Challenges Associated with Optimisation of Blending, Mixing and Compaction Temperature for Asphalt Mixture Modified with Crumb Rubber Modifier (CRM)

2012 ◽  
Vol 256-259 ◽  
pp. 1837-1844 ◽  
Author(s):  
Iman Mohammadi ◽  
Hadi Khabbaz
Keyword(s):  
Asphalt Mixture ◽  
Crumb Rubber ◽  
Test Methods ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Compaction Temperature ◽  
Modified Asphalt ◽  
Wide Range ◽  
Modified Binder ◽  
Very High

The use of modified asphalt binders has become much more common over the past two decades. Many types of modifier have been used in paving asphalts to enhance the performance of asphalt pavements in a wide range of climates and loading conditions. Among various asphalts binder modifiers, the recycled crumb rubber has been used very successfully for many years. Generally in production of CRM binder, mixing and compaction temperature is determined by measuring of binder viscosity. The ordinary method used for viscosity measurement of unmodified binder leads to a very high Mixing and Compaction Temperature (MCT) for CRM binder. The aims of this paper are to identify, develop and give some recommendations on a reliable laboratory approach for blending of CRM with binder, as well as introducing appropriate laboratory test methods for optimisation of MCT of crumb rubber modified binder asphalt.

scholarly journals Characterization of neat and modified asphalt binders and mixtures in relation to permanent deformation

2019 ◽  
Vol 26 (1) ◽  
pp. 379-387
Author(s):  
Iuri S. Bessa ◽  
Márcia M. Takahashi ◽  
Kamilla L. Vasconcelos ◽  
Liedi L. B. Bernucci
Keyword(s):  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Rutting Resistance ◽  
Modified Asphalt ◽  
Recoverable Compliance ◽  
Modified Binder ◽  
Deformation Tests

AbstractThe addition of polymers on asphalt binders aims to enhance their performance, especially at high temperatures, which correspond to rutting resistance. The Superpave rutting parameter (|G*|/sinδ) has been considered to be inadequate to characterize the performance of modified materials, therefore the Multiple Stress Creep and Recovery (MSCR) test was developed, providing the parameter non-recoverable compliance (Jnr). This research has the main objective of correlating asphalt binders performance-based characterization with rutting resistance of asphalt mixtures, and presents results obtained for one conventional (50/70 penetration grade) and two modified asphalt binders (2.1% RET and 1.9% RET) regarding their rheological characteristics. With the use of the dynamic shear rheometer (DSR), master curves and MSCR results were obtained for the three binders. In addition, permanent deformation tests were performed on the asphalt mixtures by means of laboratory traffic simulation. The rutting characterization indicated higher permanent deformation resistance for the modified binders for the asphalt binder and the asphalt mixture testing. The main conclusions were that the use of modified binder reduced in approximately 50% the Jnr values and the rut depth; also, the asphalt binders’ characteristics were able to predict the asphalt mixtures rutting resistance.

Evaluation of Stability, Nature of Modifier, and Short-Term Aging of Modified Binders Using New Tests: LAST, PAT, and Modified RTFO

1998 ◽  
Vol 1638 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Hussain U. Bahia ◽  
Huachun Zhai ◽  
Andres Rangel
Keyword(s):  
Storage Stability ◽  
Data Interpretation ◽  
Test Methods ◽  
Asphalt Binders ◽  
Short Term ◽  
Testing Procedures ◽  
Modified Asphalt ◽  
Typical Data ◽  
Modified Binders ◽  
Modified Binder

In a recent survey of users and producers of modified asphalts, stability and short-term aging were two of the main concerns regarding the use of modified asphalts. In an NCHRP project, a concentrated effort was put into development of revised or new testing procedures to better characterize the nature of modified asphalt and to solve some of the difficulties with using existing aging procedures developed for neat asphalts and modified asphalts. Three main procedures have been proposed to complement the existing Superpave procedures: the laboratory asphalt stability test, for measuring the storage stability of asphalt binders; the particulate additive test, for separation of particulate additives; and the modified rolling thin film oven test for short-term aging. The background behind the development of these test methods is explained, and typical data collected for a number of modified asphalts are presented. The results indicate that these tests show high promise in covering characteristics not covered by the current Superpave binder specifications and in solving some of the problems with the existing aging methods. The results also indicate that the behavior of modified binder can be very complex and that the method of data interpretation is very critical.

scholarly journals Influence of the Skid Resistance of Ultrathin Wearing Course with Various Types of Asphalt Binders

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hongfu Liu ◽  
Teng Guo ◽  
Chenxi Yang ◽  
Yunyong Huang ◽  
Xuelian Li
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Skid Resistance ◽  
Modified Asphalt ◽  
Vehicle Loading ◽  
Before And After ◽  
Warm Mix Additives ◽  
Styrene Butadiene

