Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

Sustainable Recycling Techniques of Pavement Materials

Special Issue Editors
Special Issue Information
Keywords
Related Special Issue
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: closed (20 August 2022) | Viewed by 30526

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special issue Sustainable Recycling Techniques of Pavement Materials book cover image

Share This Special Issue

Special Issue Editors

Prof. Dr. Qiang Li

E-Mail Website
Guest Editor

College of Civil Engineering, Nanjing Forestry University, Nanjing, China
Interests: pavement materials; multiscale characterization; recycled asphalt pavement; sustainable maintenance; smart pavement construction

Dr. Jiaqing Wang

E-Mail Website
Guest Editor

College of Civil Engineering, Nanjing Forestry University, Nanjing, China
Interests: sustainable infrastructure materials; rubberized concrete; fiber-reinforced concrete; utilization of MSW; asphalt concrete materials; material macro and micro characterizations; FEM fracture analysis
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Kaijian Huang

E-Mail Website
Guest Editor

College of Civil Engineering, Nanjing Forestry University, Nanjing, China
Interests: pavement structures and materials; multiphysics simulation of pavement structures; eco-concrete materials; biomaterials for concrete repairing; smart pavement concrete

Prof. Dr. Dongdong Ge

E-Mail Website
Guest Editor

School of Traffic & Transportation Engineering, Changsha University of Science & Technology, Changsha, China
Interests: asphalt testing and characterization; asphalt pavement materials; asphalt pavement design; asphalt pavement evaluation; recycled materials for pavement
Special Issues, Collections and Topics in MDPI journals

Dr. Fangyuan Gong

E-Mail Website
Guest Editor

School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin, China
Interests: material and structure of road engineering; intelligent detection and repair of pavement disease; micro-structure evaluation and analysis of road materials; development and preparation of sustainable road materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

With the rapid development of infrastructure constructions, more and more existing pavements need to be recycled and reconstructed, especially recycled asphalt pavement, which consists of the world’s most recycled materials. Of all the ubiquitous things in our environment, roads are probably one of the least noticed. Our pavements see tremendous volumes of traffic and withstand considerable variations in weather and climate, and they do this on a pretty tight budget. This is only possible because all the scientists, engineers, contractors, and public works crews keep up with this incredible but straightforward material called asphalt. Therefore, innovative techniques for recycling and processing materials that could be used for new pavement construction have attracted more attention, considering their benefits in different properties. In recent years, warm and cold recycling techniques were proposed for recycled asphalt pavement (RAP) due to their benefits in temperature reductions that can effectively decrease energy consumption and CO₂ emissions. In addition, pavement materials containing municipal solid waste (MSW) were also widely studied, including but not limited to rubberized concrete, rubberized asphalt, and alternative cementitious materials for concrete pavements. Both of the techniques or materials above were applied to improve the mechanical and durability performances of newly constructed pavements and reduce the environmental effects of landfills and greenhouse gas (GHG) emissions. The exploration of their effects on the various properties of materials and structures in pavements has also been widely conducted. During the exploration, not only experimental investigations but also simulations and life cycle assessments were operated in multiple aspects to evaluate, optimize, and predict the various properties.

This Special Issue will focus on innovative and efficient techniques and materials for pavement recycling and reconstruction. The main sub-topics include pavement recycling techniques, the effective utilization of industrial and construction waste in pavement engineering, improvements in sustainable techniques for pavement materials (e.g., warm and cold recycling technology for old asphalt pavement and GHG emission reduction techniques for RAP, etc.), green low-carbon and durable pavement structures and materials, the evaluation and simulation of sustainable pavement materials, the investigation of durability performance enhancement by recycled pavement materials, and life cycle assessment (LCA) regarding the utilization of recycled and waste materials in pavement construction.

It is our pleasure to invite you to submit a manuscript for this Special Issue. Articles and review papers are acceptable for this topic.

