en.Wedoany.com Reported - Shimizu Corporation has developed a new concrete technology named "SUSMICS-Ca," which incorporates biochar made from woody biomass to significantly suppress ammonia gas release, theoretically shortening the traditional curing period by about one-fifth. This is a first-of-its-kind technology in Japan.
Facilities such as art museums, galleries, and semiconductor factories require a "curing period" of prolonged concrete drying before they can be put into use. Cement and admixtures in concrete continuously release trace amounts of ammonia gas through chemical reactions. Ammonia gas can discolor oil paints and interfere with the formation of ultra-fine electronic circuits during semiconductor manufacturing, leading to severe product defects. Guidelines from Japan's Agency for Cultural Affairs recommend a curing period of "two summers" after concrete pouring to ensure indoor ammonia concentrations drop below 30 ppb. This means the building cannot open for nearly two years after completion, imposing significant opportunity costs on owners.
Shimizu Corporation unveiled this new technology at a technical briefing held on June 24, 2026, at its Technology Research Institute in Etchujima, Koto-ku, Tokyo. Keiichi Yano, a researcher in the Resource Recycling Group of the Construction Infrastructure Technology Center at the institute, emphasized that the core of the technology is biochar made by heating woody biomass, such as sawdust that absorbs carbon dioxide. SUSMICS is an acronym for Sustainable·SMI·Carbon Storage and serves as the umbrella term for this series of environmentally friendly construction technologies. Previously, the company had developed SUSMICS-C for concrete, SUSMICS-G for ground improvement soil, SUSMICS-A for asphalt, and SUSMICS-S for soil cement.
Regarding biochar, the 2019 revised IPCC (Intergovernmental Panel on Climate Change) guidelines define it as "a solid material produced by heating biomass at temperatures exceeding 350°C under controlled oxygen levels to prevent combustion." Keisuke Kojima, head of the Resource Recycling Group, stated that the advantage of using biochar in concrete is that it fixes over eight times (actually about six times) more carbon dioxide per kilogram than calcium carbonate, enabling efficient carbon removal. All ready-mix concrete plants nationwide can produce this new material, which offers workability and quality comparable to ordinary concrete and supports on-site pouring. When used in combination with low-carbon cement such as blast furnace slag cement Type B/C, it can achieve "carbon-negative emissions," where the environmental load is negative.
The newly announced SUSMICS-Ca is a derivative technology of SUSMICS-C, with the suffix "Ca" derived from the abbreviation of "Concrete for ammonia." This technology originates from the SUSMICS-C series, which began development in 2021 and was completed in 2022, and has since been applied to road paving, horizontal concrete, and indoor flooring. SUSMICS-Ca not only reduces carbon dioxide emissions but also suppresses ammonia gas release. During manufacturing, 20 to 80 kilograms of biochar are added per cubic meter of concrete.
Keisuke Kojima added that ensuring uniform mixing of biochar was a major challenge during development. The company has established strict mix design rules to guarantee the fluidity, strength, and durability of the concrete, ultimately producing a version suitable for use as structural material. The manufacturing difference between SUSMICS-Ca and regular SUSMICS-C lies in the selection of admixtures that release less ammonia, with a cost ratio of approximately 1.5 to 2 times.
