Innovative Approaches to Bitumen Modification: Comparison of Rice Husk Ash, Pyrolysis Carbon Black, and Waste Face Mask Polymers

Abstract

Passengers expect a smooth and safe transition along the roads. Bitumen is mainly used in flexible pavement construction. However, inherent shortcomings of bituminous pavement such as rutting, fatigue, thermal cracking and water submergence cause issues related to the pavement performance and its durability. To overcome these shortcomings, modifiers are added to the bitumen to improve its properties. With the advent of sustainable concepts, addition of waste-based material into construction materials to improve their performance while addressing the waste management issue is an emerging area of research. Many researches have utilized waste-based materials as bitumen modifiers. Out of them, Pyrolysis Carbon Black (PCB), Rice Husk Ash (RHA) and Waste Face Mask (FM) have been selected for this study by considering the availability on a local basis. Although there are many waste-based modifiers, a critical comparison has not been carried out among them and it is essential to compare these alternatives in multiple aspects to have a better understanding before selecting the most suitable option. Therefore, this study aims to conduct a comprehensive comparison among three alternatives under performance, environmental and, economic impacts. To evaluate the performance, mechanical and rheological properties are assessed under the suitability to Sri Lankan context. The environmental and economic impacts are evaluated by calculating embodied GHG emission (ECO2-e), embodied energy (EE) and cost values to prepare 1kg of binder. The results indicate PCB is the best modifier for the Sri Lankan practice. PCB-modified binder has 13% decreased EE value and 5% decreased ECO2-e values. Further, the study reveals that PCB is the best cost-effective option by having 13% cost reduction compared to conventional binder. Pavement performance also has improved while adhering to the Sri Lankan Specifications. RHA can be recommended as the second-best alternative.