Prof. Dr. Qiang Li
Dr. Jiaqing Wang
Prof. Dr. Kaijian Huang
Prof. Dr. Dongdong Ge
Dr. Fangyuan Gong
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 submissions that pass pre-check are 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. Materials is an international peer-reviewed open access semimonthly 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 2600 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

pavement recycling techniques
industrial and construction waste utilization in pavement engineering
sustainable techniques for pavement materials
green low-carbon and durable pavement structures and materials
evaluation and simulation of sustainable pavement materials
infrastructure durability improvements by recycled pavement materials
life cycle assessment (GHG emission reduction/life cycle cost decrease attributed to the utilization of waste in pavement materials)

Related Special Issue

Sustainable Recycling Techniques of Pavement Materials II in Materials (7 articles)

Published Papers (14 papers)

Download All Papers

Editorial

Jump to: Research, Review

5 pages, 176 KiB

Open AccessEditorial

Sustainable Recycling Techniques of Pavement Materials

by Jiaqing Wang, Qiang Li, Kaijian Huang, Dongdong Ge and Fangyuan Gong

Materials 2022, 15(24), 8710; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15248710 - 07 Dec 2022

Cited by 3 | Viewed by 929

Abstract

Innovative sustainable techniques for transportation infrastructure enhancement have been proposed in recent decades [...] Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

Research

Jump to: Editorial, Review

19 pages, 10346 KiB

Open AccessArticle

Analysis of the Influence of Waste Seashell as Modified Materials on Asphalt Pavement Performance

by Guopeng Fan, Honglin Liu, Chaochao Liu, Yanhua Xue, Zihao Ju, Sha Ding, Yuling Zhang and Yuanbo Li

Materials 2022, 15(19), 6788; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15196788 - 30 Sep 2022

Cited by 7 | Viewed by 1477

Abstract

An increasing amount of waste seashells in China has caused serious environmental pollution and resource waste. This paper aims to solve these problems by using waste seashells as modified materials to prepare high-performance modified asphalt. In this study, seashell powder (SP) and stratum corneum-exfoliated seashell powder (SCESP) were adopted to prepare 10%, 20% and 30% of seashell powder-modified asphalt (SPMA) and stratum corneum-exfoliated seashell powder-modified asphalt (SCESPMA) by the high-speed shear apparatus, respectively. The appearance and composition of two kinds of SPs were observed and determined by the scanning electron microscope (SEM). The types of functional groups, temperature frequency characteristics, low temperature performance and adhesion of SPMA were tested by the Fourier-transform infrared (FTIR) spectrometer, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and contact angle meter. The results show that the SP and SCESP are rough and porous, and their main component is CaCO₃, which is physically miscible to asphalt. When the loading frequency ranges from 0.1 Hz to 10 Hz, the complex shear modulus (G*) and phase angle (δ) of SPMA and SCESPMA increase and decrease, respectively. At the same load frequency, SCESPMA has a larger G* and a smaller δ than SPMA. At the same temperature, SCESPMA has a larger rutting factor (G*/sin δ) and better high-temperature deformation resistance than SPMA. SP and SCESP reduce the low-temperature cracking resistance of asphalt, of which SCESP has a more adverse effect on the low-temperature performance of asphalt than SP. When SP and SCESP are mixed with asphalt, the cohesion work (Waa), adhesion work (Was) and comprehensive evaluation parameters of water stability (ER1, ER2 and ER3) of asphalt are improved. It is shown that both SP and SCESP have good water damage resistance, of which SCESP has better water damage resistance than SP. These research results have important reference value for the application of waste biological materials in asphalt pavement. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

17 pages, 3510 KiB

Open AccessEditor’s ChoiceArticle

Study on the Stability of Bio-Oil Modified Prime Coat Oil Based on Molecular Dynamics

by Shuang Shi, Lanqin Lin, Zhaoguang Hu, Linhao Gu and Yanning Zhang

Materials 2022, 15(19), 6737; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15196737 - 28 Sep 2022

