Sustainable roadway construction using recycled aggregates with geosynthetics

Han, Jie; Thakur, Jitendra K.

doi:10.1016/j.scs.2013.11.011

Cited by 53 publications

(24 citation statements)

References 13 publications

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“…This is why the majority of sustainability tests provide results in the form of fines produced during these tests [16]. The presence of fines within a granular material can have several positive or negative effects depending on the content on the following three parameters [17][18][19][20][21]:…”

Section: Introductionmentioning

confidence: 99%

Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

et al. 2020

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Fine recycled aggregates are produced in large quantities when crushing Construction and Demolition Waste (C&DW). Even if coarse recycled aggregates are commonly used for road foundations, fine particles are often rejected as they are considered detrimental for the long-term behaviour of foundations. Physicochemical, mineralogical and mechanical characterizations (through X-ray diffraction, X-ray fluorescence, the chloride and sulphate contents, Los Angeles abrasion, micro-Deval resistance and static plate load tests) were performed on raw and treated fine recycled materials for understanding both the effects of the preparation, the compaction and the freeze–thaw cycles on the properties and the evolution of fine particles. Special attention was provided to the shape analysis of fines by means of image analyser. The results showed that the main characteristic parameters to be considered are the sieving curve and the proportion of grades. The mixes containing the highest quantity of fine particles, specifically lower than 63 µm, usually inducing a higher water demand and a higher capillary rise. This can be explained by specific surface and bluntness parameters which increase with the finer particles, inducing a higher surface roughness and, consequently, a higher potential interaction with water. Compaction did not seem to have a major effect on the production of fines (despite some breakdown occurred during compaction) and on the shape of materials (the bluntness and convexity increased slightly, while the elongation values remained similar after the compaction process). The static plate load tests showed that bearing capacity is slightly lower than the specifications for the road foundation after compaction. However, the studied material could meet the maximum criteria for secondary roads foundation construction on the wear resistance criteria. Recycled aggregates from C&DW without sufficient quality could be blended with other aggregates to enable their usage for upper-level road foundation.

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Section: Introductionmentioning

confidence: 99%

Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

et al. 2020

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“…They found that the geocell-reinforced RAP bases showed a stable response, whereas the unreinforced RAP base showed an unstable response. Han and Thakur (2015) summarized the recent research on the sustainable roadway construction using recycled aggregates with geosynthetics. They also reported that geocell-reinforced RAP used as base course material is a sustainable pavement construction technology.…”

Section: Introductionmentioning

confidence: 99%

Factors Influencing Deformations of Geocell-Reinforced Recycled Asphalt Pavement Bases under Cyclic Loading

Thakur¹,

Han

Parsons

2017

J. Mater. Civ. Eng.

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A significant amount of recycled asphalt pavement (RAP) material is produced from flexible pavement rehabilitation projects. RAP can be used as a base course material for sustainable pavement construction. Performance of a pavement largely depends on the strength of its foundation, which consists of the subgrade and base course layers. Geocell was used in this study to increase the strength of RAP bases. Nine large-scale laboratory cyclic plate loading tests were conducted on unreinforced and geocell-reinforced RAP bases with three different thicknesses (150, 230, and 300 mm) over weak and moderate subgrades to investigate the influence of geocell confinement, base course thickness, base course strength, and subgrade strength on permanent and resilient deformations of RAP bases. The subgrade was prepared by mixing Kansas River sand with kaolin and compacted at weak [target California bearing ratio ðCBRÞ¼2%] and moderate (target CBR ¼ 5%) strengths. The test results showed that geocell confinement improved the performance of reinforced RAP bases by reducing permanent surface deformations and increasing resilient deformations and percentages of resilient deformation as compared with those of unreinforced bases. The RAP bases over the moderate subgrade performed better than those over the weak subgrade. Subgrade strength had a more pronounced effect than geocell confinement on the properties of RAP bases. Geocell confinement was more beneficial for the bases over the weak subgrade than those over the moderate subgrade. The relative improvement factors (RIFs) of the reinforced bases with respect to the unreinforced bases and the bases over the moderate subgrade with respect to the bases over the weak subgrade ranged from 1.1 to 11.4 and 1.2 to 17.2, respectively. The permanent deformation increased with the number of loading cycles and the RIFs increased with the permanent surface deformation of RAP base sections.

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“…Recycled Asphalt Pavement (RAP), is obtained from spent asphalt extracted from roads that have reached the end of their design life (Arulrajah et al, 2014;Rahman et al, 2014). RAP contains asphalt binder (3-7%) and aggregates (93-97%) by weight (Han & Thakur, 2015), and is an ideal recycled waste material for reuse in pavement applications. RAP often exhibits low strength and stiffness performances, hence chemical stabilization of RAP is used extensively for developing bound pavement base/sub-base material (Hoyos et al, 2011;Saride et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Wetting and Drying Characteristics of Recycled Asphalt Pavement-Fly Ash Blend as a Sustainable Pavement Material

Hoy¹,

Horpibulsuk²,

Rachan³

et al. 2017

dtmse

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ABSTRACT:The usage of Recycled Asphalt Pavement (RAP) and Fly Ash (FA) blend in pavement applications contributes to the sustainable usage of such waste by-products. Although RAP-FA blend has been proven as a pavement material based on strength and leachate requirement, the durability of this blend when exposed to an aggressive environment has not been investigated to date. This research presents the effect of wetting-drying (w-d) cycles on the strength and microstructural changes of RAP-FA blend. The strength characteristic of this material was determined by Unconfined Compression Strength (UCS) test. The mineralogical and microstructural changes of the compound pavement material were also analyzed using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Test results show that the UCS of RAP-FA blend increases with increasing the number of w-d cycles (C), reaching its peak at 6 w-d cycles. The XRD and SEM analyses indicate that the increased UCS of RAP-FA blend is due to stimulation of the chemical reaction between the high amount of Calcium in RAP and the high amount of Silica and Alumina in FA during w-d cycles leading to production of more Calcium Silicate Hydrate (C-S-H) and Calcium Aluminate Hydrate (C-A-H). For C > 6, the significant macro-cracks due to the loss of moisture content during drying stage cause strength reduction. However, its reduced UCS is still greater than the minimum strength requirement even at C = 20. The outcome from this research confirms the viability of using RAP-FA blends as an alternative sustainable pavement material.

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Sustainable roadway construction using recycled aggregates with geosynthetics

Cited by 53 publications

References 13 publications

Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

Factors Influencing Deformations of Geocell-Reinforced Recycled Asphalt Pavement Bases under Cyclic Loading

Wetting and Drying Characteristics of Recycled Asphalt Pavement-Fly Ash Blend as a Sustainable Pavement Material

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