Evaluation of rubber influence on cracking resistance of crumb rubber modified binders with wax additives

2016 ◽  
Vol 43 (4) ◽  
pp. 326-333 ◽  
Author(s):  
Hyun Hwan Kim ◽  
Soon-Jae Lee

Cracking properties of crumb rubber modified (CRM) asphalt binders containing wax additive were evaluated through the dynamic shear rheometer test at 25 °C and the bending beam rheometer test at −12 °C. The CRM binders were produced using three rubber contents of 5%, 10%, and 15% by the binder weight, and then mixed with two commercial wax additives of LEADCAP and Sasobit. Three states of original, short-term and long-term aging were applied to evaluate the cracking properties using rolling thin film oven and pressure aging vessel. From the results, it is concluded that (1) the increase of rubber content significantly decreases the binder stiffness at lower temperature, (2) the higher the rubber content, the lower the G*sinδ of CRM binders with wax additives at intermediate temperature, and (3) the rubber can be used to improve the cracking resistance of asphalt binders modified with wax.

Author(s):  
Robert Y. Liang ◽  
Suckhong Lee

Aging of asphalt has been an important subject area that has received extensive studies in recent years. Test results of short-term and long-term aging behavior of crumb rubber modifier (CRM) modified asphalt paving materials are presented. Eighteen combinations of CRM modified binders in terms of CRM size, CRM content, and base asphalt cement grade were studied by Brookfield viscometer test and dynamic shear rheometer test. The short-term aged binders were prepared using thin film oven test. Viscosity was measured at 350°F in the Brookfield thermosel after mixing at 375°F for 2 hr. The test results showed that the size and percentage of CRM affected the viscosity development in the modified binders: the smaller the CRM size and the higher the CRM content, the higher the viscosity measured after 2-hr reaction at 375°F. Short-term aging exerted more viscosity increase in the CRM modified binders than in the unmodified binders. Modified binders showed less weight loss than unmodified binders. The modified binders showed higher complex modulus G* than unmodified. Short-term aging increased G*, with modified binders exhibiting higher increase. The Marshall mix design yielded various CRM modified mixes. The result of indirect tensile strength tests showed that short-term and long-term aging increased the measured tensile strengths. The resilient modulus test results, in general, supported the general understanding that aging tended to increase resilient modulus.


2017 ◽  
Vol 12 (2) ◽  
pp. 71-81 ◽  
Author(s):  
Mieczysław Słowik ◽  
Marcin Bilski

The tests and analyses presented in the paper are related to the 20/30, 35/50 and 50/70 penetration grade road bitumens as well as the asphalt binders obtained through modification of the 35/50 and 50/70 bitumens. The latter were modified by adding to it 3%, 5% and 7% of the Gilsonite natural asphalt and 15%, 25% and 35% of the Trinidad Epuré Z 0/8 natural asphalt. The aim of the study was to assess the changes in the functional and rheological properties of theroad bitumens that were modified by adding to them the Gilsonite and Trinidad Epuré natural asphalts. The modified asphalt binders were subjected to the laboratory simulated short-term and long-term aging, where two methods, designed as part of the Strategic Highway Research Program, were used, i.e. the Rolling Thin Film Oven Test and the Pressure Aging Vessel, respectively. The study of the asphalt binders both those that were subjected to aging and those unaged includes thermal susceptibility (the Penetration Index) and resistance to cracking at low temperatures by tests carried out using the Bending Beam Rheometer. The analysis of the results revealed that the unfavourable impact of the aging process on the asphalt binder properties is limited if a suitable amount of the natural asphalt is used as a modifier.


Environments ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 47
Author(s):  
Lim Min Khiong ◽  
Md. Safiuddin ◽  
Mohammad Abdul Mannan ◽  
Resdiansyah

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.


Author(s):  
Zhurinov M.Zh., ◽  
◽  
Teltayev B.B., ◽  
Kalybay A.A., ◽  
Rossi C.O., ◽  
...  