Ultrathin wearing course (UTWC) has been widely applied in both asphalt pavements preventive maintenance and functional overlay. This study’s objective is to evaluate the influence of different modified asphalt binders with warm mix additives on the skid resistance of UTWC and to reveal the attenuation law of skid resistance of UTWC. Three types of modified asphalt binders (Styrene-Butadiene-Styrene- (SBS-) modified asphalt, Acrylester Rubber- (AR-) modified asphalt, and SinoTPS-modified asphalt) and sasobit warm mix asphalt additive were selected to prepare asphalt mixtures. The Model Mobile Load Simulator 3 (MMLS3) was used to simulate repeated vehicle loading and abrasion. The British Pendulum Number (BPN) and Mean Texture Depth (MTD) were chosen to evaluate the skid resistance of the UTWC. The Analysis of Range (ANOR) and Analysis of Variance (ANOVA) were used to verify the significance of asphalt binder on the antiskid performance of the UTWC. ANOR and ANOVA show that the influence of different modified asphalt binders on the skid resistance of the UTWC is significant. The SinoTPS modified asphalt mixture can maintain high texture roughness before and after abrasion, providing excellent and durable skid resistance. The influence of the addition of a warm mixing additive on the skid resistance of UTWC is not significant, and changes in microtexture mainly reflect its impact on antiskid performance. The decay curve of three modified asphalt binders of the skid resistance of the UTWC can be well fitted into an exponential function. The conclusion will play an essential role in selecting the asphalt binder in a UTWC to improve the antiskid performance.

Applicability of Superpave Binder Testing Protocols to Modified Binders

1997 ◽  
Vol 1586 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Hussain U. Bahia ◽  
Dario Perdomo ◽  
Pamela Turner
Keyword(s):  
Elastic Recovery ◽  
Crumb Rubber ◽  
Test Methods ◽  
Rate Dependency ◽  
Modified Asphalt ◽  
Modified Binders ◽  
Modified Binder ◽  
Physical And Chemical ◽  
Departments Of Transportation ◽  
Testing Protocols

An effort is made to summarize current practices for modifying paving asphalts. The types and classes of modifiers used, or considered, for paving applications are reviewed. The applicability of the Superpave binder specification (AASHTO MP1) is reviewed critically, and the modified-asphalt characteristics that are not considered in this specification are evaluated. Conventional testing results of modified binders are compared with Superpave testing results. The results indicate that a variety of additives can be classified, on the basis of their composition and their effects on asphalts, as polymers (elastomeric and plastomeric), fillers, fibers, hydrocarbons, antistripping agents, oxidants, antioxidants, crumb rubber, and extenders. These additives vary significantly in their physical and chemical characteristics and are expected to have widely variable effects on performance-related properties of asphalts. The assumptions supporting the criteria in the Superpave binder specification may not be valid for some modified binder systems. Furthermore, the testing protocols included in the specification do not consider certain important characteristics that are typical of particular modified binders. Among these characteristics are strain dependency, thixotropy, loading-rate dependency, and time-temperature equivalency. Conventional measurements used currently by state departments of transportation such as ductility, elastic recovery, and resilience, were collected. The ranking of five modified systems on the basis of conventional and Superpave measurements was analyzed. The analysis does not indicate that the conventional test methods are consistent in their rankings, nor does it indicate that these measures add much to the information deduced from the Superpave data.

scholarly journals Assessment of simultaneous incorporation of crumb rubber and asphaltite in asphalt binders

DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 257-263
Author(s):  
Javier Eduardo Mantilla Forero ◽  
Eduardo Alberto Castañeda Pinzón
Keyword(s):  
Service Use ◽  
Road Construction ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Cole Plot ◽  
Modified Asphalt ◽  
Different Temperatures ◽  
First Time

Every day, roads are submitted to greater stresses. Thereby, additives have been incorporated to asphalt mixtures to enhance pavements performance. The purpose of this experimental study is to characterize for the first time, to date, the viscoelastic properties of asphalt samples modified with recycled rubber —from used vehicles tires— and asphaltite in the same mixture, at different temperatures and frequencies. All with the aim of optimizing the material properties and coming up with a proposal to an environmental issue: discarded vehicles tires and their after-service use. The stiffness of briquettes was analyzed by axial compression test. The results were principally represented in Black Space and Cole-Cole plot and indicate a substantial increase in stiffness and elasticity of the modified asphalt throughout the whole temperature range. This shows that the simultaneous addition of these two ingredients to the bitumen is a favorable alternative in road construction using asphalt pavements.

scholarly journals Material Properties and Environmental Benefits of Hot-Mix Asphalt Mixes Including Local Crumb Rubber Obtained from Scrap Tires

