Rapid Maintenance of Asphalt Concrete using Calcium Alginate Capsules with Waste Cooking Oil as a Rejuvenator

Abstract

Bitumen possesses the unique phenomena of intrinsic self-healing, given the adequate rest period is provided to it. Asphalt is more preferred material used for pavement construction due to its low- cost, noise reduction and comfortable driving experience. Microcracks appear in asphalt pavement when it is subjected to repeated traffic loading, temperature variation, weather changes and oxidation, reducing the tensile strength and increasing the viscosity of bitumen. Reducing the premature aging of asphalt through the incorporation of self-healing technology in road design process can enhance the life span of asphalt pavements with considerable reduction in maintenance cost. Self-healing asphalt will reduce the number of natural resources used to maintain the road networks, decreases the traffic disruption caused by road maintenance, decreases the CO2 emission and increases the road safety. This research focuses on the use of encapsulated rejuvenator in the design process to understand the healing phenomena of asphalt pavements. Na-alginate capsules were prepared which contains the waste cooking oil as rejuvenator. Asphalt samples with different capsules content (0.5%,0.75%,1%) were prepared. In-situ crack healing method was used to improve the intrinsically limited self-healing properties of bitumen to increase the service life of road. When the initial crack appears on surface, the energy released during this crack ruptures the capsule and releases the oil contained within. The released rejuvenator reduces the viscosity of nearby cracked area through the diffusion process and helps pavement restore its original properties. Moisture sensitivity of asphalt mixture containing capsule was measured using ITS. Capsules containing samples were less prone to moisture as compared to the controlled sample. Tensile strength of capsule-induced asphalt mixture was better as compared to the controlled samples. Semi-circular bending and Three point bending test were conducted to measure the healing index. Self-healing behavior of capsule-induced asphalt was calculated using the semicircular bending and three point bending test. Results of SCB and Three-point bending were used to explain the relationship between healing time and temperature. The encapsulated rejuvenator increased the healing capability of asphalt. Cost analysis is performed for a section of particular length, to have the idea about the economic aspects of the project. Initial cost of modified samples was higher than the controlled samples, but maintenance cost was considerably low.