Volume 21, Issue 4 (2021)
MCEJ 2021, 21(4): 153-166 |
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doosti م, KAVUSSI A, azarnia M. Evaluation of fatigue resistance of HMA mixes containing processed asphalt rubber. MCEJ 2021; 21 (4) :153-166
URL: http://mcej.modares.ac.ir/article-16-43714-en.html
URL: http://mcej.modares.ac.ir/article-16-43714-en.html
1- M.Sc. Student, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Iran
2- Professor, Faculty of Civil and Environmental Engineering, Tarbiat Modarres University, Tehran , KAVUSSIA@MODARES.ac.ir
3- Phd. Student, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Iran
2- Professor, Faculty of Civil and Environmental Engineering, Tarbiat Modarres University, Tehran , KAVUSSIA@MODARES.ac.ir
3- Phd. Student, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Iran
Abstract: (1840 Views)
Over the past decades, pavement researchers have taken different approaches to enhance rheological properties of bitumen and performance of asphalt mixtures. Application of additives such as Crumb Rubber is one of the most economic approaches.
The use of Crumb Rubber not only improves performance of asphalt mixtures by increasing fatigue life and rutting resistance of mixes but it reduces moisture susceptibility of mixes and bring about several environmental benefits. Despite the above mentioned advantages, mixing Crumb Rubber with bitumen in conventional dry and wet processing results in problems such as increased production cost, initial aging, and coagulation of rubber modified bitumen, as well as phase separation of the modified binder.
In order to overcome the above problems, an innovative technique was developed to produce CRM mixtures in TMU Road Research Centre. This method, named Processed Crumb Rubber Modifier (PCRM), was consisted of incorporating surface activate materials in rubber-bitumen blends and produce rubber type granules.
Since this material is new, extensive experimental research works are required to evaluate properties of the P-CRM modified bitumen and performance of asphalt mixtures prepared with that. In this research, with producing reacted and activated rubber bitumen, the moisture susceptibility and fatigue resistance of asphalt mixtures, prepared with P-CRM and CRM were investigated. This was with testing mixes under Indirect Tensile Strength (ITS) and Indirect Tensile Fatigue Test (ITFT). In addition, properties of the P-CRM content specimens were compared with those of the wet-processed rubber modified bitumen.
Moisture susceptibility testing results showed that the application of Crumb Rubber in modifying bitumen with wet processing as well as with P-CRM method increased indirect tensile strength of the specimens in both dry and saturated conditions. However, specimens prepared using P-CRM material had better performance in saturated conditions. On the other hand, results of mixes tested under ITFT indicated that fatigue resistance of specimens containing P-CRM was greater (compared with the control specimens and those modified using CRM).
The use of Crumb Rubber not only improves performance of asphalt mixtures by increasing fatigue life and rutting resistance of mixes but it reduces moisture susceptibility of mixes and bring about several environmental benefits. Despite the above mentioned advantages, mixing Crumb Rubber with bitumen in conventional dry and wet processing results in problems such as increased production cost, initial aging, and coagulation of rubber modified bitumen, as well as phase separation of the modified binder.
In order to overcome the above problems, an innovative technique was developed to produce CRM mixtures in TMU Road Research Centre. This method, named Processed Crumb Rubber Modifier (PCRM), was consisted of incorporating surface activate materials in rubber-bitumen blends and produce rubber type granules.
Since this material is new, extensive experimental research works are required to evaluate properties of the P-CRM modified bitumen and performance of asphalt mixtures prepared with that. In this research, with producing reacted and activated rubber bitumen, the moisture susceptibility and fatigue resistance of asphalt mixtures, prepared with P-CRM and CRM were investigated. This was with testing mixes under Indirect Tensile Strength (ITS) and Indirect Tensile Fatigue Test (ITFT). In addition, properties of the P-CRM content specimens were compared with those of the wet-processed rubber modified bitumen.
Moisture susceptibility testing results showed that the application of Crumb Rubber in modifying bitumen with wet processing as well as with P-CRM method increased indirect tensile strength of the specimens in both dry and saturated conditions. However, specimens prepared using P-CRM material had better performance in saturated conditions. On the other hand, results of mixes tested under ITFT indicated that fatigue resistance of specimens containing P-CRM was greater (compared with the control specimens and those modified using CRM).
Keywords: Fatigue resistance, moisture susceptibility Crumb rubber modified bitumen, Processed Crumb Rubber (P-CRM).
Article Type: Original Research |
Subject:
Roads and Transportation
Received: 2020/06/16 | Accepted: 2021/01/18 | Published: 2021/08/1
Received: 2020/06/16 | Accepted: 2021/01/18 | Published: 2021/08/1
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