A comparative analysis of the low temperature resistance for a nanocarbon bitumen and other 30 neat and modified bitumens has been performed in the work. The stiffness at the temperatures of -24°С, -30°С and -36°С under technical system Superpave has been accepted as an indicator of low temperature resistance of the bitumens. The stiffness of the bitumens has been determined on a bending beam rheometer (standard ASTM D 6648-08). Before testing the bitumens have been subjected to the double artificial aging: short-term aging – under standard AASHTO Т 240-13 and long-term aging – under standard ASTM D 6521-08. The nanocarbon bitumen has been prepared in the laboratory of the Kazakhstan Highway Research Institute (KazdorNII) with the use of a road bitumen of the grade BND 70/100 produced by the Pavlodar petrochemical plant (PNHZ) and a nanocarbon powder (2% by weight) manufactured from a coal rock of the deposit “Saryadyr” “Corporation “ON-Olzha” LLP, Akmola region, Kazakhstan). The nanocarbon powder (150-200 nm) has been manufactured by three-stage size reduction of the coal rock: I – a mechanical dispergator (up to 2-3 mm), II – an aerodynamic mill (up to 20 mcm), III – a reactor with a rotating electromagnetic field. The neat bitumens of the grades BND 50/70, BND 70/100, BND 100/130 have been produced by the plants of Kazakhstan and Russia; they satisfy the requirements of the standard ST RK 1373-2013. The modified bitumens have been prepared in the laboratory of KazdorNII with the use of the neat bitumens, 7 types of the polymers, crumb rubber and polyphosphoric acid and they satisfy the requirements of the standard ST RK 2534-2014. It has been determined that the nanocarbon bitumen is one of the most resistant at the low temperatures: -24°С, -30°С and -36°С.


Author(s):  
David J. Mensching ◽  
Adrian Andriescu ◽  
Christopher DeCarlo ◽  
Xinjun Li ◽  
Jack S. Youtcheff

The use of re-refined engine oil bottoms (REOBs) in asphalt pavements is a topic of much debate because the aging susceptibility and quantity of the additive in the binder may affect field performance. In this study, four mixtures with varying REOB contents (up to 15%) were long-term oven aged by using a high-temperature, short-duration method (135°C, 24 h) and compared with existing data on mixtures aged with more conventional short-term and long-term oven-aging procedures. The recovered binders underwent Superpave® grading, double-edge notched tension, and extended bending beam rheometer testing, and the binders were subjected to dynamic modulus, cyclic fatigue testing in the asphalt mixture performance tester, and thermal stress restrained specimen testing. Results showed a general insensitivity when short-term oven-aged (135°C, 4 h) materials were compared with long-term oven-aged (85°C, 5 days) materials, whereas the aging process at 135°C over 24 h resulted in substantial changes to the stiffness and relaxation properties across high-, intermediate-, and low-temperature modes. The difference between the stiffness-based and slope-based low-temperature performance grades appears to be an indicator for REOB modification, with the test for physical hardening of the binder being more sensitive than standard bending beam rheometer testing. The details in this paper provide information for the asphalt pavement community to consider as specifications. Standard practices are developed to address REOB modification.


2017 ◽  
Vol 737 ◽  
pp. 554-559
Author(s):  
Pavel Coufalik ◽  
Ondrej Dasek ◽  
Petr Hyzl ◽  
Iva Krcmova

This paper compares the different approaches to assessing asphalt binders used in Europe and the Unites States. A series of pavement bitumens is assessed using European standards and also by the Performance Graded Asphalt Binder Specification based on AASHTO MP 1, which was developed as part of the Strategic Highway Research Program (SHRP) in the United States of America. The results show that the European approach places high requirements on the pavement bitumens in relation to their behavior at low-temperatures, while in case of the American approach, the key parameter is fatigue behavior after short-term and long-term aging. It is evident that it is necessary to evaluate properties of pavement bitumens after long-term aging in Europe, too.


2020 ◽  
Vol 3 (2) ◽  
pp. 47
Author(s):  
Nulhanuddin Nulhanuddin ◽  
Devi Andriyani

This study aims to determine the effect of short-term and long-term exchange rates and crumb rubber exports on the economic growth of Indonesia. The data used are secondary data for 39 years from 1980 to 2018 accessed on www.world.bank.wdi.data.bank.org, www.pertanian.go.id, www.bps.go.id, and www.bps.go.id. The data analysis method used is the Autoregressive Distributed Lag (ARDL) approach with the help of EViews 10 software. The results show that the economic growth is stationary at the level and exchange rate and exports of stationary crumb rubber at the first difference level and have cointegration in the long-term relationship. The test results in the short-term analysis of the exchange rate have a positive and significant effect, and exports have a positive but insignificant effect on economic growth, while in the long run, the exchange rate has a negative effect but insignificant, and exports have a positive but insignificant effect on the economic growth of Indonesia. Keywords:economic growth, exchange rates, exports and the ARDL approach.  


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