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Feasibility study of biochar as alternative filler to limestone filler investigated at the asphalt mastic level
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Date
2025-12-05
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Journal Article
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Abstract
In the context of increasing concerns over climate change and the push for carbon neutrality by 2050, this study explores the potential use of biochar as filler in asphalt mixtures, aiming to compensate for greenhouse gas emissions associated with road construction and providing a long-term sink for carbon sequestration. Therefore, the physical, rheological and chemical properties of asphalt mastic were assessed as limestone filler was replaced in volume equivalent increments with biochar filler and for different ageing conditions. The investigation revealed that replacing limestone filler with biochar filler in asphalt mastic did not significantly alter the rheological properties of the unaged mastic. A minor trend of decreasing complex modulus with increasing biochar content was observed. Especially after long-term ageing, a distinct pattern was observed for rheological indices. The reduced stiffness likely has caused the higher accumulated strain for biochar-containing mastic after ageing. The affected rheological changes originate from the particle size distribution and porosity of biochar used as a limestone filler substitute, as no changes in the functional groups were detected by FTIR spectroscopy. The results suggest that biochar can effectively replace limestone filler without compromising the overall performance of asphalt mastic. Due to biochar's porosity and its interaction with water, a potential application in the production of warm mix asphalt is envisaged.
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Volume
502