Investigation of self-healing of hot mix asphalt containing waste oil against fatigue cracks

Nowadays, the importance of hot bituminous mixtures in terms of transportation is quite high. Bituminous hot mixes become brittle with the increase in stiffness due to the increasing traffic load and climatic conditions over time. This situation causes cracks and deterioration in the superstructure. For this reason, it is necessary to observe the bituminous mixture layers regularly, and to carry out maintenance and repair activities. However, this may not always be possible for economic or technical reasons. For this reason, the idea of self-healing hot mix with bitumen has gained importance in recent years. Studies on self-healing of asphalt are grouped under three main headings: induction heating, microwave heating, and the use of capsules. It is the preferred method of using capsules in the study. In the thesis study, waste vegetable oil and waste mineral oil were used as rejuvenating materials. In our country, tons of waste oil is released every year and these cause pollution of water, soil and air. The most appropriate method for the management of these wastes will be to create a different usage area that will not harm the environment and have commercial value. One of these areas is the use of waste oils as rejuvenating material in BSKs at environmentally appropriate proportions. Capsules produced with waste mineral and vegetable oils were added to the bituminous hot mix samples at 4 different rates by aggregate weight. After that, these samples were subjected to long-term aging and then 4-point bending fatigue test was applied. The healing effect of the capsules in the samples on the cracks and the effect on the fatigue life in case of deterioration in the coating were evaluated. In addition, the relationship of the healing with temperature and time was investigated by applying the rest cure at different temperatures and at different times to the beam samples. Although the mechanical properties of BSKs were adversely affected by the use of capsules, the test results remained within the limit values of the Highways Technical Specification. Considering the 4- point bending fatigue test results, it was determined that the use of capsules had a positive effect on the healing of cracks and prolonging the fatigue life of samples with deterioration, and it was observed that capsules containing waste mineral oil gave better results than capsules containing waste vegetable oil. In addition, it was determined that the improvement increased in direct proportion with the increase of curing temperature and curing times. Keywords: Bituminous hot mixture, Self healing, Capsule, Waste vegetable oil, Waste mineral oil, Mechanical properties, Rejuvenating, Fatigue