Effects of Crumb Rubber Size and Concentration on Marshall Parameters of Rubberized Asphalt Mixture

The application of waste tire rubber in highway engineering mainly focuses on the modification of asphalt rather than the asphalt mixture, which restricts the application of waste tire. The addition of rubber has an effect on the performance of the mixture because of the obvious difference between rubber and mineral aggregates. This paper makes a research on the preparation technology of the specimens made of crumb rubber modified asphalt mixture in the laboratory by means of the study of selection of rubber、aggregate gradation、compaction temperature and so on. The effect of compaction was investigated in terms of the air void of the specimens under different preparation conditions. The optimal preparation process of rubberized asphalt mixture is put forward which could be proved to effectively control the pavement damages such as loose、stripping and so on.

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Investigation of the Formation Mechanism and Environmental Risk of Tire—Pavement Wearing Waste (TPWW)

Sustainability ◽

10.3390/su13158172 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8172

Author(s):

Kechen Wang ◽

Xiangyu Chu ◽

Jiao Lin ◽

Qilin Yang ◽

Zepeng Fan ◽

...

Keyword(s):

Formation Mechanism ◽

Organic Contaminants ◽

Asphalt Mixture ◽

Fine Fraction ◽

Crumb Rubber ◽

Environmental Benefit ◽

The Road ◽

Open Graded Friction Course ◽

Volatile Alkanes ◽

Physical And Chemical

Tire—pavement interaction behaviours result in large amounts of wearing waste matter, which attaches to the surface of the pavement and is directly exposed to the surrounding environment. This kind of matter imposes a great challenge to the environment of the road area. The current study is devoted to carrying out a comprehensive investigation of the formation mechanism of tire—pavement wearing waste (TPWW), as well as the resulting environmental risks. A self-developed piece of accelerated polishing equipment, the Harbin advanced polishing machine (HAPM), was employed to simulate the wearing process between vehicle tires and pavement surfaces, and the TPWW was collected to conduct morphological, physical, and chemical characterisations. The results from this study show that the production rate of TPWW decreases with the increase in polishing duration, and the coarse particles (diameters greater than 0.425 mm) account for most of the TPWW obtained. The fine fraction (diameter smaller than 0.425 mm) of the TPWW comprises variously sized and irregularly shaped rubber particles from the tire, as well as uniformly sized and angular fine aggregates. The environmental analysis results show that volatile alkanes (C9–C16) are the major organic contaminants in TPWW. The Open-Graded Friction Course (OGFC) asphalt mixture containing crumb rubber as a modifier showed the highest risk of heavy metal pollution, and special concern must be given to tire materials for the purpose of improving the environmental conditions of road areas. The use of polyurethane as a binder material in the production of pavement mixtures has an environmental benefit in terms of pollution from both organic contaminants and heavy metals.

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Rejuvenation Mechanism of Asphalt Mixtures Modified with Crumb Rubber

CivilEng ◽

10.3390/civileng2020020 ◽

2021 ◽

Vol 2 (2) ◽

pp. 370-384

Author(s):

Hossein Noorvand ◽

Kamil Kaloush ◽

Jose Medina ◽

Shane Underwood

Keyword(s):

Tensile Strength ◽

Dynamic Loading ◽

Creep Compliance ◽

Asphalt Mixture ◽

Crumb Rubber ◽

Indirect Tensile Strength ◽

Laboratory Evaluation ◽

Strength Testing ◽

Noise Mitigation ◽

Indirect Tensile

Asphalt aging is one of the main factors causing asphalt pavements deterioration. Previous studies reported on some aging benefits of asphalt rubber mixtures through laboratory evaluation. A field observation of various pavement sections of crumb rubber modified asphalt friction courses (ARFC) in the Phoenix, Arizona area indicated an interesting pattern of transverse/reflective cracking. These ARFC courses were placed several years ago on existing jointed plain concrete pavements for highway noise mitigation. Over the years, the shoulders had very noticeable and extensive cracking over the joints; however, the driving lanes of the pavement showed less cracking formation in severity and extent. The issue with this phenomenon is that widely adopted theories that stem from continuum mechanics of materials and layered mechanics of pavement systems cannot directly explain this phenomenon. One hypothesis could be that traffic loads continually manipulate the pavement over time, which causes some maltenes (oils and resins) compounds absorbed in the crumb rubber particles to migrate out leading to rejuvenation of the mastic in the asphalt mixture. To investigate the validity of such a hypothesis, an experimental laboratory testing was undertaken to condition samples with and without dynamic loads at high temperatures. This was followed by creep compliance and indirect tensile strength testing. The results showed the higher creep for samples aged with dynamic loading compared to those aged without loading. Higher creep compliance was attributed to higher flexibility of samples due to the rejuvenation of the maltenes. This was also supported by the higher fracture energy results obtained for samples conditioned with dynamic loading from indirect tensile strength testing.

