Civil Engineering and Architecture 11(5A): 3051-3062, 2023 http://www.hrpub.org DOI: 10.13189/cea.2023.110819 Rheological Characteristics of Asphalt with a Crumb Rubber and Solid Natural Rubber Combination Hendrik Jimmyanto 1 , Joni Arliansyah 2,* , Edi Kadarsa 2 1 Engineering Science Doctoral Program, Faculty of Engineering, Sriwijaya University, Indonesia 2 Department of Civil Engineering, Faculty of Engineering, Sriwijaya University, Indonesia Received April 1, 2023; Revised July 3, 2023; Accepted August 15, 2023 Cite This Paper in the Following Citation Styles (a): [1] Hendrik Jimmyanto, Joni Arliansyah, Edi Kadarsa , "Rheological Characteristics of Asphalt with a Crumb Rubber and Solid Natural Rubber Combination," Civil Engineering and Architecture, Vol. 11, No. 5A, pp. 3051 - 3062, 2023. DOI: 10.13189/cea.2023.110819. (b): Hendrik Jimmyanto, Joni Arliansyah, Edi Kadarsa (2023). Rheological Characteristics of Asphalt with a Crumb Rubber and Solid Natural Rubber Combination. Civil Engineering and Architecture, 11(5A), 3051 - 3062. DOI: 10.13189/cea.2023.110819. Copyright©2023 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract Approximately 95% of the world's roadways are made of flexible pavements traditionally bound with bitumen. Modern roads must use the least amount of energy and raw materials for sustainable environmental development. Asphalt polymer technology can solve this issue using bio-binders and rubber waste, such as old tires, to enhance road infrastructure. Because crumb rubber can improve the mechanical and functional performance of mixtures, its use in asphalt paving has gained popularity. In addition, other renewable rubbers, such as liquid natural rubber (called latex) and solid natural rubber, can be used. Natural rubber is an elastomer used to repair concrete and asphalt. The mechanical characteristics of rubber asphalt, created by blending solid natural rubber, asphalt, and crumb rubber in a specific ratio, were examined in this study. Rheological testing with a dynamic shear rheometer was used to study the mechanistic behavior of rubber asphalt. The rubber combination utilized had an asphalt composition of 7% and 10% by weight and a crumb rubber to solid natural rubber weight ratio of 65:35. The results indicated that the asphalt stiffness modulus increased from 157.08% to 189.55% when combining crumb and solid natural rubber. Moreover, Superpave specifications state that using a mixture of solid natural and crumb rubber can increase rutting resistance and fatigue resistance at high temperatures. Keywords Crumb Rubber, Solid Natural Rubber, Rubber Asphalt, Rheological Testing 1. Introduction Globally, rapid urbanization and rising transportation needs necessitate better road surfaces with lower maintenance requirements. The development of road transport infrastructure is a top priority in Indonesia because highways provide services for the movement of approximately 80–90% of people and the flow of commodities. This can be seen from the government's spending on maintaining or building new roadways. The result is increased demand for natural aggregates and asphalt [1]. Bitumen is a classic binder for road materials, and flexible pavements using bitumen constitute approximately 95% of the world's highways. Although asphalt binders are used only in small amounts, they are crucial for performing asphalt mixtures [2,3]. Asphalt is an extremely intricate, viscoelastic, rheological, and noncrystalline substance that is mostly soluble in carbon disulfide (CS 2 ) and has adhesive and waterproofing properties. It is black or dark brown in color. Asphalt binders can be categorized as viscoelastic substances with temperature- and time-dependent properties. In other words, they behave like Newtonian fluids at high temperatures; however, at intermediate temperatures, they change into viscoelastic liquids, and at low temperatures, they behave like brittle viscoelastic materials that can crack under moderate loads [2,4]. Modern road construction must use the least amount of energy and raw materials to achieve sustainable environmental development. The scarcity of nonrenewable