CO₂-SUICOM is a concrete that is carbon negative^*1. One cubic meter of SUICOM can absorb 18 kg of CO₂, which is more than the 14 kg of CO₂ that a single cedar tree (which will grow up to 20 m) can absorb in one year. In Japan, SUICOM has already been used over the past 10 years in 14 projects (total volume cast: 75 m3), which include the Tokyo Gaikan Expressway, pavement blocks, and construction work (balcony sections of residential apartments). As a result of these applications of SUICOM, 7,500 kg of CO₂ has been absorbed.

*1 A state in which more greenhouse gases are absorbed than are emitted.

Experiment with plastic bag

Jointly developed by Kajima Technical Research Institute, Chugoku Electric Power, Denka, and Landes, SUICOM is a technology that was commercialized in 2008. In addition to the conventional technology based on replacing cement, which emits a lot of CO₂ during its production, with other cement, the use of γ-C2S (Gamma C2S), which is a special admixture that absorbs and fixes CO₂, has made it possible to achieve zero or less CO₂ emissions from concrete (“carbon negative”). Cement hardens by reacting with water, but Gamma C2S has the unique feature that it hardens by reacting with CO₂ rather than water; in other words, CO₂ is absorbed and fixed during the cement-hardening process.

This Japan-developed technology, which uses a special cement admixture to absorb and fix CO₂, is the world’s first to reduce CO₂ emissions to zero or below. It has thus attracted attention from academic circles in ways such as receiving the Japan Society of Civil Engineers’ Environmental Award.
And as part of a NEDO-commissioned research project^*3, we are working on developing the technology while considering it as an urgent task to expand the scope of its application to on-site pouring of ready-mixed concrete and pouring of large quantities of concrete.

*2 New Energy and Industrial Technology Development Organization (NEDO)

*3 NEDO publicly commissioned projects
Applied for “Development of carbon-recycling technology for next-generation thermal power generation” and “Technology development at a CO₂-effective-utilization base”
Selected for “Research and development of CO₂-effective-utilization concrete”

Interview with a Senior Research Fellow