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Can crumb rubber modifier effectively replace the use of polymer- modified bitumen in asphalt mixture?

Sustainable and Resilient Infrastructure ◽

10.1080/23789689.2021.1965428 ◽

2021 ◽

pp. 1-16

Author(s):

Lily D. Poulikakos ◽

William Buttlar ◽

Nicolas Schüwer ◽

Davide Lo Presti ◽

Tobias Balmer ◽

...

Keyword(s):

Asphalt Mixture ◽

Crumb Rubber ◽

Modified Bitumen ◽

Polymer Modified Bitumen

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Evaluation of the Effects of Engineered Crumb Rubber (ECR) on Asphalt Mixture Characteristics

Journal of Testing and Evaluation ◽

10.1520/jte20210077 ◽

2021 ◽

Vol 50 (2) ◽

pp. 20210077

Author(s):

Punyaslok Rath ◽

J. Meister ◽

B. Jahangiri ◽

W. Buttlar

Keyword(s):

Asphalt Mixture ◽

Crumb Rubber

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Functional and environmental performance of plant-produced crumb rubber asphalt mixtures using the dry process

Materials and Structures ◽

10.1617/s11527-021-01790-y ◽

2021 ◽

Vol 54 (5) ◽

Author(s):

M. Bueno ◽

R. Haag ◽

N. Heeb ◽

P. Mikhailenko ◽

L. Boesiger ◽

...

Keyword(s):

Environmental Performance ◽

High Performance ◽

Large Scale ◽

Fatigue Behavior ◽

Permanent Deformation ◽

Asphalt Mixture ◽

Crumb Rubber ◽

Asphalt Mixtures ◽

Gaseous Emissions ◽

Dry Process

AbstractIncorporating crumb rubber (CR) using the dry process, directly in the asphalt mixture rather than into the bituminous binder requires no plant retrofitting, and therefore is the most practical industrial method for CR incorporation into asphalt mixtures. Nevertheless, very few large scale studies have been conducted. This work uses a holistic approach and reports on the functional and environmental performance of asphalt mixtures with different concentrations of CR fabricated employing the dry process in asphalt plants. Gaseous emissions were monitored during the production and laboratory leaching tests simulating the release of pollutants during rain, was conducted to evaluate the toxicology of both the CR material alone and the modified asphalt mixtures. In addition, laboratory compacted samples were tested to assess their fatigue behavior. Furthermore, noise relevant surface properties of large roller compacted slabs were evaluated before and after being subjected to a load simulator (MMLS3) to evaluate their resistance to permanent deformation. The results confirm that comparable performance can be achieved with the incorporation of CR using the dry process for high performance surfaces such as semi-dense asphalt, which usually require the use of polymer modified binders. Environmental performance improvement can be achieved by a washing step of the CR material that could remove polar CR additives which have commonly been used as vulcanization accelerator during rubber production.

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Laboratory Assessment of Workability of Asphalt Rubber Hot Mixes Using Warm Mix Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.193-194.452 ◽

2012 ◽

Vol 193-194 ◽

pp. 452-457 ◽

Cited By ~ 1

Author(s):

Meng Yun Huang ◽

Jing Hui Liu ◽

Xi Zhang ◽

Dan Ni Li

Keyword(s):

Asphalt Binder ◽

Asphalt Mixture ◽

Crumb Rubber ◽

Laboratory Assessment ◽

Asphalt Mixes ◽

Modified Asphalt ◽

The Road ◽

Asphalt Rubber ◽

Synergy Effects ◽

Save Energy

Using the waste crumb rubber modified asphalt to pave the road surface could reduce cost and save energy. However，in order to obtain adequate workability, the mixing temperature and compaction temperature of rubberized asphalt binder and its mixture is much higher than those of conventional asphalt mixtures. Warm Mix Asphalt (WMA) is the name given to certain technologies that reduce the production and placement temperatures of asphalt mixes. One of the main benefits advertised is the increased workability at conventional and lower compaction temperatures with the WMA addition. This paper evaluates whether there are any synergy effects of using warm mix technologies and Asphalt Rubber(AR) hot mixes. This paper summarizes a lab research to evaluate the workability of Asphalt Rubber hot mixes containing warm mix technologies. Both asphalt binder and asphalt mixture were evaluated and compared. The research suggests that combining WMA technology with Asphalt Rubber mixtures is a win-win.

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