Special Issue "The Use of Recycled Materials to Promote Pavement Sustainability Performance"

A special issue of Recycling (ISSN 2313-4321).

Deadline for manuscript submissions: 31 December 2021.

Special Issue Editors

Prof. Dr. José Neves
E-Mail Website
Guest Editor
CERIS, Department of Civil Engineering, Architecture and Georesources, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal
Interests: road and airfield infrastructure systems; pavement design and analysis; pavement materials; pavement construction and maintenance technologies; pavement management and performance; sustainability; safety; transportation geotechnics; testing and evaluation; quality management systems; intelligent transportation systems
Special Issues and Collections in MDPI journals
Dr. Ana Cristina Freire
E-Mail Website1 Website2 Website3
Guest Editor
Laboratório Nacional de Engenharia Civil, Av. do Brasil, 101. 1700-066 Lisboa, Portugal
Interests: pavement materials and construction technologies, including innovative technologies and alternative/recycled/sustainable materials; behavior assessment of road and airport pavements; circular economy; extreme weather events; mitigation of climate change effects; life cycle assessment (LCA); greenhouse gas (GHG) emissions

Special Issue Information

Dear Colleagues,

Recycling of road pavement materials allows the use of raw materials in a more sustainable way and contributes to the creation of a circular economy. The entire life cycle of the products in the pavement, through focusing on their design, promoting circular economy processes, and fostering sustainable consumption, aims to ensure that the resources used are kept in the economy for as long as possible.

Carrying out recycling policies may have significant impacts on the civil engineering activities, including the construction and exploitation of transport infrastructure. Through a global framework supported by sustainable production with green technologies, pavement engineering can also contribute to successfully achieving sustainable development goals.

The implementation of consumption and production patterns based on recycling, along with the adoption of an industrial symbiosis approach, can promote sustainable urban development under a carbon-neutral economy through the use of green technologies. Due to intense research and practice, recycling has been used in pavement construction, maintenance, and rehabilitation in recent decades. Recycling of road pavement materials prevents extraction of non-renewable resources and minimizes waste production. It can save energy and decrease greenhouse gas emissions, therefore reducing pollution. Recycling effectively helps to reduce environmental impacts and to combat climate change as a whole.

The purpose of this Special Issue is to collect and publish specific original technical and research papers, including review papers, focusing on recycling of road pavement materials (e.g., unbound granular materials, asphalt mixtures, concrete, cement and other hydraulically bound mixtures, aggregates, binders, and additives) to promote pavement sustainability performance.

Prof. Dr. José Neves
Dr. Ana Cristina Freire
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Recycling is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Road pavement materials
  • Recycled products in pavement construction
  • Urban heat island effects
  • Sustainable production
  • Industrial symbiosis
  • Carbon-neutral economy
  • Green technology
  • Sustainable development
  • Circular economy
  • Sustainable urban development
  • Recycling policy

Published Papers (10 papers)

