TA596 : Laboratory evaluation of the self-healing index in green asphalt mixtures
Thesis > Central Library of Shahrood University > Civil & Architectural Engineering > MSc > 2021
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Abstarct: Reduction of non-renewable natural resources such as rock materials and pollution caused by the accumulation of waste materials in nature are the most important reasons for using recycled materials in the construction of green asphalt mixtures. On the other hand, the self-healing phenomenon is one of the significant features of asphalt mixtures that reduces the economic costs of healing and maintenance and the environmental costs of asphalt reproduction. In this research, in order to construction environmentally friendly green asphalt mixtures, particle size of steel slag were ranged from 4.75-9.5 mm with a 60% replacement in a volume ratio of limestone aggregate and the proportions of the red mud waste has been used respectively 50% and 100% by a ratio of limestone filler and the self-healing index and moisture sensitivity of these mixtures have been evaluated. In order to investigate the self-healing index, the semi-circular bending test (SCB) was performed by 7 damage-healing cycles using the microwave irradiation heating method. Results indicated that the steel slag and 50% red mud waste in the first healing cycle, the amount of optimum healing rate compared to the control sample, respectively; 53.01% and 32.35% have increased. Also, due to the importance of moisture damage, indirect tensile strength (ITS) test according to AASHTO T283 was performed on cylindrical specimens and the results showed that the amount of moisture resistance in mixtures containing steel slag and 50% red mud decreased by 16% and 21%, respectively, compared to the control sample. The use of 50% and 100% carbonation cake as a replacement for limestone filler in mixtures containing steel slag has increased the moisture resistance by 9% and 13%, respectively. Also, this weakness of resistance in the sample containing 50% of red mud was compensated by using 50% of carbonation cake and moisture resistance was increased by 12%. by examining the results of Marshall Quotient (MQ), it was found that steel slag, 50% red mud and 50% carbonation cake increased the stiffness of asphalt mixture compared to the control sample by 1.4, 1.51and 0.05 (KN/mm), respectively.
Keywords:
#Self-healing #Microwave #Steel slag #Red mud #Carbonation cake #Moisture sensitivity Keeping place: Central Library of Shahrood University
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