apanese construction company Shimizu Corporation and its affiliate Nippon Road have begun developing technology for decarbonized pavement by mixing biochar, which is effective in sequestering carbon dioxide, with asphalt mix. Biochar derived from woods with high carbon content and residual carbon content is used. The companies will jointly develop a carbon-negative paving material that absorbs and sequesters more carbon internally than the CO2 emissions associated with the production of the mix and will aim for actual use by March 2024.

The project will combine Shimizu Corporation's expertise in mixing biochar with construction materials cultivated in the concrete field with Nippon Road's asphalt mix production technology. Biochar made from sawdust is used as a substitute for sand and stone powder in the composite. The material can absorb and fixes 2.3 grams of CO2 per kilogram.

Carbon negativity can be achieved by mixing 25 kg or more of powdered or granulated biochar per ton of composite material. The two companies will conduct on-site testing to verify the workability and durability of the biochar-blended mix, and plan to apply it to road pavements. (2023/05/15)