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Research

Article
Laboratory Properties of Waste PET Plastic-Modified Asphalt Mixes
Recycling 2021, 6(3), 49; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6030049 - 14 Jul 2021
Viewed by 785
Abstract
Commercial polymers have been used in pavement modification for decades; however, a major drawback of these polymers is their high cost. Waste plastic polymers could be used as a sustainable and cost-effective additive for improving asphalt properties, attaining combined environmental–economic benefits. Since 2019, [...] Read more.
Commercial polymers have been used in pavement modification for decades; however, a major drawback of these polymers is their high cost. Waste plastic polymers could be used as a sustainable and cost-effective additive for improving asphalt properties, attaining combined environmental–economic benefits. Since 2019, in Australia, trial segments of roads have been built using waste materials, including plastic, requiring that laboratory evaluations first be carried out. This study aims to examine and evaluate the effect of using a domestic waste plastic, polyethylene terephthalate (PET), in modifying C320 bitumen. The assessment of several contents of PET-modified bitumen is carried out in two phases: modified bitumen binders and modified asphalt mixtures. Dynamic shear rheometer (DSR) and rolling thin film oven tests (RTFOT) were utilised to investigate the engineering properties and visco-elastic behaviour of plastic-modified bitumen binders. For evaluating the engineering properties of the plastic-modified asphalt mixtures, the Marshall stability, Marshall flow, Marshall quotient and rutting tests were conducted. The results demonstrated that 6–8% is the ideal percentage of waste plastic proposed to amend and enhance the stiffness and elasticity behaviour of asphalt binders. Furthermore, the 8% waste PET-modified asphalt mixture showed the most improvement in stability and rutting resistance, as indicated by increased Marshal stability, increased Marshall quotient and decreased rut depth. Future fatigue and modulus stiffness tests on waste plastic-modified asphalt mixtures are suggested to further investigate the mechanical properties. Full article
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Article
Estimating the Cost-Competitiveness of Recycling-Based Geopolymer Concretes
Recycling 2021, 6(3), 46; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6030046 - 05 Jul 2021
Viewed by 1015
Abstract
The cement industry is a major contributor to greenhouse gas emissions on a global scale. Consequently, there has been an increasing interest, in both academia and business, in low-carbon concretes in which Ordinary Portland Cement (OPC) is partially or fully replaced with industrial [...] Read more.
The cement industry is a major contributor to greenhouse gas emissions on a global scale. Consequently, there has been an increasing interest, in both academia and business, in low-carbon concretes in which Ordinary Portland Cement (OPC) is partially or fully replaced with industrial side streams. However, the realization of the environmental benefits of such materials depends on how competitive they are in the construction market, where low costs are a major competitive factor. This is not straightforward, as many types of concretes exist. Raw material prices vary, and costs can be influenced by governmental regulations via carbon pricing. This study presents a case study estimating the cost prices of four different geopolymer concretes with different material compositions and carbon footprints, considering the raw material price variability and the potential impact of carbon emissions regulation (carbon price). The case study demonstrates how material mix cost comparisons can be made openly and systematically. The results imply that carbon pricing, at the rates currently applied, does not significantly change the cost price difference between traditional and geopolymer concretes. Instead, cost-competitiveness of low carbon concretes depends heavily on the material mix type and the availability of critical side streams. Full article
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Article
Mechanical Properties of Tin Slag Mortar
Recycling 2021, 6(2), 42; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6020042 - 21 Jun 2021
Viewed by 640
Abstract
The increased demand for cement mortar due to rapid infrastructural growth and development has led to an alarming depletion of fine aggregate. This has prompted the need for a more sustainable material as a total/partial replacement for natural fine aggregate. This study proposes [...] Read more.
The increased demand for cement mortar due to rapid infrastructural growth and development has led to an alarming depletion of fine aggregate. This has prompted the need for a more sustainable material as a total/partial replacement for natural fine aggregate. This study proposes the use of tin slag (TS) as a replacement for fine aggregate in concrete to bridge this sustainability gap. TS was used to replace fine aggregate at replacement levels of 0%, 25%, 50%, 75%, and 100% in cement mortar. Fresh and hardened properties of TS mortar were obtained. Flow tests showed that, as the TS quantity and the w/c ratio increased, the mortar flow increased. Similarly, the compressive strength increased as the TS replacement increased up to 50% replacement, after which a decline in strength was observed. However, with the TS replacement of fine aggregate up to 100%, a compressive strength of 6% above control was attained. The morphological features confirm that specimens with TS had a denser microstructure because of its shape characteristics (elongated, irregular, and rough), and, thus, plugged holes better than the control mortar. The natural sand’s contribution to strength was a result of better aggregate hardness as compared to TS. Hence, TS can be used as alternative for fine aggregate in sustainable construction. Full article
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Article
Physical and Mechanical Properties of Sustainable Hydraulic Mortar Based on Marble Slurry with Waste Glass
Recycling 2021, 6(2), 37; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6020037 - 09 Jun 2021
Viewed by 784
Abstract
This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). [...] Read more.