Cited by 5 | Viewed by 1452

Abstract

To explore the effect of different emulsifier contents on the stability performance of biomass-emulsified asphalt, three types of emulsified asphalt with 1%, 3%, and 5% anionic emulsifiers were prepared and analyzed by molecular dynamics simulation and macroscopic experiments. Firstly, we used molecular simulation software (Material Studio, MS) to construct a model of biomass-emulsified asphalt with different emulsifier contents and analyzed the microscopic mechanism of the emulsifier to improve the stability of the emulsified asphalt by the radial distribution function, interaction energy, interfacial layer thickness, and solubility parameters of the emulsified asphalt system with different emulsifier contents. The results were validated by macro and micro tests including storage stability, particle size determination, and infrared spectroscopy. The results show that at low emulsifier contents, the emulsifier can reduce the interfacial tension between the oil–water interface and expand the transition region between the two phases (interfacial layer thickness), which will prevent interparticle agglomeration and reduce the emulsion particle size, thus reducing the settling rate and ensuring the stability of the emulsion. When the emulsifier content is further increased beyond the critical micelle concentration, the emulsifiers will agglomerate with each other and show larger peaks in the radial distribution function, and the phenomenon of emulsifier agglomeration will appear in the five-day storage stability test, resulting in a corresponding decrease in the proximity of the infrared absorption peak area ratio in the same wavelength band of the upper and lower layers of the biomass-emulsified asphalt, and the emulsion stability decreases instead. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

19 pages, 18489 KiB

Open AccessArticle

Study on the Performance of Steel Slag and Its Asphalt Mixture with Oxalic Acid and Water Erosion

by Xiaoming Huang, Feng Yan, Rongxin Guo and Huan He

Materials 2022, 15(19), 6642; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15196642 - 25 Sep 2022

Cited by 4 | Viewed by 1259

Abstract

The reuse of steel slag, a large-scale solid waste from steel production, has good social and environmental benefits. The application of a steel slag asphalt mixture is mainly hindered by its volume expansion in water. The expansion of steel slag can be inhibited by oxalic acid. The expansion rate and adhesion of steel slag were investigated, and the immersion stability of steel slag and its asphalt mixture was evaluated by water erosion. By means of XRD, XRF, TG, SEM, etc., the influence mechanism of oxalic acid and water erosion on the properties of steel slag and its asphalt mixture was discussed. The results show that oxalic acid can not only inhibit the expansion of steel slag but also improve its crush resistance, with a reduction in the expansion rate of steel slag by 53%. Oxalic acid is able to leach alkaline metal elements, reducing its adhesion with asphalt. After 10 days of water erosion, the rutting stability and bending crack resistance of the treated steel slag mixture decreased by 37% and 43.2%, respectively. Calcium oxalate is generated on the surface of treated steel slag, which improves the surface compactness, effectively inhibits the expansion of steel slag caused by water erosion, and improves the performance of steel slag and its asphalt mixture. Water erosion can accelerate the hydration and shedding of calcium-containing substances on the surface of steel slag, reduce the adhesion of steel slag, and lead to degradation in the performance of steel slag and its asphalt mixture. Oxalic acid is able to effectively inhibit the expansion of steel slag, and the treated steel slag can be used as recycled aggregate in asphalt mixture, effectively solving the problems of road aggregate deficiency and environmental pollution caused by steel slag. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

19 pages, 5302 KiB

Open AccessArticle

Experimental Study on Carbonation of Cement-Based Materials in Underground Engineering

by Jun Zheng, Gang Zeng, Hui Zhou and Guanghua Cai

Materials 2022, 15(15), 5238; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15155238 - 29 Jul 2022

Cited by 2 | Viewed by 1139

Abstract

The corrosive water environment has a decisive influence on the durability of a diversion tunnel lining. In this paper, the effects of carbonation on cement-based materials in water-immersion and saturated-humidity environments were studied by increasing the CO₂ concentration. The results show that under conditions of water-immersion and saturated humidity, the color of the non-carbonation region is dark, while the carbonation region is gray, and the color boundary is obvious. However, in an atmospheric environment, there is no zone with a dark color and the color boundary is not obvious. In a saturated-humidity environment, the carbonation depth increases over time and changes greatly, and its value is about 16.71 mm at 200 days. While in a water-immersion environment, the carbonation depth varies little with time and the value is only 2.31 mm. The carbonation depths of cement mortar samples in different environments generally follow a linear relationship with the square root of time. The carbonation coefficient in a saturated-humidity environment is more than nine times that in the water-immersion environment. In a water-immersion environment, the carbonation causes a large loss of calcium in cement-based materials, and their Ca/Si ratio obviously decreases. The calcium silicon ratio (Ca/Si) of cement-based materials in a water-immersion environment is 0.11, which is much less than 1.51 in a water-saturated environment and 1.49 in an atmospheric environment. In a saturated-humidity environment, the carbonation only reduces the pH of the pore solution in the carbonation region, and the structural stability of cement-based materials is not degraded. The number of pores of all radii after carbonation in a water-immersion environment exceeds that in a saturated-humidity environment, and the total pore volume and average pore radius in a water-immersion environment are also larger than in a saturated-humidity environment, so the water-immersion environment accelerates the development and expansion of pores. The research results can provide some theoretical and technical support for the design, construction, and safe operation of diversion tunnel linings. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

