Partial Replacement of Asphalt Bitumen with Sugarcane Molasses
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Date
2017-05
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Addis Ababa University
Abstract
Hot Asphalt Mixtures (HMA) is particulate composite material consisting of mineral aggregates, asphalt binder and air voids. Asphalt binder is considered as the most expensive and economically variable material. Because of the increase in energy cost, the need for improvement of pavement quality as well as concern over pollution and alternative binders are needed to modify, partially or totally replace asphalt binder. This research study is intended for partially replacement of asphalt binder with Molasses.
The study compares neat asphalt binder and asphalt binder containing molasses using laboratory tests including rheological and conventional test, Marshall flow and stability with corresponding volumetric properties and moisture susceptibility using Indirect Tensile Strength (ITS) test. Including the control specimen six binders were obtained by mixing the asphalt binder with five different percentages of Molasses by weight of asphalt binder (3%, 6%, 9%, 12% and 15%).
The rheological binder tests were conducted using a Dynamic Shear Rheometer (DSR). Three rheological tests were conducted namely Amplitude Sweep Test (AST), Frequency Sweep Test (FST) and Multi-Stress Creep and Recovery (MSCR). The AST was conducted to determine the Linear Visco-Elastic (LVE) Range, FST were conducted to construct the master curve and the MSCR test was conducted to determine the rut parameter (Jnr). The AST and FST are conducted at three temperatures (21.1°, 37.8°, and 54.4 °C) while the MSCR test were conducted at four temperatures (52°, 58°, 64° & 70°C).The asphalt mixture testing includes the Marshall mix design which was used to determine the Optimum Bitumen Content (OBC) for the conventional HMA. The asphalt binder was replaced by the five percentages of Molasses using the OBC. The same HMA compositions were tested for moisture susceptibility using ITS.
The research concludes that partial replacement of molasses improves the stiffness and rutting resisting performance of binders at high temperature ranges and has a little effect on the HMA mixture however; it is highly moisture susceptible for all the mixes
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including the conventional mix. Overall, the research indicates that, it is feasible to partially replace asphalt binder with Molasses up to 9%.
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Road and Transport Engineering