Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base

Garach, Laura; López, Mónica; Agrela, Francisco; Ordóñez, Javier; Alegre, Javier; Moya, José Antonio

doi:10.3390/ma8125493

Cited by 25 publications

(18 citation statements)

References 31 publications

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“…Recycled Concrete Aggregate (RCA) and Mixed Recycled Aggregate (MRA) were studied by Garach et al (2015) using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) for possible use as road pavement material. The XRD showed a significant proportion of dolomite, chlorite, calcite and quartz in both the RCA and the MRA.…”

Section: Introductionmentioning

confidence: 99%

Effect of Reclaimed Asphalt Pavement Stabilization on the Microstructure and Strength of Black Cotton Soil

Alhaji¹,

Alhassan²

2018

IJTech

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Black Cotton Soil (BCS) collected from Guyuk, Adamawa State-Northeastern Nigeria, was treated with 0 to 100% Reclaimed Asphalt Pavement (RAP) in 10% steps to evaluate the microstructure and strength of the compacted mixtures. The index property results show that the BCS and RAP are classified under clay of high plasticity (CH) and poorly graded sand (SP) respectively, according to the Unified Soil Classification System (USCS). An extraction test gave a RAP bitumen content of 5.99%, which is within the value of 5-6% recommended in the literature. An x-ray diffraction test carried out on both the BCS and RAP showed that the BCS predominantly consisted of quartz, microcline, albite and kaolinite, which is similar to the results obtained in the literature, while the RAP, however, consisted of quartz, albite, orthoclase, phylogopite and actinolite, which is slightly different to what is reported in the literature, probably due to the source of the bitumen. The results of compaction, at a modified energy level, conducted on the mixtures, show that the Maximum Dry Density (MDD) increased from 1.890 to 2.034 mg/m 3 at 30% RAP content, after which the value fell to1.925 mg/m 3 at 100% RAP content. The Optimum Moisture Content (OMC) however, decreased from 13.7% at 0% RAP, to 8.8% at between 40-60% RAP content, after which the value increased marginally to 9.5% at 90% RAP. Similar to the MDD, the California Bearing Ratio (CBR) increased from 11% at 0% RAP to a maximum of 35% at 30% RAP content, after which the value fell to 5% at 100% RAP content. 30% RAP is therefore the optimal mixture giving the highest strength and can be used as a sub-base material for roads with light traffic use, according to the Nigerian General Specification for Road and Bridge Works. Hence the 3.07% bitumen obtained for this mixture can be adopted as the fixation point for BCS-RAP mixtures. Durability was found to be far lower than the resistance to loss in strength of 80% suggested in the literature.

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Section: Introductionmentioning

confidence: 99%

Effect of Reclaimed Asphalt Pavement Stabilization on the Microstructure and Strength of Black Cotton Soil

Alhaji¹,

Alhassan²

2018

IJTech

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“…The technological, ecological and economical aspects of recycled asphalt use in road construction are discussed in Liu et al (2016). Garach et al (2015) dealt with the mechanical properties of recycled materials formed with cement binders for non-reinforced active zone of the road formation. Similar to other authors (Tabsh and Abdelfatah 2009, Kang et al 2011, Rao et al 2011, Xuan et al 2012, they came to the conclusion that these materials show lower density, higher absorption capacity and lower mechanical strength than natural materials.…”

Section: Use Of Recycled Materials For Forest Road Reinforcementmentioning

confidence: 99%

Recycled Asphalt as an Alternative to Natural Aggregates for Forest Road Reinforcement

Hrůza

Blahuta

Pelikán

et al. 2019

Croat. j. for. eng. (Online)