This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). The first was used as raw material to produce the mortar binder by a kilning and slaking process, while the second was used as a pozzolanic additive. The chemical and morphological characterization of the marble slurry was done by XRD, FTIR, STA and SEM analyses. Glass powder was analyzed through particle size distribution measurements, XRD and standard pozzolanic tests. Hydraulic mortars constituted by slaked lime from kilned marble slurry and waste glass powder (LGS) were prepared beside commercial Natural Hydraulic Lime (NHL) based mortars (NGS) and air-hardening lime (LSS)-based mortars. Mechanical and absorption properties of the mortars were investigated as a function of the grain size of the glass powder by means of three-point bending and compressive strength tests, capillary uptake, helium pycnometry and simultaneous thermal analysis. The results demonstrated that the formulation LGS exhibits significantly improved mechanical and absorption properties compared to air-hardening mortars (LSS). It confirms the possibility of producing a more sustainable hydraulic mortar exclusively from waste materials for civil engineering. Full article
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Article
Performance Assessment of Reclaimed Asphalt Pavement (RAP) in Road Surface Mixtures
Recycling 2021, 6(2), 32; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6020032 - 13 May 2021
Cited by 2 | Viewed by 900
Abstract
Considerable amounts of Reclaimed Asphalt Pavement (RAP) are produced every year, as the road network requires maintenance to ensure the safety and comfort of its users. RAP is a 100% recyclable material and a useful fit to be re-introduced into another cycle without [...] Read more.
Considerable amounts of Reclaimed Asphalt Pavement (RAP) are produced every year, as the road network requires maintenance to ensure the safety and comfort of its users. RAP is a 100% recyclable material and a useful fit to be re-introduced into another cycle without downgrading its functionality. Despite the current knowledge about the benefits associated with RAP use, it is not yet largely applied in several countries. This paper aims to validate, on the basis of both short- and long-term mechanical behaviours, the application of a bituminous mixture with a high RAP incorporation rate (75%) in road pavement wearing courses. A crude tall oil rejuvenator was used. Both short- and long-term oven ageing procedures were employed to simulate the ageing that occurs during mixture production and in-service life, respectively. The tests for validating the RAP mixture as an alternative solution comprised stiffness, resistance to fatigue, permanent deformation, and determination of the water sensitivity. Furthermore, the RAP bitumen mobilisation degree was evaluated and a mixing protocol was established. In comparison with virgin bituminous mixtures, it was found that, in general, the high RAP mixtures presented similar or better behaviour. The ageing process had a hardening effect namely in terms of stiffness and resistance to permanent deformation, without significant effects on the resistance to fatigue and water damage. Full article
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Article
Mechanical Properties of Concrete with Recycled Concrete Aggregate and Fly Ash
Recycling 2021, 6(2), 23; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6020023 - 01 Apr 2021
Cited by 1 | Viewed by 906
Abstract
Recycled concrete aggregate (RCA) collected from the demolition of old reinforced concrete structures can be reused to prepare structural and non-structural concrete, thereby protecting the environment by preserving natural resources. This study explores RCA’s use, collected from the crushed concrete of different building [...] Read more.
Recycled concrete aggregate (RCA) collected from the demolition of old reinforced concrete structures can be reused to prepare structural and non-structural concrete, thereby protecting the environment by preserving natural resources. This study explores RCA’s use, collected from the crushed concrete of different building projects in Riyadh, to manufacture fresh self-compacting concrete (SCC) and investigate its properties in the fresh and hardened state. Four SCC mixes were prepared by replacing natural aggregate (NA) with RCA at 0%, 25%, 50%, and 75% replacement levels. The water-cement (w/c) ratio was maintained constant at 0.38 for all the mixes. Slump Flow, J-ring, and V-funnel tests were performed on the SCC mixes in the fresh state, and the compressive strength of hardened concrete was determined after seven, 14, and 28 days. Water absorption and split tensile tests were also carried out for all the mixes. The findings revealed that it is possible to reach compressive strengths higher than 40 MPa at 28 days for RCA replacement level of 75% by using a superplasticizer and low w/c ratio. The decrease in compressive strength concerning the SCC-NA mix was 25% for 75% replacement level. The highest split tensile strength at 28 days was around 3.3 MPa for a 50% replacement level. The lowest water absorption was 3.2% for SCC-NA, which was gradually increased and was highest at 5.6% for 75% replacement level. Full article
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Article
The Effect of Recycled HDPE Plastic Additions on Concrete Performance
Recycling 2021, 6(1), 18; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6010018 - 06 Mar 2021
Cited by 2 | Viewed by 1695
Abstract
This study examined HDPE (high-density polyethylene) plastic waste as an added material for concrete mixtures. The selection of HDPE was based on its increased strength, hardness, and resistance to high temperatures compared with other plastics. It focused on how HDPE plastic can be [...] Read more.
This study examined HDPE (high-density polyethylene) plastic waste as an added material for concrete mixtures. The selection of HDPE was based on its increased strength, hardness, and resistance to high temperatures compared with other plastics. It focused on how HDPE plastic can be used as an additive in concrete to increase its tensile strength and compressive strength. 156 specimens were used to identify the effect of adding different percentages and sizes of HDPE lamellar particles to lower, medium, and higher strength concrete for non-structural applications. HDPE 0.5 mm thick lamellar particles with sizes of 10 × 10 mm, 5 × 20 mm, and 2.5 × 40 mm were added at 2.5%, 5%, 10%, and 20% by weight of cement. The results showed that the medium concrete class (with compressive strength equal to 10 MPa) had the best response to the addition of HDPE. The 5% HDPE addition represented the optimal mix for all concrete types, while the 5 × 20 mm size was best. Full article
