Improvement of bitumen performance properties with nano magnesium spinel and colemanite

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JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, vol.33, no.3, pp.939-951, 2018 (SCI-Expanded) identifier identifier


In this study, it is aimed to improve the rutting and fatigue strength performance of modified bitumen in hot regions. Additives such as nano magnesium spinet oxide and colemanite are used for modifying 50/70 penetration normal bitumen. The additives at the micro size are milled until the desired nano particle size (180-200 nm) with mechanical abrasion method. Modified bitumen samples are prepared with additive ratios of %1, 3, 5 and 8 by weight of the bitumen. The modified bitumen is prepared by mixing at 150 degrees C for 30 minutes by the help of a mechanical mixer with a capacity of 1500 rpm. Superpave bitumen tests such as; Dynamic Shear Rheometer (DSR), Rolling Thin Film Oven (RTFO), Pressure Aging Vessel (PAV) and Bending Beam Rheometer (BBR) tests are conducted on modified and normal bitumen samples in addition to the conventional bitumen tests. According to the test results, the modification process with the addition of each material significantly increased the rutting strength of bitumen at high temperatures. The addition of %8 magnesium spinet oxide and colemanite provided approximately 4 degrees C increase in the failure temperature compared with normal bitumen. According to the fatigue test results, at 25 degrees C test temperature, the decrease in the fatigue resistance parameter G*.Sin delta for the samples modified with %5 nano magnesium spinet oxide and %5 nano colemanite are %46 and %60 respectively. The results of the bending beam rheometer test indicate that the creep stiffness of the samples increased as a result of the modification with both additives.