scholarly journals Preliminary Studies to Use Textile Fibers Obtained from Recycled Tires to Reinforce Asphalt Mixtures

2018 ◽  
Vol 7 (2) ◽  
pp. 14-30
Author(s):  
Jorge C. Pais ◽  
António Ferreira ◽  
Caio Santos ◽  
Paulo Pereira ◽  
Davide Lo Presti
Keyword(s):  
Asphalt Mixture ◽  
Tensile Tests ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Valuable Resource ◽  
Scrap Tires ◽  
Textile Fibers ◽  
Asphalt Rubber ◽  
Indirect Tensile

Abstract The use of crumb rubber in the modification of asphalt has occurred because of the problems related to disposal of scrap tires. However, the use of scrap tires in asphalt pavements, known as asphalt rubber pavements, can minimize environmental impacts and maximize conservation of natural resources. The textile fibers from recycled tires are typically disposed of in landfills or used in energetic valorization, but similar to other fibers, they can be used as a valuable resource in the reinforcement of engineering materials such as asphalt mixtures. Thus, this work aims at studying the use of textile fibers recycled from ground tires in the reinforcement of conventional asphalt mixtures. The application of textile fibers from ground tires was evaluated through laboratory tests on specimens extracted from slabs produced in the laboratory. Indirect tensile tests were performed on a series of nine asphalt mixtures with different fiber and asphalt contents and compared with a conventional mixture. The results obtained from a 50/70 pen asphalt were used to define three asphalt mixture configurations to be used with 35/50 pen asphalt. The results indicate that the textile fibers recycled from used tires can be a valuable resource in the reinforcement of asphalt mixtures.

scholarly journals Laboratory and Field Aging Effect on Bitumen Chemistry and Rheology in Porous Asphalt Mixture

2019 ◽  
Vol 2673 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Ruxin Jing ◽  
Aikaterini Varveri ◽  
Xueyan Liu ◽  
Athanasios Scarpas ◽  
Sandra Erkens
Keyword(s):  
Asphalt Mixture ◽  
Chemical Properties ◽  
Aging Effect ◽  
Tensile Tests ◽  
Asphalt Pavements ◽  
Porous Asphalt ◽  
Oxidative Aging ◽  
Infrared Spectrometer ◽  
Short And Long Term ◽  
Indirect Tensile

Oxidative aging takes place in bituminous materials during the construction and service life of asphalt pavements and has a significant effect on their performance. In this study, porous asphalt cores were obtained from field test sections each year from 2014 to 2017. The evolution of the properties of the field cores and the recovered bitumen with time was investigated. Cyclic indirect tensile tests were performed to determine changes in the mechanical behavior of porous asphalt due to aging. Additionally, bitumen was extracted and recovered from 13 mm slices along the depth of the cores. The rheological and chemical properties of the recovered bitumen, as well as that of original bitumen aged in standard short- and long-term aging protocols, were investigated by means of dynamic shear rheometer and Fourier transform infrared spectrometer. The results show that the degree of aging is spatially dependent, resulting in a stiffness gradient within the asphalt layer. Moreover, the results demonstrate a weak relation between field aging and the standard laboratory aging protocols.

scholarly journals Investigating the Effects of Chopped Basalt Fiber on the Performance of Porous Asphalt Mixture

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Sheng Wang ◽  
Aihong Kang ◽  
Peng Xiao ◽  
Bo Li ◽  
Weili Fu
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Asphalt Mixture ◽  
Basalt Fiber ◽  
Tensile Tests ◽  
Asphalt Mixtures ◽  
Basalt Fibers ◽  
Strength Performance ◽  
Porous Asphalt ◽  
Indirect Tensile

