Strength and Micro-Mechanism Analysis of Cement-Emulsified Asphalt Cold Recycled Mixture

Pi, Yuhui; Li, Yan; Pi, Yingxing; Huang, Zhe; Li, Zhe

doi:10.3390/ma13010128

Cited by 19 publications

(12 citation statements)

References 28 publications

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“…The evaporation residue of emulsified asphalt prepared by electric furnaces causes the aging of the evaporation residue, which easily affects test results. In order to reflect the demulsification process of emulsified asphalt [ 2 ], the evaporation residue of emulsified asphalt was prepared using the low-temperature evaporation method of ASTM D7497-09. The specific method is illustrated in Figure 3 .…”

Section: Experimental Details and Methodsmentioning

confidence: 99%

“…The cold recycling technology of emulsified asphalt plant mix is energy saving and environmentally friendly, and can utilize recycled asphalt pavement (RAP) materials in large quantities, so it is a research hotspot in the field of road engineering at home and abroad [ 1 , 2 , 3 , 4 ]. Emulsified asphalt cold recycled mixture has problems such as low initial strength, poor crack resistance after molding, and insufficient water stability.…”

Section: Introductionmentioning

confidence: 99%

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Modification Mechanism and Rheological Properties of Emulsified Asphalt Evaporative Residues Reinforced by Coupling-Modified Fiber

Kong

et al. 2021

Materials

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In order to solve the problems of the smooth surface of basalt fiber and its weak interfacial adhesion with emulsified asphalt cold recycled mixture, a silane coupling agent (KH550) was used to treat the surface of basalt fiber and the effects of treatment concentration and soaking time on fiber modification were studied. The influence of silane coupling-modified basalt fiber (MBF) on the rheological properties of emulsified asphalt evaporation residue was studied at high and low temperatures using three routine index tests: a dynamic shear rheological test (DSR), a bending beam rheological test (BBR), and a force ductility test. The elemental changes of the fiber before and after modification and the microstructure of the emulsified asphalt evaporation residue with the coupling-modified fiber were analyzed by Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS), which is used to study the modification mechanism of emulsified asphalt evaporation residue reinforced by coupling-modified fiber. The results indicate that the concentration and soaking time of the silane coupling agent have a great influence on the surface morphology and mechanical properties of the fiber, and that the optimal treatment concentration is 1.0% and the optimal soaking time is 60 min. The addition of coupling-modified fibers can reduce the phase angle and unrecoverable creep compliance of emulsified asphalt evaporation residue, increase the rutting factor and creep recovery rate, and improve the elastic recovery ability and permanent deformation resistance. However, excessive fiber will weaken the ductility of emulsified asphalt at low temperatures. The appropriate content of silane coupling-modified fiber (MBF) is 1.5%. After silane coupling modification, the fiber surface becomes rough and cohesion is enhanced between the fiber and the emulsified asphalt base. Silane coupling-modified basalt fiber (MBF) acts as reinforcement for stability and bridging cracks.

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Section: Experimental Details and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modification Mechanism and Rheological Properties of Emulsified Asphalt Evaporative Residues Reinforced by Coupling-Modified Fiber

Kong

et al. 2021

Materials

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“…The most common stabilization agents include emulsified asphalt, foamed asphalt, and cement [14,20,21]. Factors influencing the volumetric and mechanical properties of CRM were intensively investigated by many researchers, e.g., curing time and temperature [22][23][24], compacting method [25], cement content and type [26][27][28][29][30], RAP source and content [31,32], asphalt content [27,[33][34][35], gradation [21,25,36], water content [28,37], rejuvenator content [38], additive or active fillers [18,19,39,40], asphalt type, and extra aggregates [41]. At the same time, the effect of RAI or composite RAP/RAI on the performance, mechanical behavior, and small strain characteristic of CRM stabilized by emulsified asphalt or cement has been studied by many scholars [42,43].…”

Section: Introductionmentioning

confidence: 99%

Study on Cold Recycled Asphalt Mixtures with Emulsified/Foamed Asphalt in the Laboratory and On-Site

Zhao

Su²,

Su³

et al. 2022

Coatings

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Millions of tons of reclaimed asphalt pavement (RAP) and reclaimed aggregate or reclaimed inorganic binder stabilized aggregate (RAI) is produced every year in China. The cold recycled mixture (CRM) technology reduces fuel consumption, emissions, and cost and utilizes the high content of RAP. In this paper, six types of CRM with varying RAP/RAI composition and asphalt binders were investigated. The laboratory tests included strength indicators, high temperature stability, low temperature crack resistance, water stability, and dynamic modulus. A full-scale trial section was constructed after the laboratory tests. Except for low temperature failure strain without secondary compaction in the mixture design, test results illustrated that the performances of different CRMs met the specifications. The cement addition limited the thermo-viscoelastic behavior of the CRM. The RAI contents had reduced the water sensitivity of CRM, and the emulsified asphalt CRM had better performance than the foamed asphalt CRM. The performances of samples cored from the test section in the field met the specifications and were lower than that in the laboratory. The curing conditions in the field were not as effective as in the laboratory. The curing conditions and compaction method should simulate the conditions in the field to guide the CRM selection and mixture design.

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“…Unger et al [ 20 ] mixed emulsified asphalt as a recycling agent with 100% reclaimed asphalt pavement (RAP) to form a new test section of pavement base, used a falling weight deflectometer (FWD) to detect its structure, and concluded that the method of using emulsified asphalt to regenerate RAP asphalt mixtures is relatively reliable. Pi et al [ 21 ] investigated the strength formation mechanism of emulsified asphalt cold recycled mixtures and analyzed the influences of the gradation, emulsified asphalt content, cement content and other factors on the performance of the cold recycled mixtures; the optimal amounts of emulsified asphalt and cement in RAP material were determined through testing. When cement is used as the regeneration agent of a recycled mixture base, higher cement contents can effectively improve the compressive strength of the mixture [ 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of emulsified recycled cement-stabilized macadam based on step-by-step filling gradation design

Liu

Sun

et al. 2022

PLoS ONE

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Since the recycling of waste original cement-stabilized macadam (OCSM) base has important environmental and economic significance, the addition of emulsified asphalt to OCSM to form emulsified recycled OCSM (ER-OCSM) can improve the flexibility of recycled mixtures. However, the influence of emulsified asphalt on the mechanical performance of such mixtures remains to be investigated. This study presents a gradation design and ER-OCSM established using the step-by-step filling method and investigated the mechanical properties of the ER-OCSM mixture. The apparent characteristics, crushing value and needle-like particle content of the OCSM milling material were tested. Based on step-by-step filling theory, the appropriate test method to achieve a uniform and dense state according to the characteristics of different aggregates was selected, and the dense skeleton gradation design method for recycled cement macadam was obtained. The mechanical properties of the ER-OCSM were analyzed by performing indoor physical laboratory tests. The natural gradation of the OCSM milling material exceeded the gradation range recommended in the Technical Guide for the Promotion of Science and Technology of the Construction Project of the Main Highway in Jiangsu Province (Trial), but the designed gradations were basically within the range. At the same age and temperature, the flexural strength and dynamic elastic modulus of the ER-OCSM decreased gradually with an increase in the emulsified asphalt content. Because ER-OCSM had temperature-sensitive characteristics, the adhesiveness of the asphalt between particles in the mixture decreased with increasing temperature, which was manifested as the unconfined compressive strength, flexural tensile strength and dynamic elastic modulus decreasing with an increase in temperature (the decrease was slight within 5–25°C but noticeable within 25–60°C). Furthermore, a higher emulsified asphalt content caused a more noticeable decrease. The flexural strength of the tested ER-OCSM showed noticeable correlations with the splitting strength, unconfined compressive strength and dynamic elastic modulus. The proper addition of emulsified asphalt can reduce the rigidity of ER-OCSM. However, the emulsified asphalt content should be strictly controlled; otherwise, the mechanical properties of the material will decrease greatly, adversely impacting the comprehensive road use performance.

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Strength and Micro-Mechanism Analysis of Cement-Emulsified Asphalt Cold Recycled Mixture

Cited by 19 publications

References 28 publications

Modification Mechanism and Rheological Properties of Emulsified Asphalt Evaporative Residues Reinforced by Coupling-Modified Fiber

Modification Mechanism and Rheological Properties of Emulsified Asphalt Evaporative Residues Reinforced by Coupling-Modified Fiber

Study on Cold Recycled Asphalt Mixtures with Emulsified/Foamed Asphalt in the Laboratory and On-Site

Mechanical properties of emulsified recycled cement-stabilized macadam based on step-by-step filling gradation design

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