Comprehensive Evaluation of the Ageing Behavior of Bio-Based Binders and Conventional Bitumen through Chemical and Mechanical Analysis

WPB: Bitumen, a waterproof and viscoelastic material derived from petroleum, is widely used across various industries due to its unique mechanical and chemical properties. Its primary applications include road construction, roofing, and waterproofing, with the paving industry consuming approximately 95% of total global production, amounting to nearly 100 million metric tons annually. In asphalt pavements, bitumen serves as a binder that holds mineral aggregates together, forming materials like asphalt concrete or bituminous concrete. This strong adhesive capability ensures structural integrity and long-term durability.

The Need for Bio-Based Alternatives

Since bitumen originates from fossil fuels, its availability is limited, leading to growing interest in renewable bio-based alternatives. However, bitumen’s complex chemical composition is responsible for its unique properties, making full replacement a challenge. Currently, partial substitution of up to 50% has been identified as a practical solution. The incorporation of bio-based materials alters the composition and affects ageing behavior, which can significantly impact performance over time.

Environmental Regulations and Sustainability Challenges

With stringent environmental policies promoting emission reductions and the conservation of fossil resources, there is increasing pressure to adopt sustainable alternatives. These regulations target the entire lifecycle of materials, from resource extraction and transportation to manufacturing, usage, and disposal. This raises a crucial question: Does replacing fossil-based bitumen with bio-based alternatives compromise durability, or is it possible to achieve both sustainability and long-term performance?

Laboratory Ageing and Analytical Methods

To evaluate the ageing behavior of bio-based binders, laboratory artificial ageing procedures are conducted under controlled conditions. Three different bio-binders were analyzed alongside an unmodified base bitumen and a reference bitumen. The bio-additive content ranged from 10% to 50%.

Two primary ageing simulation methods were applied:

 • Short-term ageing (STA)

 • Long-term ageing (LTA)

The binders were subjected to various ageing-inducing factors, including:

 • High temperatures

 • Light exposure

 • Reactive oxygen species (ROS)

For chemical analysis, Fourier Transform Infrared (FTIR) spectroscopy was used to identify structural changes, while mechanical properties were assessed through Dynamic Shear Rheometer (DSR) testing to evaluate performance under different conditions.

Key Findings on Ageing Resistance

Results indicate that thermal ageing alone has a limited impact, and a single cycle of the Pressure Ageing Vessel (PAV) test does not induce the same level of ageing as more intensive long-term ageing methods, such as:

 • Viennese Binder Ageing (VBA)

 • Light ageing (LA)

The VBA method revealed that bio-binders 1 and 2 experienced significant ageing, while bio-binder 3 demonstrated higher resistance to ROS exposure.

Light Ageing and Rheological Performance

Light-induced ageing varied across different binders and was highly dependent on the specific light source (LA1–LA3). Compared to conventional 70/100 bitumen, all bio-binders exhibited lower susceptibility to ageing.

 • Bio-binder 1 showed unique rheological properties, performing exceptionally well at both intermediate and high temperatures while demonstrating enhanced performance at low temperatures.

 • Bio-binder 2 displayed mechanical characteristics close to those of the reference bitumen.

 • Bio-binder 3 exhibited higher sensitivity to light ageing compared to ROS exposure.

These findings highlight the potential advantages and limitations of bio-based binders, suggesting that certain bio-additives may contribute to enhanced ageing resistance while others may require further optimization to ensure durability under real-world conditions.

By Bitumenmag

Bitumen, Bio-Bitumen, Binder