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The objective of the present paper is to confirm or reject the possible use of recycled asphalt to reinforce forest haul roads regarding the technical requirements set by the standards and directives relevant to the construction of forest road surfaces. The hypothesis is based on the presumption that recycled materials, if correctly used, can reach the same construction properties as standard materials, hence their application does not have a negative effect on reinforcement quality. On a selected stretch of forest road, three test sections were constructed with the use of recycled asphalt, however, each of them with a different technological solution. The first section was reinforced with unbound mixture – Type1 without added water, the second section was constructed using a version of vibrated macadam technology, and recycled asphalt was applied to the third section by the method of basic compacting. In each of the sections, tacheometric cross profile measurement was carried out at monthly intervals to monitor the changes in the cross profile shape, and the number of passages of fully loaded logging trucks was registered; static load tests were performed at pre-defined time intervals to determine the deformation moduli such as deformation characteristics of the road surface structural layers. In all three reinforcement versions, the values of deformation moduli observed during the static load tests were between 68–90 % of the values set by relevant standards for these technologies using natural aggregates. However, the tacheometric measurements did not reveal statistically significant changes in the shape of the reinforcement cross-section. Based on the obtained results, applying recycled asphalt to reinforce forest roads seems to be a suitable alternative to natural quarry aggregate used in unbound structural layers. Recycled material needs to meet the regulatory limits for foreign elements and pass ecotoxicity tests, which is evidenced by a certificate on material compliance issued by the test laboratory.

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“…Numerous researchers [72,[116][117][118][119][120] have reported using recycled waste materials in civil engineering applications worldwide. CB, RCA and reclaimed asphalt pavement (RAP) have been reported to be suitable for pipe backfilling materials for stormwater and sewer pipes.…”

Section: Aggregate Selection and Availabilitymentioning

confidence: 99%

“…[116] RCA and CB have been used for unbound subbase materials. [117][118][119] Blast furnace slag has been found suitable for use in road subbases. [120] LWAA have been used in several construction applications including lightweight concrete, lightweight blocks, lightweight geotechnical fill, insulation products, filters, and drainage.…”

Section: Aggregate Selection and Availabilitymentioning

confidence: 99%

Technological Review of Permeable Pavement Systems for Applications in Small Island Developing States

Monrose

Tota-Maharaj

2018

CLEAN Soil Air Water

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This paper presents a technological review of permeable pavement systems (PPS) for applications in urban areas of small island developing states (SIDS). This review includes a literature survey of PPS, challenges and opportunities of climate change and urban development in SIDS and key aspects worth considering for widespread acceptance and use of PPS in SIDS. SIDS comprise of several nations located across the Atlantic, Pacific and Indian Oceans and the Caribbean, Mediterranean and South China seas. They are particularly susceptible to the effects of climate change and increasing urbanisation. Urban stormwater management and flooding are often serious challenges faced by authorities in most SIDS. PPS are resilient infrastructure which can assist in mitigating flooding by reducing runoff and peak flows and improving the landscape perviousness. PPS can further improve stormwater runoff quality to receiving natural waters by reducing pollutant loadings of suspended solids, heavy metals and hydrocarbons. Unlike most territorial states, the geographical and geologically confined nature of most SIDS present unique parameters for consideration when designing permeable pavements for SIDS. This literature survey found that some of the most important parameters include traffic loads, cost, construction aggregate choice and availability, permeability of existing soil at the intended location, depth of water table, potential for groundwater contamination, slope of the pavement, stormwater reuse option, clogging, maintenance and support from policy makers. Continued practical research into the use of permeable pavements for urban runoff management in SIDS is ongoing with the expectation of PPS being utilised in many SIDS.

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Improvement of Bearing Capacity in Recycled Aggregates Suitable for Use as Unbound Road Sub-Base

Cited by 25 publications

References 31 publications

Effect of Reclaimed Asphalt Pavement Stabilization on the Microstructure and Strength of Black Cotton Soil

Effect of Reclaimed Asphalt Pavement Stabilization on the Microstructure and Strength of Black Cotton Soil

Recycled Asphalt as an Alternative to Natural Aggregates for Forest Road Reinforcement

Technological Review of Permeable Pavement Systems for Applications in Small Island Developing States

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