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Article
Mechanical and Market Study for Sand/Recycled-Plastic Cobbles in a Medium-Size Colombian City
Recycling 2021, 6(1), 17; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6010017 - 04 Mar 2021
Viewed by 1024
Abstract
The need to satisfy the increasing demand for building materials and the challenge of reusing plastic to help improve the critical environmental crisis has led to the recycling of plastic waste, which is further exploited and transformed into new and creative materials for [...] Read more.
The need to satisfy the increasing demand for building materials and the challenge of reusing plastic to help improve the critical environmental crisis has led to the recycling of plastic waste, which is further exploited and transformed into new and creative materials for the construction industry. This study looked into the use of low-density recycled polyethylene (LDPE) to produce non-conventional plastic sand cobbles. LDPE waste was melted in order to obtain enough fluid consistency which was then mixed with sand in a 25/75 plastic-sand ratio respectively, such a mixture helped producing cobbles of 10 cm × 20 cm × 4 cm. Water absorption, weight, and density measurements were performed on both commercial and non-conventional plastic sand cobbles. Moreover, compression, bending, and wear resistance were also conducted as part of their mechanical characterization. Plastic sand cobbles showed lower water absorption and density values than commercial cobbles. The mechanical properties evaluated showed that plastic sand cobbles have a higher modulus of rupture and wear resistance than commercial cobbles. In addition, plastic sand cobbles meet the Colombian Technical Standard in lightweight traffic for pedestrians and vehicle, officially known as Norma Técnica Colombiana (NTC), with 25.5 MPa, 16.3 MPa, and 12 mm compression resistance, modulus of rupture and footprint length in wear resistance respectively. Finally, a market study was conducted to establish a factory to produce this type of cobbles in Ibague, Colombia. Not only the study showed positive financial indicators, which means that it is feasible running a factory to manufacture plastic sand cobbles in the city of Ibague, but it also concluded that nonconventional plastic sand cobbles could be explored to provide a comprehensive alternative to LDPE waste. Full article
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Article
Mechanical Property Assessment of Interlocking Plastic Pavers Manufactured from Electronic Industry Waste in Brazil
Recycling 2021, 6(1), 15; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling6010015 - 25 Feb 2021
Viewed by 1020
Abstract
The estimated production of world electronic waste until 2017 is approximately 6 Gt. Despite this enormous problem, there are no clear regulations regarding the orientation for disposal or treatment of this type of residuals in many countries. There is a federal public policy [...] Read more.
The estimated production of world electronic waste until 2017 is approximately 6 Gt. Despite this enormous problem, there are no clear regulations regarding the orientation for disposal or treatment of this type of residuals in many countries. There is a federal public policy in Brazil that supports a network of Computer Reconditioning Centers—CRCs. These CRCs train young people and recover or recycle electronic equipment. Through this work, CRCs produce interlocking plastic pavers for application on pavements from recycled electronic industry waste. This article presents the characterization of these interlocking paver’s mechanical properties when applied on the pavement. This characterization is a necessary step to show the effectiveness of this product. We show that the plastic pavers behave similarly to the artifacts manufactured in concrete, thus creating commercial opportunities for this initiative, and contributing to the Brazilian Solid Waste Policy. Full article
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Article
Assessment of Eco-Friendly Pavement Construction and Maintenance Using Multi-Recycled RAP Mixtures
Recycling 2020, 5(3), 17; https://0-doi-org.brum.beds.ac.uk/10.3390/recycling5030017 - 14 Aug 2020
Cited by 7 | Viewed by 2250
Abstract
The demand for more sustainable solutions has led an ever-growing number of stakeholders to being committed to pursue the principles of sustainability in pavement management. Different stakeholders have been looking for tools and methodologies to evaluate the environmental impacts of the solutions, for [...] Read more.
The demand for more sustainable solutions has led an ever-growing number of stakeholders to being committed to pursue the principles of sustainability in pavement management. Different stakeholders have been looking for tools and methodologies to evaluate the environmental impacts of the solutions, for which the life cycle assessment (LCA) proved to be an appropriate methodology. This paper is focused on the LCA of road pavement multi-recycling based on the use of bituminous mixtures with high rates of reclaimed asphalt pavement (RAP). In order to promote the circular economy, a comparative analysis was performed on a road pavement section by taking into account different scenarios, which stem from the combination of production, construction and rehabilitation activities incorporating different RAP rates in new bituminous mixtures: 0% (as reference), 25%, 50%, 75% and 100%, respectively. LCA results have been expressed in terms of four damage categories: human health, ecosystem quality, climate change and resources. Results have shown that both recycled and multi-recycled bituminous mixtures lead to substantial benefits in comparison with the solution employing virgin materials, hence embodying a sustainable approach. The benefits grow with the increase in the RAP rate with an average decrease of 19%, 23%, 31% and 33% in all the impact categories for a 25%, 50%, 75% and 100% of RAP rate. Full article
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