Porous asphalt mixture is a type of asphalt mixture with good drainage. However, it has poor tensile strength performance and durability. Chopped basalt fibers (CBF) have been proved to be an effective additive to improve the mechanical and fatigue performance of asphalt mixtures, but little attention has been paid on porous asphalt mixture. This paper examined the effect of chopped basalt fibers with different lengths (nonfiber, 3 mm, 6 mm, 9 mm, and 12 mm) and contents (3% and 4%) on the performance of the porous asphalt mixture. A series of tests were conducted to figure out the optimum fiber length and content, including draindown test, cantabro abrasion test, freeze-thaw split tensile test, wheel tracking test, low-temperature cracking resistance test, and four-point bending beam test. Thereafter, indirect tensile tests at different temperatures were conducted to investigate the tensile strength properties of porous asphalt mixtures with optimum fiber length and content. Besides, the macroscopic and microscopic morphology of fracture sections of the samples after indirect tensile tests were studied by using a single-lens reflex (SLR) camera and scanning electron microscopy (SEM) so as to further explore the reinforced mechanism of chopped basalt fibers. The results show that the addition of chopped basalt fibers can generally improve the performance of porous asphalt mixture since chopped basalt fibers form a three-dimensional network structure in the porous asphalt mixture.

scholarly journals Investigation of Crack Propagation and Healing of Asphalt Concrete Using Digital Image Correlation

2019 ◽  
Vol 9 (12) ◽  
pp. 2459 ◽  
Author(s):  
Navid Hasheminejad ◽  
Cedric Vuye ◽  
Alexandros Margaritis ◽  
Bart Ribbens ◽  
Geert Jacobs ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Image Correlation ◽  
Asphalt Pavements ◽  
Rest Periods ◽  
Tensile Fatigue ◽  
Indirect Tensile ◽  
Time Required

The fatigue performance and healing ability of asphalt pavements are important for mixture design, rehabilitation, and maintenance of the roads. By analyzing these parameters in an asphalt mixture, it is possible to predict the crack formation and propagation in asphalt pavements and healing of these cracks during the rest periods. The healing effect in asphalt mixtures has been observed and verified by many researchers and different methods exist to evaluate this phenomenon. However, current methods are still inadequate to fully observe and quantify the healing phenomenon in asphalt mixtures. In this study, a digital image correlation (DIC) method is used to calculate the strain map on the surface of cylindrical asphalt specimens during the indirect tensile fatigue test. This strain map is used to detect the location of crack initiations and development of the microcracks during the experiments. Next, the specimens are unloaded and the temperature of the climate chamber is increased to 60 °C for 18 h to investigate the healing phenomenon on the surface of the specimens. It is observed that the strain reduces near the microcrack areas especially at the tip of the microcracks. Furthermore, using DIC it is possible to observe the healing rate and the minimum time required to heal the microcracks on the surface of the specimens.

scholarly journals Rejuvenation Mechanism of Asphalt Mixtures Modified with Crumb Rubber

CivilEng ◽  
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.

scholarly journals Fatigue Resistance Characterization of Warm Asphalt Rubber by Multiple Approaches

2018 ◽  
Vol 8 (9) ◽  
pp. 1495 ◽  
Author(s):  
Jiangmiao Yu ◽  
Xianshu Yu ◽  
Zheming Gao ◽  
Feng Guo ◽  
Duanyi Wang ◽  
...  
Keyword(s):  
Fatigue Test ◽  
Fatigue Resistance ◽  
Crumb Rubber ◽  
Waste Recycling ◽  
Fatigue Performance ◽  
Four Point Bending ◽  
Asphalt Rubber ◽  
Shear Fatigue ◽  
Tensile Fatigue ◽  
Indirect Tensile

Warm asphalt rubber (WAR) mixture is a sustainable paving material with advantages including waste recycling and noise reducing. A comprehensive understanding of the fatigue performance of WAR specimens is helpful to its wide application. However, research on evaluating the fatigue performance of WAR binder and mixtures is very limited. This paper applies five fatigue analysis approaches to evaluate the fatigue life of WAR samples with three different warm mix asphalt (WMA) additives. The conventional G*sinδ, linear amplitude sweep (LAS), indirect tensile fatigue test (ITFT), and four-point bending beam (4PB) test were conducted based on available standards. In addition, a novel shear fatigue test was performed on WAR mortars. Test results indicated that the incorporation of crumb rubber has a significantly positive effect on fatigue resistance. WAR with chemical and foaming additives exhibited a poorer performance than asphalt rubber (AR), but their fatigue performance was still greatly superior to the non-rubberized samples. Finally, LAS as well as mortar shear fatigue and 4PB tests provided the same prediction of fatigue resistance, while the results of G*sinδ and the ITFT were inconsistent. It is recommended to use LAS, the mortar shear fatigue test, and the 4PB test for the fatigue resistance evaluation of rubberized specimens. The validation of the findings with more materials and field performances is recommended.

scholarly journals Laboratory Evaluation of the Use of Florida Washed Shell in Open-Graded Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe
Keyword(s):  
Tensile Strength ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Void Content ◽  
Coarse Aggregates ◽  
Significant Difference ◽  
Indirect Tensile ◽  
Marshall Stability

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.

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

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.

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

2012 ◽  
Vol 193-194 ◽  
pp. 452-457 ◽  
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.

Pavement Performance of Hot In-Place Recycling for Waste Asphalt Mixtures

2013 ◽  
Vol 668 ◽  
pp. 292-296
Author(s):  
Ya Li Ye ◽  
Chuan Yi Zhuang ◽  
Jia Bo Hu
Keyword(s):  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Pavement Performance ◽  
Test Results ◽  
Technical Parameters ◽  
Stable Performance ◽  
Wheel Tracking Test ◽  
Asphalt Content ◽  
Wheel Tracking

With the early asphalt pavements have been into the stage of medium maintenance or overhaul, recycling is a very important way for waste asphalt mixtures. A sample was taken in the expressway from Huhhot to Baotou, and the waste mixtures were extracted from field and sieved; so that the new aggregates can be determined and mix design was carried. With the aid of the penetration, the softening point and the viscosity in 135°C test, the quantity of the regenerant and the asphalt content were ascertained. Through the high temperature stable performance, the anti-low temperature performance, the water stability and the Hamburg wheel-tracking test, the appropriate gradation and the optimum asphalt content were determined. The test results showed that the pavement performance of the waste asphalt mixture was enhanced obviously with hot in-place recycling, and it has achieved technical parameters for old asphalt mixture.

scholarly journals Performance Evaluation of Warm- and Hot-Mix Asphalt Mixtures Based on Laboratory and Accelerated Pavement Tests

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Yongjoo Kim ◽  
Jaejun Lee ◽  
Cheolmin Baek ◽  
Sunglin Yang ◽  
Sooahn Kwon ◽  
...  
Keyword(s):  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Strength Test ◽  
Asphalt Mixtures ◽  
Limited Data ◽  
Tensile Strength Test ◽  
Paving Asphalt ◽  
Dynamic Modulus Test ◽  
Indirect Tensile ◽  
Lower Temperature

A number of warm-mix asphalt (WMA) technologies are used to reduce the temperature at which the asphalt mixtures are produced and compacted, apparently without compromising the performance of the pavement. The main objective of this study is to determine whether the use of an innovative wax-based LEADCAP WMA additive influences the performance of the asphalt mixture, which is produced and compacted at significantly low temperatures. The WMA pavement using LEADCAP additive (WMA-LEADCAP) along with a control HMA pavement was evaluated with respect to their performances of rutting resistance, crack resistance, and viscoelastic property based on the laboratory dynamic modulus test, indirect tensile strength test, and in-door accelerated pavement test (APT) results. With the limited data carried out, the LEADCAP additive is effective in producing and paving asphalt mixture at approximately 30°C lower temperature than a control HMA mixture, and the performances of WMA-LEADCAP pavement are comparable to a control HMA pavement.

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