Concrete Mixed with CO2-Fixed Synthetic Calcium Carbonate 'Calcarbo' Adopted for the First Time in Public Works in Shiga Prefecture
Haikou Onoda Remicon, Idemitsu Kosan, and Nippon Concrete Industries announced that concrete mixed with 'Calcarbo' has been adopted for a river improvement project in Shiga Prefecture, achieving a CO2 reduction of 610kg.
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- 📰 Published: April 2, 2026 at 23:40
- 🔍 Collected: April 2, 2026 at 19:37
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Haikou Onoda Remicon Co., Ltd. (Headquarters: Kyoto City, Kyoto Prefecture, Representative Director: Kazuhiro Yamauchi), Idemitsu Kosan Co.,Ltd. (Headquarters: Chiyoda-ku, Tokyo, Representative Director, President and Chief Executive Officer: Noriaki Sakai), and Nippon Concrete Industries Co., Ltd. (Headquarters: Minato-ku, Tokyo, Representative Director and President: Yoshihiko Sugita) conducted a trial construction at the Ane River and Gioui River in Shiga Prefecture using concrete mixed with synthetic calcium carbonate 'Calcarbo'*1. The adoption of concrete mixed with Calcarbo is the first of its kind in public works in Shiga Prefecture. Moving forward, the three companies will expand their construction track record, primarily in Shiga Prefecture, and accelerate the spread of this technology.
*1 Synthetic calcium carbonate in which CO2 from exhaust gas is fixed into concrete sludge (waste remaining at the final stage of manufacturing concrete products).
Since the three companies were selected for the Shiga Prefecture subsidy projects in 2024 (Reiwa 6 Shiga Prefecture Near-Future Technology Social Implementation Promotion Project Subsidy and Reiwa 7 Shiga Prefecture Small and Medium Enterprise New Technology Development Project Subsidy), they have continued efforts toward the social implementation of concrete mixed with Calcarbo. Because it was confirmed that the concrete mixed with Calcarbo possesses sufficient strength as a civil engineering and construction material, it was adopted for the first time in this river improvement work.
Conventional concrete is mainly composed of cement, water, and aggregates (sand, pebbles, etc.). Calcarbo can replace a portion of the cement, realizing the fixation of CO2 in civil engineering and construction materials and the effective use of waste. Furthermore, by replacing a portion of the cement with Calcarbo, the amount of cement used can be reduced, leading to a reduction in CO2 emitted during cement manufacturing. This contributes to the decarbonization of the entire concrete manufacturing process. In this construction project, a CO2 reduction of approximately 610 kg was achieved.
Going forward, the three companies will continue researching concrete mixed with Calcarbo and aim to obtain material certification from public institutions such as the General Building Research Corporation of Japan (GBRC)*2.
*1 Synthetic calcium carbonate in which CO2 from exhaust gas is fixed into concrete sludge (waste remaining at the final stage of manufacturing concrete products).
Since the three companies were selected for the Shiga Prefecture subsidy projects in 2024 (Reiwa 6 Shiga Prefecture Near-Future Technology Social Implementation Promotion Project Subsidy and Reiwa 7 Shiga Prefecture Small and Medium Enterprise New Technology Development Project Subsidy), they have continued efforts toward the social implementation of concrete mixed with Calcarbo. Because it was confirmed that the concrete mixed with Calcarbo possesses sufficient strength as a civil engineering and construction material, it was adopted for the first time in this river improvement work.
Conventional concrete is mainly composed of cement, water, and aggregates (sand, pebbles, etc.). Calcarbo can replace a portion of the cement, realizing the fixation of CO2 in civil engineering and construction materials and the effective use of waste. Furthermore, by replacing a portion of the cement with Calcarbo, the amount of cement used can be reduced, leading to a reduction in CO2 emitted during cement manufacturing. This contributes to the decarbonization of the entire concrete manufacturing process. In this construction project, a CO2 reduction of approximately 610 kg was achieved.
Going forward, the three companies will continue researching concrete mixed with Calcarbo and aim to obtain material certification from public institutions such as the General Building Research Corporation of Japan (GBRC)*2.