26 pages, 12204 KiB

Open AccessArticle

Performance Prediction of Cement Stabilized Soil Incorporating Solid Waste and Propylene Fiber

by Genbao Zhang, Zhiqing Ding, Yufei Wang, Guihai Fu, Yan Wang, Chenfeng Xie, Yu Zhang, Xiangming Zhao, Xinyuan Lu and Xiangyu Wang

Materials 2022, 15(12), 4250; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15124250 - 15 Jun 2022

Cited by 8 | Viewed by 1471

Abstract

Cement stabilized soil (CSS) yields wide application as a routine cementitious material due to cost-effectiveness. However, the mechanical strength of CSS impedes development. This research assesses the feasible combined enhancement of unconfined compressive strength (UCS) and flexural strength (FS) of construction and demolition (C&D) waste, polypropylene fiber, and sodium sulfate. Moreover, machine learning (ML) techniques including Back Propagation Neural Network (BPNN) and Random Forest (FR) were applied to estimate UCS and FS based on the comprehensive dataset. The laboratory tests were conducted at 7-, 14-, and 28-day curing age, indicating the positive effect of cement, C&D waste, and sodium sulfate. The improvement caused by polypropylene fiber on FS was also evaluated from the 81 experimental results. In addition, the beetle antennae search (BAS) approach and 10-fold cross-validation were employed to automatically tune the hyperparameters, avoiding tedious effort. The consequent correlation coefficients (R) ranged from 0.9295 to 0.9717 for BPNN, and 0.9262 to 0.9877 for RF, respectively, indicating the accuracy and reliability of the prediction. K-Nearest Neighbor (KNN), logistic regression (LR), and multiple linear regression (MLR) were conducted to validate the BPNN and RF algorithms. Furthermore, box and Taylor diagrams proved the BAS-BPNN and BAS-RF as the best-performed model for UCS and FS prediction, respectively. The optimal mixture design was proposed as 30% cement, 20% C&D waste, 4% fiber, and 0.8% sodium sulfate based on the importance score for each variable. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

18 pages, 8155 KiB

Open AccessArticle

Investigation on Water Transformation and Pore Structure of Cement-Stabilized Dredged Sediment Based on NMR Technology

by Shiquan Wang, Xingxing He, Guanghua Cai, Lei Lang, Hongrui Ma, Shunmei Gong and Zhiyong Niu

Materials 2022, 15(9), 3178; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15093178 - 28 Apr 2022

Cited by 6 | Viewed by 1519

Abstract

Cement-stabilized dredged sediment (CDS) when used as a new road construction material cannot only solve the problem of abandoned sediment disposal, but also effectively save natural soil resources. This study aimed to evaluate the strength and permeability of CDS and establish corresponding prediction models from the perspective of a stabilization mechanism. The soil–water composition and pore size distribution were investigated by the nuclear magnetic resonance (NMR) technique. The results demonstrated that more liquid pore water inside the CDS specimen transformed into combined water with cement hydration. The amount of combined water, which essentially characterized the hydration process of cement, presented a linear relationship with log (t). The cementation and filling action of hydrates resulted in the transformation of large pores into smaller ones, hence the optimal pore size decreased with an increasing curing period and cement content. The stress–strain curves and hydraulic conductivity were determined based on unconfined compression and flexible wall penetration tests, respectively. The unconfined compressive strength increased exponentially with the amount of combined water, and the functional correlations of hydraulic conductivity and micropore parameters were established. The reliability of the NMR technique as a new method to study the microscopic evolution mechanism of the strength and permeability of CDS was further verified by scanning electron microscopy and mercury intrusion porosimetry tests. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

