Experimental Study on Modified Asphalt Pavement by Using Waste Materials

Abstract

India, being one of the fastest urbanizing countries, faces a significant challenge in managing tyre waste, which increases by 15-20% annually due to the rising number of vehicles. This study aims to enhance road construction efficiency and reduce costs by incorporating various waste materials such as scrap tyres, waste engine oil, and coal fly ash into asphalt mixtures. Bitumen is modified by adding crumb rubber at levels of 5%, 10%, and 15%, which enhances its binding strength, elasticity, stability, and flow characteristics. Additionally, coal fly ash is introduced as a filler (at 3%, 6%, and 9% by weight of aggregates) to improve the workability and durability of the mix. To address cracking and extend pavement life, waste engine oil is used as an additive, contributing to improved self-healing capacity, aging resistance, and fatigue performance. The modified asphalt mix is evaluated using the Marshall Stability method and the results are compared between conventional and modified asphalt mixes to determine overall improvements in performances.

Introduction

Pavements are essential components of transportation infrastructure that provide safe, smooth, and durable surfaces for traffic. Among different pavement types, flexible pavements are widely used due to their cost-effectiveness and adaptability to varying traffic and environmental conditions. The main binding material used in flexible pavements is bitumen, a viscoelastic substance derived from crude oil. Over time, bitumen undergoes ageing, which causes it to harden and become brittle, leading to pavement defects such as cracking and rutting. This reduces road service life and increases maintenance costs.

To address this issue, the project investigates the use of waste materials—Waste Engine Oil (WEO), Crumb Rubber (CR), and Coal Fly Ash (FA)—as modifiers or rejuvenators in bituminous mixes. These materials improve pavement performance while also promoting sustainable waste management. Crumb rubber enhances elasticity and strength, fly ash improves workability and durability, and waste engine oil helps restore flexibility and resistance to ageing in bitumen.

The project aims to study the effects of these additives on the stability and rheological properties of asphalt mixes and compare them with conventional bitumen mixtures. The materials used include VG 30 grade bitumen, crumb rubber as modifier, coarse aggregates, fly ash as filler, and waste engine oil as an additive.

Various laboratory tests were conducted on aggregates and bitumen, including impact test, abrasion test, specific gravity test, ductility test, softening point test, and penetration test. Results showed that crumb rubber increased the softening point and stiffness of bitumen, while waste engine oil increased ductility and penetration, acting as a softening agent. A balanced combination such as 2% WEO + 10% CR provided optimal properties.

Additionally, the Marshall Stability Test indicated improved stability and density of asphalt mixes with fly ash, particularly at 6% fly ash content, demonstrating better pavement performance.

Conclusion

This study investigated the potential use of Waste Engine Oil (WEO), Crumb Rubber (CR), and Fly Ash (FA) as modifiers in asphalt pavement. The results indicate that these waste materials can significantly improve the mechanical and rheological properties of asphalt while also offering a sustainable solution for waste management. WEO acts as a rejuvenator that improves binder flexibility and resistance to aging, CR enhances elasticity, stability, and fatigue resistance, and Fly Ash functions as a mineral filler that improves density, strength, and workability of the asphalt mix. The Marshall Stability Test played a key role in evaluating the performance of the modified asphalt mixtures. Through this test, important parameters such as stability, flow value, and durability characteristics of the asphalt mixes were determined. The stability value indicates the load-carrying capacity of the mixture, while the flow value represents the deformation behaviour under load. By analysing these parameters, the Marshall method helped identify the optimum proportions of WEO, CR, and FA that provide a balanced combination of strength, flexibility, and durability for pavement applications. The findings suggest that asphalt mixtures modified with these waste materials can improve pavement performance and extend service life while reducing environmental impacts and material costs. However, factors such as optimum dosage, storage stability, and large-scale field performance still require further investigation. Overall, incorporating WEO, CR, and FA in asphalt mixtures, together with performance evaluation using the Marshall Stability Test, provides a promising and sustainable approach for modern road construction and supports circular economy practices in civil engineering.

References

[1] M. Raza et al., “Waste engine oil as a sustainable approach for asphalt rejuvenation and modification: A review,” Heliyon, vol. 10, p. e40737, 2024. [2] Amrita et al., “Crumb rubber modified asphalt: Fundamentals to recent developments,” IntechOpen, 2024. [3] Zahraa et al., “Analytical review on potential use of waste engine oil in asphalt and pavement engineering,” ResearchGate, 2024. [4] M. Saleh et al., “Effects of aging on asphalt mixture and pavement performance,” Construction and Building Materials, vol. 258, p. 120309, 2020. [5] A. Woszuk et al., “Fly ash as low cost and environmentally friendly filler and its effect on the properties of mix asphalt,” Journal of Cleaner Production, vol. 235, pp. 493–502, 2019. [6] Priyanka et al., “Use of fly ash as mineral filler for bituminous paving mixes,” IJRET: International Journal of Research in Engineering and Technology, eISSN: 2319-1163, pISSN: 2321-7308, 2015.

Copyright

Copyright © 2026 Muhammed Favas K, Rinshidha T, Sneha R P, Mohammed N P, Asst. Prof. Safiya N N. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.