Lime Enhances Asphalt Durability and Road Longevity

WPB: Hydrated lime serves as an additive that prevents the separation of bitumen from aggregates, promoting better adhesion within asphalt mixtures.

According to European studies, incorporating hydrated lime into asphalt can significantly extend the lifespan of road surfaces. This additive offers a range of benefits, including enhanced resilience to climate-related stresses. Research from both Europe and the United States highlights hydrated lime’s potential to improve asphalt performance.

One of the key roles of hydrated lime is its ability to act as an anti-stripping agent, ensuring a strong bond between the bitumen binder and aggregate. Additionally, it slows the aging process of bitumen, improves resistance to moisture, and reduces rutting by stiffening the binder. It also minimizes crack formation at low temperatures, enhancing the overall durability of the road.

Studies indicate that adding less than 2% hydrated lime to asphalt mixtures can increase their service life by as much as 25%. This improvement reduces the frequency of road maintenance, leading to fewer potholes and a decrease in repair-related disruptions.

In the United States, hydrated lime has been widely used for decades, not only as an anti-stripping agent but also to bolster asphalt’s resistance to moisture. Research has shown that it can slow bitumen aging by reducing oxidation, further extending the lifespan of road surfaces.

For years, hydrated lime has been a critical component in asphalts used for UK and international airport runways. In the UK, it is recognized as a versatile additive within National Highways specifications and is listed as a durability enhancement option to support zero-carbon goals.

Its widespread adoption across Europe and the US is driven by its ability to create more durable and high-performing roads. In some areas, its use is mandatory due to the significant improvements it offers in road resilience.

Research conducted by the University of Nottingham has demonstrated that hydrated lime absorbs undesirable compounds, such as carbonyls and asphaltenes, within bitumen. This reduces the oxidative reactions that typically make bitumen harder and more brittle with time, thereby minimizing cracking and pothole formation.

When comparing mastics made with hydrated lime to those using only granite or limestone fillers, hydrated lime consistently resulted in softer asphalt after aging. This reduced stiffness contributes to better long-term performance.

Further insights are expected from a long-term study on a section of the A38 in Devon, where hydrated lime was incorporated into asphalt in 2021.

By Bitumenmag

Road, Bitumen, Asphalt