20 pages, 7104 KiB

Open AccessArticle

Mechanical Performance of 3D Printed Concrete in Steam Curing Conditions

by Bolin Wang, Xiaofei Yao, Min Yang, Runhong Zhang, Jizhuo Huang, Xiangyu Wang, Zhejun Dong and Hongyu Zhao

Materials 2022, 15(8), 2864; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15082864 - 13 Apr 2022

Cited by 9 | Viewed by 1964

Abstract

Three-dimensional (3D) concrete printing (3DCP) technology attracts significant attention from research and industry. Moreover, adequate mechanical performance is one of the primary properties for materials, meeting the demand of structural safety using 3DCP technology. However, research on curing conditions as the significant influence factor of mechanical capacity is required to accelerate the practical application of 3DCP technology. This study aims to explore the impact of various steam curing conditions (heating rate, constant temperature time, and constant temperature) on the mechanical performance of printed concrete containing solid wastes. Moreover, the optimal steam curing conditions are obtained for compressive, tensile, and flexural properties in different directions. Subsequently, anisotropies in the mechanical properties of printed composites and interlayer bonding behaviors are investigated when various curing conditions are employed. The result shows that steam curing conditions and solid waste incorporation improves the interlayer bond for 3D printed cement-based composites. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

14 pages, 3519 KiB

Open AccessArticle

Aging Behavior of High-Viscosity Modified Asphalt Binder Based on Infrared Spectrum Test

by Wenxuan Zhang, Qiang Li, Jiaqing Wang, Yuanpeng Meng and Zhou Zhou

Materials 2022, 15(8), 2778; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15082778 - 10 Apr 2022

Cited by 11 | Viewed by 1682

Abstract

In the rapid development of sponge city construction in China, porous asphalt pavement has been widely used. The high-viscosity modified asphalt used for porous asphalt pavements is utilised in a complex aging environment. In this study, infrared spectroscopy was used to test the changes in the functional groups of high-viscosity modified asphalt under the influence of ultraviolet radiation intensity, high temperature, and water corrosion conditions. The research results showed that under the influence of several environmental factors, the high-viscosity modified asphalt has no chemical reaction but does undergo physical changes. From the perspective of the functional group index, the carbonyl index is more suitable for evaluating the degree of ultraviolet aging, and the sulfoxide group index is more suitable for evaluating the effect of temperature on aging. The high-viscosity modified asphalt aging kinetic models, established with different functional group indexes as indicators, have different activation energies. The aging kinetic model established with the carbonyl index is more suitable for simulating traditional thermal-oxidative aging. This study provides a better plan to reveal the influence of different environmental factors on the aging performance of high-viscosity modified asphalt under complex environmental conditions. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

23 pages, 54926 KiB

Open AccessArticle

Characterizing and Predicting the Resilient Modulus of Recycled Aggregates from Building Demolition Waste with Breakage-Induced Gradation Variation

by Yuanjie Xiao, Kunfeng Kong, Umar Faruk Aminu, Zhiyong Li, Qiang Li, Hongwei Zhu and Degou Cai

Materials 2022, 15(7), 2670; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15072670 - 05 Apr 2022

Cited by 9 | Viewed by 1590

Abstract

Building demolition waste (BDW) has been massively stockpiled due to increasingly rapid urbanization and modernization. The use of recycled BDW as unbound granular base/subbase materials is among the sustainable, cost-effective, and environmentally friendly pavement construction alternatives. The resilient modulus is an important mechanical property of BDW-derived aggregates and mechanistic design input of pavements incorporating BDW. This paper presents the results of a comprehensive laboratory study on the shear strength and resilient modulus characteristics of BDW-derived aggregate materials. A series of monotonic triaxial compression tests and repeated-load triaxial (RLT) tests were conducted with five different gradations representing particle breakage and different stress paths. The apparent cohesion and internal friction angle of recycled BDW aggregates under consolidated drained conditions ranged from 35.3 to 57.5 kPa and from 30.2° to 54.3°, respectively. The apparent cohesion and internal friction angle also increased and decreased non-linearly with the increasing relative content of fine particles, respectively. The resilient modulus of recycled BDW aggregates gradually decreased with increasing relative content of fine particles at the same stress level. Both the deviator stress and confining pressure exhibited significant influences on the resilient modulus, while the effect of confining pressure was more profound. Based on laboratory testing data, a mechanistic-empirical model was developed to predict the resilient modulus of recycled BDW aggregates from gradation and stress-state variables. The findings could be useful for extended engineering applications of BDW in unbound granular pavement base/subbase construction. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

