binders have received widespread attention due to its environmental and economic benefits. This study aims to evaluate the properties of water-foamed asphalt under three environmental conditions (high-temperature evaporation, low-temperature frozen and the freeze–thaw cycle). Conventional physical properties tests, dynamic shear rheometer test (DSR), differential scanning calorimetry test (DSC) and scanning electron microscope test (SEM) are employed to assess the physical, rheological thermal and microscopic characteristics of samples. Conventional physical properties test results showed that the performance of a foamed binder had declined under three environmental processes and the foamed asphalt gradually returned to the characteristics before being foamed, with the increase of process time. A comprehensive evaluation index, deterioration degree was proposed based on the test results and entropy theory, and the deterioration process of the foamed binder under three environmental conditions was quantified. Moreover, freeze–thaw (F–T) cycles had been proved to have the most significant influence on the performance of a foamed binder among three environmental factors, which was a key issue that limits the application and promotion of foamed asphalt in seasonal frozen regions. The DSR test showed that the resistance to high-temperature permanent deformation of the foamed binder was improved after F–T cycles, and the fatigue resistance became worse. The sensitivity analysis of complex modulus and frequency illustrated that foamed asphalt after F–T cycles were more sensitive to the loading frequency and less sensitive to the temperature. The DSC test indicated that the thermal stability of foamed asphalt was improved after F–T cycles. The disappearance of circular “cavitation” observed through SEM test revealed that moisture of foamed asphalt was gradually precipitated and self-healing phenomenon occurred during F–T cycles.

Section: Dynamic Shear Rheometer Test (Dsr)mentioning

confidence: 99%

Laboratory Investigation on Physical, Rheological Thermal and Microscopic Characteristics of Water-Foamed Asphalt under Three Environmental Conditions

Li³

et al. 2020

Coatings

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“…The R group can react strongly with different matrix resins or organic materials, such as vinyl, epoxy, sulfhydryl, amino, etc. [24,25].…”

Section: Nano Hydrophobic Silane Silicamentioning

confidence: 99%

“…In the previous study, the incorporation method of nano hydrophobic silane silica was discussed in detail [25]. A high shear mixer with the speed of 2000 rpm was used for incorporating the nano hydrophobic silane silica into the base asphalt.…”

Section: Asphalt Sample Preparationmentioning

confidence: 99%

Laboratory Assessment of Deteriorating Performance of Nano Hydrophobic Silane Silica Modified Asphalt in Spring-Thaw Season

Chen

et al. 2019

Applied Sciences

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In the seasonal frozen regions, freeze-thaw (F-T) damage is the main pavement damage, causing a variety of poor conditions in bitumen pavement, such as cracks, pits, potholes, and slush. In previous studies, we evaluated the effect of nano hydrophobic silane silica (NHSS) on the degradation of asphalt mixture under F-T cycles, and established the damage model of NHSS modified asphalt mixture in spring-thawing season. To gain more understanding of the influence of NHSS on asphalt in spring-thawing season, NHSS modified asphalt was systematically analyzed under F-T aging process in this study. The main research objective of this paper was to investigate the deteriorating properties of NHSS modified asphalt under Freeze-thaw aging process. Within this article, the physicochemical characteristics of NHSS modified asphalt were determined by using various laboratory tests, which included basic property test, dynamic shear rheometer test (DSR), Fourier transform infrared spectroscopy test (FTIR) and thermogravimetric analysis (TGA). The results showed that the incorporation of NHSS could inhibit the F-T aging process of asphalt. Moreover, the chemical composition and thermal stability of asphalt under F-T aging process was analyzed through FITR and TGA test parameters. The results illustrated that the sulfoxide functional groups content index was more suitable for evaluating the aging degree of asphalt in the spring-thawing season and the F-T aging process had a great impact on the thermal property of NHSS modified asphalt.

“…Asphalt pavement possesses superior qualities in performance, such as its surface smoothness, low noise, convenient construction and maintenance, and has been widely used around the world [1][2][3][4][5]. With the aggravation of traffic loads and the continuous rise in global average temperatures, rutting disease of asphalt pavement under high temperatures has been a focus for road researchers [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Micro Deformation Mechanism of Asphalt Mixtures under High Temperatures Based on a Self-Developed Laboratory Test

Meng

et al. 2020

Materials

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Rutting has always been considered the main disease in asphalt pavement. Dealing with rutting disease would be benefitted by understanding the formation of rutting and testing the rutting performance of mixtures more reasonably. The objective of this paper is to systematically investigate the rutting mechanism by employing a self-designed rutting tester along with the corresponding numerical simulations. The deformation of different positions of the existing tracking tester was found to be inconsistent, and the loading was not in line with reality. Accordingly, a more practical tester was proposed: the reduced scale circular tracking (RSCT) tester integrates the functions of asphalt mixture fabrication and rutting monitoring. The results demonstrated that the loading of the new tester is closer to the actual situation. In addition, determining the stress and displacement characteristics of particles in the asphalt mixture was found to be difficult due to the limitations of the testing methods. Therefore, a two-dimensional virtual rutting test based on the RSCT was built using PFC2D (Particle Flow Code 2 Dimension) to investigate the mechanism of formation in rutting and to obtain the corresponding guidance. The numerical simulation showed that all particles of the specimen tended to move away from the load location. The main cause of rutting formation was the eddy current flow of asphalt mastic driven by coarse aggregates. The aggregates with diameters ranging from 9.5 to 4.75 mm were observed to have the greatest contribution to rutting deformation. Therefore, the aggregate amount of these spans should be focused on in the design of mixture grading.