© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). MATEC Web of Conferences 195, 04001 (2018) https://doi.org/10.1051/matecconf/201819504001 ICRMCE 2018 Design and optimization of a rubber-bitumen blend in preparation for a rubberized-asphalt road trial in the state of Kuwait Salah E. Zoorob 1,* , Suad K. Al-Bahar 1 , and Saud F. Al-Otaibi 1 1 Construction and Building Materials Program, Kuwait Institute for Scientific Research, P.O. Box 24885 Safat, 13109 Kuwait. Abstract. In this paper, test results are presented from laboratory trials of blending discarded tire derived crumb rubber with 60/70pen grade Kuwaiti bitumen. The virgin bitumen, in addition to 15% and 18% crumb rubber blends were tested for PG grading and multiple stress creep recovery at temperatures in the range from 40°C to 70°C. Elastic recovery and non- recoverable creep compliance showed optimum performance at 18% rubber content. The optimized rubberized-bitumen blend was next converted into a pelletized form which was then used as a partial substitute to the conventional bitumen in the manufacture of continuously graded hot mix asphalts at various binder contents. The rubberized-bitumen pellet contents trialed were 2.5%, 3.0% and 3.5% by mass of mix. The Marshall method of mix design was used to assess the various mixes and the overall volumetric, stability and flow results, though satisfactory, was not entirely sufficient to aid in the selection of the best performing formulation. 1 Introduction The State of Kuwait’s total length of main paved roads is slightly in excess of 7518 km (equivalent to an area of 87,411,674 km 2 ). The network suffers from a number of asphalt pavement distress mechanisms including; fatigue cracking, rutting, bleeding, potholes and raveling. The primary causes vary from one site to the other and include; incorrect bitumen grade, excessive binder oxidation, incorrect mix designs and binder contents, high traffic loading, settlement failure in the lower layers, inadequate compaction, very high climatic temperatures, lack of high-quality local mineral aggregates, etc. For many decades, the only bitumen that was available for use in road construction in Kuwait has been a standard 60/70pen grade bitumen which in rheological terms is equivalent to a US Performance Grade PG 64-10. The designation PG 64-10 indicates that the bitumen will “in theory” satisfy performance requirements for a temperature zone that has an average maximum consecutive 7-day pavement temperature of less than 64°C and a minimum temperature greater than -10°C. In recent years, Kuwait has been experiencing exceptionally hot summers, as a notable example, on the 20 th July 2017 the maximum air temperature in Kuwait City was reported officially at 54°C. Figure 1 shows an example of * Corresponding author: [email protected]
Design and optimization of a rubber-bitumen blend in preparation for a rubberized-asphalt road trial in the state of Kuwait
Jun 20, 2023
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