22 pages, 4413 KiB

Open AccessArticle

Preparation of Artificial Pavement Coarse Aggregate Using 3D Printing Technology

by Weixiong Li, Duanyi Wang, Bo Chen, Kaihui Hua, Zhiyong Huang, Chunlong Xiong and Huayang Yu

Materials 2022, 15(4), 1575; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15041575 - 20 Feb 2022

Cited by 7 | Viewed by 2200

Abstract

Coarse aggregate is the main component of asphalt mixtures, and differences in its morphology directly impact road performance. The utilization of standard aggregates can benefit the standard design and performance improvement. In this study, 3D printing technology was adopted to prepare artificial aggregates with specific shapes for the purpose of making the properties of artificial aggregates to be similar to the properties of natural aggregates. Through a series of material experiments, the optimal cement-based material ratio for the preparation of high-strength artificial aggregates and corresponding manufacturing procedures have been determined. The performance of the artificial aggregates has been verified by comparing the physical and mechanical properties with those of natural aggregates. Results indicate that using 3D printing technology to generate the standard coarse aggregate is feasible, but its high cost in implementation cannot be ignored. The 3D shape of the artificial aggregate prepared by the grouting molding process has a good consistency with the natural aggregate, and the relative deviation of the overall macro-scale volume index of the artificial aggregate is within 4%. The average Los Angeles abrasion loss of artificial cement-based aggregate is 15.2%, which is higher than that of diabase aggregate, but significantly lower than that of granite aggregate and limestone aggregate. In a nutshell, 3D printed aggregates prepared using the optimized cement-based material ratio and corresponding manufacturing procedures have superior physical and mechanical performance, which provides technical support for the test standardization and engineering application of asphalt pavements. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

16 pages, 5327 KiB

Open AccessArticle

The Performance Evaluation of Asphalt Mortar and Asphalt Mixture Containing Municipal Solid Waste Incineration Fly Ash

by Xiaowen Zhao, Dongdong Ge, Jiaqing Wang, Dianwen Wu and Jun Liu

Materials 2022, 15(4), 1387; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15041387 - 14 Feb 2022

Cited by 12 | Viewed by 1781

Abstract

The aim of the research is to quantify the property of asphalt mortar and asphalt mixture containing municipal solid waste incineration (MSWI) fly ash. The potential of partially replacing mineral fillers with MSWI fly ash in asphalt mixture production was investigated. Five different MSWI fly ash replacement ratios, which include 0%, 25%, 50%, 75%, and 100%, were adopted to assess the influence of fly ash dosage, and the optimum fly ash replacement ratio was proposed. The rheological characteristics of asphalt mortar with MSWI fly ash were assessed with the dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The high temperature properties of the mixture with MSWI fly ash were assessed with the Marshall stability test and the rutting test. The low temperature cracking property was determined with the indirect tensile strength test at low temperatures. The moisture stability property was identified with the immersed Marshall test and the freeze-thaw cycles conditioned indirect tensile strength test. Based on the test results, the addition of fly ash and mineral filler remarkably increased the ǀG*ǀ of the asphalt mortar. The δ of asphalt decreased as the dosage of fly ash and mineral filler increased. The addition of fly ash and mineral filler degraded the low temperature characteristics of the mortar. Fly ash improved the high temperature characteristics of the asphalt mixture. The asphalt mixture with MSWI fly ash was more susceptible to thermal cracking than the control sample. The addition of fly ash weakened the moisture stability of the asphalt mixture. In order to guarantee the low temperature characteristics and the moisture susceptibility of the asphalt mixture, the fly ash replacement ratio was recommended to be set around 25%. With proper mixture design and fly ash dosage, the asphalt mixture would have adequate performance, as well as reduced environmental impact. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