Environments ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 47
Author(s):  
Lim Min Khiong ◽  
Md. Safiuddin ◽  
Mohammad Abdul Mannan ◽  
Resdiansyah
Keyword(s):  
Asphalt Binder ◽  
Crumb Rubber ◽  
Environmental Benefits ◽  
Asphalt Binders ◽  
Rubber Content ◽  
Scrap Tires ◽  
Asphalt Mixes ◽  
Temperature Resistance ◽  
Modified Asphalt ◽  
Marshall Stability

This paper presents the results of a laboratory-based experimental investigation on the properties of asphalt binder and hot-mix asphalt (HMA) mixes modified by locally available crumb rubber, which was used as a partial replacement of asphalt by weight. In this study, fine crumb rubber with a particle size in the range of 0.3–0.6 mm, obtained from scrap tires, was added to the asphalt binder through the wet process. Crumb rubber contents of 5%, 10%, 15%, and 19% by weight of asphalt were added to the virgin binder in order to prepare the modified asphalt binder samples, while the unmodified asphalt binder was used as the control sample. The crumb rubber modified binder samples were examined for measuring viscosity indirectly using the penetration test, and temperature resistance using the softening point test. Later, both the modified and unmodified asphalt binders were used to produce HMA mixes. Two categories of HMA mix commonly used in Malaysia—namely, AC 14 (dense-graded) and SMA 14 (gap-graded)—were produced using the modified asphalt binders containing 5%, 10%, 15%, and 19% crumb rubber. Two AC 14 and SMA 14 control mixes were also produced, incorporating the unmodified asphalt binder (0% crumb rubber). All of the AC 14 and SMA 14 asphalt mixes were examined in order to determine their volumetric properties, such as bulk density, voids in total mix (VTM), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA). In addition, the Marshall stability, Marshall flow, and stiffness of all of the AC 14 and SMA 14 mixes were determined. Test results indicated that the modified asphalt binders possessed higher viscosity and temperature resistance than the unmodified asphalt binder. The viscosity and temperature resistance of the asphalt binders increased with the increase in their crumb rubber content. The increased crumb rubber content also led to improvements in the volumetric properties (bulk density, VTM, VMA, and VFA) of the AC 14 and SMA 14 mixes. In addition, the performance characteristics of the AC 14 and SMA 14 mixes—such as Marshall stability, Marshall flow, and stiffness—increased with the increase in crumb rubber content. However, the AC 14 mixes performed much better than the SMA 14 mixes. The overall research findings suggest that crumb rubber can be used to produce durable and sustainable HMA mixes, with manifold environmental benefits, for use in flexible pavements carrying the heavy traffic load of highways.

scholarly journals Assessment Mixing and Compaction Temperatures for Modified HMA Using Superpave High Shear Viscosity Methods

2018 ◽  
Vol 21 (4) ◽  
pp. 516-522 ◽  
Author(s):  
Alaa Hussein Abed ◽  
Ali Hwaidi Nasser
Keyword(s):  
Shear Viscosity ◽  
Asphalt Mixture ◽  
High Shear ◽  
Compaction Temperature ◽  
Modified Asphalt ◽  
Performance Grade ◽  
Modified Binders ◽  
Different Temperatures ◽  
Marshall Stability

The objective of this study is determining the mixing and compaction temperature of the modified asphalt mixture. Results of binder tests showed that the addition of 3% SBS  to control asphalt (PG 64-16) would achieve the desired performance level (PG 76-16) a performance grade that fits our climate with traffic loads. When using 5% SBS the performance grade of binder increased three grades (PG 82-16) and when increasing SBS content to 8% the performance grade increased four grades (PG 88-16). At shear rate of 500 (s-1), the modified asphalt viscosity can be obtained at different temperatures and the viscosity temperature curve can be achieved. As a result, the mixing and compaction temperature of modified asphalt can be determined to reach 0.17 ± 0.02 Pa.s and 0.28 ± 0.03 Pa.s for mixing and compaction, respectively. It is noted that SBS modified reached a viscosity of 3 Pa.s when 8 % additive. Additive contents above these values may not be suitable for good workability and pump ability according to Superpave specifications. While addition of 5% SBS with control asphalt, more than 3.7times at 135°C Increase the viscosity. Marshall Stability test indicated that the strength for the SBS specimens increases as compared to the conventional specimens. An increase of about 39%, 74%, 102%, was observed with 3%SBS 5%SBS 8%SBS modified binders, respectively. The Marshall test results for 8%SBS binders required compaction temperatures above 175°C need to keep up quality of HMA item while limiting natural effect amid development, these proposals are unsatisfactory Modified mixtures the 5% SBS modification was determined to be the maximum useful content. The Superpave method to estimate mixing and compaction temperatures show are not practical for use with modified binders. Also,  it is observed that good agreement values between the average Marshall compaction temperature and the High Shear Viscosity Method (HSRV) and   lower than Superpave methods Where the decline ranges from 15 ºC to 17 ºC.

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