Microstructure of synthetic composite interfaces and verification of mixing order in cold-recycled asphalt emulsion mixture

Although there are typical and well-known standard methods for designing hot mix asphalt in the world, there is no unique design method for cold recycled asphalt mixes. The current methods are mainly local or even dependent on technology owners due to the diversity of materials and qualitative control limitations. Currently, most of the design methods are based on 4 inch mold. The major problem of these methods is that in the mix design, the effect of aggregates larger than 25 mm is neglected, while this size of aggregates is used in the recycling projects. Therefore, there is a significant difference between in-situ and laboratory mix behaviors. So, 6-inch mold is used. In this study, a simple mix design has been obtained for reclaimed asphalt pavements (RAP) considering the different amount of emulsified asphalt, Portland cement, three gradations, moisture contents, temperatures, and curing times. For this reason, 315 samples were prepared. The results show that the mixes with aggregates larger than 25 mm have a significant difference with 25 mm and smaller aggregates sizes in terms of mechanical properties and moisture susceptibility. Therefore, 6-inch molds should be used for RAP materials that are larger than 25 mm in the mix design.

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Performance Evaluation of Cold Recycled Asphalt Mixtures with Asphalt Emulsion and Inorganic Additives

International Journal of Highway Engineering ◽

10.7855/ijhe.2017.19.2.137 ◽

2017 ◽

Vol 19 (2) ◽

pp. 137-142 ◽

Cited By ~ 1

Author(s):

Chang Kyu Park ◽

kyungsu Kim ◽

Won Jae Kim ◽

Hyun Jong Lee

Keyword(s):

Performance Evaluation ◽

Asphalt Mixtures ◽

Asphalt Emulsion ◽

Recycled Asphalt

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Dynamic characteristics of 100% cold recycled asphalt mixture using asphalt emulsion and cement

Journal of Cleaner Production ◽

10.1016/j.jclepro.2017.04.065 ◽

2017 ◽

Vol 156 ◽

pp. 337-344 ◽

Cited By ~ 39

Author(s):

Juntao Lin ◽

Jinxiang Hong ◽

Yue Xiao

Keyword(s):

Dynamic Characteristics ◽

Asphalt Mixture ◽

Asphalt Emulsion ◽

Recycled Asphalt

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Construction and Performance of Fly Ash-Stabilized Cold In-Place Recycled Asphalt Pavement in Wisconsin

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1730-19 ◽

2000 ◽

Vol 1730 (1) ◽

pp. 161-166 ◽

Cited By ~ 2

Author(s):

James A. Crovetti

Keyword(s):

Fly Ash ◽

Base Layer ◽

Asphalt Pavements ◽

Ride Quality ◽

Asphalt Emulsion ◽

Recycled Asphalt ◽

Structural Capacity ◽

Performance Trends ◽

And Performance ◽

Aggregate Base

Cold in-place recycling (CIR) is a common rehabilitation practice used in Wisconsin to improve the ride quality and structural capacity of deteriorated asphalt pavements. In recent years, increased emphasis has been placed on incorporating stabilizers into the CIR materials to improve the structural capacity of the CIR base layer. This improvement can serve to increase the performance life of the completed pavement or to allow for a reduced hot-mix asphalt (HMA) surface thickness. The city of Mequon, Wisconsin, included asphalt emulsion and fly ash CIR stabilization over a portion of its CIR projects in 1997. Presented are the findings relating to the constructability of the fly ash–stabilized CIR pavement as well as performance trends for the CIR pavements based on distress and deflection testing results. CIR is a common rehabilitation practice used in Wisconsin to improve the ride quality and structural capacity of deteriorated asphalt pavements. In one type of CIR application, existing HMA layers are pulverized, graded, and compacted, then used as a base layer for a new HMA surface. The pulverization process is completed to provide uniformity of support to the HMA surface and to significantly reduce or eliminate the occurrence of reflection cracking of the HMA surface. In most CIR applications, pulverization is completed through the full thickness of the existing HMA layers, as well as through the top 25 to 50 mm of aggregate base. Penetration into unbound aggregate base materials aids in cooling of the bits on the pulverizer mandrel. After pulverization, graders typically are used to spread the materials to the desired width and shape. Compaction is achieved by using vibrating steel drum and pneumatic-tire rollers. The moisture content of the CIR materials is adjusted, as necessary, by surface spraying from a water tanker truck.

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Laboratory Investigation into Early-Age Strength Improvement of Cold Recycled Asphalt Mixture Containing Asphalt Emulsion and Cement

Advances in Civil Engineering ◽

10.1155/2019/7274204 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Yinfei Du ◽

Lingxiang Kong ◽

Tangzhong Wei

Keyword(s):

Cement Hydration ◽

Coupling Effect ◽

Asphalt Mixture ◽

Negative Ions ◽

Curing Temperature ◽

Early Age ◽

Asphalt Emulsion ◽

Recycled Asphalt ◽

Curing Conditions ◽

Strength Improvement

Cold recycled asphalt mixture (CRAM) has been reported to be able to provide a cleaner method to rehabilitate damaged asphalt pavement. This work used the CRAM containing emulsified asphalt (AE) and cement to investigate the methods of improving its early-age strength by considering mixture composition, including the types of AE and cement and the contents of AE, cement, and moisture. The curing conditions, such as temperature and humidity, were also involved. The results show that the mixture should be carefully designed to determine optimum AE and moisture content. Also, high cement content was helpful to increase the early-age strength. By changing the curing environment, it was found that raising curing temperature and applying a relatively low humidity contributed to the early-age strength improvement. The interaction of cement hydration and AE demulsification was investigated using microimage and laboratory experiments. The results show that AE particles were easy to cluster because of the negative ions released by cement hydration. AE delayed the early cement hydration but improved the later intensity of cement hydration. The coupling effect of AE and cement resulted in higher early-age strength than those of the mixtures only with cement or only with AE. The results presented in this work are expected to give guidance for preparing a CRAM with high early-age strength.

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