A Review of Crumb Rubber Modification in Dry Mixed Rubberised Asphalt Mixtures

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Norhidayah Abdul Hassan ◽  
Gordon D. Airey ◽  
Ramadhansyah Putra Jaya ◽  
Nordiana Mashros ◽  
Md. Maniruzzaman A. Aziz

This paper provides an overview of crumb rubber modified asphalt mixtures with particular reference to the dry process. The dry process involves the blending of crumb rubber with hot aggregates prior to mixing with bitumen. In comparison to the wet process (process of incorporating crumb rubber into bitumen prior to mixing with aggregates), this mixture type has a number technical issues. The lack of standards and inconsistent performance have resulted in scepticism among practitioners and researchers in accepting the dry process for rubber modification even though it has the potential to recycle more crumb rubber compared to the wet process. This has resulted in the overwhelming majority of asphalt paving projects involving crumb rubber using the wet process. Therefore, to better understand the mixture, details pertaining to dry mixed rubberised asphalt are discussed in this paper with sufficient information from previous research. The discussions highlight several critical issues regarding its modification concept (the function and behaviour of rubber particles within the mixture), mixture design criteria and mechanical performance of this mixture type. This is necessary in order to identify the factors that play a significant role in improving the mixtures properties for future studies. Additionally, the review will be a positive step in the direction of achieving an appropriate design standard for dry mixed rubberized asphalt mixtures.

Author(s):  
Ibrahim A. Abdalfattah ◽  
Walaa S. Mogawer ◽  
Kevin D. Stuart

This study addresses the effects of recycled polyethylene (RPE) on the performances of both asphalt binders and asphalt mixtures. Whether using RPE in an asphalt mixture might leach harmful chemicals into rainwater or melted snow was also determined. Two processes, wet and dry, were used to formulate the RPE modified asphalt binders and mixtures. In the wet process, RPE was added to asphalt binder. In the dry process, it was added to heated aggregates. RPE from two sources and PG 64-22 virgin asphalt binders from two sources were used in this study. In conclusion, RPE improved the rutting resistance of the asphalt binders and asphalt mixtures. However, it had adverse effects on their resistance to intermediate-temperature and non-load associated cracking. The dry process could produce a mixture with a higher RPE dosage compared with the wet process using one virgin asphalt binder but not the other; thus, the virgin asphalt binder source was a significant factor for the dry process. Based on an embryotoxicity test, it was found that RPE can be used by the asphalt paving industry without creating any significant environmental risks.


2021 ◽  
Author(s):  
Ovidijus Šernas ◽  
Audrius Vaitkus ◽  
Deimantė Kilaitė

The use of crumb rubber made from end of life tyres for asphalt mixtures modification in order to improve their properties or just utilize waste products may be considered as potential solution. Crumb rubber can be used as a bitumen modifier (wet process) or supplementary component of the asphalt mixture (dry process). Dry modification process has more potential due relatively unsophisticated technology and higher possible to use amount of crumb rubber comparing to the wet process. The performance of asphalt mixtures modified by dry process mainly depends on several factors as crumb rubber type, content and size. However, limited number of publications reported the results of dry method crumb rubber modified asphalt mixtures performance. This paper summarizes the latest findings from literature review on the modification technologies and specifications related to dry modification process, the effect of crumb rubber type and amount on modified asphalt mixture performance in terms of stiffness, rutting resistance, water sensitivity, resistance to fatigue and low temperature cracking. The algorithm of crumb rubber modified asphalt mix design was introduced.


Author(s):  
Salih Kocak ◽  
M. Emin Kutay

Three major methods are used to produce crumb rubber modified asphalt pavement: the dry process (CRDry), the terminal blend process (CRTB), and the wet process (CRWet). Although the CRDry process replaces the portion of fine aggregate in the asphalt mixture with crumb rubber (CR) particles, the CRWet process incorporates CR particles into hot liquid asphalt before it is mixed with aggregates. CRTB is known as a special type of CRWet process in which the CR is blended with asphalt binder at the asphalt terminal. In general, the CRWet process can integrate 15% to 22% CR by weight of the binder. This amount ranges from 10% to 12% in the CRTB process as a result of the limitations associated with transportation and pumping. This study investigated the feasibility of increasing the CR content of CRTB modified asphalt mixtures. The addition to the mixture of about 0.5% CR (by weight of the mix) through the CRDry process doubled the amount of rubber to be found in a conventional CRTB mix. The relative performances of the CRTB and the CRTB+CRDry processes [i.e., crumb rubber hybrid (CRHY)] were investigated with respect to their linear viscoelastic properties, rutting susceptibility, moisture damage, resistance to fatigue, and low temperature cracking. It was shown that it was possible to increase the amount of CR in the mixture through the use of the CRHY method proposed here, without adverse effect on the performance of the mixture.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2870
Author(s):  
Israel Rodríguez-Fernández ◽  
Maria Chiara Cavalli ◽  
Lily Poulikakos ◽  
Moises Bueno

Semi-Dense Asphalt (SDA) mixtures are nowadays recommended for the surface layer of low noise roads in urban areas due to their optimal functional characteristics. Moreover, the use of polymer-modified bitumen (PmB) in its design results in high mechanical performance. However, this type of highly modified bitumen implies significant economic and environmental disadvantages. The polymer modification increases the production cost, involves higher mixing temperatures, and makes the recycling process of the asphalt mixtures challenging. As a potential alternative to PmB in SDA mixtures, this experimental work analyses the dry process for the incorporation of crumb rubber (CR) from waste tires. Particularly, the main objective was to study the aging effect and the recyclability of asphalt mixtures prepared in the laboratory with two different types of CR. The volumetric properties and mechanical performance of the mixtures artificially aged and rejuvenated were evaluated. The results obtained show that mixtures with CR have adequate performance, being less susceptible to aging than a conventional polymer-modified mixture. Furthermore, the rheological response of asphalt binder samples recovered from the mixtures at different aging states was analyzed. It was observed that the effect of the rejuvenator depended on the CR type, but this fact did not negatively influence the performance of the recycled mixtures.


2020 ◽  
Vol 259 ◽  
pp. 119662 ◽  
Author(s):  
Israel Rodríguez-Fernández ◽  
Farrokh Tarpoudi Baheri ◽  
Maria Chiara Cavalli ◽  
Lily D. Poulikakos ◽  
Moises Bueno

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
M. Bueno ◽  
R. Haag ◽  
N. Heeb ◽  
P. Mikhailenko ◽  
L. Boesiger ◽  
...  

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.


2019 ◽  
Vol 24 (2) ◽  
pp. 148
Author(s):  
Sri Mulyani ◽  
Nono Nono ◽  
Nyoman Suaryana

Asphalt polymer has superior characteristics than conventional asphalt. Styrene Butadiene Styrene (SBS) is a polymer that has proven its performance in heavy traffic, but it must be imported and expensive. Crumb rubber have high potential to be used as an asphalt modifier. Asphalt modified crumb rubber has high viscosity and is not homogeneous, so that the utilization cannot be delayed. This reduces workability in the field. This study aims to obtain asphalt modified crumb rubber which is easier to use by adding materials that do not affect its performance. RejIRE is a low viscosity additive to restore the properties of bitumen on crumb rubber modified. Experiments were carried out by adding variations in RejIRE levels to crumb rubber modified asphalt to determine its characteristics. Continued investigation of the performance of hot paved mixtures for wearing courses compared to asphalt mixtures with Pen 60/70 asphalt and SBS modified asphalt mixtures. The result is the addition of 0.75% RejIRE on asphalt crumb rubber modification have high workability. Overall the performance of the mix with SBS modified asphalt is better, but the mixture of hot paved with modified asphalt crumb rubber has a resistance to permanent deformation superior to the other paved mixtures.


2013 ◽  
Vol 48 ◽  
pp. 691-699 ◽  
Author(s):  
Francisco Javier López-Moro ◽  
María Candelas Moro ◽  
Francisco Hernández-Olivares ◽  
Bernabé Witoszek-Schultz ◽  
Manuel Alonso-Fernández

Since 1960 Using crumb rubber modifier (CRM) in hot asphalt mixtures has become a frequent practice in road construction. Using the CRM by the dry process method is not commonly used, although it has great advantages such as it is less fuel consuming and it does not require storage container like the wet process method. This research evaluates the mechanical properties of dense graded asphalt rubber mixtures manufactured using the dry process. The results obtained from this mixture compared with similar asphalt mixture without CRM. The mechanical properties of all mixtures evaluated using a set of tests such Marshall Stability and flow test, moisture susceptibility test, indirect tensile strength test, dynamic modulus and flow number test. The research results showed that using CRM with 0.75% of aggregate’s weight increased the mixture’s stability, flow and enhanced its cracking and permanent deformation resistance.


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