14 pages, 2236 KiB

Open AccessArticle

Evaluation of High-Temperature and Low-Temperature Performances of Lignin–Waste Engine Oil Modified Asphalt Binder and Its Mixture

by Xue Xue, Junfeng Gao, Jiaqing Wang and Yujing Chen

Materials 2022, 15(1), 52; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15010052 - 22 Dec 2021

Cited by 7 | Viewed by 2364

Abstract

This research aims to explore the high-temperature and low-temperature performances of lignin–waste engine oil-modified asphalt binder and its mixture. For this research, the lignin with two contents (4%, 6%) and waste engine oil with two contents (3%, 5%) were adopted to modify the control asphalt binder (PG 58-28). The high-temperature rheological properties of the lignin–waste engine oil-modified asphalt binder were investigated by the viscosity obtained by the Brookfield viscometer and the temperature sweep test by the dynamic shear rheometer. The low-temperature rheological property of the lignin–waste engine oil-modified asphalt binder was evaluated by the stiffness and m-value at two different temperatures (−18 °C, −12 °C) obtained by the bending beam rheometer. The high-temperature and the low-temperature performances of the lignin–waste engine oil-modified asphalt mixture were explored by the rutting test and low-temperature bending beam test. The results displayed that the rotational viscosity and rutting factor improved with the addition of lignin and decreased with the incorporation of waste engine oil. Adding the lignin into the control asphalt binder enhanced the elastic component while adding the waste engine oil lowered the elastic component of the asphalt binder. The stiffness of asphalt binder LO60 could not meet the requirement in the specification, but the waste engine oil made it reach the requirement based on the bending beam rheometer test. The waste engine oil could enhance the low-temperature performance. The dynamic stabilities of LO40- and LO60-modified asphalt mixture increased by about 9.05% and 17.41%, compared to the control mixture, respectively. The maximum tensile strain of LO45 and LO65 increased by 16.39% and 25.28% compared to that of LO40 and LO60, respectively. The high- and low-temperature performances of the lignin–waste engine oil-modified asphalt LO65 was higher than that of the control asphalt. The dynamic stability had a good linear relationship with viscosity, the rutting factor of the unaged at 58 °C, and the rutting factor of the aged at 58 °C, while the maximum tensile strain had a good linear relationship with m-value at −18 °C. This research provides a theoretical basis for the further applications of lignin–waste engine oil-modified asphalt. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

26 pages, 16972 KiB

Open AccessReview

Using Waste Plastics as Asphalt Modifier: A Review

by Fengchi Xu, Yao Zhao and Kangjian Li

Materials 2022, 15(1), 110; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15010110 - 24 Dec 2021

Cited by 42 | Viewed by 7491

Abstract

The use of waste products in the production of asphalt binders and asphalt mixtures has become widespread due to economic and environmental benefits. In particular, the use of recycled waste plastic in asphalt binders and mixtures is gaining more attention. This review presents analyses and comparisons of various forms of waste plastic used in asphalt modification, and approaches to incorporating waste plastic into asphalt mixtures, both for single and composite modifications. It focuses on the properties of waste plastics, asphalt binders, and asphalt mixtures. Overall, the incorporation of plastic waste into asphalt mixtures can significantly improve high-temperature performance and has potential economic and environmental benefits. The performance of modified asphalt is highly dependent on multiple factors, such as waste sources, waste plastic dosages, blending conditions, and the pretreatment methods for waste plastic. There are different ways to apply waste plastics to blend into a mixture. In addition, this paper discusses the current challenges for waste plastic-modified asphalt, including the stability, low-temperature performance, modification mechanism, and laboratory problems of the blends. The use of chemical methods, such as additives and functionalization, is considered an effective way to achieve better interactions between waste plastics and the binder, as well as achieving a higher sufficiency utilization rate of waste plastics. Although both methods provide alternative options to produce waste plastic-modified asphalt with stability and high performance, the optimal proportion of materials used in the blends and the microcosmic mechanism of composite modified asphalt are not clear, and should be explored further. Full article

(This article belongs to the Special Issue Sustainable Recycling Techniques of Pavement Materials)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Sustainable Recycling Techniques of Pavement Materials

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issue

Published Papers (14 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI