Suggesting a Simple Design Method for Cold Recycled Asphalt Mixes With Asphalt Emulsion

Moghadam, Bahador Bazrafshan; Mollashahi, Hamid Farhad

doi:10.3846/13923730.2017.1343200

Cited by 13 publications

(6 citation statements)

References 21 publications

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“…An important issue concerning FA-stabilized materials is the absence of a mix design methodology suitable for CIR mixes [16]. Some researchers have pinpointed the moisture susceptibility of Foamed Asphalt base materials [17], especially prior to Asphalt Concrete (AC) overlay construction [18], while others have concluded that FA outperforms bitumen emulsion for base stabilization in terms of increased moisture and frost resistance [8,18].…”

Section: Introductionmentioning

confidence: 99%

Structural Performance of Foamed Asphalt Base in a Full Depth Reclaimed and Sustainable Pavement

2023

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Environmental awareness and budgetary constraints in road construction and rehabilitation require innovative and at the same time environmentally friendly solutions in favor of resource conservation, in any type of pavement intervention. In the meantime, surface interventions in severely deteriorated pavements are insufficient, increasing as such the recycling potential of existing materials in Full Depth Reclamation (FDR). This study addresses the efficiency of an FDR process in which the recycled base course of an existing semi-rigid pavement is stabilized with Foamed Asphalt (FA). The adverse effects of FA curing, which have a significant impact on pavement evaluation, particularly in the early stages of a pavement’s life cycle, prompted the conduct of a comprehensive testing campaign at two different periods, shortly after pavement rehabilitation and five years thereafter. The campaign included nondestructive testing at the aforementioned periods using Ground Penetrating Radar (GPR) and the Falling Weight Deflectometer (FWD), which facilitate the structural evaluation of the FA base. Using the collected nondestructive testing data, the principles of Multi-Layer Elastic Theory (MLET) and Genetic Algorithms (GA) are used to investigate the performance of the FA base. Both analysis tools captured the FA strength increase in the second period, but an increased variance of the FA modulus was observed mainly in the first test period, probably due to the curing effect. In addition, GA showed an advantage over other, more conventional tools for back-analysis of pavement stiffness, resulting in an interesting correlation potential of FA modulus to a deflection-based parameter reflecting the condition of the FA layer. Overall, the study contributes to the development of a practical methodology suitable for the evaluation of non-conventional and sustainable pavement structures.

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Section: Introductionmentioning

confidence: 99%

Structural Performance of Foamed Asphalt Base in a Full Depth Reclaimed and Sustainable Pavement

2023

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“…Thus, much research has focused on improving the properties of cement-emulsified asphalt mortar and mixtures [ 4 , 5 , 6 ]. Specifically, mechanical properties, including indirect tensile strength (ITS), indirect tensile stiffness modulus, creep stiffness, and durability in term of water sensitivity of cement-emulsified asphalt mixture have been investigated [ 7 , 8 , 9 , 10 ]. Meanwhile, road performance, such as wheel-tracking and fatigue performance, have also been studied [ 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Fiber-Reinforcing Effect in the Mechanical and Road Performance of Cement-Emulsified Asphalt Mixtures

Zhu

Qin

et al. 2021

Materials

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Cement-emulsified asphalt mixture (CEAM), a kind of cold mix asphalt mixture, has the advantages of energy conservation and emission reduction as well as easy construction. However, the performance of CEAM is not as good as hot mixed asphalt mixtures. Hence, in this study, two different fibers were adopted as the reinforcing phase to improve the comprehensive properties of CEAM. The results indicated that the addition proportion and curing time were crucial to fiber-reinforced cement-emulsified asphalt mixture (FRCEAM). The compressive strengths, water stability, and raveling resistances of FRCEAM preparations with polyester or brucite fibers (FRCEAM-PF and -BF, respectively) were enhanced significantly. FRCEAM-PF had the maximum flexural tensile strength and strain, which meant that its low-temperature performance was the best compared to FRCEAM-PF and CEAM. However, the contribution of PF to CEAM high-temperature stability was greater than that of BF. Fiber addition to CEAM not only enhanced the cycles of fatigue loading but also reduced sensitivity to changes in stress level. Furthermore, FRCEAM-BF durability was slightly better than that of FRCEAM-PF. SEM analysis indicated that fibers provided bridging and meshing effects. Although PF and BF showed different enhancement effects, both mixtures met the requirements for hot mixed asphalt mixtures.

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“…Lee et al (2003) believed that the Marshall compaction method could not simulate the compaction effect of the field road compaction machinery, and proposed to use the gyratory compactor to compact and form a cold recycled mixture. Moghadam and Mollashahi (2017) thought that when the particle size was larger than 25 mm, a significant difference in the mechanical properties and water stability was found between the 4-inch and 6-inch specimens. Guo compared the Marshall compaction test with the gyratory compaction test and showed that the voids of the Marshall compaction specimen were basically the same as that of 40 50 times of gyratory compaction specimen (Guo, 2013).…”

Section: Introductionmentioning

confidence: 99%

Study on the Laboratory Mixing and Compaction Methodology of Emulsified Asphalt Cold Recycled Mixture

Liu

Han

Wu³

et al. 2020

Front. Mater.

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Emulsified asphalt cold recycled mixture is commonly used in the upper base course of expressway reconstruction asphalt pavement. When the following layer is paved with hot-mix asphalt (HMA) mixture, the aging asphalt in the recycled material is activated due to the temperature conduction effect of the HMA mixture, so that the cold recycled layer produces "secondary thermal compaction" under the action of a roller. Based on this phenomenon, the present study aimed to discuss the influence of different molding methods and mixing processes on the volume parameters and mechanical properties of cold recycled emulsified asphalt mixture. The influences of Marshall compaction times, gyratory compaction times, curing time, and specimen-forming temperature on the voids and splitting strength of cold recycled mixture were studied. The field core sample was compared with the laboratory-forming method, which accords with the field compaction condition of the cold recycled upper base. first-time compaction number of large Marshall is 150 times and secondary compaction number is 75 times (Shorthand for 150 + 75), the compaction times of the gyratory specimen is "30 + 15." The curing time of the cold recycled mixture should not exceed 3 h and should not be constructed in low-temperature weather to ensure the quality of pavement construction. The use of a new stage and step laboratory mixing process simulating the plant mixing, compared with the traditional mixing process, increases the splitting strength by at least 13%.

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Suggesting a Simple Design Method for Cold Recycled Asphalt Mixes With Asphalt Emulsion

Cited by 13 publications

References 21 publications

Structural Performance of Foamed Asphalt Base in a Full Depth Reclaimed and Sustainable Pavement

Structural Performance of Foamed Asphalt Base in a Full Depth Reclaimed and Sustainable Pavement

Fiber-Reinforcing Effect in the Mechanical and Road Performance of Cement-Emulsified Asphalt Mixtures

Study on the Laboratory Mixing and Compaction Methodology of Emulsified Asphalt Cold Recycled Mixture

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